X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/f39198789b82c1dd545743778f9d2633a2af8bd8..f68211671cf3230b3ddbe948f3802418ee03d378:/zlib/deflate.c
diff --git a/zlib/deflate.c b/zlib/deflate.c
index 69695770..8e9a3e65 100644
--- a/zlib/deflate.c
+++ b/zlib/deflate.c
@@ -52,7 +52,7 @@
#include "deflate.h"
const char deflate_copyright[] =
- " deflate 1.2.8 Copyright 1995-2013 Jean-loup Gailly and Mark Adler ";
+ " deflate 1.2.8.f-Proxmark3 Copyright 1995-2013 Jean-loup Gailly and Mark Adler ";
/*
If you use the zlib library in a product, an acknowledgment is welcome
in the documentation of your product. If for some reason you cannot
@@ -60,6 +60,15 @@ const char deflate_copyright[] =
copyright string in the executable of your product.
*/
+//-----------------------------------------------------------------------------
+// This version of zlib is modified for use within the Proxmark3 project.
+// Files from the original distribution which are not required for this
+// purpose are not included. All modifications can easily be found
+// by searching for #ifdef ZLIB_PM3_TUNED and #ifndef ZLIB_PM3_TUNED.
+//-----------------------------------------------------------------------------
+
+
+
/* ===========================================================================
* Function prototypes.
*/
@@ -1153,7 +1162,11 @@ local uInt longest_match(s, cur_match)
register Bytef *scan = s->window + s->strstart; /* current string */
register Bytef *match; /* matched string */
register int len; /* length of current match */
+#ifdef ZLIB_PM3_TUNED
+ int best_len = MIN_MATCH-1; // lift the restriction on prev-length
+#else
int best_len = s->prev_length; /* best match length so far */
+#endif
int nice_match = s->nice_match; /* stop if match long enough */
IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
s->strstart - (IPos)MAX_DIST(s) : NIL;
@@ -1721,6 +1734,81 @@ local block_state deflate_fast(s, flush)
return block_done;
}
+
+#ifdef ZLIB_PM3_TUNED
+local uInt try_harder(s, strstart, lookahead, hash_head)
+ deflate_state *s;
+ uInt strstart;
+ uInt lookahead;
+ IPos hash_head;
+{
+ uInt strstart_save = s->strstart;
+ s->strstart = strstart;
+ uInt lookahead_save = s->lookahead;
+ s->lookahead = lookahead;
+ uInt ins_h_save = s->ins_h;
+ uInt combined_gain;
+ uInt best_combined_gain = 0;
+ uInt match_length;
+ uInt prev_length = s->prev_length < MIN_MATCH ? 1 : s->prev_length;
+ uInt best_prev_length = prev_length;
+ uInt current_match_start = s->match_start;
+ uInt current_match_length = s->match_length;
+
+ do {
+ if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
+ match_length = longest_match (s, hash_head);
+ /* longest_match() sets match_start */
+ } else {
+ match_length = MIN_MATCH - 1;
+ }
+#if TOO_FAR <= 32767
+ if (match_length == MIN_MATCH && s->strstart - s->match_start > TOO_FAR) {
+ match_length = MIN_MATCH-1;
+ }
+#endif
+ if (s->strstart == strstart) { // store match at current position
+ current_match_length = match_length;
+ current_match_start = s->match_start;
+ }
+ if (s->strstart - strstart + 1 < MIN_MATCH) { // previous match reduced to one or two literals
+ combined_gain = 0; // need one literal per byte: no gain (assuming 8 bits per literal)
+ } else {
+ combined_gain = s->strstart - strstart + 1 - MIN_MATCH; // (possibly truncated) previous_length - 3 literals
+ }
+ if (match_length < MIN_MATCH) {
+ combined_gain += 0; // no gain
+ } else {
+ combined_gain += match_length - MIN_MATCH; // match_length bytes are coded as three literals
+ }
+ if (combined_gain >= best_combined_gain) { // in case of a tie we prefer the longer prev_length
+ best_combined_gain = combined_gain;
+ best_prev_length = s->strstart - strstart + 1;
+ }
+ s->strstart++;
+ s->lookahead--;
+ UPDATE_HASH(s, s->ins_h, s->window[(s->strstart) + (MIN_MATCH-1)]);
+ hash_head = s->head[s->ins_h];
+ } while (s->strstart <= strstart-1 + prev_length // try to truncate the previous match to 1, 3, ... prev_length
+ && s->strstart <= s->window_size - MIN_LOOKAHEAD); // watch out for the end of the input
+
+ s->strstart = strstart_save;
+ s->lookahead = lookahead_save;
+ s->ins_h = ins_h_save;
+ s->match_length = current_match_length;
+ s->match_start = current_match_start;
+ if (best_prev_length >= MIN_MATCH) {
+ s->prev_length = best_prev_length;
+ s->match_length = MIN_MATCH - 1;
+ } else {
+ s->prev_length = MIN_MATCH - 1;
+ }
+ return best_combined_gain;
+}
+#endif
+
+
+
#ifndef FASTEST
/* ===========================================================================
* Same as above, but achieves better compression. We use a lazy
@@ -1757,11 +1845,16 @@ local block_state deflate_slow(s, flush)
INSERT_STRING(s, s->strstart, hash_head);
}
- /* Find the longest match, discarding those <= prev_length.
- */
+ /* Find the longest match, discarding those <= prev_length. */
s->prev_length = s->match_length, s->prev_match = s->match_start;
s->match_length = MIN_MATCH-1;
+#ifdef ZLIB_PM3_TUNED
+ if (s->prev_length < s->max_lazy_match) {
+ try_harder(s, s->strstart, s->lookahead, hash_head);
+ }
+
+#else
if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
s->strstart - hash_head <= MAX_DIST(s)) {
/* To simplify the code, we prevent matches with the string
@@ -1784,6 +1877,7 @@ local block_state deflate_slow(s, flush)
s->match_length = MIN_MATCH-1;
}
}
+#endif /* ZLIB_PM3_TUNED */
/* If there was a match at the previous step and the current
* match is not better, output the previous match:
*/