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Copy pathtransmogrify.h
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743 lines (615 loc) · 19.6 KB
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#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. */
/*[clinic input]
class B "PyObject *" "&PyType_Type"
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=2935558188d97c76]*/
#include "clinic/transmogrify.h.h"
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));
}
/*[clinic input]
B.expandtabs as stringlib_expandtabs
tabsize: int = 8
Return a copy where all tab characters are expanded using spaces.
If tabsize is not given, a tab size of 8 characters is assumed.
[clinic start generated code]*/
static PyObject *
stringlib_expandtabs_impl(PyObject *self, int tabsize)
/*[clinic end generated code: output=069cb7fae72e4c2b input=3c6d3b12aa3ccbea]*/
{
const char *e, *p;
char *q;
Py_ssize_t i, j;
PyObject *u;
/* First pass: determine size of output string */
i = j = 0;
e = STRINGLIB_STR(self) + STRINGLIB_LEN(self);
for (p = STRINGLIB_STR(self); p < e; p++) {
if (*p == '\t') {
if (tabsize > 0) {
Py_ssize_t incr = tabsize - (j % tabsize);
if (j > PY_SSIZE_T_MAX - incr)
goto overflow;
j += incr;
}
}
else {
if (j > PY_SSIZE_T_MAX - 1)
goto overflow;
j++;
if (*p == '\n' || *p == '\r') {
if (i > PY_SSIZE_T_MAX - j)
goto overflow;
i += j;
j = 0;
}
}
}
if (i > PY_SSIZE_T_MAX - j)
goto overflow;
/* Second pass: create output string and fill it */
u = STRINGLIB_NEW(NULL, i + j);
if (!u)
return NULL;
j = 0;
q = STRINGLIB_STR(u);
for (p = STRINGLIB_STR(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;
overflow:
PyErr_SetString(PyExc_OverflowError, "result too long");
return NULL;
}
static inline PyObject *
pad(PyObject *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) {
return return_self(self);
}
u = STRINGLIB_NEW(NULL, left + STRINGLIB_LEN(self) + right);
if (u) {
if (left)
memset(STRINGLIB_STR(u), fill, left);
memcpy(STRINGLIB_STR(u) + left,
STRINGLIB_STR(self),
STRINGLIB_LEN(self));
if (right)
memset(STRINGLIB_STR(u) + left + STRINGLIB_LEN(self),
fill, right);
}
return u;
}
/*[clinic input]
B.ljust as stringlib_ljust
width: Py_ssize_t
fillchar: char = b' '
/
Return a left-justified string of length width.
Padding is done using the specified fill character.
[clinic start generated code]*/
static PyObject *
stringlib_ljust_impl(PyObject *self, Py_ssize_t width, char fillchar)
/*[clinic end generated code: output=c79ca173c5ff8337 input=eff2d014bc7d80df]*/
{
if (STRINGLIB_LEN(self) >= width) {
return return_self(self);
}
return pad(self, 0, width - STRINGLIB_LEN(self), fillchar);
}
/*[clinic input]
B.rjust as stringlib_rjust
width: Py_ssize_t
fillchar: char = b' '
/
Return a right-justified string of length width.
Padding is done using the specified fill character.
[clinic start generated code]*/
static PyObject *
stringlib_rjust_impl(PyObject *self, Py_ssize_t width, char fillchar)
/*[clinic end generated code: output=7df5d728a5439570 input=218b0bd31308955d]*/
{
if (STRINGLIB_LEN(self) >= width) {
return return_self(self);
}
return pad(self, width - STRINGLIB_LEN(self), 0, fillchar);
}
/*[clinic input]
B.center as stringlib_center
width: Py_ssize_t
fillchar: char = b' '
/
Return a centered string of length width.
Padding is done using the specified fill character.
[clinic start generated code]*/
static PyObject *
stringlib_center_impl(PyObject *self, Py_ssize_t width, char fillchar)
/*[clinic end generated code: output=d8da2e055288b4c2 input=3776fd278765d89b]*/
{
Py_ssize_t marg, left;
if (STRINGLIB_LEN(self) >= width) {
return return_self(self);
}
marg = width - STRINGLIB_LEN(self);
left = marg / 2 + (marg & width & 1);
return pad(self, left, marg - left, fillchar);
}
/*[clinic input]
B.zfill as stringlib_zfill
width: Py_ssize_t
/
Pad a numeric string with zeros on the left, to fill a field of the given width.
The original string is never truncated.
[clinic start generated code]*/
static PyObject *
stringlib_zfill_impl(PyObject *self, Py_ssize_t width)
/*[clinic end generated code: output=0b3c684a7f1b2319 input=2da6d7b8e9bcb19a]*/
{
Py_ssize_t fill;
PyObject *s;
char *p;
if (STRINGLIB_LEN(self) >= width) {
return return_self(self);
}
fill = width - STRINGLIB_LEN(self);
s = pad(self, fill, 0, '0');
if (s == NULL)
return NULL;
p = STRINGLIB_STR(s);
if (p[fill] == '+' || p[fill] == '-') {
/* move sign to beginning of string */
p[0] = p[fill];
p[fill] = '0';
}
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 is 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
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