Objects/stringobject.c

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/* String object implementation */

#include "Python.h"

#include <ctype.h>

#ifdef COUNT_ALLOCS
int null_strings, one_strings;
#endif

static PyStringObject *characters[UCHAR_MAX + 1];
static PyStringObject *nullstring;

/* This dictionary holds all interned strings.  Note that references to
   strings in this dictionary are *not* counted in the string's ob_refcnt.
   When the interned string reaches a refcnt of 0 the string deallocation
   function will delete the reference from this dictionary.

   Another way to look at this is that to say that the actual reference 
   count of a string is:  s->ob_refcnt + (s->ob_sstate?2:0)
*/
static PyObject *interned;


/*
   For both PyString_FromString() and PyString_FromStringAndSize(), the
   parameter `size' denotes number of characters to allocate, not counting any
   null terminating character.

   For PyString_FromString(), the parameter `str' points to a null-terminated
   string containing exactly `size' bytes.

   For PyString_FromStringAndSize(), the parameter the parameter `str' is
   either NULL or else points to a string containing at least `size' bytes.
   For PyString_FromStringAndSize(), the string in the `str' parameter does
   not have to be null-terminated.  (Therefore it is safe to construct a
   substring by calling `PyString_FromStringAndSize(origstring, substrlen)'.)
   If `str' is NULL then PyString_FromStringAndSize() will allocate `size+1'
   bytes (setting the last byte to the null terminating character) and you can
   fill in the data yourself.  If `str' is non-NULL then the resulting
   PyString object must be treated as immutable and you must not fill in nor
   alter the data yourself, since the strings may be shared.

   The PyObject member `op->ob_size', which denotes the number of "extra
   items" in a variable-size object, will contain the number of bytes
   allocated for string data, not counting the null terminating character.  It
   is therefore equal to the equal to the `size' parameter (for
   PyString_FromStringAndSize()) or the length of the string in the `str'
   parameter (for PyString_FromString()).
*/
PyObject *
PyString_FromStringAndSize(const char *str, Py_ssize_t size)
{
        register PyStringObject *op;
        assert(size >= 0);
        if (size == 0 && (op = nullstring) != NULL) {
#ifdef COUNT_ALLOCS
                null_strings++;
#endif
                Py_INCREF(op);
                return (PyObject *)op;
        }
        if (size == 1 && str != NULL &&
            (op = characters[*str & UCHAR_MAX]) != NULL)
        {
#ifdef COUNT_ALLOCS
                one_strings++;
#endif
                Py_INCREF(op);
                return (PyObject *)op;
        }

        /* Inline PyObject_NewVar */
        op = (PyStringObject *)PyObject_MALLOC(sizeof(PyStringObject) + size);
        if (op == NULL)
                return PyErr_NoMemory();
        PyObject_INIT_VAR(op, &PyString_Type, size);
        op->ob_shash = -1;
        op->ob_sstate = SSTATE_NOT_INTERNED;
        if (str != NULL)
                memcpy(op->ob_sval, str, size);
        op->ob_sval[size] = '\0';
        /* share short strings */
        if (size == 0) {
                PyObject *t = (PyObject *)op;
                PyString_InternInPlace(&t);
                op = (PyStringObject *)t;
                nullstring = op;
                Py_INCREF(op);
        } else if (size == 1 && str != NULL) {
                PyObject *t = (PyObject *)op;
                PyString_InternInPlace(&t);
                op = (PyStringObject *)t;
                characters[*str & UCHAR_MAX] = op;
                Py_INCREF(op);
        }
        return (PyObject *) op;
}

PyObject *
PyString_FromString(const char *str)
{
        register size_t size;
        register PyStringObject *op;

        assert(str != NULL);
        size = strlen(str);
        if (size > INT_MAX) {
                PyErr_SetString(PyExc_OverflowError,
                        "string is too long for a Python string");
                return NULL;
        }
        if (size == 0 && (op = nullstring) != NULL) {
#ifdef COUNT_ALLOCS
                null_strings++;
#endif
                Py_INCREF(op);
                return (PyObject *)op;
        }
        if (size == 1 && (op = characters[*str & UCHAR_MAX]) != NULL) {
#ifdef COUNT_ALLOCS
                one_strings++;
#endif
                Py_INCREF(op);
                return (PyObject *)op;
        }

        /* Inline PyObject_NewVar */
        op = (PyStringObject *)PyObject_MALLOC(sizeof(PyStringObject) + size);
        if (op == NULL)
                return PyErr_NoMemory();
        PyObject_INIT_VAR(op, &PyString_Type, size);
        op->ob_shash = -1;
        op->ob_sstate = SSTATE_NOT_INTERNED;
        memcpy(op->ob_sval, str, size+1);
        /* share short strings */
        if (size == 0) {
                PyObject *t = (PyObject *)op;
                PyString_InternInPlace(&t);
                op = (PyStringObject *)t;
                nullstring = op;
                Py_INCREF(op);
        } else if (size == 1) {
                PyObject *t = (PyObject *)op;
                PyString_InternInPlace(&t);
                op = (PyStringObject *)t;
                characters[*str & UCHAR_MAX] = op;
                Py_INCREF(op);
        }
        return (PyObject *) op;
}

PyObject *
PyString_FromFormatV(const char *format, va_list vargs)
{
        va_list count;
        Py_ssize_t n = 0;
        const char* f;
        char *s;
        PyObject* string;

#ifdef VA_LIST_IS_ARRAY
        memcpy(count, vargs, sizeof(va_list));
#else
#ifdef  __va_copy
        __va_copy(count, vargs);
#else
        count = vargs;
#endif
#endif
        /* step 1: figure out how large a buffer we need */
        for (f = format; *f; f++) {
                if (*f == '%') {
                        const char* p = f;
                        while (*++f && *f != '%' && !isalpha(Py_CHARMASK(*f)))
                                ;

                        /* skip the 'l' in %ld, since it doesn't change the
                           width.  although only %d is supported (see
                           "expand" section below), others can be easily
                           added */
                        if (*f == 'l' && *(f+1) == 'd')
                                ++f;
                        /* likewise for %zd */
                        if (*f == 'z' && *(f+1) == 'd')
                                ++f;                    

                        switch (*f) {
                        case 'c':
                                (void)va_arg(count, int);
                                /* fall through... */
                        case '%':
                                n++;
                                break;
                        case 'd': case 'i': case 'x':
                                (void) va_arg(count, int);
                                /* 20 bytes is enough to hold a 64-bit
                                   integer.  Decimal takes the most space.
                                   This isn't enough for octal. */
                                n += 20;
                                break;
                        case 's':
                                s = va_arg(count, char*);
                                n += strlen(s);
                                break;
                        case 'p':
                                (void) va_arg(count, int);
                                /* maximum 64-bit pointer representation:
                                 * 0xffffffffffffffff
                                 * so 19 characters is enough.
                                 * XXX I count 18 -- what's the extra for?
                                 */
                                n += 19;
                                break;
                        default:
                                /* if we stumble upon an unknown
                                   formatting code, copy the rest of
                                   the format string to the output
                                   string. (we cannot just skip the
                                   code, since there's no way to know
                                   what's in the argument list) */
                                n += strlen(p);
                                goto expand;
                        }
                } else
                        n++;
        }
 expand:
        /* step 2: fill the buffer */
        /* Since we've analyzed how much space we need for the worst case,
           use sprintf directly instead of the slower PyOS_snprintf. */
        string = PyString_FromStringAndSize(NULL, n);
        if (!string)
                return NULL;

        s = PyString_AsString(string);

        for (f = format; *f; f++) {
                if (*f == '%') {
                        const char* p = f++;
                        Py_ssize_t i;
                        int longflag = 0;
                        int size_tflag = 0;
                        /* parse the width.precision part (we're only
                           interested in the precision value, if any) */
                        n = 0;
                        while (isdigit(Py_CHARMASK(*f)))
                                n = (n*10) + *f++ - '0';
                        if (*f == '.') {
                                f++;
                                n = 0;
                                while (isdigit(Py_CHARMASK(*f)))
                                        n = (n*10) + *f++ - '0';
                        }
                        while (*f && *f != '%' && !isalpha(Py_CHARMASK(*f)))
                                f++;
                        /* handle the long flag, but only for %ld.  others
                           can be added when necessary. */
                        if (*f == 'l' && *(f+1) == 'd') {
                                longflag = 1;
                                ++f;
                        }
                        /* handle the size_t flag. */
                        if (*f == 'z' && *(f+1) == 'd') {
                                size_tflag = 1;
                                ++f;
                        }

                        switch (*f) {
                        case 'c':
                                *s++ = va_arg(vargs, int);
                                break;
                        case 'd':
                                if (longflag)
                                        sprintf(s, "%ld", va_arg(vargs, long));
                                else if (size_tflag) {
                                        /* Instead of checking whether the C
                                           library supports %zd, handle the
                                           common cases. */
                                        #if SIZEOF_SIZE_T == SIZEOF_LONG
                                        sprintf(s, "%ld", va_arg(vargs, long));
                                        #elif defined(MS_WINDOWS)
                                        sprintf(s, "%Id", va_arg(vargs, size_t));
                                        #else
                                        #error Cannot print size_t values
                                        #endif
                                }
                                else
                                        sprintf(s, "%d", va_arg(vargs, int));
                                s += strlen(s);
                                break;
                        case 'i':
                                sprintf(s, "%i", va_arg(vargs, int));
                                s += strlen(s);
                                break;
                        case 'x':
                                sprintf(s, "%x", va_arg(vargs, int));
                                s += strlen(s);
                                break;
                        case 's':
                                p = va_arg(vargs, char*);
                                i = strlen(p);
                                if (n > 0 && i > n)
                                        i = n;
                                memcpy(s, p, i);
                                s += i;
                                break;
                        case 'p':
                                sprintf(s, "%p", va_arg(vargs, void*));
                                /* %p is ill-defined:  ensure leading 0x. */
                                if (s[1] == 'X')
                                        s[1] = 'x';
                                else if (s[1] != 'x') {
                                        memmove(s+2, s, strlen(s)+1);
                                        s[0] = '0';
                                        s[1] = 'x';
                                }
                                s += strlen(s);
                                break;
                        case '%':
                                *s++ = '%';
                                break;
                        default:
                                strcpy(s, p);
                                s += strlen(s);
                                goto end;
                        }
                } else
                        *s++ = *f;
        }

 end:
        _PyString_Resize(&string, s - PyString_AS_STRING(string));
        return string;
}

PyObject *
PyString_FromFormat(const char *format, ...)
{
        PyObject* ret;
        va_list vargs;

#ifdef HAVE_STDARG_PROTOTYPES
        va_start(vargs, format);
#else
        va_start(vargs);
#endif
        ret = PyString_FromFormatV(format, vargs);
        va_end(vargs);
        return ret;
}


PyObject *PyString_Decode(const char *s,
                          Py_ssize_t size,
                          const char *encoding,
                          const char *errors)
{
    PyObject *v, *str;

    str = PyString_FromStringAndSize(s, size);
    if (str == NULL)
        return NULL;
    v = PyString_AsDecodedString(str, encoding, errors);
    Py_DECREF(str);
    return v;
}

PyObject *PyString_AsDecodedObject(PyObject *str,
                                   const char *encoding,
                                   const char *errors)
{
    PyObject *v;

    if (!PyString_Check(str)) {
        PyErr_BadArgument();
        goto onError;
    }

    if (encoding == NULL) {
#ifdef Py_USING_UNICODE
        encoding = PyUnicode_GetDefaultEncoding();
#else
        PyErr_SetString(PyExc_ValueError, "no encoding specified");
        goto onError;
#endif
    }

    /* Decode via the codec registry */
    v = PyCodec_Decode(str, encoding, errors);
    if (v == NULL)
        goto onError;

    return v;

 onError:
    return NULL;
}

PyObject *PyString_AsDecodedString(PyObject *str,
                                   const char *encoding,
                                   const char *errors)
{
    PyObject *v;

    v = PyString_AsDecodedObject(str, encoding, errors);
    if (v == NULL)
        goto onError;

#ifdef Py_USING_UNICODE
    /* Convert Unicode to a string using the default encoding */
    if (PyUnicode_Check(v)) {
        PyObject *temp = v;
        v = PyUnicode_AsEncodedString(v, NULL, NULL);
        Py_DECREF(temp);
        if (v == NULL)
            goto onError;
    }
#endif
    if (!PyString_Check(v)) {
        PyErr_Format(PyExc_TypeError,
                     "decoder did not return a string object (type=%.400s)",
                     v->ob_type->tp_name);
        Py_DECREF(v);
        goto onError;
    }

    return v;

 onError:
    return NULL;
}

PyObject *PyString_Encode(const char *s,
                          Py_ssize_t size,
                          const char *encoding,
                          const char *errors)
{
    PyObject *v, *str;

    str = PyString_FromStringAndSize(s, size);
    if (str == NULL)
        return NULL;
    v = PyString_AsEncodedString(str, encoding, errors);
    Py_DECREF(str);
    return v;
}

PyObject *PyString_AsEncodedObject(PyObject *str,
                                   const char *encoding,
                                   const char *errors)
{
    PyObject *v;

    if (!PyString_Check(str)) {
        PyErr_BadArgument();
        goto onError;
    }

    if (encoding == NULL) {
#ifdef Py_USING_UNICODE
        encoding = PyUnicode_GetDefaultEncoding();
#else
        PyErr_SetString(PyExc_ValueError, "no encoding specified");
        goto onError;
#endif
    }

    /* Encode via the codec registry */
    v = PyCodec_Encode(str, encoding, errors);
    if (v == NULL)
        goto onError;

    return v;

 onError:
    return NULL;
}

PyObject *PyString_AsEncodedString(PyObject *str,
                                   const char *encoding,
                                   const char *errors)
{
    PyObject *v;

    v = PyString_AsEncodedObject(str, encoding, errors);
    if (v == NULL)
        goto onError;

#ifdef Py_USING_UNICODE
    /* Convert Unicode to a string using the default encoding */
    if (PyUnicode_Check(v)) {
        PyObject *temp = v;
        v = PyUnicode_AsEncodedString(v, NULL, NULL);
        Py_DECREF(temp);
        if (v == NULL)
            goto onError;
    }
#endif
    if (!PyString_Check(v)) {
        PyErr_Format(PyExc_TypeError,
                     "encoder did not return a string object (type=%.400s)",
                     v->ob_type->tp_name);
        Py_DECREF(v);
        goto onError;
    }

    return v;

 onError:
    return NULL;
}

static void
string_dealloc(PyObject *op)
{
        switch (PyString_CHECK_INTERNED(op)) {
                case SSTATE_NOT_INTERNED:
                        break;

                case SSTATE_INTERNED_MORTAL:
                        /* revive dead object temporarily for DelItem */
                        op->ob_refcnt = 3;
                        if (PyDict_DelItem(interned, op) != 0)
                                Py_FatalError(
                                        "deletion of interned string failed");
                        break;

                case SSTATE_INTERNED_IMMORTAL:
                        Py_FatalError("Immortal interned string died.");

                default:
                        Py_FatalError("Inconsistent interned string state.");
        }
        op->ob_type->tp_free(op);
}

/* Unescape a backslash-escaped string. If unicode is non-zero,
   the string is a u-literal. If recode_encoding is non-zero,
   the string is UTF-8 encoded and should be re-encoded in the
   specified encoding.  */

PyObject *PyString_DecodeEscape(const char *s,
                                Py_ssize_t len,
                                const char *errors,
                                Py_ssize_t unicode,
                                const char *recode_encoding)
{
        int c;
        char *p, *buf;
        const char *end;
        PyObject *v;
        Py_ssize_t newlen = recode_encoding ? 4*len:len;
        v = PyString_FromStringAndSize((char *)NULL, newlen);
        if (v == NULL)
                return NULL;
        p = buf = PyString_AsString(v);
        end = s + len;
        while (s < end) {
                if (*s != '\\') {
                  non_esc:
#ifdef Py_USING_UNICODE
                        if (recode_encoding && (*s & 0x80)) {
                                PyObject *u, *w;
                                char *r;
                                const char* t;
                                Py_ssize_t rn;
                                t = s;
                                /* Decode non-ASCII bytes as UTF-8. */
                                while (t < end && (*t & 0x80)) t++;
                                u = PyUnicode_DecodeUTF8(s, t - s, errors);
                                if(!u) goto failed;

                                /* Recode them in target encoding. */
                                w = PyUnicode_AsEncodedString(
                                        u, recode_encoding, errors);
                                Py_DECREF(u);
                                if (!w) goto failed;

                                /* Append bytes to output buffer. */
                                r = PyString_AsString(w);
                                rn = PyString_Size(w);
                                memcpy(p, r, rn);
                                p += rn;
                                Py_DECREF(w);
                                s = t;
                        } else {
                                *p++ = *s++;
                        }
#else
                        *p++ = *s++;
#endif
                        continue;
                }
                s++;
                if (s==end) {
                        PyErr_SetString(PyExc_ValueError,
                                        "Trailing \\ in string");
                        goto failed;
                }
                switch (*s++) {
                /* XXX This assumes ASCII! */
                case '\n': break;
                case '\\': *p++ = '\\'; break;
                case '\'': *p++ = '\''; break;
                case '\"': *p++ = '\"'; break;
                case 'b': *p++ = '\b'; break;
                case 'f': *p++ = '\014'; break; /* FF */
                case 't': *p++ = '\t'; break;
                case 'n': *p++ = '\n'; break;
                case 'r': *p++ = '\r'; break;
                case 'v': *p++ = '\013'; break; /* VT */
                case 'a': *p++ = '\007'; break; /* BEL, not classic C */
                case '0': case '1': case '2': case '3':
                case '4': case '5': case '6': case '7':
                        c = s[-1] - '0';
                        if ('0' <= *s && *s <= '7') {
                                c = (c<<3) + *s++ - '0';
                                if ('0' <= *s && *s <= '7')
                                        c = (c<<3) + *s++ - '0';
                        }
                        *p++ = c;
                        break;
                case 'x':
                        if (isxdigit(Py_CHARMASK(s[0])) 
                            && isxdigit(Py_CHARMASK(s[1]))) {
                                unsigned int x = 0;
                                c = Py_CHARMASK(*s);
                                s++;
                                if (isdigit(c))
                                        x = c - '0';
                                else if (islower(c))
                                        x = 10 + c - 'a';
                                else
                                        x = 10 + c - 'A';
                                x = x << 4;
                                c = Py_CHARMASK(*s);
                                s++;
                                if (isdigit(c))
                                        x += c - '0';
                                else if (islower(c))
                                        x += 10 + c - 'a';
                                else
                                        x += 10 + c - 'A';
                                *p++ = x;
                                break;
                        }
                        if (!errors || strcmp(errors, "strict") == 0) {
                                PyErr_SetString(PyExc_ValueError, 
                                                "invalid \\x escape");
                                goto failed;
                        }
                        if (strcmp(errors, "replace") == 0) {
                                *p++ = '?';
                        } else if (strcmp(errors, "ignore") == 0)
                                /* do nothing */;
                        else {
                                PyErr_Format(PyExc_ValueError,
                                             "decoding error; "
                                             "unknown error handling code: %.400s",
                                             errors);
                                goto failed;
                        }
#ifndef Py_USING_UNICODE
                case 'u':
                case 'U':
                case 'N':
                        if (unicode) {
                                PyErr_SetString(PyExc_ValueError,
                                          "Unicode escapes not legal "
                                          "when Unicode disabled");
                                goto failed;
                        }
#endif
                default:
                        *p++ = '\\';
                        s--;
                        goto non_esc; /* an arbitry number of unescaped
                                         UTF-8 bytes may follow. */
                }
        }
        if (p-buf < newlen)
                _PyString_Resize(&v, p - buf);
        return v;
  failed:
        Py_DECREF(v);
        return NULL;
}

static Py_ssize_t
string_getsize(register PyObject *op)
{
        char *s;
        Py_ssize_t len;
        if (PyString_AsStringAndSize(op, &s, &len))
                return -1;
        return len;
}

static /*const*/ char *
string_getbuffer(register PyObject *op)
{
        char *s;
        Py_ssize_t len;
        if (PyString_AsStringAndSize(op, &s, &len))
                return NULL;
        return s;
}

Py_ssize_t
PyString_Size(register PyObject *op)
{
        if (!PyString_Check(op))
                return string_getsize(op);
        return ((PyStringObject *)op) -> ob_size;
}

/*const*/ char *
PyString_AsString(register PyObject *op)
{
        if (!PyString_Check(op))
                return string_getbuffer(op);
        return ((PyStringObject *)op) -> ob_sval;
}

int
PyString_AsStringAndSize(register PyObject *obj,
                         register char **s,
                         register Py_ssize_t *len)
{
        if (s == NULL) {
                PyErr_BadInternalCall();
                return -1;
        }

        if (!PyString_Check(obj)) {
#ifdef Py_USING_UNICODE
                if (PyUnicode_Check(obj)) {
                        obj = _PyUnicode_AsDefaultEncodedString(obj, NULL);
                        if (obj == NULL)
                                return -1;
                }
                else
#endif
                {
                        PyErr_Format(PyExc_TypeError,
                                     "expected string or Unicode object, "
                                     "%.200s found", obj->ob_type->tp_name);
                        return -1;
                }
        }

        *s = PyString_AS_STRING(obj);
        if (len != NULL)
                *len = PyString_GET_SIZE(obj);
        else if (strlen(*s) != PyString_GET_SIZE(obj)) {
                PyErr_SetString(PyExc_TypeError,
                                "expected string without null bytes");
                return -1;
        }
        return 0;
}

/* Methods */

static int
string_print(PyStringObject *op, FILE *fp, int flags)
{
        Py_ssize_t i;
        char c;
        int quote;

        /* XXX Ought to check for interrupts when writing long strings */
        if (! PyString_CheckExact(op)) {
                int ret;
                /* A str subclass may have its own __str__ method. */
                op = (PyStringObject *) PyObject_Str((PyObject *)op);
                if (op == NULL)
                        return -1;
                ret = string_print(op, fp, flags);
                Py_DECREF(op);
                return ret;
        }
        if (flags & Py_PRINT_RAW) {
#ifdef __VMS
                if (op->ob_size) fwrite(op->ob_sval, (int) op->ob_size, 1, fp);
#else
                fwrite(op->ob_sval, 1, (int) op->ob_size, fp);
#endif
                return 0;
        }

        /* figure out which quote to use; single is preferred */
        quote = '\'';
        if (memchr(op->ob_sval, '\'', op->ob_size) &&
            !memchr(op->ob_sval, '"', op->ob_size))
                quote = '"';

        fputc(quote, fp);
        for (i = 0; i < op->ob_size; i++) {
                c = op->ob_sval[i];
                if (c == quote || c == '\\')
                        fprintf(fp, "\\%c", c);
                else if (c == '\t')
                        fprintf(fp, "\\t");
                else if (c == '\n')
                        fprintf(fp, "\\n");
                else if (c == '\r')
                        fprintf(fp, "\\r");
                else if (c < ' ' || c >= 0x7f)
                        fprintf(fp, "\\x%02x", c & 0xff);
                else
                        fputc(c, fp);
        }
        fputc(quote, fp);
        return 0;
}

PyObject *
PyString_Repr(PyObject *obj, int smartquotes)
{
        register PyStringObject* op = (PyStringObject*) obj;
        size_t newsize = 2 + 4 * op->ob_size;
        PyObject *v;
        if (newsize > INT_MAX) {
                PyErr_SetString(PyExc_OverflowError,
                        "string is too large to make repr");
        }
        v = PyString_FromStringAndSize((char *)NULL, newsize);
        if (v == NULL) {
                return NULL;
        }
        else {
                register Py_ssize_t i;
                register char c;
                register char *p;
                int quote;

                /* figure out which quote to use; single is preferred */
                quote = '\'';
                if (smartquotes && 
                    memchr(op->ob_sval, '\'', op->ob_size) &&
                    !memchr(op->ob_sval, '"', op->ob_size))
                        quote = '"';

                p = PyString_AS_STRING(v);
                *p++ = quote;
                for (i = 0; i < op->ob_size; i++) {
                        /* There's at least enough room for a hex escape
                           and a closing quote. */
                        assert(newsize - (p - PyString_AS_STRING(v)) >= 5);
                        c = op->ob_sval[i];
                        if (c == quote || c == '\\')
                                *p++ = '\\', *p++ = c;
                        else if (c == '\t')
                                *p++ = '\\', *p++ = 't';
                        else if (c == '\n')
                                *p++ = '\\', *p++ = 'n';
                        else if (c == '\r')
                                *p++ = '\\', *p++ = 'r';
                        else if (c < ' ' || c >= 0x7f) {
                                /* For performance, we don't want to call
                                   PyOS_snprintf here (extra layers of
                                   function call). */
                                sprintf(p, "\\x%02x", c & 0xff);
                                p += 4;
                        }
                        else
                                *p++ = c;
                }
                assert(newsize - (p - PyString_AS_STRING(v)) >= 1);
                *p++ = quote;
                *p = '\0';
                _PyString_Resize(
                        &v, (int) (p - PyString_AS_STRING(v)));
                return v;
        }
}

static PyObject *
string_repr(PyObject *op)
{
        return PyString_Repr(op, 1);
}

static PyObject *
string_str(PyObject *s)
{
        assert(PyString_Check(s));
        if (PyString_CheckExact(s)) {
                Py_INCREF(s);
                return s;
        }
        else {
                /* Subtype -- return genuine string with the same value. */
                PyStringObject *t = (PyStringObject *) s;
                return PyString_FromStringAndSize(t->ob_sval, t->ob_size);
        }
}

static Py_ssize_t
string_length(PyStringObject *a)
{
        return a->ob_size;
}

static PyObject *
string_concat(register PyStringObject *a, register PyObject *bb)
{
        register size_t size;
        register PyStringObject *op;
        if (!PyString_Check(bb)) {
#ifdef Py_USING_UNICODE
                if (PyUnicode_Check(bb))
                    return PyUnicode_Concat((PyObject *)a, bb);
#endif
                PyErr_Format(PyExc_TypeError,
                             "cannot concatenate 'str' and '%.200s' objects",
                             bb->ob_type->tp_name);
                return NULL;
        }
#define b ((PyStringObject *)bb)
        /* Optimize cases with empty left or right operand */
        if ((a->ob_size == 0 || b->ob_size == 0) &&
            PyString_CheckExact(a) && PyString_CheckExact(b)) {
                if (a->ob_size == 0) {
                        Py_INCREF(bb);
                        return bb;
                }
                Py_INCREF(a);
                return (PyObject *)a;
        }
        size = a->ob_size + b->ob_size;
        /* XXX check overflow */
        /* Inline PyObject_NewVar */
        op = (PyStringObject *)PyObject_MALLOC(sizeof(PyStringObject) + size);
        if (op == NULL)
                return PyErr_NoMemory();
        PyObject_INIT_VAR(op, &PyString_Type, size);
        op->ob_shash = -1;
        op->ob_sstate = SSTATE_NOT_INTERNED;
        memcpy(op->ob_sval, a->ob_sval, a->ob_size);
        memcpy(op->ob_sval + a->ob_size, b->ob_sval, b->ob_size);
        op->ob_sval[size] = '\0';
        return (PyObject *) op;
#undef b
}

static PyObject *
string_repeat(register PyStringObject *a, register Py_ssize_t n)
{
        register Py_ssize_t i;
        register Py_ssize_t j;
        register Py_ssize_t size;
        register PyStringObject *op;
        size_t nbytes;
        if (n < 0)
                n = 0;
        /* watch out for overflows:  the size can overflow int,
         * and the # of bytes needed can overflow size_t
         */
        size = a->ob_size * n;
        if (n && size / n != a->ob_size) {
                PyErr_SetString(PyExc_OverflowError,
                        "repeated string is too long");
                return NULL;
        }
        if (size == a->ob_size && PyString_CheckExact(a)) {
                Py_INCREF(a);
                return (PyObject *)a;
        }
        nbytes = (size_t)size;
        if (nbytes + sizeof(PyStringObject) <= nbytes) {
                PyErr_SetString(PyExc_OverflowError,
                        "repeated string is too long");
                return NULL;
        }
        op = (PyStringObject *)
                PyObject_MALLOC(sizeof(PyStringObject) + nbytes);
        if (op == NULL)
                return PyErr_NoMemory();
        PyObject_INIT_VAR(op, &PyString_Type, size);
        op->ob_shash = -1;
        op->ob_sstate = SSTATE_NOT_INTERNED;
        op->ob_sval[size] = '\0';
        if (a->ob_size == 1 && n > 0) {
                memset(op->ob_sval, a->ob_sval[0] , n);
                return (PyObject *) op;
        }
        i = 0;
        if (i < size) {
                memcpy(op->ob_sval, a->ob_sval, a->ob_size);
                i = a->ob_size;
        }
        while (i < size) {
                j = (i <= size-i)  ?  i  :  size-i;
                memcpy(op->ob_sval+i, op->ob_sval, j);
                i += j;
        }
        return (PyObject *) op;
}

/* String slice a[i:j] consists of characters a[i] ... a[j-1] */

static PyObject *
string_slice(register PyStringObject *a, register Py_ssize_t i, 
             register Py_ssize_t j)
     /* j -- may be negative! */
{
        if (i < 0)
                i = 0;
        if (j < 0)
                j = 0; /* Avoid signed/unsigned bug in next line */
        if (j > a->ob_size)
                j = a->ob_size;
        if (i == 0 && j == a->ob_size && PyString_CheckExact(a)) {
                /* It's the same as a */
                Py_INCREF(a);
                return (PyObject *)a;
        }
        if (j < i)
                j = i;
        return PyString_FromStringAndSize(a->ob_sval + i, j-i);
}

static int
string_contains(PyObject *a, PyObject *el)
{
        char *s = PyString_AS_STRING(a);
        const char *sub = PyString_AS_STRING(el);
        char *last;
        Py_ssize_t len_sub = PyString_GET_SIZE(el);
        Py_ssize_t shortsub;
        char firstchar, lastchar;

        if (!PyString_CheckExact(el)) {
#ifdef Py_USING_UNICODE
                if (PyUnicode_Check(el))
                        return PyUnicode_Contains(a, el);
#endif
                if (!PyString_Check(el)) {
                        PyErr_SetString(PyExc_TypeError,
                            "'in <string>' requires string as left operand");
                        return -1;
                }
        }

        if (len_sub == 0)
                return 1;
        /* last points to one char beyond the start of the rightmost 
           substring.  When s<last, there is still room for a possible match
           and s[0] through s[len_sub-1] will be in bounds.
           shortsub is len_sub minus the last character which is checked
           separately just before the memcmp().  That check helps prevent
           false starts and saves the setup time for memcmp().
        */
        firstchar = sub[0];
        shortsub = len_sub - 1;
        lastchar = sub[shortsub];
        last = s + PyString_GET_SIZE(a) - len_sub + 1;
        while (s < last) {
                s = memchr(s, firstchar, last-s);
                if (s == NULL)
                        return 0;
                assert(s < last);
                if (s[shortsub] == lastchar && memcmp(s, sub, shortsub) == 0)
                        return 1;
                s++;
        }
        return 0;
}

static PyObject *
string_item(PyStringObject *a, register Py_ssize_t i)
{
        PyObject *v;
        char *pchar;
        if (i < 0 || i >= a->ob_size) {
                PyErr_SetString(PyExc_IndexError, "string index out of range");
                return NULL;
        }
        pchar = a->ob_sval + i;
        v = (PyObject *)characters[*pchar & UCHAR_MAX];
        if (v == NULL)
                v = PyString_FromStringAndSize(pchar, 1);
        else {
#ifdef COUNT_ALLOCS
                one_strings++;
#endif
                Py_INCREF(v);
        }
        return v;
}

static PyObject*
string_richcompare(PyStringObject *a, PyStringObject *b, int op)
{
        int c;
        Py_ssize_t len_a, len_b;
        Py_ssize_t min_len;
        PyObject *result;

        /* Make sure both arguments are strings. */
        if (!(PyString_Check(a) && PyString_Check(b))) {
                result = Py_NotImplemented;
                goto out;
        }
        if (a == b) {
                switch (op) {
                case Py_EQ:case Py_LE:case Py_GE:
                        result = Py_True;
                        goto out;
                case Py_NE:case Py_LT:case Py_GT:
                        result = Py_False;
                        goto out;
                }
        }
        if (op == Py_EQ) {
                /* Supporting Py_NE here as well does not save
                   much time, since Py_NE is rarely used.  */
                if (a->ob_size == b->ob_size
                    && (a->ob_sval[0] == b->ob_sval[0]
                        && memcmp(a->ob_sval, b->ob_sval,
                                  a->ob_size) == 0)) {
                        result = Py_True;
                } else {
                        result = Py_False;
                }
                goto out;
        }
        len_a = a->ob_size; len_b = b->ob_size;
        min_len = (len_a < len_b) ? len_a : len_b;
        if (min_len > 0) {
                c = Py_CHARMASK(*a->ob_sval) - Py_CHARMASK(*b->ob_sval);
                if (c==0)
                        c = memcmp(a->ob_sval, b->ob_sval, min_len);
        }else
                c = 0;
        if (c == 0)
                c = (len_a < len_b) ? -1 : (len_a > len_b) ? 1 : 0;
        switch (op) {
        case Py_LT: c = c <  0; break;
        case Py_LE: c = c <= 0; break;
        case Py_EQ: assert(0);  break; /* unreachable */
        case Py_NE: c = c != 0; break;
        case Py_GT: c = c >  0; break;
        case Py_GE: c = c >= 0; break;
        default:
                result = Py_NotImplemented;
                goto out;
        }
        result = c ? Py_True : Py_False;
  out:
        Py_INCREF(result);
        return result;
}

int
_PyString_Eq(PyObject *o1, PyObject *o2)
{
        PyStringObject *a, *b;
        a = (PyStringObject*)o1;
        b = (PyStringObject*)o2;
        return a->ob_size == b->ob_size
          && *a->ob_sval == *b->ob_sval
          && memcmp(a->ob_sval, b->ob_sval, a->ob_size) == 0;
}

static long
string_hash(PyStringObject *a)
{
        register Py_ssize_t len;
        register unsigned char *p;
        register long x;

        if (a->ob_shash != -1)
                return a->ob_shash;
        len = a->ob_size;
        p = (unsigned char *) a->ob_sval;
        x = *p << 7;
        while (--len >= 0)
                x = (1000003*x) ^ *p++;
        x ^= a->ob_size;
        if (x == -1)
                x = -2;
        a->ob_shash = x;
        return x;
}

static PyObject*
string_subscript(PyStringObject* self, PyObject* item)
{
        if (PyInt_Check(item) || PyLong_Check(item)) {
                Py_ssize_t i = PyInt_AsSsize_t(item);
                if (i == -1 && PyErr_Occurred())
                        return NULL;
                if (i < 0)
                        i += PyString_GET_SIZE(self);
                return string_item(self,i);
        }
        else if (PySlice_Check(item)) {
                Py_ssize_t start, stop, step, slicelength, cur, i;
                char* source_buf;
                char* result_buf;
                PyObject* result;

                if (PySlice_GetIndicesEx((PySliceObject*)item, 
                                 PyString_GET_SIZE(self),
                                 &start, &stop, &step, &slicelength) < 0) {
                        return NULL;
                }

                if (slicelength <= 0) {
                        return PyString_FromStringAndSize("", 0);
                }
                else {
                        source_buf = PyString_AsString((PyObject*)self);
                        result_buf = PyMem_Malloc(slicelength);
                        if (result_buf == NULL)
                                return PyErr_NoMemory();

                        for (cur = start, i = 0; i < slicelength; 
                             cur += step, i++) {
                                result_buf[i] = source_buf[cur];
                        }
                        
                        result = PyString_FromStringAndSize(result_buf, 
                                                            slicelength);
                        PyMem_Free(result_buf);
                        return result;
                }
        } 
        else {
                PyErr_SetString(PyExc_TypeError, 
                                "string indices must be integers");
                return NULL;
        }
}

static Py_ssize_t
string_buffer_getreadbuf(PyStringObject *self, Py_ssize_t index, const void **ptr)
{
        if ( index != 0 ) {
                PyErr_SetString(PyExc_SystemError,
                                "accessing non-existent string segment");
                return -1;
        }
        *ptr = (void *)self->ob_sval;
        return self->ob_size;
}

static Py_ssize_t
string_buffer_getwritebuf(PyStringObject *self, Py_ssize_t index, const void **ptr)
{
        PyErr_SetString(PyExc_TypeError,
                        "Cannot use string as modifiable buffer");
        return -1;
}

static Py_ssize_t
string_buffer_getsegcount(PyStringObject *self, Py_ssize_t *lenp)
{
        if ( lenp )
                *lenp = self->ob_size;
        return 1;
}

static Py_ssize_t
string_buffer_getcharbuf(PyStringObject *self, Py_ssize_t index, const char **ptr)
{
        if ( index != 0 ) {
                PyErr_SetString(PyExc_SystemError,
                                "accessing non-existent string segment");
                return -1;
        }
        *ptr = self->ob_sval;
        return self->ob_size;
}

static PySequenceMethods string_as_sequence = {
        (lenfunc)string_length, /*sq_length*/
        (binaryfunc)string_concat, /*sq_concat*/
        (ssizeargfunc)string_repeat, /*sq_repeat*/
        (ssizeargfunc)string_item, /*sq_item*/
        (ssizessizeargfunc)string_slice, /*sq_slice*/
        0,              /*sq_ass_item*/
        0,              /*sq_ass_slice*/
        (objobjproc)string_contains /*sq_contains*/
};

static PyMappingMethods string_as_mapping = {
        (lenfunc)string_length,
        (binaryfunc)string_subscript,
        0,
};

static PyBufferProcs string_as_buffer = {
        (readbufferproc)string_buffer_getreadbuf,
        (writebufferproc)string_buffer_getwritebuf,
        (segcountproc)string_buffer_getsegcount,
        (charbufferproc)string_buffer_getcharbuf,
};



#define LEFTSTRIP 0
#define RIGHTSTRIP 1
#define BOTHSTRIP 2

/* Arrays indexed by above */
static const char *stripformat[] = {"|O:lstrip", "|O:rstrip", "|O:strip"};

#define STRIPNAME(i) (stripformat[i]+3)

#define SPLIT_APPEND(data, left, right)                         \
        str = PyString_FromStringAndSize((data) + (left),       \
                                         (right) - (left));     \
        if (str == NULL)                                        \
                goto onError;                                   \
        if (PyList_Append(list, str)) {                         \
                Py_DECREF(str);                                 \
                goto onError;                                   \
        }                                                       \
        else                                                    \
                Py_DECREF(str);

#define SPLIT_INSERT(data, left, right)                         \
        str = PyString_FromStringAndSize((data) + (left),       \
                                         (right) - (left));     \
        if (str == NULL)                                        \
                goto onError;                                   \
        if (PyList_Insert(list, 0, str)) {                      \
                Py_DECREF(str);                                 \
                goto onError;                                   \
        }                                                       \
        else                                                    \
                Py_DECREF(str);

static PyObject *
split_whitespace(const char *s, Py_ssize_t len, int maxsplit)
{
        Py_ssize_t i, j;
        PyObject *str;
        PyObject *list = PyList_New(0);

        if (list == NULL)
                return NULL;

        for (i = j = 0; i < len; ) {
                while (i < len && isspace(Py_CHARMASK(s[i])))
                        i++;
                j = i;
                while (i < len && !isspace(Py_CHARMASK(s[i])))
                        i++;
                if (j < i) {
                        if (maxsplit-- <= 0)
                                break;
                        SPLIT_APPEND(s, j, i);
                        while (i < len && isspace(Py_CHARMASK(s[i])))
                                i++;
                        j = i;
                }
        }
        if (j < len) {
                SPLIT_APPEND(s, j, len);
        }
        return list;
  onError:
        Py_DECREF(list);
        return NULL;
}

static PyObject *
split_char(const char *s, Py_ssize_t len, char ch, int maxcount)
{
        register Py_ssize_t i, j;
        PyObject *str;
        PyObject *list = PyList_New(0);

        if (list == NULL)
                return NULL;

        for (i = j = 0; i < len; ) {
                if (s[i] == ch) {
                        if (maxcount-- <= 0)
                                break;
                        SPLIT_APPEND(s, j, i);
                        i = j = i + 1;
                } else
                        i++;
        }
        if (j <= len) {
                SPLIT_APPEND(s, j, len);
        }
        return list;

  onError:
        Py_DECREF(list);
        return NULL;
}

PyDoc_STRVAR(split__doc__,
"S.split([sep [,maxsplit]]) -> list of strings\n\
\n\
Return a list of the words in the string S, using sep as the\n\
delimiter string.  If maxsplit is given, at most maxsplit\n\
splits are done. If sep is not specified or is None, any\n\
whitespace string is a separator.");

static PyObject *
string_split(PyStringObject *self, PyObject *args)
{
        Py_ssize_t len = PyString_GET_SIZE(self), n, i, j;
        int err;
        int maxsplit = -1;
        const char *s = PyString_AS_STRING(self), *sub;
        PyObject *list, *item, *subobj = Py_None;

        if (!PyArg_ParseTuple(args, "|Oi:split", &subobj, &maxsplit))
                return NULL;
        if (maxsplit < 0)
                maxsplit = INT_MAX;
        if (subobj == Py_None)
                return split_whitespace(s, len, maxsplit);
        if (PyString_Check(subobj)) {
                sub = PyString_AS_STRING(subobj);
                n = PyString_GET_SIZE(subobj);
        }
#ifdef Py_USING_UNICODE
        else if (PyUnicode_Check(subobj))
                return PyUnicode_Split((PyObject *)self, subobj, maxsplit);
#endif
        else if (PyObject_AsCharBuffer(subobj, &sub, &n))
                return NULL;

        if (n == 0) {
                PyErr_SetString(PyExc_ValueError, "empty separator");
                return NULL;
        }
        else if (n == 1)
                return split_char(s, len, sub[0], maxsplit);

        list = PyList_New(0);
        if (list == NULL)
                return NULL;

        i = j = 0;
        while (i+n <= len) {
                if (s[i] == sub[0] && memcmp(s+i, sub, n) == 0) {
                        if (maxsplit-- <= 0)
                                break;
                        item = PyString_FromStringAndSize(s+j, i-j);
                        if (item == NULL)
                                goto fail;
                        err = PyList_Append(list, item);
                        Py_DECREF(item);
                        if (err < 0)
                                goto fail;
                        i = j = i + n;
                }
                else
                        i++;
        }
        item = PyString_FromStringAndSize(s+j, len-j);
        if (item == NULL)
                goto fail;
        err = PyList_Append(list, item);
        Py_DECREF(item);
        if (err < 0)
                goto fail;

        return list;

 fail:
        Py_DECREF(list);
        return NULL;
}

static PyObject *
rsplit_whitespace(const char *s, Py_ssize_t len, int maxsplit)
{
        Py_ssize_t i, j;
        PyObject *str;
        PyObject *list = PyList_New(0);

        if (list == NULL)
                return NULL;

        for (i = j = len - 1; i >= 0; ) {
                while (i >= 0 && isspace(Py_CHARMASK(s[i])))
                        i--;
                j = i;
                while (i >= 0 && !isspace(Py_CHARMASK(s[i])))
                        i--;
                if (j > i) {
                        if (maxsplit-- <= 0)
                                break;
                        SPLIT_INSERT(s, i + 1, j + 1);
                        while (i >= 0 && isspace(Py_CHARMASK(s[i])))
                                i--;
                        j = i;
                }
        }
        if (j >= 0) {
                SPLIT_INSERT(s, 0, j + 1);
        }
        return list;
  onError:
        Py_DECREF(list);
        return NULL;
}

static PyObject *
rsplit_char(const char *s, Py_ssize_t len, char ch, int maxcount)
{
        register Py_ssize_t i, j;
        PyObject *str;
        PyObject *list = PyList_New(0);

        if (list == NULL)
                return NULL;

        for (i = j = len - 1; i >= 0; ) {
                if (s[i] == ch) {
                        if (maxcount-- <= 0)
                                break;
                        SPLIT_INSERT(s, i + 1, j + 1);
                        j = i = i - 1;
                } else
                        i--;
        }
        if (j >= -1) {
                SPLIT_INSERT(s, 0, j + 1);
        }
        return list;

 onError:
        Py_DECREF(list);
        return NULL;
}

PyDoc_STRVAR(rsplit__doc__,
"S.rsplit([sep [,maxsplit]]) -> list of strings\n\
\n\
Return a list of the words in the string S, using sep as the\n\
delimiter string, starting at the end of the string and working\n\
to the front.  If maxsplit is given, at most maxsplit splits are\n\
done. If sep is not specified or is None, any whitespace string\n\
is a separator.");

static PyObject *
string_rsplit(PyStringObject *self, PyObject *args)
{
        Py_ssize_t len = PyString_GET_SIZE(self), n, i, j;
        int err;
        int maxsplit = -1;
        const char *s = PyString_AS_STRING(self), *sub;
        PyObject *list, *item, *subobj = Py_None;

        if (!PyArg_ParseTuple(args, "|Oi:rsplit", &subobj, &maxsplit))
                return NULL;
        if (maxsplit < 0)
                maxsplit = INT_MAX;
        if (subobj == Py_None)
                return rsplit_whitespace(s, len, maxsplit);
        if (PyString_Check(subobj)) {
                sub = PyString_AS_STRING(subobj);
                n = PyString_GET_SIZE(subobj);
        }
#ifdef Py_USING_UNICODE
        else if (PyUnicode_Check(subobj))
                return PyUnicode_RSplit((PyObject *)self, subobj, maxsplit);
#endif
        else if (PyObject_AsCharBuffer(subobj, &sub, &n))
                return NULL;

        if (n == 0) {
                PyErr_SetString(PyExc_ValueError, "empty separator");
                return NULL;
        }
        else if (n == 1)
                return rsplit_char(s, len, sub[0], maxsplit);

        list = PyList_New(0);
        if (list == NULL)
                return NULL;

        j = len;
        i = j - n;
        while (i >= 0) {
                if (s[i] == sub[0] && memcmp(s+i, sub, n) == 0) {
                        if (maxsplit-- <= 0)
                                break;
                        item = PyString_FromStringAndSize(s+i+n, j-i-n);
                        if (item == NULL)
                                goto fail;
                        err = PyList_Insert(list, 0, item);
                        Py_DECREF(item);
                        if (err < 0)
                                goto fail;
                        j = i;
                        i -= n;
                }
                else
                        i--;
        }
        item = PyString_FromStringAndSize(s, j);
        if (item == NULL)
                goto fail;
        err = PyList_Insert(list, 0, item);
        Py_DECREF(item);
        if (err < 0)
                goto fail;

        return list;

 fail:
        Py_DECREF(list);
        return NULL;
}


PyDoc_STRVAR(join__doc__,
"S.join(sequence) -> string\n\
\n\
Return a string which is the concatenation of the strings in the\n\
sequence.  The separator between elements is S.");

static PyObject *
string_join(PyStringObject *self, PyObject *orig)
{
        char *sep = PyString_AS_STRING(self);
        const Py_ssize_t seplen = PyString_GET_SIZE(self);
        PyObject *res = NULL;
        char *p;
        Py_ssize_t seqlen = 0;
        size_t sz = 0;
        Py_ssize_t i;
        PyObject *seq, *item;

        seq = PySequence_Fast(orig, "");
        if (seq == NULL) {
                return NULL;
        }

        seqlen = PySequence_Size(seq);
        if (seqlen == 0) {
                Py_DECREF(seq);
                return PyString_FromString("");
        }
        if (seqlen == 1) {
                item = PySequence_Fast_GET_ITEM(seq, 0);
                if (PyString_CheckExact(item) || PyUnicode_CheckExact(item)) {
                        Py_INCREF(item);
                        Py_DECREF(seq);
                        return item;
                }
        }

        /* There are at least two things to join, or else we have a subclass
         * of the builtin types in the sequence.  
         * Do a pre-pass to figure out the total amount of space we'll
         * need (sz), see whether any argument is absurd, and defer to
         * the Unicode join if appropriate.
         */
        for (i = 0; i < seqlen; i++) {
                const size_t old_sz = sz;
                item = PySequence_Fast_GET_ITEM(seq, i);
                if (!PyString_Check(item)){
#ifdef Py_USING_UNICODE
                        if (PyUnicode_Check(item)) {
                                /* Defer to Unicode join.
                                 * CAUTION:  There's no gurantee that the
                                 * original sequence can be iterated over
                                 * again, so we must pass seq here.
                                 */
                                PyObject *result;
                                result = PyUnicode_Join((PyObject *)self, seq);
                                Py_DECREF(seq);
                                return result;
                        }
#endif
                        PyErr_Format(PyExc_TypeError,
                                     "sequence item %i: expected string,"
                                     " %.80s found",
                                     /*XXX*/(int)i, item->ob_type->tp_name);
                        Py_DECREF(seq);
                        return NULL;
                }
                sz += PyString_GET_SIZE(item);
                if (i != 0)
                        sz += seplen;
                if (sz < old_sz || sz > INT_MAX) {
                        PyErr_SetString(PyExc_OverflowError,
                                "join() is too long for a Python string");
                        Py_DECREF(seq);
                        return NULL;
                }
        }

        /* Allocate result space. */
        res = PyString_FromStringAndSize((char*)NULL, sz);
        if (res == NULL) {
                Py_DECREF(seq);
                return NULL;
        }

        /* Catenate everything. */
        p = PyString_AS_STRING(res);
        for (i = 0; i < seqlen; ++i) {
                size_t n;
                item = PySequence_Fast_GET_ITEM(seq, i);
                n = PyString_GET_SIZE(item);
                memcpy(p, PyString_AS_STRING(item), n);
                p += n;
                if (i < seqlen - 1) {
                        memcpy(p, sep, seplen);
                        p += seplen;
                }
        }

        Py_DECREF(seq);
        return res;
}

PyObject *
_PyString_Join(PyObject *sep, PyObject *x)
{
        assert(sep != NULL && PyString_Check(sep));
        assert(x != NULL);
        return string_join((PyStringObject *)sep, x);
}

static void
string_adjust_indices(Py_ssize_t *start, Py_ssize_t *end, Py_ssize_t len)
{
        if (*end > len)
                *end = len;
        else if (*end < 0)
                *end += len;
        if (*end < 0)
                *end = 0;
        if (*start < 0)
                *start += len;
        if (*start < 0)
                *start = 0;
}

static Py_ssize_t
string_find_internal(PyStringObject *self, PyObject *args, int dir)
{
        const char *s = PyString_AS_STRING(self), *sub;
        Py_ssize_t len = PyString_GET_SIZE(self);
        Py_ssize_t n, i = 0, last = INT_MAX;
        PyObject *subobj;

        /* XXX ssize_t i */
        if (!PyArg_ParseTuple(args, "O|O&O&:find/rfind/index/rindex",
                &subobj, _PyEval_SliceIndex, &i, _PyEval_SliceIndex, &last))
                return -2;
        if (PyString_Check(subobj)) {
                sub = PyString_AS_STRING(subobj);
                n = PyString_GET_SIZE(subobj);
        }
#ifdef Py_USING_UNICODE
        else if (PyUnicode_Check(subobj))
                return PyUnicode_Find((PyObject *)self, subobj, i, last, dir);
#endif
        else if (PyObject_AsCharBuffer(subobj, &sub, &n))
                return -2;

        string_adjust_indices(&i, &last, len);

        if (dir > 0) {
                if (n == 0 && i <= last)
                        return (long)i;
                last -= n;
                for (; i <= last; ++i)
                        if (s[i] == sub[0] && memcmp(&s[i], sub, n) == 0)
                                return (long)i;
        }
        else {
                Py_ssize_t j;

                if (n == 0 && i <= last)
                        return last;
                for (j = last-n; j >= i; --j)
                        if (s[j] == sub[0] && memcmp(&s[j], sub, n) == 0)
                                return j;
        }

        return -1;
}


PyDoc_STRVAR(find__doc__,
"S.find(sub [,start [,end]]) -> int\n\
\n\
Return the lowest index in S where substring sub is found,\n\
such that sub is contained within s[start,end].  Optional\n\
arguments start and end are interpreted as in slice notation.\n\
\n\
Return -1 on failure.");

static PyObject *
string_find(PyStringObject *self, PyObject *args)
{
        Py_ssize_t result = string_find_internal(self, args, +1);
        if (result == -2)
                return NULL;
        return PyInt_FromSsize_t(result);
}


PyDoc_STRVAR(index__doc__,
"S.index(sub [,start [,end]]) -> int\n\
\n\
Like S.find() but raise ValueError when the substring is not found.");

static PyObject *
string_index(PyStringObject *self, PyObject *args)
{
        Py_ssize_t result = string_find_internal(self, args, +1);
        if (result == -2)
                return NULL;
        if (result == -1) {
                PyErr_SetString(PyExc_ValueError,
                                "substring not found");
                return NULL;
        }
        return PyInt_FromSsize_t(result);
}


PyDoc_STRVAR(rfind__doc__,
"S.rfind(sub [,start [,end]]) -> int\n\
\n\
Return the highest index in S where substring sub is found,\n\
such that sub is contained within s[start,end].  Optional\n\
arguments start and end are interpreted as in slice notation.\n\
\n\
Return -1 on failure.");

static PyObject *
string_rfind(PyStringObject *self, PyObject *args)
{
        Py_ssize_t result = string_find_internal(self, args, -1);
        if (result == -2)
                return NULL;
        return PyInt_FromSsize_t(result);
}


PyDoc_STRVAR(rindex__doc__,
"S.rindex(sub [,start [,end]]) -> int\n\
\n\
Like S.rfind() but raise ValueError when the substring is not found.");

static PyObject *
string_rindex(PyStringObject *self, PyObject *args)
{
        Py_ssize_t result = string_find_internal(self, args, -1);
        if (result == -2)
                return NULL;
        if (result == -1) {
                PyErr_SetString(PyExc_ValueError,
                                "substring not found");
                return NULL;
        }
        return PyInt_FromSsize_t(result);
}


static PyObject *
do_xstrip(PyStringObject *self, int striptype, PyObject *sepobj)
{
        char *s = PyString_AS_STRING(self);
        Py_ssize_t len = PyString_GET_SIZE(self);
        char *sep = PyString_AS_STRING(sepobj);
        Py_ssize_t seplen = PyString_GET_SIZE(sepobj);
        Py_ssize_t i, j;

        i = 0;
        if (striptype != RIGHTSTRIP) {
                while (i < len && memchr(sep, Py_CHARMASK(s[i]), seplen)) {
                        i++;
                }
        }

        j = len;
        if (striptype != LEFTSTRIP) {
                do {
                        j--;
                } while (j >= i && memchr(sep, Py_CHARMASK(s[j]), seplen));
                j++;
        }

        if (i == 0 && j == len && PyString_CheckExact(self)) {
                Py_INCREF(self);
                return (PyObject*)self;
        }
        else
                return PyString_FromStringAndSize(s+i, j-i);
}


static PyObject *
do_strip(PyStringObject *self, int striptype)
{
        char *s = PyString_AS_STRING(self);
        Py_ssize_t len = PyString_GET_SIZE(self), i, j;

        i = 0;
        if (striptype != RIGHTSTRIP) {
                while (i < len && isspace(Py_CHARMASK(s[i]))) {
                        i++;
                }
        }

        j = len;
        if (striptype != LEFTSTRIP) {
                do {
                        j--;
                } while (j >= i && isspace(Py_CHARMASK(s[j])));
                j++;
        }

        if (i == 0 && j == len && PyString_CheckExact(self)) {
                Py_INCREF(self);
                return (PyObject*)self;
        }
        else
                return PyString_FromStringAndSize(s+i, j-i);
}


static PyObject *
do_argstrip(PyStringObject *self, int striptype, PyObject *args)
{
        PyObject *sep = NULL;

        if (!PyArg_ParseTuple(args, (char *)stripformat[striptype], &sep))
                return NULL;

        if (sep != NULL && sep != Py_None) {
                if (PyString_Check(sep))
                        return do_xstrip(self, striptype, sep);
#ifdef Py_USING_UNICODE
                else if (PyUnicode_Check(sep)) {
                        PyObject *uniself = PyUnicode_FromObject((PyObject *)self);
                        PyObject *res;
                        if (uniself==NULL)
                                return NULL;
                        res = _PyUnicode_XStrip((PyUnicodeObject *)uniself,
                                striptype, sep);
                        Py_DECREF(uniself);
                        return res;
                }
#endif
                else {
                        PyErr_Format(PyExc_TypeError,
#ifdef Py_USING_UNICODE
                                     "%s arg must be None, str or unicode",
#else
                                     "%s arg must be None or str",
#endif
                                     STRIPNAME(striptype));
                        return NULL;
                }
                return do_xstrip(self, striptype, sep);
        }

        return do_strip(self, striptype);
}


PyDoc_STRVAR(strip__doc__,
"S.strip([chars]) -> string or unicode\n\
\n\
Return a copy of the string S with leading and trailing\n\
whitespace removed.\n\
If chars is given and not None, remove characters in chars instead.\n\
If chars is unicode, S will be converted to unicode before stripping");

static PyObject *
string_strip(PyStringObject *self, PyObject *args)
{
        if (PyTuple_GET_SIZE(args) == 0)
                return do_strip(self, BOTHSTRIP); /* Common case */
        else
                return do_argstrip(self, BOTHSTRIP, args);
}


PyDoc_STRVAR(lstrip__doc__,
"S.lstrip([chars]) -> string or unicode\n\
\n\
Return a copy of the string S with leading whitespace removed.\n\
If chars is given and not None, remove characters in chars instead.\n\
If chars is unicode, S will be converted to unicode before stripping");

static PyObject *
string_lstrip(PyStringObject *self, PyObject *args)
{
        if (PyTuple_GET_SIZE(args) == 0)
                return do_strip(self, LEFTSTRIP); /* Common case */
        else
                return do_argstrip(self, LEFTSTRIP, args);
}


PyDoc_STRVAR(rstrip__doc__,
"S.rstrip([chars]) -> string or unicode\n\
\n\
Return a copy of the string S with trailing whitespace removed.\n\
If chars is given and not None, remove characters in chars instead.\n\
If chars is unicode, S will be converted to unicode before stripping");

static PyObject *
string_rstrip(PyStringObject *self, PyObject *args)
{
        if (PyTuple_GET_SIZE(args) == 0)
                return do_strip(self, RIGHTSTRIP); /* Common case */
        else
                return do_argstrip(self, RIGHTSTRIP, args);
}


PyDoc_STRVAR(lower__doc__,
"S.lower() -> string\n\
\n\
Return a copy of the string S converted to lowercase.");

static PyObject *
string_lower(PyStringObject *self)
{
        char *s = PyString_AS_STRING(self), *s_new;
        Py_ssize_t i, n = PyString_GET_SIZE(self);
        PyObject *new;

        new = PyString_FromStringAndSize(NULL, n);
        if (new == NULL)
                return NULL;
        s_new = PyString_AsString(new);
        for (i = 0; i < n; i++) {
                int c = Py_CHARMASK(*s++);
                if (isupper(c)) {
                        *s_new = tolower(c);
                } else
                        *s_new = c;
                s_new++;
        }
        return new;
}


PyDoc_STRVAR(upper__doc__,
"S.upper() -> string\n\
\n\
Return a copy of the string S converted to uppercase.");

static PyObject *
string_upper(PyStringObject *self)
{
        char *s = PyString_AS_STRING(self), *s_new;
        Py_ssize_t i, n = PyString_GET_SIZE(self);
        PyObject *new;

        new = PyString_FromStringAndSize(NULL, n);
        if (new == NULL)
                return NULL;
        s_new = PyString_AsString(new);
        for (i = 0; i < n; i++) {
                int c = Py_CHARMASK(*s++);
                if (islower(c)) {
                        *s_new = toupper(c);
                } else
                        *s_new = c;
                s_new++;
        }
        return new;
}


PyDoc_STRVAR(title__doc__,
"S.title() -> string\n\
\n\
Return a titlecased version of S, i.e. words start with uppercase\n\
characters, all remaining cased characters have lowercase.");

static PyObject*
string_title(PyStringObject *self)
{
        char *s = PyString_AS_STRING(self), *s_new;
        Py_ssize_t i, n = PyString_GET_SIZE(self);
        int previous_is_cased = 0;
        PyObject *new;

        new = PyString_FromStringAndSize(NULL, n);
        if (new == NULL)
                return NULL;
        s_new = PyString_AsString(new);
        for (i = 0; i < n; i++) {
                int c = Py_CHARMASK(*s++);
                if (islower(c)) {
                        if (!previous_is_cased)
                            c = toupper(c);
                        previous_is_cased = 1;
                } else if (isupper(c)) {
                        if (previous_is_cased)
                            c = tolower(c);
                        previous_is_cased = 1;
                } else
                        previous_is_cased = 0;
                *s_new++ = c;
        }
        return new;
}

PyDoc_STRVAR(capitalize__doc__,
"S.capitalize() -> string\n\
\n\
Return a copy of the string S with only its first character\n\
capitalized.");

static PyObject *
string_capitalize(PyStringObject *self)
{
        char *s = PyString_AS_STRING(self), *s_new;
        Py_ssize_t i, n = PyString_GET_SIZE(self);
        PyObject *new;

        new = PyString_FromStringAndSize(NULL, n);
        if (new == NULL)
                return NULL;
        s_new = PyString_AsString(new);
        if (0 < n) {
                int c = Py_CHARMASK(*s++);
                if (islower(c))
                        *s_new = toupper(c);
                else
                        *s_new = c;
                s_new++;
        }
        for (i = 1; i < n; i++) {
                int c = Py_CHARMASK(*s++);
                if (isupper(c))
                        *s_new = tolower(c);
                else
                        *s_new = c;
                s_new++;
        }
        return new;
}


PyDoc_STRVAR(count__doc__,
"S.count(sub[, start[, end]]) -> int\n\
\n\
Return the number of occurrences of substring sub in string\n\
S[start:end].  Optional arguments start and end are\n\
interpreted as in slice notation.");

static PyObject *
string_count(PyStringObject *self, PyObject *args)
{
        const char *s = PyString_AS_STRING(self), *sub, *t;
        Py_ssize_t len = PyString_GET_SIZE(self), n;
        Py_ssize_t i = 0, last = INT_MAX;
        Py_ssize_t m, r;
        PyObject *subobj;

        if (!PyArg_ParseTuple(args, "O|O&O&:count", &subobj,
                _PyEval_SliceIndex, &i, _PyEval_SliceIndex, &last))
                return NULL;

        if (PyString_Check(subobj)) {
                sub = PyString_AS_STRING(subobj);
                n = PyString_GET_SIZE(subobj);
        }
#ifdef Py_USING_UNICODE
        else if (PyUnicode_Check(subobj)) {
                Py_ssize_t count;
                count = PyUnicode_Count((PyObject *)self, subobj, i, last);
                if (count == -1)
                        return NULL;
                else
                        return PyInt_FromLong((long) count);
        }
#endif
        else if (PyObject_AsCharBuffer(subobj, &sub, &n))
                return NULL;

        string_adjust_indices(&i, &last, len);

        m = last + 1 - n;
        if (n == 0)
                return PyInt_FromSsize_t(m-i);

        r = 0;
        while (i < m) {
                if (!memcmp(s+i, sub, n)) {
                        r++;
                        i += n;
                } else {
                        i++;
                }
                if (i >= m)
                        break;
                t = memchr(s+i, sub[0], m-i);
                if (t == NULL)
                        break;
                i = t - s;
        }
        return PyInt_FromSsize_t(r);
}

PyDoc_STRVAR(swapcase__doc__,
"S.swapcase() -> string\n\
\n\
Return a copy of the string S with uppercase characters\n\
converted to lowercase and vice versa.");

static PyObject *
string_swapcase(PyStringObject *self)
{
        char *s = PyString_AS_STRING(self), *s_new;
        Py_ssize_t i, n = PyString_GET_SIZE(self);
        PyObject *new;

        new = PyString_FromStringAndSize(NULL, n);
        if (new == NULL)
                return NULL;
        s_new = PyString_AsString(new);
        for (i = 0; i < n; i++) {
                int c = Py_CHARMASK(*s++);
                if (islower(c)) {
                        *s_new = toupper(c);
                }
                else if (isupper(c)) {
                        *s_new = tolower(c);
                }
                else
                        *s_new = c;
                s_new++;
        }
        return new;
}


PyDoc_STRVAR(translate__doc__,
"S.translate(table [,deletechars]) -> string\n\
\n\
Return a copy of the string S, where all characters occurring\n\
in the optional argument deletechars are removed, and the\n\
remaining characters have been mapped through the given\n\
translation table, which must be a string of length 256.");

static PyObject *
string_translate(PyStringObject *self, PyObject *args)
{
        register char *input, *output;
        register const char *table;
        register Py_ssize_t i, c, changed = 0;
        PyObject *input_obj = (PyObject*)self;
        const char *table1, *output_start, *del_table=NULL;
        Py_ssize_t inlen, tablen, dellen = 0;
        PyObject *result;
        int trans_table[256];
        PyObject *tableobj, *delobj = NULL;

        if (!PyArg_UnpackTuple(args, "translate", 1, 2,
                              &tableobj, &delobj))
                return NULL;

        if (PyString_Check(tableobj)) {
                table1 = PyString_AS_STRING(tableobj);
                tablen = PyString_GET_SIZE(tableobj);
        }
#ifdef Py_USING_UNICODE
        else if (PyUnicode_Check(tableobj)) {
                /* Unicode .translate() does not support the deletechars
                   parameter; instead a mapping to None will cause characters
                   to be deleted. */
                if (delobj != NULL) {
                        PyErr_SetString(PyExc_TypeError,
                        "deletions are implemented differently for unicode");
                        return NULL;
                }
                return PyUnicode_Translate((PyObject *)self, tableobj, NULL);
        }
#endif
        else if (PyObject_AsCharBuffer(tableobj, &table1, &tablen))
                return NULL;

        if (tablen != 256) {
                PyErr_SetString(PyExc_ValueError,
                  "translation table must be 256 characters long");
                return NULL;
        }

        if (delobj != NULL) {
                if (PyString_Check(delobj)) {
                        del_table = PyString_AS_STRING(delobj);
                        dellen = PyString_GET_SIZE(delobj);
                }
#ifdef Py_USING_UNICODE
                else if (PyUnicode_Check(delobj)) {
                        PyErr_SetString(PyExc_TypeError,
                        "deletions are implemented differently for unicode");
                        return NULL;
                }
#endif
                else if (PyObject_AsCharBuffer(delobj, &del_table, &dellen))
                        return NULL;
        }
        else {
                del_table = NULL;
                dellen = 0;
        }

        table = table1;
        inlen = PyString_Size(input_obj);
        result = PyString_FromStringAndSize((char *)NULL, inlen);
        if (result == NULL)
                return NULL;
        output_start = output = PyString_AsString(result);
        input = PyString_AsString(input_obj);

        if (dellen == 0) {
                /* If no deletions are required, use faster code */
                for (i = inlen; --i >= 0; ) {
                        c = Py_CHARMASK(*input++);
                        if (Py_CHARMASK((*output++ = table[c])) != c)
                                changed = 1;
                }
                if (changed || !PyString_CheckExact(input_obj))
                        return result;
                Py_DECREF(result);
                Py_INCREF(input_obj);
                return input_obj;
        }

        for (i = 0; i < 256; i++)
                trans_table[i] = Py_CHARMASK(table[i]);

        for (i = 0; i < dellen; i++)
                trans_table[(int) Py_CHARMASK(del_table[i])] = -1;

        for (i = inlen; --i >= 0; ) {
                c = Py_CHARMASK(*input++);
                if (trans_table[c] != -1)
                        if (Py_CHARMASK(*output++ = (char)trans_table[c]) == c)
                                continue;
                changed = 1;
        }
        if (!changed && PyString_CheckExact(input_obj)) {
                Py_DECREF(result);
                Py_INCREF(input_obj);
                return input_obj;
        }
        /* Fix the size of the resulting string */
        if (inlen > 0)
                _PyString_Resize(&result, output - output_start);
        return result;
}


/* What follows is used for implementing replace().  Perry Stoll. */

/*
  mymemfind

  strstr replacement for arbitrary blocks of memory.

  Locates the first occurrence in the memory pointed to by MEM of the
  contents of memory pointed to by PAT.  Returns the index into MEM if
  found, or -1 if not found.  If len of PAT is greater than length of
  MEM, the function returns -1.
*/
static Py_ssize_t
mymemfind(const char *mem, Py_ssize_t len, const char *pat, Py_ssize_t pat_len)
{
        register Py_ssize_t ii;

        /* pattern can not occur in the last pat_len-1 chars */
        len -= pat_len;

        for (ii = 0; ii <= len; ii++) {
                if (mem[ii] == pat[0] && memcmp(&mem[ii], pat, pat_len) == 0) {
                        return ii;
                }
        }
        return -1;
}

/*
  mymemcnt

   Return the number of distinct times PAT is found in MEM.
   meaning mem=1111 and pat==11 returns 2.
           mem=11111 and pat==11 also return 2.
 */
static Py_ssize_t
mymemcnt(const char *mem, Py_ssize_t len, const char *pat, Py_ssize_t pat_len)
{
        register Py_ssize_t offset = 0;
        Py_ssize_t nfound = 0;

        while (len >= 0) {
                offset = mymemfind(mem, len, pat, pat_len);
                if (offset == -1)
                        break;
                mem += offset + pat_len;
                len -= offset + pat_len;
                nfound++;
        }
        return nfound;
}

/*
   mymemreplace

   Return a string in which all occurrences of PAT in memory STR are
   replaced with SUB.

   If length of PAT is less than length of STR or there are no occurrences
   of PAT in STR, then the original string is returned. Otherwise, a new
   string is allocated here and returned.

   on return, out_len is:
       the length of output string, or
       -1 if the input string is returned, or
       unchanged if an error occurs (no memory).

   return value is:
       the new string allocated locally, or
       NULL if an error occurred.
*/
static char *
mymemreplace(const char *str, Py_ssize_t len,           /* input string */
             const char *pat, Py_ssize_t pat_len,       /* pattern string to find */
             const char *sub, Py_ssize_t sub_len,       /* substitution string */
             Py_ssize_t count,                          /* number of replacements */
             Py_ssize_t *out_len)
{
        char *out_s;
        char *new_s;
        Py_ssize_t nfound, offset, new_len;

        if (len == 0 || (pat_len == 0 && sub_len == 0) || pat_len > len)
                goto return_same;

        /* find length of output string */
        nfound = (pat_len > 0) ? mymemcnt(str, len, pat, pat_len) : len + 1;
        if (count < 0)
                count = INT_MAX;
        else if (nfound > count)
                nfound = count;
        if (nfound == 0)
                goto return_same;

        new_len = len + nfound*(sub_len - pat_len);
        if (new_len == 0) {
                /* Have to allocate something for the caller to free(). */
                out_s = (char *)PyMem_MALLOC(1);
                if (out_s == NULL)
                        return NULL;
                out_s[0] = '\0';
        }
        else {
                assert(new_len > 0);
                new_s = (char *)PyMem_MALLOC(new_len);
                if (new_s == NULL)
                        return NULL;
                out_s = new_s;

                if (pat_len > 0) {
                        for (; nfound > 0; --nfound) {
                                /* find index of next instance of pattern */
                                offset = mymemfind(str, len, pat, pat_len);
                                if (offset == -1)
                                        break;

                                /* copy non matching part of input string */
                                memcpy(new_s, str, offset);
                                str += offset + pat_len;
                                len -= offset + pat_len;

                                /* copy substitute into the output string */
                                new_s += offset;
                                memcpy(new_s, sub, sub_len);
                                new_s += sub_len;
                        }
                        /* copy any remaining values into output string */
                        if (len > 0)
                                memcpy(new_s, str, len);
                }
                else {
                        for (;;++str, --len) {
                                memcpy(new_s, sub, sub_len);
                                new_s += sub_len;
                                if (--nfound <= 0) {
                                        memcpy(new_s, str, len);
                                        break;
                                }
                                *new_s++ = *str;
                        }
                }
        }
        *out_len = new_len;
        return out_s;

  return_same:
        *out_len = -1;
        return (char *)str; /* cast away const */
}


PyDoc_STRVAR(replace__doc__,
"S.replace (old, new[, count]) -> string\n\
\n\
Return a copy of string S with all occurrences of substring\n\
old replaced by new.  If the optional argument count is\n\
given, only the first count occurrences are replaced.");

static PyObject *
string_replace(PyStringObject *self, PyObject *args)
{
        const char *str = PyString_AS_STRING(self), *sub, *repl;
        char *new_s;
        const Py_ssize_t len = PyString_GET_SIZE(self);
        Py_ssize_t sub_len, repl_len, out_len;
        int count = -1;
        PyObject *new;
        PyObject *subobj, *replobj;

        if (!PyArg_ParseTuple(args, "OO|i:replace",
                              &subobj, &replobj, &count))
                return NULL;

        if (PyString_Check(subobj)) {
                sub = PyString_AS_STRING(subobj);
                sub_len = PyString_GET_SIZE(subobj);
        }
#ifdef Py_USING_UNICODE
        else if (PyUnicode_Check(subobj))
                return PyUnicode_Replace((PyObject *)self,
                                         subobj, replobj, count);
#endif
        else if (PyObject_AsCharBuffer(subobj, &sub, &sub_len))
                return NULL;

        if (PyString_Check(replobj)) {
                repl = PyString_AS_STRING(replobj);
                repl_len = PyString_GET_SIZE(replobj);
        }
#ifdef Py_USING_UNICODE
        else if (PyUnicode_Check(replobj))
                return PyUnicode_Replace((PyObject *)self,
                                         subobj, replobj, count);
#endif
        else if (PyObject_AsCharBuffer(replobj, &repl, &repl_len))
                return NULL;

        new_s = mymemreplace(str,len,sub,sub_len,repl,repl_len,count,&out_len);
        if (new_s == NULL) {
                PyErr_NoMemory();
                return NULL;
        }
        if (out_len == -1) {
                if (PyString_CheckExact(self)) {
                        /* we're returning another reference to self */
                        new = (PyObject*)self;
                        Py_INCREF(new);
                }
                else {
                        new = PyString_FromStringAndSize(str, len);
                        if (new == NULL)
                                return NULL;
                }
        }
        else {
                new = PyString_FromStringAndSize(new_s, out_len);
                PyMem_FREE(new_s);
        }
        return new;
}


PyDoc_STRVAR(startswith__doc__,
"S.startswith(prefix[, start[, end]]) -> bool\n\
\n\
Return True if S starts with the specified prefix, False otherwise.\n\
With optional start, test S beginning at that position.\n\
With optional end, stop comparing S at that position.");

static PyObject *
string_startswith(PyStringObject *self, PyObject *args)
{
        const char* str = PyString_AS_STRING(self);
        Py_ssize_t len = PyString_GET_SIZE(self);
        const char* prefix;
        Py_ssize_t plen;
        Py_ssize_t start = 0;
        Py_ssize_t end = INT_MAX;
        PyObject *subobj;

        if (!PyArg_ParseTuple(args, "O|O&O&:startswith", &subobj,
                _PyEval_SliceIndex, &start, _PyEval_SliceIndex, &end))
                return NULL;
        if (PyString_Check(subobj)) {
                prefix = PyString_AS_STRING(subobj);
                plen = PyString_GET_SIZE(subobj);
        }
#ifdef Py_USING_UNICODE
        else if (PyUnicode_Check(subobj)) {
                Py_ssize_t rc;
                rc = PyUnicode_Tailmatch((PyObject *)self,
                                          subobj, start, end, -1);
                if (rc == -1)
                        return NULL;
                else
                        return PyBool_FromLong((long) rc);
        }
#endif
        else if (PyObject_AsCharBuffer(subobj, &prefix, &plen))
                return NULL;

        string_adjust_indices(&start, &end, len);

        if (start+plen > len)
                return PyBool_FromLong(0);

        if (end-start >= plen)
                return PyBool_FromLong(!memcmp(str+start, prefix, plen));
        else
                return PyBool_FromLong(0);
}


PyDoc_STRVAR(endswith__doc__,
"S.endswith(suffix[, start[, end]]) -> bool\n\
\n\
Return True if S ends with the specified suffix, False otherwise.\n\
With optional start, test S beginning at that position.\n\
With optional end, stop comparing S at that position.");

static PyObject *
string_endswith(PyStringObject *self, PyObject *args)
{
        const char* str = PyString_AS_STRING(self);
        Py_ssize_t len = PyString_GET_SIZE(self);
        const char* suffix;
        Py_ssize_t slen;
        Py_ssize_t start = 0;
        Py_ssize_t end = INT_MAX;
        PyObject *subobj;

        if (!PyArg_ParseTuple(args, "O|O&O&:endswith", &subobj,
                _PyEval_SliceIndex, &start, _PyEval_SliceIndex, &end))
                return NULL;
        if (PyString_Check(subobj)) {
                suffix = PyString_AS_STRING(subobj);
                slen = PyString_GET_SIZE(subobj);
        }
#ifdef Py_USING_UNICODE
        else if (PyUnicode_Check(subobj)) {
                Py_ssize_t rc;
                rc = PyUnicode_Tailmatch((PyObject *)self,
                                          subobj, start, end, +1);
                if (rc == -1)
                        return NULL;
                else
                        return PyBool_FromLong((long) rc);
        }
#endif
        else if (PyObject_AsCharBuffer(subobj, &suffix, &slen))
                return NULL;

        string_adjust_indices(&start, &end, len);

        if (end-start < slen || start > len)
                return PyBool_FromLong(0);

        if (end-slen > start)
                start = end - slen;
        if (end-start >= slen)
                return PyBool_FromLong(!memcmp(str+start, suffix, slen));
        else
                return PyBool_FromLong(0);
}


PyDoc_STRVAR(encode__doc__,
"S.encode([encoding[,errors]]) -> object\n\
\n\
Encodes S using the codec registered for encoding. encoding defaults\n\
to the default encoding. errors may be given to set a different error\n\
handling scheme. Default is 'strict' meaning that encoding errors raise\n\
a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and\n\
'xmlcharrefreplace' as well as any other name registered with\n\
codecs.register_error that is able to handle UnicodeEncodeErrors.");

static PyObject *
string_encode(PyStringObject *self, PyObject *args)
{
    char *encoding = NULL;
    char *errors = NULL;
    PyObject *v;
    
    if (!PyArg_ParseTuple(args, "|ss:encode", &encoding, &errors))
        return NULL;
    v = PyString_AsEncodedObject((PyObject *)self, encoding, errors);
    if (v == NULL)
        goto onError;
    if (!PyString_Check(v) && !PyUnicode_Check(v)) {
        PyErr_Format(PyExc_TypeError,
                     "encoder did not return a string/unicode object "
                     "(type=%.400s)",
                     v->ob_type->tp_name);
        Py_DECREF(v);
        return NULL;
    }
    return v;

 onError:
    return NULL;
}


PyDoc_STRVAR(decode__doc__,
"S.decode([encoding[,errors]]) -> object\n\
\n\
Decodes S using the codec registered for encoding. encoding defaults\n\
to the default encoding. errors may be given to set a different error\n\
handling scheme. Default is 'strict' meaning that encoding errors raise\n\
a UnicodeDecodeError. Other possible values are 'ignore' and 'replace'\n\
as well as any other name registerd with codecs.register_error that is\n\
able to handle UnicodeDecodeErrors.");

static PyObject *
string_decode(PyStringObject *self, PyObject *args)
{
    char *encoding = NULL;
    char *errors = NULL;
    PyObject *v;
    
    if (!PyArg_ParseTuple(args, "|ss:decode", &encoding, &errors))
        return NULL;
    v = PyString_AsDecodedObject((PyObject *)self, encoding, errors);
    if (v == NULL)
        goto onError;
    if (!PyString_Check(v) && !PyUnicode_Check(v)) {
        PyErr_Format(PyExc_TypeError,
                     "decoder did not return a string/unicode object "
                     "(type=%.400s)",
                     v->ob_type->tp_name);
        Py_DECREF(v);
        return NULL;
    }
    return v;

 onError:
    return NULL;
}


PyDoc_STRVAR(expandtabs__doc__,
"S.expandtabs([tabsize]) -> string\n\
\n\
Return a copy of S where all tab characters are expanded using spaces.\n\
If tabsize is not given, a tab size of 8 characters is assumed.");

static PyObject*
string_expandtabs(PyStringObject *self, PyObject *args)
{
    const char *e, *p;
    char *q;
    Py_ssize_t i, j;
    PyObject *u;
    int tabsize = 8;

    if (!PyArg_ParseTuple(args, "|i:expandtabs", &tabsize))
        return NULL;

    /* First pass: determine size of output string */
    i = j = 0;
    e = PyString_AS_STRING(self) + PyString_GET_SIZE(self);
    for (p = PyString_AS_STRING(self); p < e; p++)
        if (*p == '\t') {
            if (tabsize > 0)
                j += tabsize - (j % tabsize);
        }
        else {
            j++;
            if (*p == '\n' || *p == '\r') {
                i += j;
                j = 0;
            }
        }

    /* Second pass: create output string and fill it */
    u = PyString_FromStringAndSize(NULL, i + j);
    if (!u)
        return NULL;

    j = 0;
    q = PyString_AS_STRING(u);

    for (p = PyString_AS_STRING(self); p < e; p++)
        if (*p == '\t') {
            if (tabsize > 0) {
                i = tabsize - (j % tabsize);
                j += i;
                while (i--)
                    *q++ = ' ';
            }
        }
        else {
            j++;
            *q++ = *p;
            if (*p == '\n' || *p == '\r')
                j = 0;
        }

    return u;
}

static PyObject *
pad(PyStringObject *self, Py_ssize_t left, Py_ssize_t right, char fill)
{
    PyObject *u;

    if (left < 0)
        left = 0;
    if (right < 0)
        right = 0;

    if (left == 0 && right == 0 && PyString_CheckExact(self)) {
        Py_INCREF(self);
        return (PyObject *)self;
    }

    u = PyString_FromStringAndSize(NULL,
                                   left + PyString_GET_SIZE(self) + right);
    if (u) {
        if (left)
            memset(PyString_AS_STRING(u), fill, left);
        memcpy(PyString_AS_STRING(u) + left,
               PyString_AS_STRING(self),
               PyString_GET_SIZE(self));
        if (right)
            memset(PyString_AS_STRING(u) + left + PyString_GET_SIZE(self),
                   fill, right);
    }

    return u;
}

PyDoc_STRVAR(ljust__doc__,
"S.ljust(width[, fillchar]) -> string\n"
"\n"
"Return S left justified in a string of length width. Padding is\n"
"done using the specified fill character (default is a space).");

static PyObject *
string_ljust(PyStringObject *self, PyObject *args)
{
    int width;
    char fillchar = ' ';

    if (!PyArg_ParseTuple(args, "i|c:ljust", &width, &fillchar))
        return NULL;

    if (PyString_GET_SIZE(self) >= width && PyString_CheckExact(self)) {
        Py_INCREF(self);
        return (PyObject*) self;
    }

    return pad(self, 0, width - PyString_GET_SIZE(self), fillchar);
}


PyDoc_STRVAR(rjust__doc__,
"S.rjust(width[, fillchar]) -> string\n"
"\n"
"Return S right justified in a string of length width. Padding is\n"
"done using the specified fill character (default is a space)");

static PyObject *
string_rjust(PyStringObject *self, PyObject *args)
{
    int width;
    char fillchar = ' ';

    if (!PyArg_ParseTuple(args, "i|c:rjust", &width, &fillchar))
        return NULL;

    if (PyString_GET_SIZE(self) >= width && PyString_CheckExact(self)) {
        Py_INCREF(self);
        return (PyObject*) self;
    }

    return pad(self, width - PyString_GET_SIZE(self), 0, fillchar);
}


PyDoc_STRVAR(center__doc__,
"S.center(width[, fillchar]) -> string\n"
"\n"
"Return S centered in a string of length width. Padding is\n"
"done using the specified fill character (default is a space)");

static PyObject *
string_center(PyStringObject *self, PyObject *args)
{
    Py_ssize_t marg, left;
    long width;
    char fillchar = ' ';

    if (!PyArg_ParseTuple(args, "l|c:center", &width, &fillchar))
        return NULL;

    if (PyString_GET_SIZE(self) >= width && PyString_CheckExact(self)) {
        Py_INCREF(self);
        return (PyObject*) self;
    }

    marg = width - PyString_GET_SIZE(self);
    left = marg / 2 + (marg & width & 1);

    return pad(self, left, marg - left, fillchar);
}

PyDoc_STRVAR(zfill__doc__,
"S.zfill(width) -> string\n"
"\n"
"Pad a numeric string S with zeros on the left, to fill a field\n"
"of the specified width.  The string S is never truncated.");

static PyObject *
string_zfill(PyStringObject *self, PyObject *args)
{
    Py_ssize_t fill;
    PyObject *s;
    char *p;

    long width;
    if (!PyArg_ParseTuple(args, "l:zfill", &width))
        return NULL;

    if (PyString_GET_SIZE(self) >= width) {
        if (PyString_CheckExact(self)) {
            Py_INCREF(self);
            return (PyObject*) self;
        }
        else
            return PyString_FromStringAndSize(
                PyString_AS_STRING(self),
                PyString_GET_SIZE(self)
            );
    }

    fill = width - PyString_GET_SIZE(self);

    s = pad(self, fill, 0, '0');

    if (s == NULL)
        return NULL;

    p = PyString_AS_STRING(s);
    if (p[fill] == '+' || p[fill] == '-') {
        /* move sign to beginning of string */
        p[0] = p[fill];
        p[fill] = '0';
    }

    return (PyObject*) s;
}

PyDoc_STRVAR(isspace__doc__,
"S.isspace() -> bool\n\
\n\
Return True if all characters in S are whitespace\n\
and there is at least one character in S, False otherwise.");

static PyObject*
string_isspace(PyStringObject *self)
{
    register const unsigned char *p
        = (unsigned char *) PyString_AS_STRING(self);
    register const unsigned char *e;

    /* Shortcut for single character strings */
    if (PyString_GET_SIZE(self) == 1 &&
        isspace(*p))
        return PyBool_FromLong(1);

    /* Special case for empty strings */
    if (PyString_GET_SIZE(self) == 0)
        return PyBool_FromLong(0);

    e = p + PyString_GET_SIZE(self);
    for (; p < e; p++) {
        if (!isspace(*p))
            return PyBool_FromLong(0);
    }
    return PyBool_FromLong(1);
}


PyDoc_STRVAR(isalpha__doc__,
"S.isalpha() -> bool\n\
\n\
Return True if all characters in S are alphabetic\n\
and there is at least one character in S, False otherwise.");

static PyObject*
string_isalpha(PyStringObject *self)
{
    register const unsigned char *p
        = (unsigned char *) PyString_AS_STRING(self);
    register const unsigned char *e;

    /* Shortcut for single character strings */
    if (PyString_GET_SIZE(self) == 1 &&
        isalpha(*p))
        return PyBool_FromLong(1);

    /* Special case for empty strings */
    if (PyString_GET_SIZE(self) == 0)
        return PyBool_FromLong(0);

    e = p + PyString_GET_SIZE(self);
    for (; p < e; p++) {
        if (!isalpha(*p))
            return PyBool_FromLong(0);
    }
    return PyBool_FromLong(1);
}


PyDoc_STRVAR(isalnum__doc__,
"S.isalnum() -> bool\n\
\n\
Return True if all characters in S are alphanumeric\n\
and there is at least one character in S, False otherwise.");

static PyObject*
string_isalnum(PyStringObject *self)
{
    register const unsigned char *p
        = (unsigned char *) PyString_AS_STRING(self);
    register const unsigned char *e;

    /* Shortcut for single character strings */
    if (PyString_GET_SIZE(self) == 1 &&
        isalnum(*p))
        return PyBool_FromLong(1);

    /* Special case for empty strings */
    if (PyString_GET_SIZE(self) == 0)
        return PyBool_FromLong(0);

    e = p + PyString_GET_SIZE(self);
    for (; p < e; p++) {
        if (!isalnum(*p))
            return PyBool_FromLong(0);
    }
    return PyBool_FromLong(1);
}


PyDoc_STRVAR(isdigit__doc__,
"S.isdigit() -> bool\n\
\n\
Return True if all characters in S are digits\n\
and there is at least one character in S, False otherwise.");

static PyObject*
string_isdigit(PyStringObject *self)
{
    register const unsigned char *p
        = (unsigned char *) PyString_AS_STRING(self);
    register const unsigned char *e;

    /* Shortcut for single character strings */
    if (PyString_GET_SIZE(self) == 1 &&
        isdigit(*p))
        return PyBool_FromLong(1);

    /* Special case for empty strings */
    if (PyString_GET_SIZE(self) == 0)
        return PyBool_FromLong(0);

    e = p + PyString_GET_SIZE(self);
    for (; p < e; p++) {
        if (!isdigit(*p))
            return PyBool_FromLong(0);
    }
    return PyBool_FromLong(1);
}


PyDoc_STRVAR(islower__doc__,
"S.islower() -> bool\n\
\n\
Return True if all cased characters in S are lowercase and there is\n\
at least one cased character in S, False otherwise.");

static PyObject*
string_islower(PyStringObject *self)
{
    register const unsigned char *p
        = (unsigned char *) PyString_AS_STRING(self);
    register const unsigned char *e;
    int cased;

    /* Shortcut for single character strings */
    if (PyString_GET_SIZE(self) == 1)
        return PyBool_FromLong(islower(*p) != 0);

    /* Special case for empty strings */
    if (PyString_GET_SIZE(self) == 0)
        return PyBool_FromLong(0);

    e = p + PyString_GET_SIZE(self);
    cased = 0;
    for (; p < e; p++) {
        if (isupper(*p))
            return PyBool_FromLong(0);
        else if (!cased && islower(*p))
            cased = 1;
    }
    return PyBool_FromLong(cased);
}


PyDoc_STRVAR(isupper__doc__,
"S.isupper() -> bool\n\
\n\
Return True if all cased characters in S are uppercase and there is\n\
at least one cased character in S, False otherwise.");

static PyObject*
string_isupper(PyStringObject *self)
{
    register const unsigned char *p
        = (unsigned char *) PyString_AS_STRING(self);
    register const unsigned char *e;
    int cased;

    /* Shortcut for single character strings */
    if (PyString_GET_SIZE(self) == 1)
        return PyBool_FromLong(isupper(*p) != 0);

    /* Special case for empty strings */
    if (PyString_GET_SIZE(self) == 0)
        return PyBool_FromLong(0);

    e = p + PyString_GET_SIZE(self);
    cased = 0;
    for (; p < e; p++) {
        if (islower(*p))
            return PyBool_FromLong(0);
        else if (!cased && isupper(*p))
            cased = 1;
    }
    return PyBool_FromLong(cased);
}


PyDoc_STRVAR(istitle__doc__,
"S.istitle() -> bool\n\
\n\
Return True if S is a titlecased string and there is at least one\n\
character in S, i.e. uppercase characters may only follow uncased\n\
characters and lowercase characters only cased ones. Return False\n\
otherwise.");

static PyObject*
string_istitle(PyStringObject *self, PyObject *uncased)
{
    register const unsigned char *p
        = (unsigned char *) PyString_AS_STRING(self);
    register const unsigned char *e;
    int cased, previous_is_cased;

    /* Shortcut for single character strings */
    if (PyString_GET_SIZE(self) == 1)
        return PyBool_FromLong(isupper(*p) != 0);

    /* Special case for empty strings */
    if (PyString_GET_SIZE(self) == 0)
        return PyBool_FromLong(0);

    e = p + PyString_GET_SIZE(self);
    cased = 0;
    previous_is_cased = 0;
    for (; p < e; p++) {
        register const unsigned char ch = *p;

        if (isupper(ch)) {
            if (previous_is_cased)
                return PyBool_FromLong(0);
            previous_is_cased = 1;
            cased = 1;
        }
        else if (islower(ch)) {
            if (!previous_is_cased)
                return PyBool_FromLong(0);
            previous_is_cased = 1;
            cased = 1;
        }
        else
            previous_is_cased = 0;
    }
    return PyBool_FromLong(cased);
}


PyDoc_STRVAR(splitlines__doc__,
"S.splitlines([keepends]) -> list of strings\n\
\n\
Return a list of the lines in S, breaking at line boundaries.\n\
Line breaks are not included in the resulting list unless keepends\n\
is given and true.");

static PyObject*
string_splitlines(PyStringObject *self, PyObject *args)
{
    register Py_ssize_t i;
    register Py_ssize_t j;
    Py_ssize_t len;
    int keepends = 0;
    PyObject *list;
    PyObject *str;
    char *data;

    if (!PyArg_ParseTuple(args, "|i:splitlines", &keepends))
        return NULL;

    data = PyString_AS_STRING(self);
    len = PyString_GET_SIZE(self);

    list = PyList_New(0);
    if (!list)
        goto onError;

    for (i = j = 0; i < len; ) {
        Py_ssize_t eol;

        /* Find a line and append it */
        while (i < len && data[i] != '\n' && data[i] != '\r')
            i++;

        /* Skip the line break reading CRLF as one line break */
        eol = i;
        if (i < len) {
            if (data[i] == '\r' && i + 1 < len &&
                data[i+1] == '\n')
                i += 2;
            else
                i++;
            if (keepends)
                eol = i;
        }
        SPLIT_APPEND(data, j, eol);
        j = i;
    }
    if (j < len) {
        SPLIT_APPEND(data, j, len);
    }

    return list;

 onError:
    Py_DECREF(list);
    return NULL;
}

#undef SPLIT_APPEND

static PyObject *
string_getnewargs(PyStringObject *v)
{
        return Py_BuildValue("(s#)", v->ob_sval, v->ob_size);
}


static PyMethodDef
string_methods[] = {
        /* Counterparts of the obsolete stropmodule functions; except
           string.maketrans(). */
        {"join", (PyCFunction)string_join, METH_O, join__doc__},
        {"split", (PyCFunction)string_split, METH_VARARGS, split__doc__},
        {"rsplit", (PyCFunction)string_rsplit, METH_VARARGS, rsplit__doc__},
        {"lower", (PyCFunction)string_lower, METH_NOARGS, lower__doc__},
        {"upper", (PyCFunction)string_upper, METH_NOARGS, upper__doc__},
        {"islower", (PyCFunction)string_islower, METH_NOARGS, islower__doc__},
        {"isupper", (PyCFunction)string_isupper, METH_NOARGS, isupper__doc__},
        {"isspace", (PyCFunction)string_isspace, METH_NOARGS, isspace__doc__},
        {"isdigit", (PyCFunction)string_isdigit, METH_NOARGS, isdigit__doc__},
        {"istitle", (PyCFunction)string_istitle, METH_NOARGS, istitle__doc__},
        {"isalpha", (PyCFunction)string_isalpha, METH_NOARGS, isalpha__doc__},
        {"isalnum", (PyCFunction)string_isalnum, METH_NOARGS, isalnum__doc__},
        {"capitalize", (PyCFunction)string_capitalize, METH_NOARGS,
         capitalize__doc__},
        {"count", (PyCFunction)string_count, METH_VARARGS, count__doc__},
        {"endswith", (PyCFunction)string_endswith, METH_VARARGS,
         endswith__doc__},
        {"find", (PyCFunction)string_find, METH_VARARGS, find__doc__},
        {"index", (PyCFunction)string_index, METH_VARARGS, index__doc__},
        {"lstrip", (PyCFunction)string_lstrip, METH_VARARGS, lstrip__doc__},
        {"replace", (PyCFunction)string_replace, METH_VARARGS, replace__doc__},
        {"rfind", (PyCFunction)string_rfind, METH_VARARGS, rfind__doc__},
        {"rindex", (PyCFunction)string_rindex, METH_VARARGS, rindex__doc__},
        {"rstrip", (PyCFunction)string_rstrip, METH_VARARGS, rstrip__doc__},
        {"startswith", (PyCFunction)string_startswith, METH_VARARGS,
         startswith__doc__},
        {"strip", (PyCFunction)string_strip, METH_VARARGS, strip__doc__},
        {"swapcase", (PyCFunction)string_swapcase, METH_NOARGS,
         swapcase__doc__},
        {"translate", (PyCFunction)string_translate, METH_VARARGS,
         translate__doc__},
        {"title", (PyCFunction)string_title, METH_NOARGS, title__doc__},
        {"ljust", (PyCFunction)string_ljust, METH_VARARGS, ljust__doc__},
        {"rjust", (PyCFunction)string_rjust, METH_VARARGS, rjust__doc__},
        {"center", (PyCFunction)string_center, METH_VARARGS, center__doc__},
        {"zfill", (PyCFunction)string_zfill, METH_VARARGS, zfill__doc__},
        {"encode", (PyCFunction)string_encode, METH_VARARGS, encode__doc__},
        {"decode", (PyCFunction)string_decode, METH_VARARGS, decode__doc__},
        {"expandtabs", (PyCFunction)string_expandtabs, METH_VARARGS,
         expandtabs__doc__},
        {"splitlines", (PyCFunction)string_splitlines, METH_VARARGS,
         splitlines__doc__},
        {"__getnewargs__",      (PyCFunction)string_getnewargs, METH_NOARGS},
        {NULL,     NULL}                     /* sentinel */
};

static PyObject *
str_subtype_new(PyTypeObject *type, PyObject *args, PyObject *kwds);

static PyObject *
string_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
        PyObject *x = NULL;
        static char *kwlist[] = {"object", 0};

        if (type != &PyString_Type)
                return str_subtype_new(type, args, kwds);
        if (!PyArg_ParseTupleAndKeywords(args, kwds, "|O:str", kwlist, &x))
                return NULL;
        if (x == NULL)
                return PyString_FromString("");
        return PyObject_Str(x);
}

static PyObject *
str_subtype_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
        PyObject *tmp, *pnew;
        Py_ssize_t n;

        assert(PyType_IsSubtype(type, &PyString_Type));
        tmp = string_new(&PyString_Type, args, kwds);
        if (tmp == NULL)
                return NULL;
        assert(PyString_CheckExact(tmp));
        n = PyString_GET_SIZE(tmp);
        pnew = type->tp_alloc(type, n);
        if (pnew != NULL) {
                memcpy(PyString_AS_STRING(pnew), PyString_AS_STRING(tmp), n+1);
                ((PyStringObject *)pnew)->ob_shash =
                        ((PyStringObject *)tmp)->ob_shash;
                ((PyStringObject *)pnew)->ob_sstate = SSTATE_NOT_INTERNED;
        }
        Py_DECREF(tmp);
        return pnew;
}

static PyObject *
basestring_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
        PyErr_SetString(PyExc_TypeError,
                        "The basestring type cannot be instantiated");
        return NULL;
}

static PyObject *
string_mod(PyObject *v, PyObject *w)
{
        if (!PyString_Check(v)) {
                Py_INCREF(Py_NotImplemented);
                return Py_NotImplemented;
        }
        return PyString_Format(v, w);
}

PyDoc_STRVAR(basestring_doc,
"Type basestring cannot be instantiated; it is the base for str and unicode.");

static PyNumberMethods string_as_number = {
        0,                      /*nb_add*/
        0,                      /*nb_subtract*/
        0,                      /*nb_multiply*/
        0,                      /*nb_divide*/
        string_mod,             /*nb_remainder*/
};


PyTypeObject PyBaseString_Type = {
        PyObject_HEAD_INIT(&PyType_Type)
        0,
        "basestring",
        0,
        0,
        0,                                      /* tp_dealloc */
        0,                                      /* tp_print */
        0,                                      /* tp_getattr */
        0,                                      /* tp_setattr */
        0,                                      /* tp_compare */
        0,                                      /* tp_repr */
        0,                                      /* tp_as_number */
        0,                                      /* tp_as_sequence */
        0,                                      /* tp_as_mapping */
        0,                                      /* tp_hash */
        0,                                      /* tp_call */
        0,                                      /* tp_str */
        0,                                      /* tp_getattro */
        0,                                      /* tp_setattro */
        0,                                      /* tp_as_buffer */
        Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
        basestring_doc,                         /* tp_doc */
        0,                                      /* tp_traverse */
        0,                                      /* tp_clear */
        0,                                      /* tp_richcompare */
        0,                                      /* tp_weaklistoffset */
        0,                                      /* tp_iter */
        0,                                      /* tp_iternext */
        0,                                      /* tp_methods */
        0,                                      /* tp_members */
        0,                                      /* tp_getset */
        &PyBaseObject_Type,                     /* tp_base */
        0,                                      /* tp_dict */
        0,                                      /* tp_descr_get */
        0,                                      /* tp_descr_set */
        0,                                      /* tp_dictoffset */
        0,                                      /* tp_init */
        0,                                      /* tp_alloc */
        basestring_new,                         /* tp_new */
        0,                                      /* tp_free */
};

PyDoc_STRVAR(string_doc,
"str(object) -> string\n\
\n\
Return a nice string representation of the object.\n\
If the argument is a string, the return value is the same object.");

PyTypeObject PyString_Type = {
        PyObject_HEAD_INIT(&PyType_Type)
        0,
        "str",
        sizeof(PyStringObject),
        sizeof(char),
        (destructor)string_dealloc,             /* tp_dealloc */
        (printfunc)string_print,                /* tp_print */
        0,                                      /* tp_getattr */
        0,                                      /* tp_setattr */
        0,                                      /* tp_compare */
        (reprfunc)string_repr,                  /* tp_repr */
        &string_as_number,                      /* tp_as_number */
        &string_as_sequence,                    /* tp_as_sequence */
        &string_as_mapping,                     /* tp_as_mapping */
        (hashfunc)string_hash,                  /* tp_hash */
        0,                                      /* tp_call */
        (reprfunc)string_str,                   /* tp_str */
        PyObject_GenericGetAttr,                /* tp_getattro */
        0,                                      /* tp_setattro */
        &string_as_buffer,                      /* tp_as_buffer */
        Py_TPFLAGS_DEFAULT | Py_TPFLAGS_CHECKTYPES | 
                Py_TPFLAGS_BASETYPE,            /* tp_flags */
        string_doc,                             /* tp_doc */
        0,                                      /* tp_traverse */
        0,                                      /* tp_clear */
        (richcmpfunc)string_richcompare,        /* tp_richcompare */
        0,                                      /* tp_weaklistoffset */
        0,                                      /* tp_iter */
        0,                                      /* tp_iternext */
        string_methods,                         /* tp_methods */
        0,                                      /* tp_members */
        0,                                      /* tp_getset */
        &PyBaseString_Type,                     /* tp_base */
        0,                                      /* tp_dict */
        0,                                      /* tp_descr_get */
        0,                                      /* tp_descr_set */
        0,                                      /* tp_dictoffset */
        0,                                      /* tp_init */
        0,                                      /* tp_alloc */
        string_new,                             /* tp_new */
        PyObject_Del,                           /* tp_free */
};

void
PyString_Concat(register PyObject **pv, register PyObject *w)
{
        register PyObject *v;
        if (*pv == NULL)
                return;
        if (w == NULL || !PyString_Check(*pv)) {
                Py_DECREF(*pv);
                *pv = NULL;
                return;
        }
        v = string_concat((PyStringObject *) *pv, w);
        Py_DECREF(*pv);
        *pv = v;
}

void
PyString_ConcatAndDel(register PyObject **pv, register PyObject *w)
{
        PyString_Concat(pv, w);
        Py_XDECREF(w);
}


/* The following function breaks the notion that strings are immutable:
   it changes the size of a string.  We get away with this only if there
   is only one module referencing the object.  You can also think of it
   as creating a new string object and destroying the old one, only
   more efficiently.  In any case, don't use this if the string may
   already be known to some other part of the code...
   Note that if there's not enough memory to resize the string, the original
   string object at *pv is deallocated, *pv is set to NULL, an "out of
   memory" exception is set, and -1 is returned.  Else (on success) 0 is
   returned, and the value in *pv may or may not be the same as on input.
   As always, an extra byte is allocated for a trailing \0 byte (newsize
   does *not* include that), and a trailing \0 byte is stored.
*/

int
_PyString_Resize(PyObject **pv, Py_ssize_t newsize)
{
        register PyObject *v;
        register PyStringObject *sv;
        v = *pv;
        if (!PyString_Check(v) || v->ob_refcnt != 1 || newsize < 0 ||
            PyString_CHECK_INTERNED(v)) {
                *pv = 0;
                Py_DECREF(v);
                PyErr_BadInternalCall();
                return -1;
        }
        /* XXX UNREF/NEWREF interface should be more symmetrical */
        _Py_DEC_REFTOTAL;
        _Py_ForgetReference(v);
        *pv = (PyObject *)
                PyObject_REALLOC((char *)v, sizeof(PyStringObject) + newsize);
        if (*pv == NULL) {
                PyObject_Del(v);
                PyErr_NoMemory();
                return -1;
        }
        _Py_NewReference(*pv);
        sv = (PyStringObject *) *pv;
        sv->ob_size = newsize;
        sv->ob_sval[newsize] = '\0';
        sv->ob_shash = -1;      /* invalidate cached hash value */
        return 0;
}

/* Helpers for formatstring */

static PyObject *
getnextarg(PyObject *args, Py_ssize_t arglen, Py_ssize_t *p_argidx)
{
        Py_ssize_t argidx = *p_argidx;
        if (argidx < arglen) {
                (*p_argidx)++;
                if (arglen < 0)
                        return args;
                else
                        return PyTuple_GetItem(args, argidx);
        }
        PyErr_SetString(PyExc_TypeError,
                        "not enough arguments for format string");
        return NULL;
}

/* Format codes
 * F_LJUST      '-'
 * F_SIGN       '+'
 * F_BLANK      ' '
 * F_ALT        '#'
 * F_ZERO       '0'
 */
#define F_LJUST (1<<0)
#define F_SIGN  (1<<1)
#define F_BLANK (1<<2)
#define F_ALT   (1<<3)
#define F_ZERO  (1<<4)

static int
formatfloat(char *buf, size_t buflen, int flags,
            int prec, int type, PyObject *v)
{
        /* fmt = '%#.' + `prec` + `type`
           worst case length = 3 + 10 (len of INT_MAX) + 1 = 14 (use 20)*/
        char fmt[20];
        double x;
        x = PyFloat_AsDouble(v);
        if (x == -1.0 && PyErr_Occurred()) {
                PyErr_SetString(PyExc_TypeError, "float argument required");
                return -1;
        }
        if (prec < 0)
                prec = 6;
        if (type == 'f' && fabs(x)/1e25 >= 1e25)
                type = 'g';
        /* Worst case length calc to ensure no buffer overrun:

           'g' formats:
             fmt = %#.<prec>g
             buf = '-' + [0-9]*prec + '.' + 'e+' + (longest exp
                for any double rep.)
             len = 1 + prec + 1 + 2 + 5 = 9 + prec

           'f' formats:
             buf = '-' + [0-9]*x + '.' + [0-9]*prec (with x < 50)
             len = 1 + 50 + 1 + prec = 52 + prec

           If prec=0 the effective precision is 1 (the leading digit is
           always given), therefore increase the length by one. 

        */
        if ((type == 'g' && buflen <= (size_t)10 + (size_t)prec) ||
            (type == 'f' && buflen <= (size_t)53 + (size_t)prec)) {
                PyErr_SetString(PyExc_OverflowError,
                        "formatted float is too long (precision too large?)");
                return -1;
        }
        PyOS_snprintf(fmt, sizeof(fmt), "%%%s.%d%c",
                      (flags&F_ALT) ? "#" : "",
                      prec, type);
        PyOS_ascii_formatd(buf, buflen, fmt, x);
        return (int)strlen(buf);
}

/* _PyString_FormatLong emulates the format codes d, u, o, x and X, and
 * the F_ALT flag, for Python's long (unbounded) ints.  It's not used for
 * Python's regular ints.
 * Return value:  a new PyString*, or NULL if error.
 *  .  *pbuf is set to point into it,
 *     *plen set to the # of chars following that.
 *     Caller must decref it when done using pbuf.
 *     The string starting at *pbuf is of the form
 *         "-"? ("0x" | "0X")? digit+
 *     "0x"/"0X" are present only for x and X conversions, with F_ALT
 *         set in flags.  The case of hex digits will be correct,
 *     There will be at least prec digits, zero-filled on the left if
 *         necessary to get that many.
 * val          object to be converted
 * flags        bitmask of format flags; only F_ALT is looked at
 * prec         minimum number of digits; 0-fill on left if needed
 * type         a character in [duoxX]; u acts the same as d
 *
 * CAUTION:  o, x and X conversions on regular ints can never
 * produce a '-' sign, but can for Python's unbounded ints.
 */
PyObject*
_PyString_FormatLong(PyObject *val, int flags, int prec, int type,
                     char **pbuf, int *plen)
{
        PyObject *result = NULL;
        char *buf;
        Py_ssize_t i;
        int sign;       /* 1 if '-', else 0 */
        int len;        /* number of characters */
        int numdigits;  /* len == numnondigits + numdigits */
        int numnondigits = 0;

        switch (type) {
        case 'd':
        case 'u':
                result = val->ob_type->tp_str(val);
                break;
        case 'o':
                result = val->ob_type->tp_as_number->nb_oct(val);
                break;
        case 'x':
        case 'X':
                numnondigits = 2;
                result = val->ob_type->tp_as_number->nb_hex(val);
                break;
        default:
                assert(!"'type' not in [duoxX]");
        }
        if (!result)
                return NULL;

        /* To modify the string in-place, there can only be one reference. */
        if (result->ob_refcnt != 1) {
                PyErr_BadInternalCall();
                return NULL;
        }
        buf = PyString_AsString(result);
        len = PyString_Size(result);
        if (buf[len-1] == 'L') {
                --len;
                buf[len] = '\0';
        }
        sign = buf[0] == '-';
        numnondigits += sign;
        numdigits = len - numnondigits;
        assert(numdigits > 0);

        /* Get rid of base marker unless F_ALT */
        if ((flags & F_ALT) == 0) {
                /* Need to skip 0x, 0X or 0. */
                int skipped = 0;
                switch (type) {
                case 'o':
                        assert(buf[sign] == '0');
                        /* If 0 is only digit, leave it alone. */
                        if (numdigits > 1) {
                                skipped = 1;
                                --numdigits;
                        }
                        break;
                case 'x':
                case 'X':
                        assert(buf[sign] == '0');
                        assert(buf[sign + 1] == 'x');
                        skipped = 2;
                        numnondigits -= 2;
                        break;
                }
                if (skipped) {
                        buf += skipped;
                        len -= skipped;
                        if (sign)
                                buf[0] = '-';
                }
                assert(len == numnondigits + numdigits);
                assert(numdigits > 0);
        }

        /* Fill with leading zeroes to meet minimum width. */
        if (prec > numdigits) {
                PyObject *r1 = PyString_FromStringAndSize(NULL,
                                        numnondigits + prec);
                char *b1;
                if (!r1) {
                        Py_DECREF(result);
                        return NULL;
                }
                b1 = PyString_AS_STRING(r1);
                for (i = 0; i < numnondigits; ++i)
                        *b1++ = *buf++;
                for (i = 0; i < prec - numdigits; i++)
                        *b1++ = '0';
                for (i = 0; i < numdigits; i++)
                        *b1++ = *buf++;
                *b1 = '\0';
                Py_DECREF(result);
                result = r1;
                buf = PyString_AS_STRING(result);
                len = numnondigits + prec;
        }

        /* Fix up case for hex conversions. */
        if (type == 'X') {
                /* Need to convert all lower case letters to upper case.
                   and need to convert 0x to 0X (and -0x to -0X). */
                for (i = 0; i < len; i++)
                        if (buf[i] >= 'a' && buf[i] <= 'x')
                                buf[i] -= 'a'-'A';
        }
        *pbuf = buf;
        *plen = len;
        return result;
}

static int
formatint(char *buf, size_t buflen, int flags,
          int prec, int type, PyObject *v)
{
        /* fmt = '%#.' + `prec` + 'l' + `type`
           worst case length = 3 + 19 (worst len of INT_MAX on 64-bit machine)
           + 1 + 1 = 24 */
        char fmt[64];   /* plenty big enough! */
        char *sign;
        long x;

        x = PyInt_AsLong(v);
        if (x == -1 && PyErr_Occurred()) {
                PyErr_SetString(PyExc_TypeError, "int argument required");
                return -1;
        }
        if (x < 0 && type == 'u') {
                type = 'd';
        }
        if (x < 0 && (type == 'x' || type == 'X' || type == 'o'))
                sign = "-";
        else
                sign = "";
        if (prec < 0)
                prec = 1;

        if ((flags & F_ALT) &&
            (type == 'x' || type == 'X')) {
                /* When converting under %#x or %#X, there are a number
                 * of issues that cause pain:
                 * - when 0 is being converted, the C standard leaves off
                 *   the '0x' or '0X', which is inconsistent with other
                 *   %#x/%#X conversions and inconsistent with Python's
                 *   hex() function
                 * - there are platforms that violate the standard and
                 *   convert 0 with the '0x' or '0X'
                 *   (Metrowerks, Compaq Tru64)
                 * - there are platforms that give '0x' when converting
                 *   under %#X, but convert 0 in accordance with the
                 *   standard (OS/2 EMX)
                 *
                 * We can achieve the desired consistency by inserting our
                 * own '0x' or '0X' prefix, and substituting %x/%X in place
                 * of %#x/%#X.
                 *
                 * Note that this is the same approach as used in
                 * formatint() in unicodeobject.c
                 */
                PyOS_snprintf(fmt, sizeof(fmt), "%s0%c%%.%dl%c",
                              sign, type, prec, type);
        }
        else {
                PyOS_snprintf(fmt, sizeof(fmt), "%s%%%s.%dl%c",
                              sign, (flags&F_ALT) ? "#" : "",
                              prec, type);
        }

        /* buf = '+'/'-'/'' + '0'/'0x'/'' + '[0-9]'*max(prec, len(x in octal))
         * worst case buf = '-0x' + [0-9]*prec, where prec >= 11
         */
        if (buflen <= 14 || buflen <= (size_t)3 + (size_t)prec) {
                PyErr_SetString(PyExc_OverflowError,
                    "formatted integer is too long (precision too large?)");
                return -1;
        }
        if (sign[0])
                PyOS_snprintf(buf, buflen, fmt, -x);
        else
                PyOS_snprintf(buf, buflen, fmt, x);
        return (int)strlen(buf);
}

static int
formatchar(char *buf, size_t buflen, PyObject *v)
{
        /* presume that the buffer is at least 2 characters long */
        if (PyString_Check(v)) {
                if (!PyArg_Parse(v, "c;%c requires int or char", &buf[0]))
                        return -1;
        }
        else {
                if (!PyArg_Parse(v, "b;%c requires int or char", &buf[0]))
                        return -1;
        }
        buf[1] = '\0';
        return 1;
}

/* fmt%(v1,v2,...) is roughly equivalent to sprintf(fmt, v1, v2, ...)

   FORMATBUFLEN is the length of the buffer in which the floats, ints, &
   chars are formatted. XXX This is a magic number. Each formatting
   routine does bounds checking to ensure no overflow, but a better
   solution may be to malloc a buffer of appropriate size for each
   format. For now, the current solution is sufficient.
*/
#define FORMATBUFLEN (size_t)120

PyObject *
PyString_Format(PyObject *format, PyObject *args)
{
        char *fmt, *res;
        Py_ssize_t arglen, argidx;
        Py_ssize_t reslen, rescnt, fmtcnt;
        int args_owned = 0;
        PyObject *result, *orig_args;
#ifdef Py_USING_UNICODE
        PyObject *v, *w;
#endif
        PyObject *dict = NULL;
        if (format == NULL || !PyString_Check(format) || args == NULL) {
                PyErr_BadInternalCall();
                return NULL;
        }
        orig_args = args;
        fmt = PyString_AS_STRING(format);
        fmtcnt = PyString_GET_SIZE(format);
        reslen = rescnt = fmtcnt + 100;
        result = PyString_FromStringAndSize((char *)NULL, reslen);
        if (result == NULL)
                return NULL;
        res = PyString_AsString(result);
        if (PyTuple_Check(args)) {
                arglen = PyTuple_GET_SIZE(args);
                argidx = 0;
        }
        else {
                arglen = -1;
                argidx = -2;
        }
        if (args->ob_type->tp_as_mapping && !PyTuple_Check(args) &&
            !PyObject_TypeCheck(args, &PyBaseString_Type))
                dict = args;
        while (--fmtcnt >= 0) {
                if (*fmt != '%') {
                        if (--rescnt < 0) {
                                rescnt = fmtcnt + 100;
                                reslen += rescnt;
                                if (_PyString_Resize(&result, reslen) < 0)
                                        return NULL;
                                res = PyString_AS_STRING(result)
                                        + reslen - rescnt;
                                --rescnt;
                        }
                        *res++ = *fmt++;
                }
                else {
                        /* Got a format specifier */
                        int flags = 0;
                        Py_ssize_t width = -1;
                        int prec = -1;
                        int c = '\0';
                        int fill;
                        PyObject *v = NULL;
                        PyObject *temp = NULL;
                        char *pbuf;
                        int sign;
                        int len;
                        char formatbuf[FORMATBUFLEN];
                             /* For format{float,int,char}() */
#ifdef Py_USING_UNICODE
                        char *fmt_start = fmt;
                        int argidx_start = argidx;
#endif

                        fmt++;
                        if (*fmt == '(') {
                                char *keystart;
                                Py_ssize_t keylen;
                                PyObject *key;
                                int pcount = 1;

                                if (dict == NULL) {
                                        PyErr_SetString(PyExc_TypeError,
                                                 "format requires a mapping");
                                        goto error;
                                }
                                ++fmt;
                                --fmtcnt;
                                keystart = fmt;
                                /* Skip over balanced parentheses */
                                while (pcount > 0 && --fmtcnt >= 0) {
                                        if (*fmt == ')')
                                                --pcount;
                                        else if (*fmt == '(')
                                                ++pcount;
                                        fmt++;
                                }
                                keylen = fmt - keystart - 1;
                                if (fmtcnt < 0 || pcount > 0) {
                                        PyErr_SetString(PyExc_ValueError,
                                                   "incomplete format key");
                                        goto error;
                                }
                                key = PyString_FromStringAndSize(keystart,
                                                                 keylen);
                                if (key == NULL)
                                        goto error;
                                if (args_owned) {
                                        Py_DECREF(args);
                                        args_owned = 0;
                                }
                                args = PyObject_GetItem(dict, key);
                                Py_DECREF(key);
                                if (args == NULL) {
                                        goto error;
                                }
                                args_owned = 1;
                                arglen = -1;
                                argidx = -2;
                        }
                        while (--fmtcnt >= 0) {
                                switch (c = *fmt++) {
                                case '-': flags |= F_LJUST; continue;
                                case '+': flags |= F_SIGN; continue;
                                case ' ': flags |= F_BLANK; continue;
                                case '#': flags |= F_ALT; continue;
                                case '0': flags |= F_ZERO; continue;
                                }
                                break;
                        }
                        if (c == '*') {
                                v = getnextarg(args, arglen, &argidx);
                                if (v == NULL)
                                        goto error;
                                if (!PyInt_Check(v)) {
                                        PyErr_SetString(PyExc_TypeError,
                                                        "* wants int");
                                        goto error;
                                }
                                width = PyInt_AsLong(v);
                                if (width < 0) {
                                        flags |= F_LJUST;
                                        width = -width;
                                }
                                if (--fmtcnt >= 0)
                                        c = *fmt++;
                        }
                        else if (c >= 0 && isdigit(c)) {
                                width = c - '0';
                                while (--fmtcnt >= 0) {
                                        c = Py_CHARMASK(*fmt++);
                                        if (!isdigit(c))
                                                break;
                                        if ((width*10) / 10 != width) {
                                                PyErr_SetString(
                                                        PyExc_ValueError,
                                                        "width too big");
                                                goto error;
                                        }
                                        width = width*10 + (c - '0');
                                }
                        }
                        if (c == '.') {
                                prec = 0;
                                if (--fmtcnt >= 0)
                                        c = *fmt++;
                                if (c == '*') {
                                        v = getnextarg(args, arglen, &argidx);
                                        if (v == NULL)
                                                goto error;
                                        if (!PyInt_Check(v)) {
                                                PyErr_SetString(
                                                        PyExc_TypeError,
                                                        "* wants int");
                                                goto error;
                                        }
                                        prec = PyInt_AsLong(v);
                                        if (prec < 0)
                                                prec = 0;
                                        if (--fmtcnt >= 0)
                                                c = *fmt++;
                                }
                                else if (c >= 0 && isdigit(c)) {
                                        prec = c - '0';
                                        while (--fmtcnt >= 0) {
                                                c = Py_CHARMASK(*fmt++);
                                                if (!isdigit(c))
                                                        break;
                                                if ((prec*10) / 10 != prec) {
                                                        PyErr_SetString(
                                                            PyExc_ValueError,
                                                            "prec too big");
                                                        goto error;
                                                }
                                                prec = prec*10 + (c - '0');
                                        }
                                }
                        } /* prec */
                        if (fmtcnt >= 0) {
                                if (c == 'h' || c == 'l' || c == 'L') {
                                        if (--fmtcnt >= 0)
                                                c = *fmt++;
                                }
                        }
                        if (fmtcnt < 0) {
                                PyErr_SetString(PyExc_ValueError,
                                                "incomplete format");
                                goto error;
                        }
                        if (c != '%') {
                                v = getnextarg(args, arglen, &argidx);
                                if (v == NULL)
                                        goto error;
                        }
                        sign = 0;
                        fill = ' ';
                        switch (c) {
                        case '%':
                                pbuf = "%";
                                len = 1;
                                break;
                        case 's':
#ifdef Py_USING_UNICODE
                                if (PyUnicode_Check(v)) {
                                        fmt = fmt_start;
                                        argidx = argidx_start;
                                        goto unicode;
                                }
#endif
                                temp = _PyObject_Str(v);
#ifdef Py_USING_UNICODE
                                if (temp != NULL && PyUnicode_Check(temp)) {
                                        Py_DECREF(temp);
                                        fmt = fmt_start;
                                        argidx = argidx_start;
                                        goto unicode;
                                }
#endif
                                /* Fall through */
                        case 'r':
                                if (c == 'r')
                                        temp = PyObject_Repr(v);
                                if (temp == NULL)
                                        goto error;
                                if (!PyString_Check(temp)) {
                                        PyErr_SetString(PyExc_TypeError,
                                          "%s argument has non-string str()");
                                        Py_DECREF(temp);
                                        goto error;
                                }
                                pbuf = PyString_AS_STRING(temp);
                                len = PyString_GET_SIZE(temp);
                                if (prec >= 0 && len > prec)
                                        len = prec;
                                break;
                        case 'i':
                        case 'd':
                        case 'u':
                        case 'o':
                        case 'x':
                        case 'X':
                                if (c == 'i')
                                        c = 'd';
                                if (PyLong_Check(v)) {
                                        temp = _PyString_FormatLong(v, flags,
                                                prec, c, &pbuf, &len);
                                        if (!temp)
                                                goto error;
                                        sign = 1;
                                }
                                else {
                                        pbuf = formatbuf;
                                        len = formatint(pbuf,
                                                        sizeof(formatbuf),
                                                        flags, prec, c, v);
                                        if (len < 0)
                                                goto error;
                                        sign = 1;
                                }
                                if (flags & F_ZERO)
                                        fill = '0';
                                break;
                        case 'e':
                        case 'E':
                        case 'f':
                        case 'F':
                        case 'g':
                        case 'G':
                                if (c == 'F')
                                        c = 'f';
                                pbuf = formatbuf;
                                len = formatfloat(pbuf, sizeof(formatbuf),
                                                  flags, prec, c, v);
                                if (len < 0)
                                        goto error;
                                sign = 1;
                                if (flags & F_ZERO)
                                        fill = '0';
                                break;
                        case 'c':
#ifdef Py_USING_UNICODE
                                if (PyUnicode_Check(v)) {
                                        fmt = fmt_start;
                                        argidx = argidx_start;
                                        goto unicode;
                                }
#endif
                                pbuf = formatbuf;
                                len = formatchar(pbuf, sizeof(formatbuf), v);
                                if (len < 0)
                                        goto error;
                                break;
                        default:
                                PyErr_Format(PyExc_ValueError,
                                  "unsupported format character '%c' (0x%x) "
                                  "at index %i",
                                  c, c,
                                  (int)(fmt - 1 - PyString_AsString(format)));
                                goto error;
                        }
                        if (sign) {
                                if (*pbuf == '-' || *pbuf == '+') {
                                        sign = *pbuf++;
                                        len--;
                                }
                                else if (flags & F_SIGN)
                                        sign = '+';
                                else if (flags & F_BLANK)
                                        sign = ' ';
                                else
                                        sign = 0;
                        }
                        if (width < len)
                                width = len;
                        if (rescnt - (sign != 0) < width) {
                                reslen -= rescnt;
                                rescnt = width + fmtcnt + 100;
                                reslen += rescnt;
                                if (reslen < 0) {
                                        Py_DECREF(result);
                                        return PyErr_NoMemory();
                                }
                                if (_PyString_Resize(&result, reslen) < 0)
                                        return NULL;
                                res = PyString_AS_STRING(result)
                                        + reslen - rescnt;
                        }
                        if (sign) {
                                if (fill != ' ')
                                        *res++ = sign;
                                rescnt--;
                                if (width > len)
                                        width--;
                        }
                        if ((flags & F_ALT) && (c == 'x' || c == 'X')) {
                                assert(pbuf[0] == '0');
                                assert(pbuf[1] == c);
                                if (fill != ' ') {
                                        *res++ = *pbuf++;
                                        *res++ = *pbuf++;
                                }
                                rescnt -= 2;
                                width -= 2;
                                if (width < 0)
                                        width = 0;
                                len -= 2;
                        }
                        if (width > len && !(flags & F_LJUST)) {
                                do {
                                        --rescnt;
                                        *res++ = fill;
                                } while (--width > len);
                        }
                        if (fill == ' ') {
                                if (sign)
                                        *res++ = sign;
                                if ((flags & F_ALT) &&
                                    (c == 'x' || c == 'X')) {
                                        assert(pbuf[0] == '0');
                                        assert(pbuf[1] == c);
                                        *res++ = *pbuf++;
                                        *res++ = *pbuf++;
                                }
                        }
                        memcpy(res, pbuf, len);
                        res += len;
                        rescnt -= len;
                        while (--width >= len) {
                                --rescnt;
                                *res++ = ' ';
                        }
                        if (dict && (argidx < arglen) && c != '%') {
                                PyErr_SetString(PyExc_TypeError,
                                           "not all arguments converted during string formatting");
                                goto error;
                        }
                        Py_XDECREF(temp);
                } /* '%' */
        } /* until end */
        if (argidx < arglen && !dict) {
                PyErr_SetString(PyExc_TypeError,
                                "not all arguments converted during string formatting");
                goto error;
        }
        if (args_owned) {
                Py_DECREF(args);
        }
        _PyString_Resize(&result, reslen - rescnt);
        return result;

#ifdef Py_USING_UNICODE
 unicode:
        if (args_owned) {
                Py_DECREF(args);
                args_owned = 0;
        }
        /* Fiddle args right (remove the first argidx arguments) */
        if (PyTuple_Check(orig_args) && argidx > 0) {
                PyObject *v;
                Py_ssize_t n = PyTuple_GET_SIZE(orig_args) - argidx;
                v = PyTuple_New(n);
                if (v == NULL)
                        goto error;
                while (--n >= 0) {
                        PyObject *w = PyTuple_GET_ITEM(orig_args, n + argidx);
                        Py_INCREF(w);
                        PyTuple_SET_ITEM(v, n, w);
                }
                args = v;
        } else {
                Py_INCREF(orig_args);
                args = orig_args;
        }
        args_owned = 1;
        /* Take what we have of the result and let the Unicode formatting
           function format the rest of the input. */
        rescnt = res - PyString_AS_STRING(result);
        if (_PyString_Resize(&result, rescnt))
                goto error;
        fmtcnt = PyString_GET_SIZE(format) - \
                 (fmt - PyString_AS_STRING(format));
        format = PyUnicode_Decode(fmt, fmtcnt, NULL, NULL);
        if (format == NULL)
                goto error;
        v = PyUnicode_Format(format, args);
        Py_DECREF(format);
        if (v == NULL)
                goto error;
        /* Paste what we have (result) to what the Unicode formatting
           function returned (v) and return the result (or error) */
        w = PyUnicode_Concat(result, v);
        Py_DECREF(result);
        Py_DECREF(v);
        Py_DECREF(args);
        return w;
#endif /* Py_USING_UNICODE */

 error:
        Py_DECREF(result);
        if (args_owned) {
                Py_DECREF(args);
        }
        return NULL;
}

void
PyString_InternInPlace(PyObject **p)
{
        register PyStringObject *s = (PyStringObject *)(*p);
        PyObject *t;
        if (s == NULL || !PyString_Check(s))
                Py_FatalError("PyString_InternInPlace: strings only please!");
        /* If it's a string subclass, we don't really know what putting
           it in the interned dict might do. */
        if (!PyString_CheckExact(s))
                return;
        if (PyString_CHECK_INTERNED(s))
                return;
        if (interned == NULL) {
                interned = PyDict_New();
                if (interned == NULL) {
                        PyErr_Clear(); /* Don't leave an exception */
                        return;
                }
        }
        t = PyDict_GetItem(interned, (PyObject *)s);
        if (t) {
                Py_INCREF(t);
                Py_DECREF(*p);
                *p = t;
                return;
        }

        if (PyDict_SetItem(interned, (PyObject *)s, (PyObject *)s) < 0) {
                PyErr_Clear();
                return;
        }
        /* The two references in interned are not counted by refcnt.
           The string deallocator will take care of this */
        s->ob_refcnt -= 2;
        PyString_CHECK_INTERNED(s) = SSTATE_INTERNED_MORTAL;
}

void
PyString_InternImmortal(PyObject **p)
{
        PyString_InternInPlace(p);
        if (PyString_CHECK_INTERNED(*p) != SSTATE_INTERNED_IMMORTAL) {
                PyString_CHECK_INTERNED(*p) = SSTATE_INTERNED_IMMORTAL;
                Py_INCREF(*p);
        }
}


PyObject *
PyString_InternFromString(const char *cp)
{
        PyObject *s = PyString_FromString(cp);
        if (s == NULL)
                return NULL;
        PyString_InternInPlace(&s);
        return s;
}

void
PyString_Fini(void)
{
        int i;
        for (i = 0; i < UCHAR_MAX + 1; i++) {
                Py_XDECREF(characters[i]);
                characters[i] = NULL;
        }
        Py_XDECREF(nullstring);
        nullstring = NULL;
}

void _Py_ReleaseInternedStrings(void)
{
        PyObject *keys;
        PyStringObject *s;
        Py_ssize_t i, n;

        if (interned == NULL || !PyDict_Check(interned))
                return;
        keys = PyDict_Keys(interned);
        if (keys == NULL || !PyList_Check(keys)) {
                PyErr_Clear();
                return;
        }

        /* Since _Py_ReleaseInternedStrings() is intended to help a leak
           detector, interned strings are not forcibly deallocated; rather, we
           give them their stolen references back, and then clear and DECREF
           the interned dict. */
           
        fprintf(stderr, "releasing interned strings\n");
        n = PyList_GET_SIZE(keys);
        for (i = 0; i < n; i++) {
                s = (PyStringObject *) PyList_GET_ITEM(keys, i);
                switch (s->ob_sstate) {
                case SSTATE_NOT_INTERNED:
                        /* XXX Shouldn't happen */
                        break;
                case SSTATE_INTERNED_IMMORTAL:
                        s->ob_refcnt += 1;
                        break;
                case SSTATE_INTERNED_MORTAL:
                        s->ob_refcnt += 2;
                        break;
                default:
                        Py_FatalError("Inconsistent interned string state.");
                }
                s->ob_sstate = SSTATE_NOT_INTERNED;
        }
        Py_DECREF(keys);
        PyDict_Clear(interned);
        Py_DECREF(interned);
        interned = NULL;
}

---