51 lines
1.7 KiB
Diff
51 lines
1.7 KiB
Diff
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From 7af6320ad78b390de42f414fabdc64dc6d67a5ea Mon Sep 17 00:00:00 2001
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From: Mark Adler <madler@alumni.caltech.edu>
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Date: Fri, 19 Jan 2024 12:19:53 -0800
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Subject: [PATCH] Fix a bug in ZLIB_DEBUG compiles in check_match().
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This avoids trying to compare a match starting one byte before the
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current window. Thanks to @zmodem (Hans) for discovering this.
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Reference:https://github.com/madler/zlib/commit/7af6320ad78b390de42f414fabdc64dc6d67a5ea
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Conflict: Patch context adaptation
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---
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deflate.c | 20 ++++++++++++++------
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1 file changed, 14 insertions(+), 6 deletions(-)
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diff --git a/deflate.c b/deflate.c
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index 8088083..396ab12 100644
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--- a/deflate.c
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+++ b/deflate.c
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@@ -1510,13 +1510,21 @@ local void check_match(s, start, match, length)
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int length;
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{
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/* check that the match is indeed a match */
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- if (zmemcmp(s->window + match,
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- s->window + start, length) != EQUAL) {
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- fprintf(stderr, " start %u, match %u, length %d\n",
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- start, match, length);
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+ Bytef *back = s->window + (int)match, *here = s->window + start;
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+ IPos len = length;
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+ if (match == (IPos)-1) {
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+ /* match starts one byte before the current window -- just compare the
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+ subsequent length-1 bytes */
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+ back++;
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+ here++;
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+ len--;
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+ }
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+ if (zmemcmp(back, here, len) != EQUAL) {
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+ fprintf(stderr, " start %u, match %d, length %d\n",
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+ start, (int)match, length);
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do {
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- fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
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- } while (--length != 0);
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+ fprintf(stderr, "(%02x %02x)", *back++, *here++);
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+ } while (--len != 0);
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z_error("invalid match");
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}
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if (z_verbose > 1) {
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--
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2.33.0
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