diff options
Diffstat (limited to 'Objects/stringlib/transmogrify.h')
| -rw-r--r-- | Objects/stringlib/transmogrify.h | 615 |
1 files changed, 525 insertions, 90 deletions
diff --git a/Objects/stringlib/transmogrify.h b/Objects/stringlib/transmogrify.h index b559b53..a314572 100644 --- a/Objects/stringlib/transmogrify.h +++ b/Objects/stringlib/transmogrify.h @@ -1,14 +1,21 @@ -/* NOTE: this API is -ONLY- for use with single byte character strings. */ -/* Do not use it with Unicode. */ +#if STRINGLIB_IS_UNICODE +# error "transmogrify.h only compatible with byte-wise strings" +#endif /* the more complicated methods. parts of these should be pulled out into the shared code in bytes_methods.c to cut down on duplicate code bloat. */ -PyDoc_STRVAR(expandtabs__doc__, -"B.expandtabs(tabsize=8) -> copy of B\n\ -\n\ -Return a copy of B where all tab characters are expanded using spaces.\n\ -If tabsize is not given, a tab size of 8 characters is assumed."); +static inline PyObject * +return_self(PyObject *self) +{ +#if !STRINGLIB_MUTABLE + if (STRINGLIB_CHECK_EXACT(self)) { + Py_INCREF(self); + return self; + } +#endif + return STRINGLIB_NEW(STRINGLIB_STR(self), STRINGLIB_LEN(self)); +} static PyObject* stringlib_expandtabs(PyObject *self, PyObject *args, PyObject *kwds) @@ -83,7 +90,7 @@ stringlib_expandtabs(PyObject *self, PyObject *args, PyObject *kwds) return NULL; } -Py_LOCAL_INLINE(PyObject *) +static inline PyObject * pad(PyObject *self, Py_ssize_t left, Py_ssize_t right, char fill) { PyObject *u; @@ -93,39 +100,25 @@ pad(PyObject *self, Py_ssize_t left, Py_ssize_t right, char fill) if (right < 0) right = 0; - if (left == 0 && right == 0 && STRINGLIB_CHECK_EXACT(self)) { -#if STRINGLIB_MUTABLE - /* We're defined as returning a copy; If the object is mutable - * that means we must make an identical copy. */ - return STRINGLIB_NEW(STRINGLIB_STR(self), STRINGLIB_LEN(self)); -#else - Py_INCREF(self); - return (PyObject *)self; -#endif /* STRINGLIB_MUTABLE */ + if (left == 0 && right == 0) { + return return_self(self); } - u = STRINGLIB_NEW(NULL, - left + STRINGLIB_LEN(self) + right); + u = STRINGLIB_NEW(NULL, left + STRINGLIB_LEN(self) + right); if (u) { if (left) memset(STRINGLIB_STR(u), fill, left); - Py_MEMCPY(STRINGLIB_STR(u) + left, - STRINGLIB_STR(self), - STRINGLIB_LEN(self)); + memcpy(STRINGLIB_STR(u) + left, + STRINGLIB_STR(self), + STRINGLIB_LEN(self)); if (right) memset(STRINGLIB_STR(u) + left + STRINGLIB_LEN(self), - fill, right); + fill, right); } return u; } -PyDoc_STRVAR(ljust__doc__, -"B.ljust(width[, fillchar]) -> copy of B\n" -"\n" -"Return B left justified in a string of length width. Padding is\n" -"done using the specified fill character (default is a space)."); - static PyObject * stringlib_ljust(PyObject *self, PyObject *args) { @@ -135,27 +128,14 @@ stringlib_ljust(PyObject *self, PyObject *args) if (!PyArg_ParseTuple(args, "n|c:ljust", &width, &fillchar)) return NULL; - if (STRINGLIB_LEN(self) >= width && STRINGLIB_CHECK_EXACT(self)) { -#if STRINGLIB_MUTABLE - /* We're defined as returning a copy; If the object is mutable - * that means we must make an identical copy. */ - return STRINGLIB_NEW(STRINGLIB_STR(self), STRINGLIB_LEN(self)); -#else - Py_INCREF(self); - return (PyObject*) self; -#endif + if (STRINGLIB_LEN(self) >= width) { + return return_self(self); } return pad(self, 0, width - STRINGLIB_LEN(self), fillchar); } -PyDoc_STRVAR(rjust__doc__, -"B.rjust(width[, fillchar]) -> copy of B\n" -"\n" -"Return B right justified in a string of length width. Padding is\n" -"done using the specified fill character (default is a space)"); - static PyObject * stringlib_rjust(PyObject *self, PyObject *args) { @@ -165,27 +145,14 @@ stringlib_rjust(PyObject *self, PyObject *args) if (!PyArg_ParseTuple(args, "n|c:rjust", &width, &fillchar)) return NULL; - if (STRINGLIB_LEN(self) >= width && STRINGLIB_CHECK_EXACT(self)) { -#if STRINGLIB_MUTABLE - /* We're defined as returning a copy; If the object is mutable - * that means we must make an identical copy. */ - return STRINGLIB_NEW(STRINGLIB_STR(self), STRINGLIB_LEN(self)); -#else - Py_INCREF(self); - return (PyObject*) self; -#endif + if (STRINGLIB_LEN(self) >= width) { + return return_self(self); } return pad(self, width - STRINGLIB_LEN(self), 0, fillchar); } -PyDoc_STRVAR(center__doc__, -"B.center(width[, fillchar]) -> copy of B\n" -"\n" -"Return B centered in a string of length width. Padding is\n" -"done using the specified fill character (default is a space)."); - static PyObject * stringlib_center(PyObject *self, PyObject *args) { @@ -196,15 +163,8 @@ stringlib_center(PyObject *self, PyObject *args) if (!PyArg_ParseTuple(args, "n|c:center", &width, &fillchar)) return NULL; - if (STRINGLIB_LEN(self) >= width && STRINGLIB_CHECK_EXACT(self)) { -#if STRINGLIB_MUTABLE - /* We're defined as returning a copy; If the object is mutable - * that means we must make an identical copy. */ - return STRINGLIB_NEW(STRINGLIB_STR(self), STRINGLIB_LEN(self)); -#else - Py_INCREF(self); - return (PyObject*) self; -#endif + if (STRINGLIB_LEN(self) >= width) { + return return_self(self); } marg = width - STRINGLIB_LEN(self); @@ -213,12 +173,6 @@ stringlib_center(PyObject *self, PyObject *args) return pad(self, left, marg - left, fillchar); } -PyDoc_STRVAR(zfill__doc__, -"B.zfill(width) -> copy of B\n" -"\n" -"Pad a numeric string B with zeros on the left, to fill a field\n" -"of the specified width. B is never truncated."); - static PyObject * stringlib_zfill(PyObject *self, PyObject *args) { @@ -231,21 +185,7 @@ stringlib_zfill(PyObject *self, PyObject *args) return NULL; if (STRINGLIB_LEN(self) >= width) { - if (STRINGLIB_CHECK_EXACT(self)) { -#if STRINGLIB_MUTABLE - /* We're defined as returning a copy; If the object is mutable - * that means we must make an identical copy. */ - return STRINGLIB_NEW(STRINGLIB_STR(self), STRINGLIB_LEN(self)); -#else - Py_INCREF(self); - return (PyObject*) self; -#endif - } - else - return STRINGLIB_NEW( - STRINGLIB_STR(self), - STRINGLIB_LEN(self) - ); + return return_self(self); } fill = width - STRINGLIB_LEN(self); @@ -262,5 +202,500 @@ stringlib_zfill(PyObject *self, PyObject *args) p[fill] = '0'; } - return (PyObject*) s; + return s; +} + + +/* find and count characters and substrings */ + +#define findchar(target, target_len, c) \ + ((char *)memchr((const void *)(target), c, target_len)) + + +static Py_ssize_t +countchar(const char *target, Py_ssize_t target_len, char c, + Py_ssize_t maxcount) +{ + Py_ssize_t count = 0; + const char *start = target; + const char *end = target + target_len; + + while ((start = findchar(start, end - start, c)) != NULL) { + count++; + if (count >= maxcount) + break; + start += 1; + } + return count; +} + + +/* Algorithms for different cases of string replacement */ + +/* len(self)>=1, from="", len(to)>=1, maxcount>=1 */ +static PyObject * +stringlib_replace_interleave(PyObject *self, + const char *to_s, Py_ssize_t to_len, + Py_ssize_t maxcount) +{ + const char *self_s; + char *result_s; + Py_ssize_t self_len, result_len; + Py_ssize_t count, i; + PyObject *result; + + self_len = STRINGLIB_LEN(self); + + /* 1 at the end plus 1 after every character; + count = min(maxcount, self_len + 1) */ + if (maxcount <= self_len) { + count = maxcount; + } + else { + /* Can't overflow: self_len + 1 <= maxcount <= PY_SSIZE_T_MAX. */ + count = self_len + 1; + } + + /* Check for overflow */ + /* result_len = count * to_len + self_len; */ + assert(count > 0); + if (to_len > (PY_SSIZE_T_MAX - self_len) / count) { + PyErr_SetString(PyExc_OverflowError, + "replace bytes are too long"); + return NULL; + } + result_len = count * to_len + self_len; + result = STRINGLIB_NEW(NULL, result_len); + if (result == NULL) { + return NULL; + } + + self_s = STRINGLIB_STR(self); + result_s = STRINGLIB_STR(result); + + if (to_len > 1) { + /* Lay the first one down (guaranteed this will occur) */ + memcpy(result_s, to_s, to_len); + result_s += to_len; + count -= 1; + + for (i = 0; i < count; i++) { + *result_s++ = *self_s++; + memcpy(result_s, to_s, to_len); + result_s += to_len; + } + } + else { + result_s[0] = to_s[0]; + result_s += to_len; + count -= 1; + for (i = 0; i < count; i++) { + *result_s++ = *self_s++; + result_s[0] = to_s[0]; + result_s += to_len; + } + } + + /* Copy the rest of the original string */ + memcpy(result_s, self_s, self_len - i); + + return result; +} + +/* Special case for deleting a single character */ +/* len(self)>=1, len(from)==1, to="", maxcount>=1 */ +static PyObject * +stringlib_replace_delete_single_character(PyObject *self, + char from_c, 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; + PyObject *result; + + self_len = STRINGLIB_LEN(self); + self_s = STRINGLIB_STR(self); + + count = countchar(self_s, self_len, from_c, maxcount); + if (count == 0) { + return return_self(self); + } + + result_len = self_len - count; /* from_len == 1 */ + assert(result_len>=0); + + 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) { + next = findchar(start, end - start, from_c); + if (next == NULL) + break; + memcpy(result_s, start, next - start); + result_s += (next - start); + start = next + 1; + } + memcpy(result_s, start, end - start); + + return result; +} + +/* len(self)>=1, len(from)>=2, to="", maxcount>=1 */ + +static PyObject * +stringlib_replace_delete_substring(PyObject *self, + const char *from_s, Py_ssize_t from_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_len = STRINGLIB_LEN(self); + self_s = STRINGLIB_STR(self); + + count = stringlib_count(self_s, self_len, + from_s, from_len, + maxcount); + + if (count == 0) { + /* no matches */ + return return_self(self); + } + + result_len = self_len - (count * from_len); + assert (result_len>=0); + + 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; + + memcpy(result_s, start, next - start); + + result_s += (next - start); + start = next + from_len; + } + memcpy(result_s, start, end - start); + return result; +} + +/* len(self)>=1, len(from)==len(to)==1, maxcount>=1 */ +static PyObject * +stringlib_replace_single_character_in_place(PyObject *self, + char from_c, char to_c, + Py_ssize_t maxcount) +{ + const char *self_s, *end; + char *result_s, *start, *next; + Py_ssize_t self_len; + PyObject *result; + + /* The result string will be the same size */ + self_s = STRINGLIB_STR(self); + self_len = STRINGLIB_LEN(self); + + next = findchar(self_s, self_len, from_c); + + if (next == NULL) { + /* No matches; return the original bytes */ + return return_self(self); + } + + /* Need to make a new bytes */ + result = STRINGLIB_NEW(NULL, self_len); + if (result == NULL) { + return NULL; + } + result_s = STRINGLIB_STR(result); + memcpy(result_s, self_s, self_len); + + /* change everything in-place, starting with this one */ + start = result_s + (next - self_s); + *start = to_c; + start++; + end = result_s + self_len; + + while (--maxcount > 0) { + next = findchar(start, end - start, from_c); + if (next == NULL) + break; + *next = to_c; + start = next + 1; + } + + return result; } + +/* len(self)>=1, len(from)==len(to)>=2, maxcount>=1 */ +static PyObject * +stringlib_replace_substring_in_place(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, *end; + char *result_s, *start; + Py_ssize_t self_len, offset; + PyObject *result; + + /* The result bytes will be the same size */ + + self_s = STRINGLIB_STR(self); + self_len = STRINGLIB_LEN(self); + + offset = stringlib_find(self_s, self_len, + from_s, from_len, + 0); + if (offset == -1) { + /* No matches; return the original bytes */ + return return_self(self); + } + + /* Need to make a new bytes */ + result = STRINGLIB_NEW(NULL, self_len); + if (result == NULL) { + return NULL; + } + result_s = STRINGLIB_STR(result); + memcpy(result_s, self_s, self_len); + + /* change everything in-place, starting with this one */ + start = result_s + offset; + memcpy(start, to_s, from_len); + start += from_len; + end = result_s + self_len; + + while ( --maxcount > 0) { + offset = stringlib_find(start, end - start, + from_s, from_len, + 0); + if (offset == -1) + break; + memcpy(start + offset, to_s, from_len); + start += offset + from_len; + } + + return result; +} + +/* len(self)>=1, len(from)==1, len(to)>=2, maxcount>=1 */ +static PyObject * +stringlib_replace_single_character(PyObject *self, + char from_c, + 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; + PyObject *result; + + self_s = STRINGLIB_STR(self); + self_len = STRINGLIB_LEN(self); + + count = countchar(self_s, self_len, from_c, maxcount); + if (count == 0) { + /* no matches, return unchanged */ + return return_self(self); + } + + /* use the difference between current and new, hence the "-1" */ + /* result_len = self_len + count * (to_len-1) */ + assert(count > 0); + if (to_len - 1 > (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 - 1); + + 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) { + next = findchar(start, end - start, from_c); + if (next == NULL) + break; + + if (next == start) { + /* replace with the 'to' */ + memcpy(result_s, to_s, to_len); + result_s += to_len; + start += 1; + } 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 + 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 |