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-rw-r--r--zlib/inffast.c159
1 files changed, 82 insertions, 77 deletions
diff --git a/zlib/inffast.c b/zlib/inffast.c
index bbee92ed1e6..0dbd1dbc09f 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) 1995-2017 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
@@ -8,26 +8,9 @@
#include "inflate.h"
#include "inffast.h"
-#ifndef ASMINF
-
-/* Allow machine dependent optimization for post-increment or pre-increment.
- Based on testing to date,
- Pre-increment preferred for:
- - PowerPC G3 (Adler)
- - MIPS R5000 (Randers-Pehrson)
- Post-increment preferred for:
- - none
- No measurable difference:
- - Pentium III (Anderson)
- - M68060 (Nikl)
- */
-#ifdef POSTINC
-# define OFF 0
-# define PUP(a) *(a)++
+#ifdef ASMINF
+# pragma message("Assembler code may have bugs -- use at your own risk")
#else
-# define OFF 1
-# define PUP(a) *++(a)
-#endif
/*
Decode literal, length, and distance codes and write out the resulting
@@ -64,13 +47,13 @@
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 */
{
struct inflate_state FAR *state;
- unsigned char FAR *in; /* local strm->next_in */
- unsigned char FAR *last; /* while in < last, enough input available */
+ z_const unsigned char FAR *in; /* local strm->next_in */
+ z_const unsigned char FAR *last; /* have enough input while in < last */
unsigned char FAR *out; /* local strm->next_out */
unsigned char FAR *beg; /* inflate()'s initial strm->next_out */
unsigned char FAR *end; /* while out < end, enough space available */
@@ -79,7 +62,7 @@ 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 */
@@ -87,7 +70,7 @@ 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 */
@@ -96,9 +79,9 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
/* copy state to local variables */
state = (struct inflate_state FAR *)strm->state;
- in = strm->next_in - OFF;
+ in = strm->next_in;
last = in + (strm->avail_in - 5);
- out = strm->next_out - OFF;
+ out = strm->next_out;
beg = out - (start - strm->avail_out);
end = out + (strm->avail_out - 257);
#ifdef INFLATE_STRICT
@@ -106,7 +89,7 @@ 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;
@@ -119,29 +102,29 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
input data or output space */
do {
if (bits < 15) {
- hold += (unsigned long)(PUP(in)) << bits;
+ hold += (unsigned long)(*in++) << bits;
bits += 8;
- hold += (unsigned long)(PUP(in)) << bits;
+ hold += (unsigned long)(*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));
+ *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) {
- hold += (unsigned long)(PUP(in)) << bits;
+ hold += (unsigned long)(*in++) << bits;
bits += 8;
}
len += (unsigned)hold & ((1U << op) - 1);
@@ -150,25 +133,25 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
}
Tracevv((stderr, "inflate: length %u\n", len));
if (bits < 15) {
- hold += (unsigned long)(PUP(in)) << bits;
+ hold += (unsigned long)(*in++) << bits;
bits += 8;
- hold += (unsigned long)(PUP(in)) << bits;
+ hold += (unsigned long)(*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;
+ hold += (unsigned long)(*in++) << bits;
bits += 8;
if (bits < op) {
- hold += (unsigned long)(PUP(in)) << bits;
+ hold += (unsigned long)(*in++) << bits;
bits += 8;
}
}
@@ -187,79 +170,101 @@ 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 {
+ *out++ = 0;
+ } while (--len);
+ continue;
+ }
+ len -= op - whave;
+ do {
+ *out++ = 0;
+ } while (--op > whave);
+ if (op == 0) {
+ from = out - dist;
+ do {
+ *out++ = *from++;
+ } while (--len);
+ continue;
+ }
+#endif
}
- from = window - OFF;
- if (write == 0) { /* very common case */
+ from = window;
+ if (wnext == 0) { /* very common case */
from += wsize - op;
if (op < len) { /* some from window */
len -= op;
do {
- PUP(out) = PUP(from);
+ *out++ = *from++;
} while (--op);
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);
+ *out++ = *from++;
} while (--op);
- from = window - OFF;
- if (write < len) { /* some from start of window */
- op = write;
+ from = window;
+ if (wnext < len) { /* some from start of window */
+ op = wnext;
len -= op;
do {
- PUP(out) = PUP(from);
+ *out++ = *from++;
} while (--op);
from = out - dist; /* rest from output */
}
}
}
else { /* contiguous in window */
- from += write - op;
+ from += wnext - op;
if (op < len) { /* some from window */
len -= op;
do {
- PUP(out) = PUP(from);
+ *out++ = *from++;
} while (--op);
from = out - dist; /* rest from output */
}
}
while (len > 2) {
- PUP(out) = PUP(from);
- PUP(out) = PUP(from);
- PUP(out) = PUP(from);
+ *out++ = *from++;
+ *out++ = *from++;
+ *out++ = *from++;
len -= 3;
}
if (len) {
- PUP(out) = PUP(from);
+ *out++ = *from++;
if (len > 1)
- PUP(out) = PUP(from);
+ *out++ = *from++;
}
}
else {
from = out - dist; /* copy direct from output */
do { /* minimum length is three */
- PUP(out) = PUP(from);
- PUP(out) = PUP(from);
- PUP(out) = PUP(from);
+ *out++ = *from++;
+ *out++ = *from++;
+ *out++ = *from++;
len -= 3;
} while (len > 2);
if (len) {
- PUP(out) = PUP(from);
+ *out++ = *from++;
if (len > 1)
- PUP(out) = PUP(from);
+ *out++ = *from++;
}
}
}
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 {
@@ -269,7 +274,7 @@ 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 */
@@ -291,8 +296,8 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
hold &= (1U << bits) - 1;
/* update state and return */
- strm->next_in = in + OFF;
- strm->next_out = out + OFF;
+ strm->next_in = in;
+ strm->next_out = out;
strm->avail_in = (unsigned)(in < last ? 5 + (last - in) : 5 - (in - last));
strm->avail_out = (unsigned)(out < end ?
257 + (end - out) : 257 - (out - end));
@@ -305,7 +310,7 @@ 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
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