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Added limits to the replace code so it does not count all of the matching 

patterns in a string, only the number needed by the max limit.
This commit is contained in:
Andrew Dalke 2006-05-26 20:25:22 +00:00
parent e4e023c4d3
commit 5132407868
1 changed files with 19 additions and 22 deletions
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41
Objects/stringobject.c
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@ -2477,7 +2477,7 @@ return_self(PyStringObject *self)
} }
Py_LOCAL(Py_ssize_t) Py_LOCAL(Py_ssize_t)
countchar(char *target, int target_len, char c) countchar(char *target, int target_len, char c, Py_ssize_t maxcount)
{ {
Py_ssize_t count=0; Py_ssize_t count=0;
char *start=target; char *start=target;
@ -2485,9 +2485,10 @@ countchar(char *target, int target_len, char c)
while ( (start=findchar(start, end-start, c)) != NULL ) { while ( (start=findchar(start, end-start, c)) != NULL ) {
count++; count++;
if (count >= maxcount)
break;
start += 1; start += 1;
} }
return count; return count;
} }
@ -2534,7 +2535,7 @@ countstring(char *target, Py_ssize_t target_len,
char *pattern, Py_ssize_t pattern_len, char *pattern, Py_ssize_t pattern_len,
Py_ssize_t start, Py_ssize_t start,
Py_ssize_t end, Py_ssize_t end,
int direction) int direction, Py_ssize_t maxcount)
{ {
Py_ssize_t count=0; Py_ssize_t count=0;
@ -2552,21 +2553,26 @@ countstring(char *target, Py_ssize_t target_len,
} }
/* zero-length substrings match everywhere */ /* zero-length substrings match everywhere */
if (pattern_len == 0) if (pattern_len == 0 || maxcount == 0) {
return target_len+1; if (target_len+1 < maxcount)
return target_len+1;
return maxcount;
}
end -= pattern_len; end -= pattern_len;
if (direction < 0) { if (direction < 0) {
for (; end >= start; end--) for (; (end >= start); end--)
if (Py_STRING_MATCH(target, end, pattern, pattern_len)) { if (Py_STRING_MATCH(target, end, pattern, pattern_len)) {
count++; count++;
if (--maxcount <= 0) break;
end -= pattern_len-1; end -= pattern_len-1;
} }
} else { } else {
for (; start <= end; start++) for (; (start <= end); start++)
if (Py_STRING_MATCH(target, start, pattern, pattern_len)) { if (Py_STRING_MATCH(target, start, pattern, pattern_len)) {
count++; count++;
if (--maxcount <= 0)
break;
start += pattern_len-1; start += pattern_len-1;
} }
} }
@ -2653,12 +2659,10 @@ replace_delete_single_character(PyStringObject *self,
self_len = PyString_GET_SIZE(self); self_len = PyString_GET_SIZE(self);
self_s = PyString_AS_STRING(self); self_s = PyString_AS_STRING(self);
count = countchar(self_s, self_len, from_c); count = countchar(self_s, self_len, from_c, maxcount);
if (count == 0) { if (count == 0) {
return return_self(self); return return_self(self);
} }
if (count > maxcount)
count = maxcount;
result_len = self_len - count; /* from_len == 1 */ result_len = self_len - count; /* from_len == 1 */
assert(result_len>=0); assert(result_len>=0);
@ -2701,10 +2705,8 @@ replace_delete_substring(PyStringObject *self, PyStringObject *from,
count = countstring(self_s, self_len, count = countstring(self_s, self_len,
from_s, from_len, from_s, from_len,
0, self_len, 1); 0, self_len, 1,
maxcount);
if (count > maxcount)
count = maxcount;
if (count == 0) { if (count == 0) {
/* no matches */ /* no matches */
@ -2857,9 +2859,7 @@ replace_single_character(PyStringObject *self,
self_s = PyString_AS_STRING(self); self_s = PyString_AS_STRING(self);
self_len = PyString_GET_SIZE(self); self_len = PyString_GET_SIZE(self);
count = countchar(self_s, self_len, from_c); count = countchar(self_s, self_len, from_c, maxcount);
if (count > maxcount)
count = maxcount;
if (count == 0) { if (count == 0) {
/* no matches, return unchanged */ /* no matches, return unchanged */
@ -2933,10 +2933,7 @@ replace_substring(PyStringObject *self,
count = countstring(self_s, self_len, count = countstring(self_s, self_len,
from_s, from_len, from_s, from_len,
0, self_len, FORWARD); 0, self_len, FORWARD, maxcount);
if (count > maxcount)
count = maxcount;
if (count == 0) { if (count == 0) {
/* no matches, return unchanged */ /* no matches, return unchanged */
return return_self(self); return return_self(self);