When using the regex code with _REGEX_LARGE_OFFSETS defined, backward
searches (where range<0) fail.
The diff below works around the problem, at least for re_search(), which
is the only regex function I'm using. The problem seems to be mixing
signed math -- 'range' is negative for backward searches -- with unsigned
"Idx"-typed variables 'length' and 'start'. "Idx" is an unsigned type when
_REGEX_LARGE_OFFSETS is defined. Behold:
-----------------------------------------
$ git diff --no-color regexec.c
diff --git a/src/regexec.c b/src/regexec.c
index 85de71d..ca10fea 100644
--- a/src/regexec.c
+++ b/src/regexec.c
@@ -410,8 +410,8 @@ re_search_2_stub (struct re_pattern_buffer *bufp,
static regoff_t
re_search_stub (struct re_pattern_buffer *bufp,
- const char *string, Idx length,
- Idx start, regoff_t range, Idx stop, struct re_registers
*regs,
+ const char *string, Idx ulength,
+ Idx ustart, regoff_t range, Idx stop, struct re_registers
*regs,
bool ret_len)
{
reg_errcode_t result;
@@ -420,7 +420,9 @@ re_search_stub (struct re_pattern_buffer *bufp,
regoff_t rval;
int eflags = 0;
re_dfa_t *dfa = bufp->buffer;
- Idx last_start = start + range;
+ regoff_t start = ustart;
+ regoff_t length = ulength;
+ regoff_t last_start = start + range;
/* Check for out-of-range. */
if (BE (start < 0 || start > length, 0))
-----------------------------------------
--
+--------------------------------------------------------------+
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+--------------------------------------------------------------+
