From: Martin Pool Date: Mon, 8 Apr 2002 01:41:37 +0000 (+0000) Subject: Rusty's patch to gzip. Here for informational purposes only. Please X-Git-Url: https://mattmccutchen.net/rsync/rsync-patches.git/commitdiff_plain/83907074396b8ce61f7e842b326a9e4835d63003 Rusty's patch to gzip. Here for informational purposes only. Please don't complain if applying it to gzip causes monkeys to fly out of your butt. --- diff --git a/gzip-rsyncable.diff b/gzip-rsyncable.diff new file mode 100644 index 0000000..724c2d5 --- /dev/null +++ b/gzip-rsyncable.diff @@ -0,0 +1,303 @@ +In message <20020403094739.GA5434@samba.org> you write: +> On 3 Apr 2002, Rusty Russell wrote: +> > In message <20020403020455.GC18851@samba.org> you write: +> > > Hi, +> > > +> > > I think you said the other day that you had a working --rsyncable +> > > patch for gzip. Could I have it please? +> +> Thanks for that. I'll put it in with our contrib patches and probably +> merge it soon. +> +> I was actually after the patch to gzip, rather than the fuzzy patch +> for rsync. I'd like to try it myself and also distribute it along +> with rsync. + +It's pending for actual gzip inclusion! The maintainer was dug up and +everything: it'll even be on by default. + +But here's the old patch, +Rusty. +-- + Anyone who quotes me in their sig is an idiot. -- Rusty Russell. + +diff -ur gzip-1.2.4.orig/deflate.c gzip-1.2.4-rsync/deflate.c +--- gzip-1.2.4.orig/deflate.c Fri Aug 13 22:35:31 1993 ++++ gzip-1.2.4-rsync/deflate.c Sat Dec 30 15:33:25 2000 +@@ -121,6 +121,14 @@ + #endif + /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ + ++#ifndef RSYNC_WIN ++# define RSYNC_WIN 4096 ++#endif ++/* Size of rsync window, must be < MAX_DIST */ ++ ++#define RSYNC_SUM_MATCH(sum) ((sum) % RSYNC_WIN == 0) ++/* Whether window sum matches magic value */ ++ + /* =========================================================================== + * Local data used by the "longest match" routines. + */ +@@ -202,6 +210,8 @@ + unsigned near good_match; + /* Use a faster search when the previous match is longer than this */ + ++local ulg rsync_sum; /* rolling sum of rsync window */ ++local ulg rsync_chunk_end; /* next rsync sequence point */ + + /* Values for max_lazy_match, good_match and max_chain_length, depending on + * the desired pack level (0..9). The values given below have been tuned to +@@ -300,6 +310,10 @@ + #endif + /* prev will be initialized on the fly */ + ++ /* rsync params */ ++ rsync_chunk_end = 0xFFFFFFFFUL; ++ rsync_sum = 0; ++ + /* Set the default configuration parameters: + */ + max_lazy_match = configuration_table[pack_level].max_lazy; +@@ -536,6 +550,8 @@ + memcpy((char*)window, (char*)window+WSIZE, (unsigned)WSIZE); + match_start -= WSIZE; + strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */ ++ if (rsync_chunk_end != 0xFFFFFFFFUL) ++ rsync_chunk_end -= WSIZE; + + block_start -= (long) WSIZE; + +@@ -563,13 +579,46 @@ + } + } + ++local void rsync_roll(start, num) ++ unsigned start; ++ unsigned num; ++{ ++ unsigned i; ++ ++ if (start < RSYNC_WIN) { ++ /* before window fills. */ ++ for (i = start; i < RSYNC_WIN; i++) { ++ if (i == start + num) return; ++ rsync_sum += (ulg)window[i]; ++ } ++ num -= (RSYNC_WIN - start); ++ start = RSYNC_WIN; ++ } ++ ++ /* buffer after window full */ ++ for (i = start; i < start+num; i++) { ++ /* New character in */ ++ rsync_sum += (ulg)window[i]; ++ /* Old character out */ ++ rsync_sum -= (ulg)window[i - RSYNC_WIN]; ++ if (rsync_chunk_end == 0xFFFFFFFFUL && RSYNC_SUM_MATCH(rsync_sum)) ++ rsync_chunk_end = i; ++ } ++} ++ ++/* =========================================================================== ++ * Set rsync_chunk_end if window sum matches magic value. ++ */ ++#define RSYNC_ROLL(s, n) \ ++ do { if (rsync) rsync_roll((s), (n)); } while(0) ++ + /* =========================================================================== + * Flush the current block, with given end-of-file flag. + * IN assertion: strstart is set to the end of the current match. + */ + #define FLUSH_BLOCK(eof) \ + flush_block(block_start >= 0L ? (char*)&window[(unsigned)block_start] : \ +- (char*)NULL, (long)strstart - block_start, (eof)) ++ (char*)NULL, (long)strstart - block_start, flush-1, (eof)) + + /* =========================================================================== + * Processes a new input file and return its compressed length. This +@@ -580,7 +629,7 @@ + local ulg deflate_fast() + { + IPos hash_head; /* head of the hash chain */ +- int flush; /* set if current block must be flushed */ ++ int flush; /* set if current block must be flushed, 2=>and padded */ + unsigned match_length = 0; /* length of best match */ + + prev_length = MIN_MATCH-1; +@@ -609,6 +658,7 @@ + + lookahead -= match_length; + ++ RSYNC_ROLL(strstart, match_length); + /* Insert new strings in the hash table only if the match length + * is not too large. This saves time but degrades compression. + */ +@@ -637,9 +687,14 @@ + /* No match, output a literal byte */ + Tracevv((stderr,"%c",window[strstart])); + flush = ct_tally (0, window[strstart]); ++ RSYNC_ROLL(strstart, 1); + lookahead--; + strstart++; + } ++ if (rsync && strstart > rsync_chunk_end) { ++ rsync_chunk_end = 0xFFFFFFFFUL; ++ flush = 2; ++ } + if (flush) FLUSH_BLOCK(0), block_start = strstart; + + /* Make sure that we always have enough lookahead, except +@@ -715,6 +770,7 @@ + */ + lookahead -= prev_length-1; + prev_length -= 2; ++ RSYNC_ROLL(strstart, prev_length+1); + do { + strstart++; + INSERT_STRING(strstart, hash_head); +@@ -727,24 +783,39 @@ + match_available = 0; + match_length = MIN_MATCH-1; + strstart++; +- if (flush) FLUSH_BLOCK(0), block_start = strstart; + ++ if (rsync && strstart > rsync_chunk_end) { ++ rsync_chunk_end = 0xFFFFFFFFUL; ++ flush = 2; ++ } ++ if (flush) FLUSH_BLOCK(0), block_start = strstart; + } else if (match_available) { + /* If there was no match at the previous position, output a + * single literal. If there was a match but the current match + * is longer, truncate the previous match to a single literal. + */ + Tracevv((stderr,"%c",window[strstart-1])); +- if (ct_tally (0, window[strstart-1])) { +- FLUSH_BLOCK(0), block_start = strstart; +- } ++ flush = ct_tally (0, window[strstart-1]); ++ if (rsync && strstart > rsync_chunk_end) { ++ rsync_chunk_end = 0xFFFFFFFFUL; ++ flush = 2; ++ } ++ if (flush) FLUSH_BLOCK(0), block_start = strstart; ++ RSYNC_ROLL(strstart, 1); + strstart++; + lookahead--; + } else { + /* There is no previous match to compare with, wait for + * the next step to decide. + */ ++ if (rsync && strstart > rsync_chunk_end) { ++ /* Reset huffman tree */ ++ rsync_chunk_end = 0xFFFFFFFFUL; ++ flush = 2; ++ FLUSH_BLOCK(0), block_start = strstart; ++ } + match_available = 1; ++ RSYNC_ROLL(strstart, 1); + strstart++; + lookahead--; + } +diff -ur gzip-1.2.4.orig/gzip.c gzip-1.2.4-rsync/gzip.c +--- gzip-1.2.4.orig/gzip.c Thu Aug 19 23:39:43 1993 ++++ gzip-1.2.4-rsync/gzip.c Fri Dec 29 21:20:54 2000 +@@ -239,6 +239,7 @@ + unsigned insize; /* valid bytes in inbuf */ + unsigned inptr; /* index of next byte to be processed in inbuf */ + unsigned outcnt; /* bytes in output buffer */ ++int rsync = 0; /* make ryncable chunks */ + + struct option longopts[] = + { +@@ -268,6 +269,7 @@ + {"best", 0, 0, '9'}, /* compress better */ + {"lzw", 0, 0, 'Z'}, /* make output compatible with old compress */ + {"bits", 1, 0, 'b'}, /* max number of bits per code (implies -Z) */ ++ {"rsyncable", 0, 0, 'R'}, /* make rsync-friendly archive */ + { 0, 0, 0, 0 } + }; + +@@ -357,6 +359,7 @@ + " -Z --lzw produce output compatible with old compress", + " -b --bits maxbits max number of bits per code (implies -Z)", + #endif ++ " --rsyncable Make rsync-friendly archive", + " file... files to (de)compress. If none given, use standard input.", + 0}; + char **p = help_msg; +@@ -516,6 +519,9 @@ + #else + recursive = 1; break; + #endif ++ case 'R': ++ rsync = 1; break; ++ + case 'S': + #ifdef NO_MULTIPLE_DOTS + if (*optarg == '.') optarg++; +diff -ur gzip-1.2.4.orig/gzip.h gzip-1.2.4-rsync/gzip.h +--- gzip-1.2.4.orig/gzip.h Fri Aug 13 22:35:33 1993 ++++ gzip-1.2.4-rsync/gzip.h Sat Dec 30 15:26:56 2000 +@@ -131,6 +131,7 @@ + extern unsigned insize; /* valid bytes in inbuf */ + extern unsigned inptr; /* index of next byte to be processed in inbuf */ + extern unsigned outcnt; /* bytes in output buffer */ ++extern int rsync; /* deflate into rsyncable chunks */ + + extern long bytes_in; /* number of input bytes */ + extern long bytes_out; /* number of output bytes */ +@@ -282,7 +283,7 @@ + /* in trees.c */ + void ct_init OF((ush *attr, int *method)); + int ct_tally OF((int dist, int lc)); +-ulg flush_block OF((char *buf, ulg stored_len, int eof)); ++ulg flush_block OF((char *buf, ulg stored_len, int pad, int eof)); + + /* in bits.c */ + void bi_init OF((file_t zipfile)); +diff -ur gzip-1.2.4.orig/gzip.texi gzip-1.2.4-rsync/gzip.texi +--- gzip-1.2.4.orig/gzip.texi Thu Aug 19 06:42:50 1993 ++++ gzip-1.2.4-rsync/gzip.texi Fri Dec 29 21:20:54 2000 +@@ -316,6 +316,14 @@ + into the directory and compress all the files it finds there (or + decompress them in the case of @code{gunzip}). + ++@item --rsyncable ++While compressing, synchronize the output occasionally based on the ++input. This reduces compression by about 1 percent most cases, but ++means that the @code{rsync} program can take advantage of similarities ++in the uncompressed input when syncronizing two files compressed with ++this flag. @code{gunzip} cannot tell the difference between a ++compressed file created with this option, and one created without it. ++ + @item --suffix @var{suf} + @itemx -S @var{suf} + Use suffix @samp{@var{suf}} instead of @samp{.gz}. Any suffix can be +diff -ur gzip-1.2.4.orig/trees.c gzip-1.2.4-rsync/trees.c +--- gzip-1.2.4.orig/trees.c Wed Aug 18 03:36:32 1993 ++++ gzip-1.2.4-rsync/trees.c Sat Dec 30 15:37:00 2000 +@@ -850,9 +850,10 @@ + * trees or store, and output the encoded block to the zip file. This function + * returns the total compressed length for the file so far. + */ +-ulg flush_block(buf, stored_len, eof) ++ulg flush_block(buf, stored_len, pad, eof) + char *buf; /* input block, or NULL if too old */ + ulg stored_len; /* length of input block */ ++ int pad; /* pad output to byte boundary */ + int eof; /* true if this is the last block for a file */ + { + ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ +@@ -944,6 +967,10 @@ + Assert (input_len == isize, "bad input size"); + bi_windup(); + compressed_len += 7; /* align on byte boundary */ ++ } else if (pad && (compressed_len % 8) != 0) { ++ send_bits((STORED_BLOCK<<1)+eof, 3); /* send block type */ ++ compressed_len = (compressed_len + 3 + 7) & ~7L; ++ copy_block(buf, 0, 1); /* with header */ + } + Tracev((stderr,"\ncomprlen %lu(%lu) ", compressed_len>>3, + compressed_len-7*eof));