mirror of https://github.com/python/cpython
702 lines
18 KiB
C
702 lines
18 KiB
C
#if STRINGLIB_IS_UNICODE
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# error "transmogrify.h only compatible with byte-wise strings"
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#endif
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/* the more complicated methods. parts of these should be pulled out into the
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shared code in bytes_methods.c to cut down on duplicate code bloat. */
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static inline PyObject *
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return_self(PyObject *self)
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{
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#if !STRINGLIB_MUTABLE
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if (STRINGLIB_CHECK_EXACT(self)) {
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Py_INCREF(self);
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return self;
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}
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#endif
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return STRINGLIB_NEW(STRINGLIB_STR(self), STRINGLIB_LEN(self));
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}
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static PyObject*
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stringlib_expandtabs(PyObject *self, PyObject *args, PyObject *kwds)
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{
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const char *e, *p;
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char *q;
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Py_ssize_t i, j;
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PyObject *u;
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static char *kwlist[] = {"tabsize", 0};
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int tabsize = 8;
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if (!PyArg_ParseTupleAndKeywords(args, kwds, "|i:expandtabs",
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kwlist, &tabsize))
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return NULL;
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/* First pass: determine size of output string */
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i = j = 0;
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e = STRINGLIB_STR(self) + STRINGLIB_LEN(self);
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for (p = STRINGLIB_STR(self); p < e; p++) {
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if (*p == '\t') {
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if (tabsize > 0) {
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Py_ssize_t incr = tabsize - (j % tabsize);
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if (j > PY_SSIZE_T_MAX - incr)
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goto overflow;
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j += incr;
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}
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}
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else {
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if (j > PY_SSIZE_T_MAX - 1)
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goto overflow;
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j++;
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if (*p == '\n' || *p == '\r') {
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if (i > PY_SSIZE_T_MAX - j)
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goto overflow;
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i += j;
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j = 0;
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}
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}
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}
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if (i > PY_SSIZE_T_MAX - j)
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goto overflow;
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/* Second pass: create output string and fill it */
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u = STRINGLIB_NEW(NULL, i + j);
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if (!u)
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return NULL;
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j = 0;
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q = STRINGLIB_STR(u);
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for (p = STRINGLIB_STR(self); p < e; p++) {
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if (*p == '\t') {
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if (tabsize > 0) {
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i = tabsize - (j % tabsize);
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j += i;
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while (i--)
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*q++ = ' ';
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}
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}
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else {
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j++;
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*q++ = *p;
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if (*p == '\n' || *p == '\r')
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j = 0;
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}
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}
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return u;
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overflow:
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PyErr_SetString(PyExc_OverflowError, "result too long");
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return NULL;
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}
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static inline PyObject *
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pad(PyObject *self, Py_ssize_t left, Py_ssize_t right, char fill)
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{
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PyObject *u;
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if (left < 0)
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left = 0;
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if (right < 0)
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right = 0;
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if (left == 0 && right == 0) {
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return return_self(self);
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}
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u = STRINGLIB_NEW(NULL, left + STRINGLIB_LEN(self) + right);
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if (u) {
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if (left)
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memset(STRINGLIB_STR(u), fill, left);
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memcpy(STRINGLIB_STR(u) + left,
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STRINGLIB_STR(self),
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STRINGLIB_LEN(self));
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if (right)
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memset(STRINGLIB_STR(u) + left + STRINGLIB_LEN(self),
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fill, right);
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}
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return u;
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}
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static PyObject *
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stringlib_ljust(PyObject *self, PyObject *args)
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{
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Py_ssize_t width;
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char fillchar = ' ';
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if (!PyArg_ParseTuple(args, "n|c:ljust", &width, &fillchar))
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return NULL;
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if (STRINGLIB_LEN(self) >= width) {
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return return_self(self);
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}
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return pad(self, 0, width - STRINGLIB_LEN(self), fillchar);
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}
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static PyObject *
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stringlib_rjust(PyObject *self, PyObject *args)
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{
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Py_ssize_t width;
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char fillchar = ' ';
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if (!PyArg_ParseTuple(args, "n|c:rjust", &width, &fillchar))
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return NULL;
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if (STRINGLIB_LEN(self) >= width) {
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return return_self(self);
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}
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return pad(self, width - STRINGLIB_LEN(self), 0, fillchar);
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}
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static PyObject *
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stringlib_center(PyObject *self, PyObject *args)
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{
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Py_ssize_t marg, left;
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Py_ssize_t width;
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char fillchar = ' ';
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if (!PyArg_ParseTuple(args, "n|c:center", &width, &fillchar))
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return NULL;
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if (STRINGLIB_LEN(self) >= width) {
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return return_self(self);
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}
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marg = width - STRINGLIB_LEN(self);
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left = marg / 2 + (marg & width & 1);
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return pad(self, left, marg - left, fillchar);
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}
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static PyObject *
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stringlib_zfill(PyObject *self, PyObject *args)
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{
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Py_ssize_t fill;
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PyObject *s;
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char *p;
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Py_ssize_t width;
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if (!PyArg_ParseTuple(args, "n:zfill", &width))
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return NULL;
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if (STRINGLIB_LEN(self) >= width) {
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return return_self(self);
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}
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fill = width - STRINGLIB_LEN(self);
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s = pad(self, fill, 0, '0');
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if (s == NULL)
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return NULL;
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p = STRINGLIB_STR(s);
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if (p[fill] == '+' || p[fill] == '-') {
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/* move sign to beginning of string */
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p[0] = p[fill];
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p[fill] = '0';
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}
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return s;
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}
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/* find and count characters and substrings */
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#define findchar(target, target_len, c) \
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((char *)memchr((const void *)(target), c, target_len))
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static Py_ssize_t
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countchar(const char *target, Py_ssize_t target_len, char c,
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Py_ssize_t maxcount)
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{
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Py_ssize_t count = 0;
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const char *start = target;
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const char *end = target + target_len;
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while ((start = findchar(start, end - start, c)) != NULL) {
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count++;
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if (count >= maxcount)
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break;
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start += 1;
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}
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return count;
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}
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/* Algorithms for different cases of string replacement */
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/* len(self)>=1, from="", len(to)>=1, maxcount>=1 */
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static PyObject *
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stringlib_replace_interleave(PyObject *self,
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const char *to_s, Py_ssize_t to_len,
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Py_ssize_t maxcount)
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{
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const char *self_s;
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char *result_s;
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Py_ssize_t self_len, result_len;
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Py_ssize_t count, i;
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PyObject *result;
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self_len = STRINGLIB_LEN(self);
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/* 1 at the end plus 1 after every character;
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count = min(maxcount, self_len + 1) */
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if (maxcount <= self_len) {
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count = maxcount;
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}
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else {
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/* Can't overflow: self_len + 1 <= maxcount <= PY_SSIZE_T_MAX. */
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count = self_len + 1;
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}
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/* Check for overflow */
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/* result_len = count * to_len + self_len; */
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assert(count > 0);
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if (to_len > (PY_SSIZE_T_MAX - self_len) / count) {
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PyErr_SetString(PyExc_OverflowError,
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"replace bytes are too long");
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return NULL;
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}
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result_len = count * to_len + self_len;
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result = STRINGLIB_NEW(NULL, result_len);
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if (result == NULL) {
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return NULL;
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}
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self_s = STRINGLIB_STR(self);
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result_s = STRINGLIB_STR(result);
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if (to_len > 1) {
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/* Lay the first one down (guaranteed this will occur) */
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memcpy(result_s, to_s, to_len);
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result_s += to_len;
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count -= 1;
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for (i = 0; i < count; i++) {
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*result_s++ = *self_s++;
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memcpy(result_s, to_s, to_len);
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result_s += to_len;
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}
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}
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else {
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result_s[0] = to_s[0];
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result_s += to_len;
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count -= 1;
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for (i = 0; i < count; i++) {
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*result_s++ = *self_s++;
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result_s[0] = to_s[0];
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result_s += to_len;
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}
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}
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/* Copy the rest of the original string */
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memcpy(result_s, self_s, self_len - i);
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return result;
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}
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/* Special case for deleting a single character */
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/* len(self)>=1, len(from)==1, to="", maxcount>=1 */
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static PyObject *
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stringlib_replace_delete_single_character(PyObject *self,
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char from_c, Py_ssize_t maxcount)
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{
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const char *self_s, *start, *next, *end;
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char *result_s;
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Py_ssize_t self_len, result_len;
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Py_ssize_t count;
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PyObject *result;
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self_len = STRINGLIB_LEN(self);
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self_s = STRINGLIB_STR(self);
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count = countchar(self_s, self_len, from_c, maxcount);
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if (count == 0) {
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return return_self(self);
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}
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result_len = self_len - count; /* from_len == 1 */
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assert(result_len>=0);
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result = STRINGLIB_NEW(NULL, result_len);
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if (result == NULL) {
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return NULL;
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}
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result_s = STRINGLIB_STR(result);
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start = self_s;
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end = self_s + self_len;
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while (count-- > 0) {
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next = findchar(start, end - start, from_c);
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if (next == NULL)
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break;
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memcpy(result_s, start, next - start);
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result_s += (next - start);
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start = next + 1;
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}
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memcpy(result_s, start, end - start);
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return result;
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}
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/* len(self)>=1, len(from)>=2, to="", maxcount>=1 */
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static PyObject *
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stringlib_replace_delete_substring(PyObject *self,
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const char *from_s, Py_ssize_t from_len,
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Py_ssize_t maxcount)
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{
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const char *self_s, *start, *next, *end;
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char *result_s;
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Py_ssize_t self_len, result_len;
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Py_ssize_t count, offset;
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PyObject *result;
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self_len = STRINGLIB_LEN(self);
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self_s = STRINGLIB_STR(self);
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count = stringlib_count(self_s, self_len,
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from_s, from_len,
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maxcount);
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if (count == 0) {
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/* no matches */
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return return_self(self);
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}
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result_len = self_len - (count * from_len);
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assert (result_len>=0);
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result = STRINGLIB_NEW(NULL, result_len);
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if (result == NULL) {
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return NULL;
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}
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result_s = STRINGLIB_STR(result);
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start = self_s;
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end = self_s + self_len;
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while (count-- > 0) {
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offset = stringlib_find(start, end - start,
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from_s, from_len,
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0);
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if (offset == -1)
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break;
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next = start + offset;
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memcpy(result_s, start, next - start);
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result_s += (next - start);
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start = next + from_len;
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}
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memcpy(result_s, start, end - start);
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return result;
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}
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/* len(self)>=1, len(from)==len(to)==1, maxcount>=1 */
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static PyObject *
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stringlib_replace_single_character_in_place(PyObject *self,
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char from_c, char to_c,
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Py_ssize_t maxcount)
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{
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const char *self_s, *end;
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char *result_s, *start, *next;
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Py_ssize_t self_len;
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PyObject *result;
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/* The result string will be the same size */
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self_s = STRINGLIB_STR(self);
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self_len = STRINGLIB_LEN(self);
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next = findchar(self_s, self_len, from_c);
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if (next == NULL) {
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/* No matches; return the original bytes */
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return return_self(self);
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}
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/* Need to make a new bytes */
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result = STRINGLIB_NEW(NULL, self_len);
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if (result == NULL) {
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return NULL;
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}
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result_s = STRINGLIB_STR(result);
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memcpy(result_s, self_s, self_len);
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/* change everything in-place, starting with this one */
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start = result_s + (next - self_s);
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*start = to_c;
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start++;
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end = result_s + self_len;
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while (--maxcount > 0) {
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next = findchar(start, end - start, from_c);
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if (next == NULL)
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break;
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*next = to_c;
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start = next + 1;
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}
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return result;
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}
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/* len(self)>=1, len(from)==len(to)>=2, maxcount>=1 */
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static PyObject *
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stringlib_replace_substring_in_place(PyObject *self,
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const char *from_s, Py_ssize_t from_len,
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const char *to_s, Py_ssize_t to_len,
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Py_ssize_t maxcount)
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{
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const char *self_s, *end;
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char *result_s, *start;
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Py_ssize_t self_len, offset;
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PyObject *result;
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/* The result bytes will be the same size */
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self_s = STRINGLIB_STR(self);
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self_len = STRINGLIB_LEN(self);
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offset = stringlib_find(self_s, self_len,
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from_s, from_len,
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0);
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if (offset == -1) {
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/* No matches; return the original bytes */
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return return_self(self);
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}
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/* Need to make a new bytes */
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result = STRINGLIB_NEW(NULL, self_len);
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if (result == NULL) {
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return NULL;
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}
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result_s = STRINGLIB_STR(result);
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memcpy(result_s, self_s, self_len);
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/* change everything in-place, starting with this one */
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start = result_s + offset;
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memcpy(start, to_s, from_len);
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start += from_len;
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end = result_s + self_len;
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while ( --maxcount > 0) {
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offset = stringlib_find(start, end - start,
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from_s, from_len,
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0);
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if (offset == -1)
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break;
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memcpy(start + offset, to_s, from_len);
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start += offset + from_len;
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}
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return result;
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}
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/* len(self)>=1, len(from)==1, len(to)>=2, maxcount>=1 */
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static PyObject *
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stringlib_replace_single_character(PyObject *self,
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char from_c,
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const char *to_s, Py_ssize_t to_len,
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Py_ssize_t maxcount)
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{
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const char *self_s, *start, *next, *end;
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char *result_s;
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Py_ssize_t self_len, result_len;
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Py_ssize_t count;
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PyObject *result;
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self_s = STRINGLIB_STR(self);
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self_len = STRINGLIB_LEN(self);
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count = countchar(self_s, self_len, from_c, maxcount);
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if (count == 0) {
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/* no matches, return unchanged */
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return return_self(self);
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}
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/* use the difference between current and new, hence the "-1" */
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/* result_len = self_len + count * (to_len-1) */
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assert(count > 0);
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if (to_len - 1 > (PY_SSIZE_T_MAX - self_len) / count) {
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PyErr_SetString(PyExc_OverflowError, "replace bytes is too long");
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return NULL;
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}
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result_len = self_len + count * (to_len - 1);
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result = STRINGLIB_NEW(NULL, result_len);
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if (result == NULL) {
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return NULL;
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}
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result_s = STRINGLIB_STR(result);
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start = self_s;
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end = self_s + self_len;
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while (count-- > 0) {
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next = findchar(start, end - start, from_c);
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if (next == NULL)
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break;
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if (next == start) {
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/* replace with the 'to' */
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memcpy(result_s, to_s, to_len);
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result_s += to_len;
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start += 1;
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} else {
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/* copy the unchanged old then the 'to' */
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memcpy(result_s, start, next - start);
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result_s += (next - start);
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memcpy(result_s, to_s, to_len);
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result_s += to_len;
|
|
start = next + 1;
|
|
}
|
|
}
|
|
/* Copy the remainder of the remaining bytes */
|
|
memcpy(result_s, start, end - start);
|
|
|
|
return result;
|
|
}
|
|
|
|
/* len(self)>=1, len(from)>=2, len(to)>=2, maxcount>=1 */
|
|
static PyObject *
|
|
stringlib_replace_substring(PyObject *self,
|
|
const char *from_s, Py_ssize_t from_len,
|
|
const char *to_s, Py_ssize_t to_len,
|
|
Py_ssize_t maxcount)
|
|
{
|
|
const char *self_s, *start, *next, *end;
|
|
char *result_s;
|
|
Py_ssize_t self_len, result_len;
|
|
Py_ssize_t count, offset;
|
|
PyObject *result;
|
|
|
|
self_s = STRINGLIB_STR(self);
|
|
self_len = STRINGLIB_LEN(self);
|
|
|
|
count = stringlib_count(self_s, self_len,
|
|
from_s, from_len,
|
|
maxcount);
|
|
|
|
if (count == 0) {
|
|
/* no matches, return unchanged */
|
|
return return_self(self);
|
|
}
|
|
|
|
/* Check for overflow */
|
|
/* result_len = self_len + count * (to_len-from_len) */
|
|
assert(count > 0);
|
|
if (to_len - from_len > (PY_SSIZE_T_MAX - self_len) / count) {
|
|
PyErr_SetString(PyExc_OverflowError, "replace bytes is too long");
|
|
return NULL;
|
|
}
|
|
result_len = self_len + count * (to_len - from_len);
|
|
|
|
result = STRINGLIB_NEW(NULL, result_len);
|
|
if (result == NULL) {
|
|
return NULL;
|
|
}
|
|
result_s = STRINGLIB_STR(result);
|
|
|
|
start = self_s;
|
|
end = self_s + self_len;
|
|
while (count-- > 0) {
|
|
offset = stringlib_find(start, end - start,
|
|
from_s, from_len,
|
|
0);
|
|
if (offset == -1)
|
|
break;
|
|
next = start + offset;
|
|
if (next == start) {
|
|
/* replace with the 'to' */
|
|
memcpy(result_s, to_s, to_len);
|
|
result_s += to_len;
|
|
start += from_len;
|
|
} else {
|
|
/* copy the unchanged old then the 'to' */
|
|
memcpy(result_s, start, next - start);
|
|
result_s += (next - start);
|
|
memcpy(result_s, to_s, to_len);
|
|
result_s += to_len;
|
|
start = next + from_len;
|
|
}
|
|
}
|
|
/* Copy the remainder of the remaining bytes */
|
|
memcpy(result_s, start, end - start);
|
|
|
|
return result;
|
|
}
|
|
|
|
|
|
static PyObject *
|
|
stringlib_replace(PyObject *self,
|
|
const char *from_s, Py_ssize_t from_len,
|
|
const char *to_s, Py_ssize_t to_len,
|
|
Py_ssize_t maxcount)
|
|
{
|
|
if (maxcount < 0) {
|
|
maxcount = PY_SSIZE_T_MAX;
|
|
} else if (maxcount == 0 || STRINGLIB_LEN(self) == 0) {
|
|
/* nothing to do; return the original bytes */
|
|
return return_self(self);
|
|
}
|
|
|
|
/* Handle zero-length special cases */
|
|
if (from_len == 0) {
|
|
if (to_len == 0) {
|
|
/* nothing to do; return the original bytes */
|
|
return return_self(self);
|
|
}
|
|
/* insert the 'to' bytes everywhere. */
|
|
/* >>> b"Python".replace(b"", b".") */
|
|
/* b'.P.y.t.h.o.n.' */
|
|
return stringlib_replace_interleave(self, to_s, to_len, maxcount);
|
|
}
|
|
|
|
/* Except for b"".replace(b"", b"A") == b"A" there is no way beyond this */
|
|
/* point for an empty self bytes to generate a non-empty bytes */
|
|
/* Special case so the remaining code always gets a non-empty bytes */
|
|
if (STRINGLIB_LEN(self) == 0) {
|
|
return return_self(self);
|
|
}
|
|
|
|
if (to_len == 0) {
|
|
/* delete all occurrences of 'from' bytes */
|
|
if (from_len == 1) {
|
|
return stringlib_replace_delete_single_character(
|
|
self, from_s[0], maxcount);
|
|
} else {
|
|
return stringlib_replace_delete_substring(
|
|
self, from_s, from_len, maxcount);
|
|
}
|
|
}
|
|
|
|
/* Handle special case where both bytes have the same length */
|
|
|
|
if (from_len == to_len) {
|
|
if (from_len == 1) {
|
|
return stringlib_replace_single_character_in_place(
|
|
self, from_s[0], to_s[0], maxcount);
|
|
} else {
|
|
return stringlib_replace_substring_in_place(
|
|
self, from_s, from_len, to_s, to_len, maxcount);
|
|
}
|
|
}
|
|
|
|
/* Otherwise use the more generic algorithms */
|
|
if (from_len == 1) {
|
|
return stringlib_replace_single_character(
|
|
self, from_s[0], to_s, to_len, maxcount);
|
|
} else {
|
|
/* len('from')>=2, len('to')>=1 */
|
|
return stringlib_replace_substring(
|
|
self, from_s, from_len, to_s, to_len, maxcount);
|
|
}
|
|
}
|
|
|
|
#undef findchar
|