289 lines
11 KiB
Diff
289 lines
11 KiB
Diff
Index: gzip-1.5/deflate.c
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===================================================================
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--- gzip-1.5.orig/deflate.c
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+++ gzip-1.5/deflate.c
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@@ -131,6 +131,14 @@
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#endif
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/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
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+#ifndef RSYNC_WIN
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+# define RSYNC_WIN 4096
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+#endif
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+/* Size of rsync window, must be < MAX_DIST */
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+
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+#define RSYNC_SUM_MATCH(sum) ((sum) % RSYNC_WIN == 0)
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+/* Whether window sum matches magic value */
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+
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/* ===========================================================================
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* Local data used by the "longest match" routines.
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*/
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@@ -212,6 +220,8 @@ local int compr_level;
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unsigned good_match;
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/* Use a faster search when the previous match is longer than this */
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+local ulg rsync_sum; /* rolling sum of rsync window */
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+local ulg rsync_chunk_end; /* next rsync sequence point */
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/* Values for max_lazy_match, good_match and max_chain_length, depending on
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* the desired pack level (0..9). The values given below have been tuned to
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@@ -314,6 +324,10 @@ void lm_init (pack_level, flags)
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#endif
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/* prev will be initialized on the fly */
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+ /* rsync params */
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+ rsync_chunk_end = 0xFFFFFFFFUL;
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+ rsync_sum = 0;
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+
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/* Set the default configuration parameters:
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*/
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max_lazy_match = configuration_table[pack_level].max_lazy;
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@@ -550,6 +564,8 @@ local void fill_window()
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memcpy((char*)window, (char*)window+WSIZE, (unsigned)WSIZE);
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match_start -= WSIZE;
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strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */
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+ if (rsync_chunk_end != 0xFFFFFFFFUL)
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+ rsync_chunk_end -= WSIZE;
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block_start -= (long) WSIZE;
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@@ -579,13 +595,46 @@ local void fill_window()
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}
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}
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+local void rsync_roll(start, num)
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+ unsigned start;
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+ unsigned num;
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+{
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+ unsigned i;
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+
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+ if (start < RSYNC_WIN) {
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+ /* before window fills. */
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+ for (i = start; i < RSYNC_WIN; i++) {
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+ if (i == start + num) return;
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+ rsync_sum += (ulg)window[i];
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+ }
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+ num -= (RSYNC_WIN - start);
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+ start = RSYNC_WIN;
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+ }
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+
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+ /* buffer after window full */
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+ for (i = start; i < start+num; i++) {
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+ /* New character in */
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+ rsync_sum += (ulg)window[i];
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+ /* Old character out */
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+ rsync_sum -= (ulg)window[i - RSYNC_WIN];
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+ if (rsync_chunk_end == 0xFFFFFFFFUL && RSYNC_SUM_MATCH(rsync_sum))
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+ rsync_chunk_end = i;
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+ }
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+}
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+
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+/* ===========================================================================
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+ * Set rsync_chunk_end if window sum matches magic value.
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+ */
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+#define RSYNC_ROLL(s, n) \
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+ do { if (rsync) rsync_roll((s), (n)); } while(0)
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+
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/* ===========================================================================
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* Flush the current block, with given end-of-file flag.
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* IN assertion: strstart is set to the end of the current match.
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*/
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#define FLUSH_BLOCK(eof) \
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flush_block(block_start >= 0L ? (char*)&window[(unsigned)block_start] : \
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- (char*)NULL, (long)strstart - block_start, (eof))
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+ (char*)NULL, (long)strstart - block_start, flush-1, (eof))
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/* ===========================================================================
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* Processes a new input file and return its compressed length. This
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@@ -596,7 +645,7 @@ local void fill_window()
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local off_t deflate_fast()
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{
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IPos hash_head; /* head of the hash chain */
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- int flush; /* set if current block must be flushed */
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+ int flush; /* set if current block must be flushed, 2=>and padded */
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unsigned match_length = 0; /* length of best match */
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prev_length = MIN_MATCH-1;
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@@ -625,7 +674,8 @@ local off_t deflate_fast()
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flush = ct_tally(strstart-match_start, match_length - MIN_MATCH);
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lookahead -= match_length;
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-
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+
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+ RSYNC_ROLL(strstart, match_length);
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/* Insert new strings in the hash table only if the match length
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* is not too large. This saves time but degrades compression.
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*/
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@@ -654,9 +704,14 @@ local off_t deflate_fast()
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/* No match, output a literal byte */
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Tracevv((stderr,"%c",window[strstart]));
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flush = ct_tally (0, window[strstart]);
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+ RSYNC_ROLL(strstart, 1);
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lookahead--;
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strstart++;
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}
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+ if (rsync && strstart > rsync_chunk_end) {
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+ rsync_chunk_end = 0xFFFFFFFFUL;
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+ flush = 2;
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+ }
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if (flush) FLUSH_BLOCK(0), block_start = strstart;
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/* Make sure that we always have enough lookahead, except
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@@ -730,6 +785,7 @@ off_t deflate()
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*/
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lookahead -= prev_length-1;
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prev_length -= 2;
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+ RSYNC_ROLL(strstart, prev_length+1);
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do {
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strstart++;
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INSERT_STRING(strstart, hash_head);
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@@ -742,24 +798,40 @@ off_t deflate()
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match_available = 0;
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match_length = MIN_MATCH-1;
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strstart++;
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- if (flush) FLUSH_BLOCK(0), block_start = strstart;
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+ if (rsync && strstart > rsync_chunk_end) {
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+ rsync_chunk_end = 0xFFFFFFFFUL;
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+ flush = 2;
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+ }
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+ if (flush) FLUSH_BLOCK(0), block_start = strstart;
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} else if (match_available) {
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/* If there was no match at the previous position, output a
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* single literal. If there was a match but the current match
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* is longer, truncate the previous match to a single literal.
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*/
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Tracevv((stderr,"%c",window[strstart-1]));
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- if (ct_tally (0, window[strstart-1])) {
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- FLUSH_BLOCK(0), block_start = strstart;
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+ flush = ct_tally (0, window[strstart-1]);
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+ if (rsync && strstart > rsync_chunk_end) {
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+ rsync_chunk_end = 0xFFFFFFFFUL;
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+ flush = 2;
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}
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+ if (flush) FLUSH_BLOCK(0), block_start = strstart;
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+ RSYNC_ROLL(strstart, 1);
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strstart++;
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lookahead--;
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} else {
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/* There is no previous match to compare with, wait for
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* the next step to decide.
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*/
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+ if (rsync && strstart > rsync_chunk_end) {
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+ /* Reset huffman tree */
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+ rsync_chunk_end = 0xFFFFFFFFUL;
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+ flush = 2;
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+ FLUSH_BLOCK(0), block_start = strstart;
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+ }
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+
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match_available = 1;
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+ RSYNC_ROLL(strstart, 1);
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strstart++;
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lookahead--;
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}
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Index: gzip-1.5/doc/gzip.texi
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===================================================================
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--- gzip-1.5.orig/doc/gzip.texi
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+++ gzip-1.5/doc/gzip.texi
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@@ -353,6 +353,14 @@ specified on the command line are direct
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into the directory and compress all the files it finds there (or
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decompress them in the case of @command{gunzip}).
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+@item --rsyncable
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+While compressing, synchronize the output occasionally based on the
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+input. This reduces compression by about 1 percent most cases, but
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+means that the @code{rsync} program can take advantage of similarities
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+in the uncompressed input when syncronizing two files compressed with
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+this flag. @code{gunzip} cannot tell the difference between a
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+compressed file created with this option, and one created without it.
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+
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@item --suffix @var{suf}
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@itemx -S @var{suf}
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Use suffix @var{suf} instead of @samp{.gz}. Any suffix can be
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Index: gzip-1.5/gzip.c
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===================================================================
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--- gzip-1.5.orig/gzip.c
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+++ gzip-1.5/gzip.c
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@@ -213,6 +213,7 @@ int ofd; /* output fil
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unsigned insize; /* valid bytes in inbuf */
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unsigned inptr; /* index of next byte to be processed in inbuf */
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unsigned outcnt; /* bytes in output buffer */
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+int rsync = 0; /* make ryncable chunks */
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static int handled_sig[] =
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{
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@@ -270,7 +271,7 @@ static const struct option longopts[] =
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{"best", 0, 0, '9'}, /* compress better */
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{"lzw", 0, 0, 'Z'}, /* make output compatible with old compress */
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{"bits", 1, 0, 'b'}, /* max number of bits per code (implies -Z) */
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-
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+ {"rsyncable", 0, 0, 'R'}, /* make rsync-friendly archive */
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{ 0, 0, 0, 0 }
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};
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@@ -353,6 +354,7 @@ local void help()
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" -Z, --lzw produce output compatible with old compress",
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" -b, --bits=BITS max number of bits per code (implies -Z)",
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#endif
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+ " --rsyncable Make rsync-friendly archive",
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"",
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"With no FILE, or when FILE is -, read standard input.",
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"",
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@@ -482,6 +484,9 @@ int main (int argc, char **argv)
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recursive = 1;
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#endif
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break;
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+
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+ case 'R':
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+ rsync = 1; break;
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case 'S':
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#ifdef NO_MULTIPLE_DOTS
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if (*optarg == '.') optarg++;
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Index: gzip-1.5/gzip.h
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===================================================================
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--- gzip-1.5.orig/gzip.h
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+++ gzip-1.5/gzip.h
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@@ -140,6 +140,7 @@ EXTERN(uch, window); /* Sliding
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extern unsigned insize; /* valid bytes in inbuf */
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extern unsigned inptr; /* index of next byte to be processed in inbuf */
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extern unsigned outcnt; /* bytes in output buffer */
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+extern int rsync; /* deflate into rsyncable chunks */
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extern off_t bytes_in; /* number of input bytes */
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extern off_t bytes_out; /* number of output bytes */
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@@ -287,7 +288,7 @@ extern off_t deflate (void);
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/* in trees.c */
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extern void ct_init (ush *attr, int *method);
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extern int ct_tally (int dist, int lc);
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-extern off_t flush_block (char *buf, ulg stored_len, int eof);
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+extern off_t flush_block (char *buf, ulg stored_len, int pad, int eof);
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/* in bits.c */
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extern void bi_init (file_t zipfile);
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Index: gzip-1.5/trees.c
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===================================================================
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--- gzip-1.5.orig/trees.c
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+++ gzip-1.5/trees.c
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@@ -856,9 +856,10 @@ local void send_all_trees(lcodes, dcodes
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* trees or store, and output the encoded block to the zip file. This function
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* returns the total compressed length for the file so far.
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*/
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-off_t flush_block(buf, stored_len, eof)
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+off_t flush_block(buf, stored_len, pad, eof)
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char *buf; /* input block, or NULL if too old */
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ulg stored_len; /* length of input block */
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+ int pad; /* pad output to byte boundary */
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int eof; /* true if this is the last block for a file */
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{
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ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
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@@ -951,6 +952,10 @@ off_t flush_block(buf, stored_len, eof)
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Assert (input_len == bytes_in, "bad input size");
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bi_windup();
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compressed_len += 7; /* align on byte boundary */
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+ } else if (pad && (compressed_len % 8) != 0) {
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+ send_bits((STORED_BLOCK<<1)+eof, 3); /* send block type */
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+ compressed_len = (compressed_len + 3 + 7) & ~7L;
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+ copy_block(buf, 0, 1); /* with header */
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}
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return compressed_len >> 3;
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