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Avoid searching past window for Z_RLE strategy.

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Without this, Z_RLE could under some circumstances read one byte past
the end of the allocated sliding window. This would normally not be a
problem unless the window is right at the end of an allocated page, or
if a bounds checker is being used.
This commit is contained in:
Mark Adler 2011-09-22 23:45:00 -07:00
parent ae1de165d7
commit faa03d5141
1 changed files with 4 additions and 3 deletions
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7
deflate.c
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@ -1761,11 +1761,11 @@ local block_state deflate_rle(s, flush)
for (;;) { for (;;) {
/* Make sure that we always have enough lookahead, except /* Make sure that we always have enough lookahead, except
* at the end of the input file. We need MAX_MATCH bytes * at the end of the input file. We need MAX_MATCH bytes
* for the longest encodable run. * for the longest run, plus one for the unrolled loop.
*/ */
if (s->lookahead < MAX_MATCH) { if (s->lookahead <= MAX_MATCH) {
fill_window(s); fill_window(s);
if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) { if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) {
return need_more; return need_more;
} }
if (s->lookahead == 0) break; /* flush the current block */ if (s->lookahead == 0) break; /* flush the current block */
@ -1788,6 +1788,7 @@ local block_state deflate_rle(s, flush)
if (s->match_length > s->lookahead) if (s->match_length > s->lookahead)
s->match_length = s->lookahead; s->match_length = s->lookahead;
} }
Assert(scan <= s->window+(uInt)(s->window_size-1), "wild scan");
} }
/* Emit match if have run of MIN_MATCH or longer, else emit literal */ /* Emit match if have run of MIN_MATCH or longer, else emit literal */