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Fix a bug that can crash deflate on some input when using Z_FIXED.

This commit is contained in:
npt-1707 2025-05-03 01:11:02 +08:00
parent 043bbb07d4
commit b4570ab7a9
3 changed files with 74 additions and 64 deletions

View file

@ -421,7 +421,7 @@ local void init_block(s)
s->dyn_ltree[END_BLOCK].Freq = 1;
s->opt_len = s->static_len = 0L;
s->last_lit = s->matches = 0;
s->sym_next = s->matches = 0;
}
#define SMALLEST 1
@ -956,7 +956,7 @@ void _tr_flush_block(s, buf, stored_len, eof)
Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
s->last_lit));
s->sym_next / 3));
if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
@ -1023,8 +1023,9 @@ int _tr_tally (s, dist, lc)
unsigned dist; /* distance of matched string */
unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */
{
s->d_buf[s->last_lit] = (ush)dist;
s->l_buf[s->last_lit++] = (uch)lc;
s->sym_buf[s->sym_next++] = dist;
s->sym_buf[s->sym_next++] = dist >> 8;
s->sym_buf[s->sym_next++] = lc;
if (dist == 0) {
/* lc is the unmatched char */
s->dyn_ltree[lc].Freq++;
@ -1039,30 +1040,7 @@ int _tr_tally (s, dist, lc)
s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;
s->dyn_dtree[d_code(dist)].Freq++;
}
#ifdef TRUNCATE_BLOCK
/* Try to guess if it is profitable to stop the current block here */
if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {
/* Compute an upper bound for the compressed length */
ulg out_length = (ulg)s->last_lit*8L;
ulg in_length = (ulg)((long)s->strstart - s->block_start);
int dcode;
for (dcode = 0; dcode < D_CODES; dcode++) {
out_length += (ulg)s->dyn_dtree[dcode].Freq *
(5L+extra_dbits[dcode]);
}
out_length >>= 3;
Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
s->last_lit, in_length, out_length,
100L - out_length*100L/in_length));
if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
}
#endif
return (s->last_lit == s->lit_bufsize-1);
/* We avoid equality with lit_bufsize because of wraparound at 64K
* on 16 bit machines and because stored blocks are restricted to
* 64K-1 bytes.
*/
return (s->sym_next == s->sym_end);
}
/* ===========================================================================
@ -1075,13 +1053,14 @@ local void compress_block(s, ltree, dtree)
{
unsigned dist; /* distance of matched string */
int lc; /* match length or unmatched char (if dist == 0) */
unsigned lx = 0; /* running index in l_buf */
unsigned sx = 0; /* running index in sym_buf */
unsigned code; /* the code to send */
int extra; /* number of extra bits to send */
if (s->last_lit != 0) do {
dist = s->d_buf[lx];
lc = s->l_buf[lx++];
if (s->sym_next != 0) do {
dist = s->sym_buf[sx++] & 0xff;
dist += (unsigned)(s->sym_buf[sx++] & 0xff) << 8;
lc = s->sym_buf[sx++];
if (dist == 0) {
send_code(s, lc, ltree); /* send a literal byte */
Tracecv(isgraph(lc), (stderr," '%c' ", lc));
@ -1106,10 +1085,10 @@ local void compress_block(s, ltree, dtree)
}
} /* literal or match pair ? */
/* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
Assert(s->pending < s->lit_bufsize + 2*lx, "pendingBuf overflow");
/* Check that the overlay between pending_buf and sym_buf is ok: */
Assert(s->pending < s->lit_bufsize + sx, "pendingBuf overflow");
} while (lx < s->last_lit);
} while (sx < s->sym_next);
send_code(s, END_BLOCK, ltree);
s->last_eob_len = ltree[END_BLOCK].Len;