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str.replace() avoids memory when it's possible

This commit is contained in:
Victor Stinner 2011-10-06 12:31:55 +02:00
parent 56c161ab00
commit 25a4b29c95
1 changed files with 84 additions and 18 deletions
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102
Objects/unicodeobject.c
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@ -1741,6 +1741,63 @@ PyUnicode_FromKindAndData(int kind, const void *buffer, Py_ssize_t size)
}
}
/* Ensure that a string uses the most efficient storage, if it is not the
case: create a new string with of the right kind. Write NULL into *p_unicode
on error. */
void
unicode_adjust_maxchar(PyObject **p_unicode)
{
PyObject *unicode, *copy;
Py_UCS4 max_char;
Py_ssize_t i, len;
unsigned int kind;
assert(p_unicode != NULL);
unicode = *p_unicode;
assert(PyUnicode_IS_READY(unicode));
if (PyUnicode_IS_ASCII(unicode))
return;
len = PyUnicode_GET_LENGTH(unicode);
kind = PyUnicode_KIND(unicode);
if (kind == PyUnicode_1BYTE_KIND) {
const Py_UCS1 *u = PyUnicode_1BYTE_DATA(unicode);
for (i = 0; i < len; i++) {
if (u[i] & 0x80)
return;
}
max_char = 127;
}
else if (kind == PyUnicode_2BYTE_KIND) {
const Py_UCS2 *u = PyUnicode_2BYTE_DATA(unicode);
max_char = 0;
for (i = 0; i < len; i++) {
if (u[i] > max_char) {
max_char = u[i];
if (max_char >= 256)
return;
}
}
}
else {
assert(kind == PyUnicode_4BYTE_KIND);
const Py_UCS4 *u = PyUnicode_4BYTE_DATA(unicode);
max_char = 0;
for (i = 0; i < len; i++) {
if (u[i] > max_char) {
max_char = u[i];
if (max_char >= 0x10000)
return;
}
}
}
assert(max_char > PyUnicode_MAX_CHAR_VALUE(unicode));
copy = PyUnicode_New(len, max_char);
copy_characters(copy, 0, unicode, 0, len);
Py_DECREF(unicode);
*p_unicode = copy;
}
PyObject*
PyUnicode_Copy(PyObject *unicode)
{
@ -9573,14 +9630,16 @@ replace(PyObject *self, PyObject *str1,
PyUnicode_WRITE(rkind, PyUnicode_DATA(u), i, u2);
}
if (mayshrink) {
PyObject *tmp = u;
u = PyUnicode_FromKindAndData(rkind, PyUnicode_DATA(tmp),
PyUnicode_GET_LENGTH(tmp));
Py_DECREF(tmp);
unicode_adjust_maxchar(&u);
if (u == NULL)
goto error;
}
} else {
int rkind = skind;
char *res;
PyObject *rstr;
Py_UCS4 maxchar;
if (kind1 < rkind) {
/* widen substring */
buf1 = _PyUnicode_AsKind(str1, rkind);
@ -9607,11 +9666,13 @@ replace(PyObject *self, PyObject *str1,
if (!buf1) goto error;
release1 = 1;
}
res = PyMem_Malloc(PyUnicode_KIND_SIZE(rkind, slen));
if (!res) {
PyErr_NoMemory();
maxchar = PyUnicode_MAX_CHAR_VALUE(self);
maxchar = Py_MAX(maxchar, PyUnicode_MAX_CHAR_VALUE(str2));
rstr = PyUnicode_New(slen, maxchar);
if (!rstr)
goto error;
}
res = PyUnicode_DATA(rstr);
memcpy(res, sbuf, PyUnicode_KIND_SIZE(rkind, slen));
/* change everything in-place, starting with this one */
memcpy(res + PyUnicode_KIND_SIZE(rkind, i),
@ -9631,16 +9692,19 @@ replace(PyObject *self, PyObject *str1,
i += len1;
}
u = PyUnicode_FromKindAndData(rkind, res, slen);
PyMem_Free(res);
if (!u) goto error;
u = rstr;
unicode_adjust_maxchar(&u);
if (!u)
goto error;
}
} else {
Py_ssize_t n, i, j, ires;
Py_ssize_t product, new_size;
int rkind = skind;
PyObject *rstr;
char *res;
Py_UCS4 maxchar;
if (kind1 < rkind) {
buf1 = _PyUnicode_AsKind(str1, rkind);
@ -9679,9 +9743,12 @@ replace(PyObject *self, PyObject *str1,
"replace string is too long");
goto error;
}
res = PyMem_Malloc(PyUnicode_KIND_SIZE(rkind, new_size));
if (!res)
maxchar = PyUnicode_MAX_CHAR_VALUE(self);
maxchar = Py_MAX(maxchar, PyUnicode_MAX_CHAR_VALUE(str2));
rstr = PyUnicode_New(new_size, maxchar);
if (!rstr)
goto error;
res = PyUnicode_DATA(rstr);
ires = i = 0;
if (len1 > 0) {
while (n-- > 0) {
@ -9731,11 +9798,10 @@ replace(PyObject *self, PyObject *str1,
sbuf + PyUnicode_KIND_SIZE(rkind, i),
PyUnicode_KIND_SIZE(rkind, slen-i));
}
if (PyUnicode_IS_ASCII(self) && PyUnicode_IS_ASCII(str2))
u = unicode_fromascii((unsigned char*)res, new_size);
else
u = PyUnicode_FromKindAndData(rkind, res, new_size);
PyMem_Free(res);
u = rstr;
unicode_adjust_maxchar(&u);
if (u == NULL)
goto error;
}
if (srelease)
PyMem_FREE(sbuf);