Rooba
/
cpython
mirror of https://github.com/python/cpython.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Check for NULL before the pointer aligning in fastsearch_memchr_1char. 

There is no guarantee that NULL is aligned.
This commit is contained in:
Serhiy Storchaka 2013-01-15 13:27:28 +02:00
parent afe4126fd3
commit 18ba40b945
1 changed files with 10 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
Objects/stringlib/fastsearch.h
View File

@ -38,25 +38,18 @@ STRINGLIB(fastsearch_memchr_1char)(const STRINGLIB_CHAR* s, Py_ssize_t n,
STRINGLIB_CHAR ch, unsigned char needle,
Py_ssize_t maxcount, int mode)
{
void *candidate;
const STRINGLIB_CHAR *found;
#define DO_MEMCHR(memchr, s, needle, nchars) do { \
candidate = memchr((const void *) (s), (needle), (nchars) * sizeof(STRINGLIB_CHAR)); \
found = (const STRINGLIB_CHAR *) _Py_ALIGN_DOWN(candidate, sizeof(STRINGLIB_CHAR)); \
} while (0)
if (mode == FAST_SEARCH) {
const STRINGLIB_CHAR *ptr = s;
const STRINGLIB_CHAR *e = s + n;
while (ptr < e) {
DO_MEMCHR(memchr, ptr, needle, e - ptr);
if (found == NULL)
void *candidate = memchr((const void *) ptr, needle, (e - ptr) * sizeof(STRINGLIB_CHAR));
if (candidate == NULL)
return -1;
if (sizeof(STRINGLIB_CHAR) == 1 || *found == ch)
return (found - s);
ptr = (const STRINGLIB_CHAR *) _Py_ALIGN_DOWN(candidate, sizeof(STRINGLIB_CHAR));
if (sizeof(STRINGLIB_CHAR) == 1 || *ptr == ch)
return (ptr - s);
/* False positive */
ptr = found + 1;
ptr++;
}
return -1;
}
@ -66,9 +59,11 @@ STRINGLIB(fastsearch_memchr_1char)(const STRINGLIB_CHAR* s, Py_ssize_t n,
faster than our hand-written loop in FASTSEARCH below */
else if (mode == FAST_RSEARCH) {
while (n > 0) {
DO_MEMCHR(memrchr, s, needle, n);
if (found == NULL)
const STRINGLIB_CHAR *found;
void *candidate = memrchr((const void *) s, needle, n * sizeof(STRINGLIB_CHAR));
if (candidate == NULL)
return -1;
found = (const STRINGLIB_CHAR *) _Py_ALIGN_DOWN(candidate, sizeof(STRINGLIB_CHAR));
n = found - s;
if (sizeof(STRINGLIB_CHAR) == 1 || *found == ch)
return n;