X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=deflate.c;h=1b3ac524b59f823ac3897a21e5f16d6d21d246e4;hb=97f825c37400d5684e096fe57c244e1eb20b509f;hp=0950391ee88ba44a67a36ce4f1b14c87f79ebaa3;hpb=92e2751b3644febd7b6ff49a5dd6825a3e4b993f;p=debian%2Fgzip diff --git a/deflate.c b/deflate.c index 0950391..1b3ac52 100644 --- a/deflate.c +++ b/deflate.c @@ -131,6 +131,14 @@ #endif /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ +#ifndef RSYNC_WIN +# define RSYNC_WIN 8192 +#endif +/* Size of rsync window, must be < MAX_DIST */ + +#define RSYNC_SUM_MATCH(sum) (((sum) & (RSYNC_WIN - 1)) == 0) +/* Whether window sum matches magic value */ + /* =========================================================================== * Local data used by the "longest match" routines. */ @@ -212,6 +220,8 @@ local int compr_level; 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 @@ -307,6 +317,10 @@ void lm_init (pack_level, flags) #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; @@ -324,6 +338,7 @@ void lm_init (pack_level, flags) strstart = 0; block_start = 0L; + rsync_chunk_end = 0xFFFFFFFFUL; #ifdef ASMV match_init(); /* initialize the asm code */ #endif @@ -543,6 +558,8 @@ local void fill_window() 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; @@ -570,6 +587,39 @@ local void fill_window() } } +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. @@ -617,6 +667,7 @@ local off_t deflate_fast() 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. */ @@ -645,9 +696,18 @@ local off_t deflate_fast() /* 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) { + ush attr = 0; /* ascii/binary flag */ + + flush = 1; + /* Reset huffman tree */ + ct_init(&attr, &method); + rsync_chunk_end = 0xFFFFFFFFUL; + } if (flush) FLUSH_BLOCK(0), block_start = strstart; /* Make sure that we always have enough lookahead, except @@ -721,6 +781,7 @@ off_t deflate() */ lookahead -= prev_length-1; prev_length -= 2; + RSYNC_ROLL(strstart, prev_length+1); do { strstart++; INSERT_STRING(strstart, hash_head); @@ -733,24 +794,51 @@ off_t deflate() match_available = 0; match_length = MIN_MATCH-1; strstart++; - if (flush) FLUSH_BLOCK(0), block_start = strstart; + if (rsync && strstart > rsync_chunk_end) { + ush attr = 0; /* ascii/binary flag */ + + /* Reset huffman tree */ + ct_init(&attr, &method); + rsync_chunk_end = 0xFFFFFFFFUL; + flush = 1; + } + 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) { + ush attr = 0; /* ascii/binary flag */ + + /* Reset huffman tree */ + ct_init(&attr, &method); + rsync_chunk_end = 0xFFFFFFFFUL; + + flush = 1; + } + 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) { + ush attr = 0; /* ascii/binary flag */ + + /* Reset huffman tree */ + ct_init(&attr, &method); + rsync_chunk_end = 0xFFFFFFFFUL; + + FLUSH_BLOCK(0), block_start = strstart; + } match_available = 1; + RSYNC_ROLL(strstart, 1); strstart++; lookahead--; }