Preparing for release of 2.6.6pre1
[rsync.git] / match.c
diff --git a/match.c b/match.c
index 719961da1c0bfc531948e231885ca1e2ffb7172e..00a38aa45abb8a310bc2d5157979d1358433e8a4 100644 (file)
--- a/match.c
+++ b/match.c
@@ -1,17 +1,17 @@
-/* 
+/*
    Copyright (C) Andrew Tridgell 1996
    Copyright (C) Paul Mackerras 1996
-   
+
    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 2 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, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
 #include "rsync.h"
 
-extern int csum_length;
-
 extern int verbose;
 extern int am_server;
+extern int do_progress;
+extern int checksum_seed;
 
-extern int remote_version;
+int updating_basis_file;
 
 typedef unsigned short tag;
 
 #define TABLESIZE (1<<16)
-#define NULL_TAG ((tag)-1)
+#define NULL_TAG (-1)
 
 static int false_alarms;
 static int tag_hits;
@@ -43,74 +43,88 @@ static int total_matches;
 extern struct stats stats;
 
 struct target {
-  tag t;
-  int i;
+       tag t;
+       int32 i;
 };
 
 static struct target *targets;
 
-static tag *tag_table;
+static int32 *tag_table;
 
 #define gettag2(s1,s2) (((s1) + (s2)) & 0xFFFF)
 #define gettag(sum) gettag2((sum)&0xFFFF,(sum)>>16)
 
 static int compare_targets(struct target *t1,struct target *t2)
 {
-  return((int)t1->t - (int)t2->t);
+       return (int)t1->t - (int)t2->t;
 }
 
 
 static void build_hash_table(struct sum_struct *s)
 {
-  int i;
+       int32 i;
 
-  if (!tag_table)
-    tag_table = (tag *)malloc(sizeof(tag)*TABLESIZE);
+       if (!tag_table)
+               tag_table = new_array(int32, TABLESIZE);
 
-  targets = (struct target *)malloc(sizeof(targets[0])*s->count);
-  if (!tag_table || !targets) 
-    out_of_memory("build_hash_table");
+       targets = new_array(struct target, s->count);
+       if (!tag_table || !targets)
+               out_of_memory("build_hash_table");
 
-  for (i=0;i<s->count;i++) {
-    targets[i].i = i;
-    targets[i].t = gettag(s->sums[i].sum1);
-  }
+       for (i = 0; i < s->count; i++) {
+               targets[i].i = i;
+               targets[i].t = gettag(s->sums[i].sum1);
+       }
 
-  qsort(targets,s->count,sizeof(targets[0]),(int (*)())compare_targets);
+       qsort(targets,s->count,sizeof(targets[0]),(int (*)())compare_targets);
 
-  for (i=0;i<TABLESIZE;i++)
-    tag_table[i] = NULL_TAG;
+       for (i = 0; i < TABLESIZE; i++)
+               tag_table[i] = NULL_TAG;
 
-  for (i=s->count-1;i>=0;i--) {    
-    tag_table[targets[i].t] = i;
-  }
+       for (i = s->count; i-- > 0; )
+               tag_table[targets[i].t] = i;
 }
 
 
 static OFF_T last_match;
 
 
-static void matched(int f,struct sum_struct *s,struct map_struct *buf,
-                   OFF_T offset,int i)
+/**
+ * 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!
+ *
+ * @param i If >0, the number of a matched token.  If 0, indicates we
+ * have only literal data.
+ **/
+static void matched(int f, struct sum_struct *s, struct map_struct *buf,
+                   OFF_T offset, int32 i)
 {
-       OFF_T n = offset - last_match;
-       int j;
-
-       if (verbose > 2 && i >= 0)
-               rprintf(FINFO,"match at %d last_match=%d j=%d len=%d n=%d\n",
-                       (int)offset,(int)last_match,i,(int)s->sums[i].len,(int)n);
+       int32 n = 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);
+       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) {
-               int n1 = MIN(CHUNK_SIZE,n-j);
-               sum_update(map_ptr(buf,last_match+j,n1),n1);
+
+       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);
        }
 
 
@@ -118,99 +132,162 @@ static void matched(int f,struct sum_struct *s,struct map_struct *buf,
                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)
+                       struct map_struct *buf, OFF_T len)
 {
-       OFF_T offset;
-       int j,k;
-       int end;
+       OFF_T offset, end, backup;
+       int32 k, want_i;
        char sum2[SUM_LENGTH];
-       uint32 s1, s2, sum; 
+       uint32 s1, s2, sum;
+       int more;
        schar *map;
 
-       if (verbose > 2)
-               rprintf(FINFO,"hash search b=%d len=%d\n",s->n,(int)len);
+       /* 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);
 
-       k = MIN(len, s->n);
-       
-       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=%d\n", sum, k);
-       
+               rprintf(FINFO, "sum=%.8x k=%ld\n", sum, (long)k);
+
        offset = 0;
-       
+
        end = len + 1 - s->sums[s->count-1].len;
-       
-       if (verbose > 3)
-               rprintf(FINFO,"hash search s->n=%d len=%d count=%d\n",
-                       s->n,(int)len,s->count);
-       
+
+       if (verbose > 3) {
+               rprintf(FINFO, "hash search s->blength=%ld len=%.0f count=%.0f\n",
+                       (long)s->blength, (double)len, (double)s->count);
+       }
+
        do {
                tag t = gettag2(s1,s2);
                int done_csum2 = 0;
-                       
-               j = tag_table[t];
+               int32 j = tag_table[t];
+
                if (verbose > 4)
-                       rprintf(FINFO,"offset=%d sum=%08x\n",(int)offset,sum);
-               
-               if (j == NULL_TAG) {
+                       rprintf(FINFO,"offset=%.0f sum=%08x\n",(double)offset,sum);
+
+               if (j == NULL_TAG)
                        goto null_tag;
-               }
 
                sum = (s1 & 0xffff) | (s2 << 16);
                tag_hits++;
-               for (; j<s->count && targets[j].t == t; j++) {
-                       int i = targets[j].i;
-                       
-                       if (sum != s->sums[i].sum1) continue;
-                       
+               do {
+                       int32 l, i = targets[j].i;
+
+                       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 %d target=%d %d sum=%08x\n",
-                                       (int)offset,j,i,sum);
-                       
+                               rprintf(FINFO,"potential match at %.0f target=%.0f %.0f sum=%08x\n",
+                                       (double)offset,(double)j,(double)i,sum);
+
                        if (!done_csum2) {
-                               int l = MIN(s->n,len-offset);
                                map = (schar *)map_ptr(buf,offset,l);
                                get_checksum2((char *)map,l,sum2);
                                done_csum2 = 1;
                        }
-                       
-                       if (memcmp(sum2,s->sums[i].sum2,csum_length) != 0) {
+
+                       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 following want_i optimization. */
+                       if (updating_basis_file) {
+                               do {
+                                       int32 i2 = targets[j].i;
+                                       if (s->sums[i2].offset != offset)
+                                               continue;
+                                       if (i2 != i) {
+                                               if (sum != s->sums[i2].sum1)
+                                                       break;
+                                               if (memcmp(sum2, s->sums[i2].sum2,
+                                                          s->s2length) != 0)
+                                                       break;
+                                               i = i2;
+                                       }
+                                       /* This chunk was at the same offset on
+                                        * both the sender and the receiver. */
+                                       s->sums[i].flags |= SUMFLG_SAME_OFFSET;
+                                       goto set_want_i;
+                               } while (++j < s->count && targets[j].t == t);
+                       }
+
+                       /* 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;
+                       }
+                   set_want_i:
+                       want_i = i + 1;
+
                        matched(f,s,buf,offset,i);
                        offset += s->sums[i].len - 1;
-                       k = MIN((len-offset), s->n);
-                       map = (schar *)map_ptr(buf,offset,k);
+                       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 (++j < s->count && targets[j].t == t);
+
        null_tag:
+               backup = 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 */
-               map = (schar *)map_ptr(buf,offset,k+1);
+               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 (k < (len-offset)) {
-                       s1 += (map[k]+CHAR_OFFSET);
+               if (more) {
+                       s1 += map[k] + CHAR_OFFSET;
                        s2 += s1;
-               } else {
+               } else
                        --k;
-               }
 
                /* By matching early we avoid re-reading the
                   data 3 times in the case where a token
@@ -218,60 +295,77 @@ static void hash_search(int f,struct sum_struct *s,
                   match. The 3 reads are caused by the
                   running match, the checksum update and the
                   literal send. */
-               if (offset-last_match >= CHUNK_SIZE+s->n && 
-                   (end-offset > CHUNK_SIZE)) {
-                       matched(f,s,buf,offset - s->n, -2);
-               }
+               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);
+
+       matched(f, s, buf, len, -1);
+       map_ptr(buf, len-1, 1);
 }
 
 
-void match_sums(int f,struct sum_struct *s,struct map_struct *buf,OFF_T len)
+/**
+ * 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[MD4_SUM_LENGTH];
 
        last_match = 0;
        false_alarms = 0;
        tag_hits = 0;
-       matches=0;
-       data_transfer=0;
+       matches = 0;
+       data_transfer = 0;
 
-       sum_init();
+       sum_init(checksum_seed);
 
-       if (len > 0 && s->count>0) {
+       if (len > 0 && s->count > 0) {
                build_hash_table(s);
-               
-               if (verbose > 2) 
+
+               if (verbose > 2)
                        rprintf(FINFO,"built hash table\n");
-               
+
                hash_search(f,s,buf,len);
-               
-               if (verbose > 2) 
+
+               if (verbose > 2)
                        rprintf(FINFO,"done hash search\n");
        } else {
-               matched(f,s,buf,len,-1);
+               OFF_T j;
+               /* by doing this in pieces we avoid too many seeks */
+               for (j = CHUNK_SIZE; j < len; j += CHUNK_SIZE)
+                       matched(f, s, buf, j, -2);
+               matched(f, s, buf, len, -1);
        }
 
        sum_end(file_sum);
+       /* If we had a read error, send a bad checksum. */
+       if (buf && buf->status != 0)
+               file_sum[0]++;
 
-       if (remote_version >= 14) {
-               if (verbose > 2)
-                       rprintf(FINFO,"sending file_sum\n");
-               write_buf(f,file_sum,MD4_SUM_LENGTH);
-       }
+       if (verbose > 2)
+               rprintf(FINFO,"sending file_sum\n");
+       write_buf(f,file_sum,MD4_SUM_LENGTH);
 
        if (targets) {
                free(targets);
                targets=NULL;
        }
-       
+
        if (verbose > 2)
                rprintf(FINFO, "false_alarms=%d tag_hits=%d matches=%d\n",
                        false_alarms, tag_hits, matches);
-       
+
        total_tag_hits += tag_hits;
        total_false_alarms += false_alarms;
        total_matches += matches;