diff options
Diffstat (limited to 'Modules')
| -rw-r--r-- | Modules/_sre.c | 61 |
1 files changed, 38 insertions, 23 deletions
diff --git a/Modules/_sre.c b/Modules/_sre.c index be59112..3183a6e 100644 --- a/Modules/_sre.c +++ b/Modules/_sre.c @@ -337,19 +337,6 @@ mark_restore(SRE_STATE* state, int lo, int hi) return 0; } -static void -lastmark_restore(SRE_STATE *state, int lastmark) -{ - if (state->lastmark > lastmark) { - memset( - state->mark + lastmark + 1, 0, - (state->lastmark - lastmark) * sizeof(void*) - ); - state->lastmark = lastmark; - state->lastindex = (lastmark == 0) ? -1 : (lastmark-1)/2+1; - } -} - /* generate 8-bit version */ #define SRE_CHAR unsigned char @@ -690,6 +677,22 @@ SRE_INFO(SRE_STATE* state, SRE_CODE* pattern) } #endif +/* macros to preserve lastmark in case of backtracking */ +#define LASTMARK_SAVE() \ + do { \ + lastmark = state->lastmark; \ + lastindex = state->lastindex; \ + } while (0) +#define LASTMARK_RESTORE() \ + do { \ + if (state->lastmark > lastmark) { \ + memset(state->mark + lastmark + 1, 0, \ + (state->lastmark - lastmark) * sizeof(void*)); \ + state->lastmark = lastmark; \ + state->lastindex = lastindex; \ + } \ + } while (0) + LOCAL(int) SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) { @@ -700,7 +703,7 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) SRE_CHAR* ptr = state->ptr; int i, count; SRE_REPEAT* rp; - int lastmark; + int lastmark, lastindex; SRE_CODE chr; SRE_REPEAT rep; /* FIXME: <fl> allocate in STATE instead */ @@ -927,7 +930,7 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) /* alternation */ /* <BRANCH> <0=skip> code <JUMP> ... <NULL> */ TRACE(("|%p|%p|BRANCH\n", pattern, ptr)); - lastmark = state->lastmark; + LASTMARK_SAVE(); for (; pattern[0]; pattern += pattern[0]) { if (pattern[1] == SRE_OP_LITERAL && (ptr >= end || (SRE_CODE) *ptr != pattern[2])) @@ -939,7 +942,7 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) i = SRE_MATCH(state, pattern + 1, level + 1); if (i) return i; - lastmark_restore(state, lastmark); + LASTMARK_RESTORE(); } return 0; @@ -979,8 +982,11 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) /* tail is empty. we're finished */ state->ptr = ptr; return 1; + } + + LASTMARK_SAVE(); - } else if (pattern[pattern[0]] == SRE_OP_LITERAL) { + if (pattern[pattern[0]] == SRE_OP_LITERAL) { /* tail starts with a literal. skip positions where the rest of the pattern cannot possibly match */ chr = pattern[pattern[0]+1]; @@ -998,11 +1004,11 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) return i; ptr--; count--; + LASTMARK_RESTORE(); } } else { /* general case */ - lastmark = state->lastmark; while (count >= (int) pattern[1]) { state->ptr = ptr; i = SRE_MATCH(state, pattern + pattern[0], level + 1); @@ -1010,7 +1016,7 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) return i; ptr--; count--; - lastmark_restore(state, lastmark); + LASTMARK_RESTORE(); } } return 0; @@ -1055,7 +1061,7 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) /* general case */ int matchmax = ((int)pattern[2] == 65535); int c; - lastmark = state->lastmark; + LASTMARK_SAVE(); while (matchmax || count <= (int) pattern[2]) { state->ptr = ptr; i = SRE_MATCH(state, pattern + pattern[0], level + 1); @@ -1065,13 +1071,13 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) c = SRE_COUNT(state, pattern+3, 1, level+1); if (c < 0) return c; + LASTMARK_RESTORE(); if (c == 0) break; assert(c == 1); ptr++; count++; } - lastmark_restore(state, lastmark); } return 0; @@ -1113,6 +1119,8 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) TRACE(("|%p|%p|MAX_UNTIL %d\n", pattern, ptr, count)); + LASTMARK_SAVE(); + if (count < rp->pattern[1]) { /* not enough matches */ rp->count = count; @@ -1122,6 +1130,7 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) return i; rp->count = count - 1; state->ptr = ptr; + LASTMARK_RESTORE(); return 0; } @@ -1129,7 +1138,6 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) /* we may have enough matches, but if we can match another item, do so */ rp->count = count; - lastmark = state->lastmark; i = mark_save(state, 0, lastmark); if (i < 0) return i; @@ -1138,7 +1146,7 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) if (i) return i; i = mark_restore(state, 0, lastmark); - state->lastmark = lastmark; + LASTMARK_RESTORE(); if (i < 0) return i; rp->count = count - 1; @@ -1182,6 +1190,8 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) return 0; } + LASTMARK_SAVE(); + /* see if the tail matches */ state->repeat = rp->prev; i = SRE_MATCH(state, pattern, level + 1); @@ -1191,6 +1201,8 @@ SRE_MATCH(SRE_STATE* state, SRE_CODE* pattern, int level) state->ptr = ptr; state->repeat = rp; + LASTMARK_RESTORE(); + if (count >= rp->pattern[2] && rp->pattern[2] != 65535) return 0; @@ -3084,3 +3096,6 @@ PyMODINIT_FUNC init_sre(void) } #endif /* !defined(SRE_RECURSIVE) */ + +/* vim:ts=4:sw=4:et +*/ |