123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410 |
- /*
- * Block matching used by the file-transfer code.
- *
- * Copyright (C) 1996 Andrew Tridgell
- * Copyright (C) 1996 Paul Mackerras
- * Copyright (C) 2003-2009 Wayne Davison
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, visit the http://fsf.org website.
- */
- #include "rsync.h"
- extern int verbose;
- extern int do_progress;
- extern int checksum_seed;
- extern int append_mode;
- int updating_basis_file;
- static int false_alarms;
- static int hash_hits;
- static int matches;
- static int64 data_transfer;
- static int total_false_alarms;
- static int total_hash_hits;
- static int total_matches;
- extern struct stats stats;
- #define TRADITIONAL_TABLESIZE (1<<16)
- static uint32 tablesize;
- static int32 *hash_table;
- #define SUM2HASH2(s1,s2) (((s1) + (s2)) & 0xFFFF)
- #define SUM2HASH(sum) SUM2HASH2((sum)&0xFFFF,(sum)>>16)
- #define BIG_SUM2HASH(sum) ((sum)%tablesize)
- static void build_hash_table(struct sum_struct *s)
- {
- static uint32 alloc_size;
- int32 i;
- /* Dynamically calculate the hash table size so that the hash load
- * for big files is about 80%. A number greater than the traditional
- * size must be odd or s2 will not be able to span the entire set. */
- tablesize = (uint32)(s->count/8) * 10 + 11;
- if (tablesize < TRADITIONAL_TABLESIZE)
- tablesize = TRADITIONAL_TABLESIZE;
- if (tablesize > alloc_size || tablesize < alloc_size - 16*1024) {
- if (hash_table)
- free(hash_table);
- hash_table = new_array(int32, tablesize);
- if (!hash_table)
- out_of_memory("build_hash_table");
- alloc_size = tablesize;
- }
- memset(hash_table, 0xFF, tablesize * sizeof hash_table[0]);
- if (tablesize == TRADITIONAL_TABLESIZE) {
- for (i = 0; i < s->count; i++) {
- uint32 t = SUM2HASH(s->sums[i].sum1);
- s->sums[i].chain = hash_table[t];
- hash_table[t] = i;
- }
- } else {
- for (i = 0; i < s->count; i++) {
- uint32 t = BIG_SUM2HASH(s->sums[i].sum1);
- s->sums[i].chain = hash_table[t];
- hash_table[t] = i;
- }
- }
- }
- static OFF_T last_match;
- /* Transmit a literal and/or match token.
- *
- * This delightfully-named function is called either when we find a
- * match and need to transmit all the unmatched data leading up to it,
- * or when we get bored of accumulating literal data and just need to
- * transmit it. As a result of this second case, it is called even if
- * we have not matched at all!
- *
- * If i >= 0, the number of a matched token. If < 0, indicates we have
- * only literal data. A -1 will send a 0-token-int too, and a -2 sends
- * only literal data, w/o any token-int. */
- static void matched(int f, struct sum_struct *s, struct map_struct *buf,
- OFF_T offset, int32 i)
- {
- int32 n = (int32)(offset - last_match); /* max value: block_size (int32) */
- int32 j;
- if (verbose > 2 && i >= 0) {
- rprintf(FINFO,
- "match at %.0f last_match=%.0f j=%d len=%ld n=%ld\n",
- (double)offset, (double)last_match, i,
- (long)s->sums[i].len, (long)n);
- }
- send_token(f, i, buf, last_match, n, i < 0 ? 0 : s->sums[i].len);
- data_transfer += n;
- if (i >= 0) {
- stats.matched_data += s->sums[i].len;
- n += s->sums[i].len;
- }
- for (j = 0; j < n; j += CHUNK_SIZE) {
- int32 n1 = MIN(CHUNK_SIZE, n - j);
- sum_update(map_ptr(buf, last_match + j, n1), n1);
- }
- if (i >= 0)
- last_match = offset + s->sums[i].len;
- else
- last_match = offset;
- if (buf && do_progress)
- show_progress(last_match, buf->file_size);
- }
- static void hash_search(int f,struct sum_struct *s,
- struct map_struct *buf, OFF_T len)
- {
- OFF_T offset, aligned_offset, end;
- int32 k, want_i, aligned_i, backup;
- char sum2[SUM_LENGTH];
- uint32 s1, s2, sum;
- int more;
- schar *map;
- /* want_i is used to encourage adjacent matches, allowing the RLL
- * coding of the output to work more efficiently. */
- want_i = 0;
- if (verbose > 2) {
- rprintf(FINFO, "hash search b=%ld len=%.0f\n",
- (long)s->blength, (double)len);
- }
- k = (int32)MIN(len, (OFF_T)s->blength);
- map = (schar *)map_ptr(buf, 0, k);
- sum = get_checksum1((char *)map, k);
- s1 = sum & 0xFFFF;
- s2 = sum >> 16;
- if (verbose > 3)
- rprintf(FINFO, "sum=%.8x k=%ld\n", sum, (long)k);
- offset = aligned_offset = aligned_i = 0;
- end = len + 1 - s->sums[s->count-1].len;
- if (verbose > 3) {
- rprintf(FINFO, "hash search s->blength=%ld len=%.0f count=%.0f\n",
- (long)s->blength, (double)len, (double)s->count);
- }
- do {
- int done_csum2 = 0;
- int32 i;
- if (verbose > 4) {
- rprintf(FINFO, "offset=%.0f sum=%04x%04x\n",
- (double)offset, s2 & 0xFFFF, s1 & 0xFFFF);
- }
- if (tablesize == TRADITIONAL_TABLESIZE) {
- if ((i = hash_table[SUM2HASH2(s1,s2)]) < 0)
- goto null_hash;
- sum = (s1 & 0xffff) | (s2 << 16);
- } else {
- sum = (s1 & 0xffff) | (s2 << 16);
- if ((i = hash_table[BIG_SUM2HASH(sum)]) < 0)
- goto null_hash;
- }
- hash_hits++;
- do {
- int32 l;
- if (sum != s->sums[i].sum1)
- continue;
- /* also make sure the two blocks are the same length */
- l = (int32)MIN((OFF_T)s->blength, len-offset);
- if (l != s->sums[i].len)
- continue;
- /* in-place: ensure chunk's offset is either >= our
- * offset or that the data didn't move. */
- if (updating_basis_file && s->sums[i].offset < offset
- && !(s->sums[i].flags & SUMFLG_SAME_OFFSET))
- continue;
- if (verbose > 3) {
- rprintf(FINFO,
- "potential match at %.0f i=%ld sum=%08x\n",
- (double)offset, (long)i, sum);
- }
- if (!done_csum2) {
- map = (schar *)map_ptr(buf,offset,l);
- get_checksum2((char *)map,l,sum2);
- done_csum2 = 1;
- }
- if (memcmp(sum2,s->sums[i].sum2,s->s2length) != 0) {
- false_alarms++;
- continue;
- }
- /* When updating in-place, the best possible match is
- * one with an identical offset, so we prefer that over
- * the adjacent want_i optimization. */
- if (updating_basis_file) {
- /* All the generator's chunks start at blength boundaries. */
- while (aligned_offset < offset) {
- aligned_offset += s->blength;
- aligned_i++;
- }
- if (offset == aligned_offset && aligned_i < s->count) {
- if (i != aligned_i) {
- if (sum != s->sums[aligned_i].sum1
- || l != s->sums[aligned_i].len
- || memcmp(sum2, s->sums[aligned_i].sum2, s->s2length) != 0)
- goto check_want_i;
- i = aligned_i;
- }
- /* This identical chunk is in the same spot in the old and new file. */
- s->sums[i].flags |= SUMFLG_SAME_OFFSET;
- want_i = i;
- }
- }
- check_want_i:
- /* we've found a match, but now check to see
- * if want_i can hint at a better match. */
- if (i != want_i && want_i < s->count
- && (!updating_basis_file || s->sums[want_i].offset >= offset
- || s->sums[want_i].flags & SUMFLG_SAME_OFFSET)
- && sum == s->sums[want_i].sum1
- && memcmp(sum2, s->sums[want_i].sum2, s->s2length) == 0) {
- /* we've found an adjacent match - the RLL coder
- * will be happy */
- i = want_i;
- }
- want_i = i + 1;
- matched(f,s,buf,offset,i);
- offset += s->sums[i].len - 1;
- k = (int32)MIN((OFF_T)s->blength, len-offset);
- map = (schar *)map_ptr(buf, offset, k);
- sum = get_checksum1((char *)map, k);
- s1 = sum & 0xFFFF;
- s2 = sum >> 16;
- matches++;
- break;
- } while ((i = s->sums[i].chain) >= 0);
- null_hash:
- backup = (int32)(offset - last_match);
- /* We sometimes read 1 byte prior to last_match... */
- if (backup < 0)
- backup = 0;
- /* Trim off the first byte from the checksum */
- more = offset + k < len;
- map = (schar *)map_ptr(buf, offset - backup, k + more + backup)
- + backup;
- s1 -= map[0] + CHAR_OFFSET;
- s2 -= k * (map[0]+CHAR_OFFSET);
- /* Add on the next byte (if there is one) to the checksum */
- if (more) {
- s1 += map[k] + CHAR_OFFSET;
- s2 += s1;
- } else
- --k;
- /* By matching early we avoid re-reading the
- data 3 times in the case where a token
- match comes a long way after last
- match. The 3 reads are caused by the
- running match, the checksum update and the
- literal send. */
- if (backup >= s->blength+CHUNK_SIZE && end-offset > CHUNK_SIZE)
- matched(f, s, buf, offset - s->blength, -2);
- } while (++offset < end);
- matched(f, s, buf, len, -1);
- map_ptr(buf, len-1, 1);
- }
- /**
- * Scan through a origin file, looking for sections that match
- * checksums from the generator, and transmit either literal or token
- * data.
- *
- * Also calculates the MD4 checksum of the whole file, using the md
- * accumulator. This is transmitted with the file as protection
- * against corruption on the wire.
- *
- * @param s Checksums received from the generator. If <tt>s->count ==
- * 0</tt>, then there are actually no checksums for this file.
- *
- * @param len Length of the file to send.
- **/
- void match_sums(int f, struct sum_struct *s, struct map_struct *buf, OFF_T len)
- {
- char file_sum[MAX_DIGEST_LEN];
- int sum_len;
- last_match = 0;
- false_alarms = 0;
- hash_hits = 0;
- matches = 0;
- data_transfer = 0;
- sum_init(checksum_seed);
- if (append_mode > 0) {
- if (append_mode == 2) {
- OFF_T j = 0;
- for (j = CHUNK_SIZE; j < s->flength; j += CHUNK_SIZE) {
- if (buf && do_progress)
- show_progress(last_match, buf->file_size);
- sum_update(map_ptr(buf, last_match, CHUNK_SIZE),
- CHUNK_SIZE);
- last_match = j;
- }
- if (last_match < s->flength) {
- int32 n = (int32)(s->flength - last_match);
- if (buf && do_progress)
- show_progress(last_match, buf->file_size);
- sum_update(map_ptr(buf, last_match, n), n);
- }
- }
- last_match = s->flength;
- s->count = 0;
- }
- if (len > 0 && s->count > 0) {
- build_hash_table(s);
- if (verbose > 2)
- rprintf(FINFO,"built hash table\n");
- hash_search(f, s, buf, len);
- if (verbose > 2)
- rprintf(FINFO,"done hash search\n");
- } else {
- OFF_T j;
- /* by doing this in pieces we avoid too many seeks */
- for (j = last_match + CHUNK_SIZE; j < len; j += CHUNK_SIZE)
- matched(f, s, buf, j, -2);
- matched(f, s, buf, len, -1);
- }
- sum_len = sum_end(file_sum);
- /* If we had a read error, send a bad checksum. */
- if (buf && buf->status != 0)
- file_sum[0]++;
- if (verbose > 2)
- rprintf(FINFO,"sending file_sum\n");
- write_buf(f, file_sum, sum_len);
- if (verbose > 2)
- rprintf(FINFO, "false_alarms=%d hash_hits=%d matches=%d\n",
- false_alarms, hash_hits, matches);
- total_hash_hits += hash_hits;
- total_false_alarms += false_alarms;
- total_matches += matches;
- stats.literal_data += data_transfer;
- }
- void match_report(void)
- {
- if (verbose <= 1)
- return;
- rprintf(FINFO,
- "total: matches=%d hash_hits=%d false_alarms=%d data=%.0f\n",
- total_matches, total_hash_hits, total_false_alarms,
- (double)stats.literal_data);
- }
|