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[HB] Fix context_length checking

This commit is contained in:
Behdad Esfahbod 2009-05-18 04:09:05 -04:00
parent d0ba055700
commit 7cff75babd
2 changed files with 14 additions and 11 deletions
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23
src/hb-ot-layout-gsubgpos-private.h
View File

@ -79,13 +79,13 @@ static inline bool match_input (LOOKUP_ARGS_DEF,
unsigned int *context_length_out) unsigned int *context_length_out)
{ {
unsigned int i, j; unsigned int i, j;
unsigned int end = MIN (buffer->in_length, buffer->in_pos + context_length);
/* XXX context_length should also be checked when skipping glyphs, right? if (HB_UNLIKELY (buffer->in_pos + count > end))
* What does context_length really mean, anyway? */ return false;
for (i = 1, j = buffer->in_pos + 1; i < count; i++, j++) { for (i = 1, j = buffer->in_pos + 1; i < count; i++, j++) {
while (!_hb_ot_layout_check_glyph_property (layout, IN_ITEM (j), lookup_flag, &property)) { while (!_hb_ot_layout_check_glyph_property (layout, IN_ITEM (j), lookup_flag, &property)) {
if (HB_UNLIKELY (j + count - i == buffer->in_length)) if (HB_UNLIKELY (j + count - i == end))
return false; return false;
j++; j++;
} }
@ -105,9 +105,10 @@ static inline bool match_backtrack (LOOKUP_ARGS_DEF,
match_func_t match_func, match_func_t match_func,
char *match_data) char *match_data)
{ {
unsigned int i, j; if (HB_UNLIKELY (buffer->out_pos < count))
return false;
for (i = 0, j = buffer->out_pos - 1; i < count; i++, j--) { for (unsigned int i = 0, j = buffer->out_pos - 1; i < count; i++, j--) {
while (!_hb_ot_layout_check_glyph_property (layout, OUT_ITEM (j), lookup_flag, &property)) { while (!_hb_ot_layout_check_glyph_property (layout, OUT_ITEM (j), lookup_flag, &property)) {
if (HB_UNLIKELY (j + 1 == count - i)) if (HB_UNLIKELY (j + 1 == count - i))
return false; return false;
@ -129,10 +130,13 @@ static inline bool match_lookahead (LOOKUP_ARGS_DEF,
unsigned int offset) unsigned int offset)
{ {
unsigned int i, j; unsigned int i, j;
unsigned int end = MIN (buffer->in_length, buffer->in_pos + context_length);
if (HB_UNLIKELY (buffer->in_pos + offset + count > end))
return false;
for (i = 0, j = buffer->in_pos + offset; i < count; i++, j++) { for (i = 0, j = buffer->in_pos + offset; i < count; i++, j++) {
while (!_hb_ot_layout_check_glyph_property (layout, OUT_ITEM (j), lookup_flag, &property)) { while (!_hb_ot_layout_check_glyph_property (layout, OUT_ITEM (j), lookup_flag, &property)) {
if (HB_UNLIKELY (j + count - i == buffer->in_length)) if (HB_UNLIKELY (j + count - i == end))
return false; return false;
j++; j++;
} }
@ -164,8 +168,8 @@ static inline bool apply_lookup (LOOKUP_ARGS_DEF,
const LookupRecord *record = lookupRecord; const LookupRecord *record = lookupRecord;
/* XXX We have to jump non-matching glyphs when applying too, right? */ /* XXX We have to jump non-matching glyphs when applying too, right? */
/* XXX We don't support lookupRecord arrays that are not increasing: /* TODO We don't support lookupRecord arrays that are not increasing:
* Should be easy for in_place ones at least. */ * Should be easy for in_place ones at least. */
for (unsigned int i = 0; i < count;) for (unsigned int i = 0; i < count;)
{ {
if (record_count && i == record->sequenceIndex) if (record_count && i == record->sequenceIndex)
@ -436,7 +440,6 @@ static inline bool chain_context_lookup (LOOKUP_ARGS_DEF,
inputCount, input, inputCount, input,
context.funcs.match, context.match_data[1], context.funcs.match, context.match_data[1],
&offset) && &offset) &&
(context_length -= offset, true) &&
match_lookahead (LOOKUP_ARGS, match_lookahead (LOOKUP_ARGS,
lookaheadCount, lookahead, lookaheadCount, lookahead,
context.funcs.match, context.match_data[2], context.funcs.match, context.match_data[2],

2
src/hb-ot-layout-open-private.h
View File

@ -35,7 +35,7 @@
#define NO_INDEX ((unsigned int) 0xFFFF) #define NO_INDEX ((unsigned int) 0xFFFF)
#define NO_CONTEXT ((unsigned int) -1) #define NO_CONTEXT ((unsigned int) -0x20000)
#define NOT_COVERED ((unsigned int) -1) #define NOT_COVERED ((unsigned int) -1)
#define MAX_NESTING_LEVEL 32 #define MAX_NESTING_LEVEL 32