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-rw-r--r--zlib/inffast.c80
1 files changed, 51 insertions, 29 deletions
diff --git a/zlib/inffast.c b/zlib/inffast.c
index e243ef8e6..4b6951fc9 100644
--- a/zlib/inffast.c
+++ b/zlib/inffast.c
@@ -1,5 +1,5 @@
/* inffast.c -- fast decoding
- * Copyright (C) 1995-2004 Mark Adler
+ * Copyright (C) 1995-2008, 2010 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
@@ -65,7 +65,7 @@
requires strm->avail_out >= 258 for each loop to avoid checking for
output space.
*/
-void inflate_fast(strm, start)
+void ZLIB_INTERNAL inflate_fast(strm, start)
z_streamp strm;
unsigned start; /* inflate()'s starting value for strm->avail_out */
{
@@ -80,7 +80,7 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
#endif
unsigned wsize; /* window size or zero if not using window */
unsigned whave; /* valid bytes in the window */
- unsigned write; /* window write index */
+ unsigned wnext; /* window write index */
unsigned char FAR *window; /* allocated sliding window, if wsize != 0 */
unsigned long hold; /* local strm->hold */
unsigned bits; /* local strm->bits */
@@ -88,7 +88,7 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
code const FAR *dcode; /* local strm->distcode */
unsigned lmask; /* mask for first level of length codes */
unsigned dmask; /* mask for first level of distance codes */
- code this; /* retrieved table entry */
+ code here; /* retrieved table entry */
unsigned op; /* code bits, operation, extra bits, or */
/* window position, window bytes to copy */
unsigned len; /* match length, unused bytes */
@@ -107,7 +107,7 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
#endif
wsize = state->wsize;
whave = state->whave;
- write = state->write;
+ wnext = state->wnext;
window = state->window;
hold = state->hold;
bits = state->bits;
@@ -125,20 +125,20 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
hold += (unsigned long)(PUP(in)) << bits;
bits += 8;
}
- this = lcode[hold & lmask];
+ here = lcode[hold & lmask];
dolen:
- op = (unsigned)(this.bits);
+ op = (unsigned)(here.bits);
hold >>= op;
bits -= op;
- op = (unsigned)(this.op);
+ op = (unsigned)(here.op);
if (op == 0) { /* literal */
- Tracevv((stderr, this.val >= 0x20 && this.val < 0x7f ?
+ Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
"inflate: literal '%c'\n" :
- "inflate: literal 0x%02x\n", this.val));
- PUP(out) = (unsigned char)(this.val);
+ "inflate: literal 0x%02x\n", here.val));
+ PUP(out) = (unsigned char)(here.val);
}
else if (op & 16) { /* length base */
- len = (unsigned)(this.val);
+ len = (unsigned)(here.val);
op &= 15; /* number of extra bits */
if (op) {
if (bits < op) {
@@ -156,14 +156,14 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
hold += (unsigned long)(PUP(in)) << bits;
bits += 8;
}
- this = dcode[hold & dmask];
+ here = dcode[hold & dmask];
dodist:
- op = (unsigned)(this.bits);
+ op = (unsigned)(here.bits);
hold >>= op;
bits -= op;
- op = (unsigned)(this.op);
+ op = (unsigned)(here.op);
if (op & 16) { /* distance base */
- dist = (unsigned)(this.val);
+ dist = (unsigned)(here.val);
op &= 15; /* number of extra bits */
if (bits < op) {
hold += (unsigned long)(PUP(in)) << bits;
@@ -188,12 +188,34 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
if (dist > op) { /* see if copy from window */
op = dist - op; /* distance back in window */
if (op > whave) {
- strm->msg = (char *)"invalid distance too far back";
- state->mode = BAD;
- break;
+ if (state->sane) {
+ strm->msg =
+ (char *)"invalid distance too far back";
+ state->mode = BAD;
+ break;
+ }
+#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
+ if (len <= op - whave) {
+ do {
+ PUP(out) = 0;
+ } while (--len);
+ continue;
+ }
+ len -= op - whave;
+ do {
+ PUP(out) = 0;
+ } while (--op > whave);
+ if (op == 0) {
+ from = out - dist;
+ do {
+ PUP(out) = PUP(from);
+ } while (--len);
+ continue;
+ }
+#endif
}
from = window - OFF;
- if (write == 0) { /* very common case */
+ if (wnext == 0) { /* very common case */
from += wsize - op;
if (op < len) { /* some from window */
len -= op;
@@ -203,17 +225,17 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
from = out - dist; /* rest from output */
}
}
- else if (write < op) { /* wrap around window */
- from += wsize + write - op;
- op -= write;
+ else if (wnext < op) { /* wrap around window */
+ from += wsize + wnext - op;
+ op -= wnext;
if (op < len) { /* some from end of window */
len -= op;
do {
PUP(out) = PUP(from);
} while (--op);
from = window - OFF;
- if (write < len) { /* some from start of window */
- op = write;
+ if (wnext < len) { /* some from start of window */
+ op = wnext;
len -= op;
do {
PUP(out) = PUP(from);
@@ -223,7 +245,7 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
}
}
else { /* contiguous in window */
- from += write - op;
+ from += wnext - op;
if (op < len) { /* some from window */
len -= op;
do {
@@ -260,7 +282,7 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
}
}
else if ((op & 64) == 0) { /* 2nd level distance code */
- this = dcode[this.val + (hold & ((1U << op) - 1))];
+ here = dcode[here.val + (hold & ((1U << op) - 1))];
goto dodist;
}
else {
@@ -270,7 +292,7 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
}
}
else if ((op & 64) == 0) { /* 2nd level length code */
- this = lcode[this.val + (hold & ((1U << op) - 1))];
+ here = lcode[here.val + (hold & ((1U << op) - 1))];
goto dolen;
}
else if (op & 32) { /* end-of-block */
@@ -306,7 +328,7 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
inflate_fast() speedups that turned out slower (on a PowerPC G3 750CXe):
- Using bit fields for code structure
- Different op definition to avoid & for extra bits (do & for table bits)
- - Three separate decoding do-loops for direct, window, and write == 0
+ - Three separate decoding do-loops for direct, window, and wnext == 0
- Special case for distance > 1 copies to do overlapped load and store copy
- Explicit branch predictions (based on measured branch probabilities)
- Deferring match copy and interspersed it with decoding subsequent codes
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-12 11:39:55 +0000