[rsync/rsync.git] / match.c

/* 
   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;

typedef unsigned short tag;

#define TABLESIZE (1<<16)
#define NULL_TAG (-1)

static int false_alarms;
static int tag_hits;
static int matches;
static int64 data_transfer;

static int total_false_alarms;
static int total_tag_hits;
static int total_matches;

extern struct stats stats;

struct target {
  tag t;
  int i;
};

static struct target *targets;

static int *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);
}


static void build_hash_table(struct sum_struct *s)
{
  int i;

  if (!tag_table)
    tag_table = (int *)malloc(sizeof(tag_table[0])*TABLESIZE);

  targets = (struct target *)malloc(sizeof(targets[0])*s->count);
  if (!tag_table || !targets) 
    out_of_memory("build_hash_table");

  for (i=0;i<(int) 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);

  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;
  }
}


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!
 *
 * @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,int i)
{
	OFF_T n = offset - last_match;
	OFF_T j;

	if (verbose > 2 && i >= 0)
		rprintf(FINFO,"match at %.0f last_match=%.0f j=%d len=%d n=%.0f\n",
			(double)offset,(double)last_match,i,s->sums[i].len,(double)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) {
		int 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) {
		show_progress(last_match, buf->file_size);

		if (i == -1) end_progress(buf->file_size);
	}
}


static void hash_search(int f,struct sum_struct *s,
			struct map_struct *buf,OFF_T len)
{
	OFF_T offset, end;
	int j,k, last_i;
	char sum2[SUM_LENGTH];
	uint32 s1, s2, sum; 
	schar *map;

	/* last_i is used to encourage adjacent matches, allowing the RLL coding of the
	   output to work more efficiently */
	last_i = -1;

	if (verbose > 2)
		rprintf(FINFO,"hash search b=%ld len=%.0f\n",
			(long) s->n, (double)len);

	/* cast is to make s->n signed; it should always be reasonably
	 * small */
	k = MIN(len, (OFF_T) 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);
	
	offset = 0;
	
	end = len + 1 - s->sums[s->count-1].len;
	
	if (verbose > 3)
		rprintf(FINFO, "hash search s->n=%ld len=%.0f count=%ld\n",
			(long) s->n, (double) len, (long) s->count);
	
	do {
		tag t = gettag2(s1,s2);
		int done_csum2 = 0;
			
		j = tag_table[t];
		if (verbose > 4)
			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 < (int) s->count && targets[j].t == t; j++) {
			int l, i = targets[j].i;
			
			if (sum != s->sums[i].sum1) continue;
			
			/* also make sure the two blocks are the same length */
			l = MIN(s->n,len-offset);
			if (l != s->sums[i].len) continue;			

			if (verbose > 3)
				rprintf(FINFO,"potential match at %.0f target=%d %d sum=%08x\n",
					(double)offset,j,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,csum_length) != 0) {
				false_alarms++;
				continue;
			}

			/* we've found a match, but now check to see
                           if last_i can hint at a better match */
			for (j++; j < (int) s->count && targets[j].t == t; j++) {
				int i2 = targets[j].i;
				if (i2 == last_i + 1) {
					if (sum != s->sums[i2].sum1) break;
					if (memcmp(sum2,s->sums[i2].sum2,csum_length) != 0) break;
					/* we've found an adjacent match - the RLL coder 
					   will be happy */
					i = i2;
					break;
				}
			}

			last_i = i;
			
			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);
			sum = get_checksum1((char *)map, k);
			s1 = sum & 0xFFFF;
			s2 = sum >> 16;
			matches++;
			break;
		}
		
	null_tag:
		/* Trim off the first byte from the checksum */
		map = (schar *)map_ptr(buf,offset,k+1);
		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);
			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 (offset > last_match &&
		    offset-last_match >= CHUNK_SIZE+s->n && 
		    (end-offset > CHUNK_SIZE)) {
			matched(f,s,buf,offset - s->n, -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[MD4_SUM_LENGTH];
	extern int write_batch;  /*  dw */

	last_match = 0;
	false_alarms = 0;
	tag_hits = 0;
	matches=0;
	data_transfer=0;

	sum_init();

	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=0;j<(len-CHUNK_SIZE);j+=CHUNK_SIZE) {
			int n1 = MIN(CHUNK_SIZE,(len-CHUNK_SIZE)-j);
			matched(f,s,buf,j+n1,-2);
		}
		matched(f,s,buf,len,-1);
	}

	sum_end(file_sum);

	if (verbose > 2)
		rprintf(FINFO,"sending file_sum\n");
	write_buf(f,file_sum,MD4_SUM_LENGTH);
	if (write_batch) /* dw */
		write_batch_delta_file(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;
	stats.literal_data += data_transfer;
}

void match_report(void)
{
	if (verbose <= 1)
		return;

	rprintf(FINFO,
		"total: matches=%d  tag_hits=%d  false_alarms=%d data=%.0f\n",
		total_matches,total_tag_hits,
		total_false_alarms,
		(double)stats.literal_data);
}
Commit	Line	Data
c627d613 AT	1	/*
	2	Copyright (C) Andrew Tridgell 1996
	3	Copyright (C) Paul Mackerras 1996
	4
	5	This program is free software; you can redistribute it and/or modify
	6	it under the terms of the GNU General Public License as published by
	7	the Free Software Foundation; either version 2 of the License, or
	8	(at your option) any later version.
	9
	10	This program is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	GNU General Public License for more details.
	14
	15	You should have received a copy of the GNU General Public License
	16	along with this program; if not, write to the Free Software
	17	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	18	*/
	19
	20	#include "rsync.h"
	21
43a481dc AT	22	extern int csum_length;
43a481dc AT	23
c627d613 AT	24	extern int verbose;
	25	extern int am_server;
	26
	27	typedef unsigned short tag;
	28
	29	#define TABLESIZE (1<<16)
100e5241	30	#define NULL_TAG (-1)
c627d613 AT	31
	32	static int false_alarms;
	33	static int tag_hits;
	34	static int matches;
a800434a	35	static int64 data_transfer;
c627d613	36
3a6a366f AT	37	static int total_false_alarms;
	38	static int total_tag_hits;
	39	static int total_matches;
c627d613	40
a800434a	41	extern struct stats stats;
c627d613 AT	42
	43	struct target {
	44	tag t;
	45	int i;
	46	};
	47
3a6a366f	48	static struct target *targets;
c627d613	49
100e5241	50	static int *tag_table;
c627d613 AT	51
	52	#define gettag2(s1,s2) (((s1) + (s2)) & 0xFFFF)
	53	#define gettag(sum) gettag2((sum)&0xFFFF,(sum)>>16)
	54
	55	static int compare_targets(struct target t1,struct target t2)
	56	{
a16bbc39	57	return((int)t1->t - (int)t2->t);
c627d613 AT	58	}
	59
	60
	61	static void build_hash_table(struct sum_struct *s)
	62	{
	63	int i;
	64
	65	if (!tag_table)
100e5241	66	tag_table = (int )malloc(sizeof(tag_table[0])TABLESIZE);
c627d613 AT	67
	68	targets = (struct target )malloc(sizeof(targets[0])s->count);
	69	if (!tag_table \|\| !targets)
	70	out_of_memory("build_hash_table");
	71
a261989c	72	for (i=0;i<(int) s->count;i++) {
c627d613 AT	73	targets[i].i = i;
	74	targets[i].t = gettag(s->sums[i].sum1);
	75	}
	76
	77	qsort(targets,s->count,sizeof(targets[0]),(int (*)())compare_targets);
	78
	79	for (i=0;i<TABLESIZE;i++)
	80	tag_table[i] = NULL_TAG;
	81
	82	for (i=s->count-1;i>=0;i--) {
	83	tag_table[targets[i].t] = i;
	84	}
	85	}
	86
	87
bcacc18b	88	static OFF_T last_match;
c627d613 AT	89
c627d613 AT	90
f5f95a38 MP	91	/**
	92	* Transmit a literal and/or match token.
	93	*
	94	* This delightfully-named function is called either when we find a
	95	* match and need to transmit all the unmatched data leading up to it,
	96	* or when we get bored of accumulating literal data and just need to
	97	* transmit it. As a result of this second case, it is called even if
	98	* we have not matched at all!
	99	*
	100	* @param i If >0, the number of a matched token. If 0, indicates we
	101	* have only literal data.
	102	**/
c6e7fcb4	103	static void matched(int f,struct sum_struct s,struct map_struct buf,
bcacc18b	104	OFF_T offset,int i)
c627d613	105	{
bcacc18b	106	OFF_T n = offset - last_match;
1309d90d	107	OFF_T j;
9e31c482	108
0d0e2e93	109	if (verbose > 2 && i >= 0)
5f808dfb AT	110	rprintf(FINFO,"match at %.0f last_match=%.0f j=%d len=%d n=%.0f\n",
5f808dfb AT	111	(double)offset,(double)last_match,i,s->sums[i].len,(double)n);
c627d613	112
45f133b9	113	send_token(f,i,buf,last_match,n,i<0?0:s->sums[i].len);
e7ebc36c	114	data_transfer += n;
70d794dc	115
a800434a AT	116	if (i >= 0) {
a800434a AT	117	stats.matched_data += s->sums[i].len;
e7ebc36c	118	n += s->sums[i].len;
a800434a	119	}
70d794dc	120
e7ebc36c AT	121	for (j=0;j<n;j+=CHUNK_SIZE) {
	122	int n1 = MIN(CHUNK_SIZE,n-j);
	123	sum_update(map_ptr(buf,last_match+j,n1),n1);
	124	}
9e31c482	125
9e31c482	126
0d0e2e93	127	if (i >= 0)
e7ebc36c	128	last_match = offset + s->sums[i].len;
0d0e2e93 AT	129	else
0d0e2e93 AT	130	last_match = offset;
eb86d661	131
5e12ce11	132	if (buf) {
4440b8aa	133	show_progress(last_match, buf->file_size);
eb86d661	134
5e12ce11 AT	135	if (i == -1) end_progress(buf->file_size);
5e12ce11 AT	136	}
9e31c482 AT	137	}
	138
	139
c6e7fcb4	140	static void hash_search(int f,struct sum_struct *s,
bcacc18b	141	struct map_struct *buf,OFF_T len)
c627d613	142	{
5f808dfb	143	OFF_T offset, end;
923fa978	144	int j,k, last_i;
e7ebc36c AT	145	char sum2[SUM_LENGTH];
e7ebc36c AT	146	uint32 s1, s2, sum;
debb4505	147	schar *map;
e7ebc36c	148
923fa978 AT	149	/* last_i is used to encourage adjacent matches, allowing the RLL coding of the
	150	output to work more efficiently */
	151	last_i = -1;
	152
e7ebc36c	153	if (verbose > 2)
e35080ce MP	154	rprintf(FINFO,"hash search b=%ld len=%.0f\n",
e35080ce MP	155	(long) s->n, (double)len);
e7ebc36c	156
e35080ce MP	157	/* cast is to make s->n signed; it should always be reasonably
	158	* small */
	159	k = MIN(len, (OFF_T) s->n);
e7ebc36c	160
debb4505	161	map = (schar *)map_ptr(buf,0,k);
e7ebc36c AT	162
	163	sum = get_checksum1((char *)map, k);
	164	s1 = sum & 0xFFFF;
	165	s2 = sum >> 16;
	166	if (verbose > 3)
9486289c	167	rprintf(FINFO, "sum=%.8x k=%d\n", sum, k);
e7ebc36c AT	168
	169	offset = 0;
	170
	171	end = len + 1 - s->sums[s->count-1].len;
	172
	173	if (verbose > 3)
e35080ce MP	174	rprintf(FINFO, "hash search s->n=%ld len=%.0f count=%ld\n",
e35080ce MP	175	(long) s->n, (double) len, (long) s->count);
e7ebc36c AT	176
	177	do {
	178	tag t = gettag2(s1,s2);
	179	int done_csum2 = 0;
	180
	181	j = tag_table[t];
	182	if (verbose > 4)
5f808dfb	183	rprintf(FINFO,"offset=%.0f sum=%08x\n",(double)offset,sum);
e7ebc36c AT	184
	185	if (j == NULL_TAG) {
	186	goto null_tag;
	187	}
	188
	189	sum = (s1 & 0xffff) \| (s2 << 16);
	190	tag_hits++;
a261989c	191	for (; j < (int) s->count && targets[j].t == t; j++) {
536541d5	192	int l, i = targets[j].i;
e7ebc36c	193
536541d5	194	if (sum != s->sums[i].sum1) continue;
e7ebc36c	195
536541d5 AT	196	/* also make sure the two blocks are the same length */
	197	l = MIN(s->n,len-offset);
	198	if (l != s->sums[i].len) continue;
	199
e7ebc36c	200	if (verbose > 3)
5f808dfb AT	201	rprintf(FINFO,"potential match at %.0f target=%d %d sum=%08x\n",
5f808dfb AT	202	(double)offset,j,i,sum);
e7ebc36c AT	203
e7ebc36c AT	204	if (!done_csum2) {
debb4505	205	map = (schar *)map_ptr(buf,offset,l);
e7ebc36c AT	206	get_checksum2((char *)map,l,sum2);
	207	done_csum2 = 1;
	208	}
	209
	210	if (memcmp(sum2,s->sums[i].sum2,csum_length) != 0) {
	211	false_alarms++;
	212	continue;
	213	}
923fa978 AT	214
	215	/* we've found a match, but now check to see
	216	if last_i can hint at a better match */
a261989c	217	for (j++; j < (int) s->count && targets[j].t == t; j++) {
34d3eed4	218	int i2 = targets[j].i;
923fa978 AT	219	if (i2 == last_i + 1) {
	220	if (sum != s->sums[i2].sum1) break;
	221	if (memcmp(sum2,s->sums[i2].sum2,csum_length) != 0) break;
	222	/* we've found an adjacent match - the RLL coder
	223	will be happy */
	224	i = i2;
	225	break;
	226	}
	227	}
	228
	229	last_i = i;
e7ebc36c AT	230
	231	matched(f,s,buf,offset,i);
	232	offset += s->sums[i].len - 1;
	233	k = MIN((len-offset), s->n);
debb4505	234	map = (schar *)map_ptr(buf,offset,k);
e7ebc36c AT	235	sum = get_checksum1((char *)map, k);
	236	s1 = sum & 0xFFFF;
	237	s2 = sum >> 16;
	238	matches++;
	239	break;
	240	}
	241
	242	null_tag:
	243	/* Trim off the first byte from the checksum */
debb4505	244	map = (schar *)map_ptr(buf,offset,k+1);
e7ebc36c AT	245	s1 -= map[0] + CHAR_OFFSET;
	246	s2 -= k * (map[0]+CHAR_OFFSET);
	247
	248	/* Add on the next byte (if there is one) to the checksum */
	249	if (k < (len-offset)) {
	250	s1 += (map[k]+CHAR_OFFSET);
	251	s2 += s1;
	252	} else {
	253	--k;
	254	}
45f133b9	255
5914bf15 PM	256	/* By matching early we avoid re-reading the
	257	data 3 times in the case where a token
	258	match comes a long way after last
	259	match. The 3 reads are caused by the
	260	running match, the checksum update and the
	261	literal send. */
0e948031 AT	262	if (offset > last_match &&
0e948031 AT	263	offset-last_match >= CHUNK_SIZE+s->n &&
5914bf15 PM	264	(end-offset > CHUNK_SIZE)) {
5914bf15 PM	265	matched(f,s,buf,offset - s->n, -2);
45f133b9	266	}
e7ebc36c AT	267	} while (++offset < end);
	268
	269	matched(f,s,buf,len,-1);
	270	map_ptr(buf,len-1,1);
c627d613 AT	271	}
	272
	273
f5f95a38 MP	274	/**
	275	* Scan through a origin file, looking for sections that match
	276	* checksums from the generator, and transmit either literal or token
	277	* data.
	278	*
538ba24f MP	279	* Also calculates the MD4 checksum of the whole file, using the md
	280	* accumulator. This is transmitted with the file as protection
	281	* against corruption on the wire.
	282	*
f5f95a38 MP	283	* @param s Checksums received from the generator. If <tt>s->count ==
	284	* 0</tt>, then there are actually no checksums for this file.
	285	*
	286	* @param len Length of the file to send.
	287	**/
	288	void match_sums(int f, struct sum_struct s, struct map_struct buf, OFF_T len)
c627d613	289	{
e7ebc36c	290	char file_sum[MD4_SUM_LENGTH];
6902ed17	291	extern int write_batch; /* dw */
e7ebc36c AT	292
	293	last_match = 0;
	294	false_alarms = 0;
	295	tag_hits = 0;
	296	matches=0;
	297	data_transfer=0;
	298
	299	sum_init();
	300
	301	if (len > 0 && s->count>0) {
	302	build_hash_table(s);
	303
	304	if (verbose > 2)
9486289c	305	rprintf(FINFO,"built hash table\n");
e7ebc36c AT	306
	307	hash_search(f,s,buf,len);
	308
	309	if (verbose > 2)
9486289c	310	rprintf(FINFO,"done hash search\n");
e7ebc36c	311	} else {
eb86d661 AT	312	OFF_T j;
	313	/* by doing this in pieces we avoid too many seeks */
	314	for (j=0;j<(len-CHUNK_SIZE);j+=CHUNK_SIZE) {
	315	int n1 = MIN(CHUNK_SIZE,(len-CHUNK_SIZE)-j);
	316	matched(f,s,buf,j+n1,-2);
	317	}
e7ebc36c AT	318	matched(f,s,buf,len,-1);
e7ebc36c AT	319	}
9e31c482	320
e7ebc36c	321	sum_end(file_sum);
c627d613	322
bc63ae3f S	323	if (verbose > 2)
	324	rprintf(FINFO,"sending file_sum\n");
	325	write_buf(f,file_sum,MD4_SUM_LENGTH);
	326	if (write_batch) /* dw */
	327	write_batch_delta_file(file_sum, MD4_SUM_LENGTH);
c627d613	328
e7ebc36c AT	329	if (targets) {
	330	free(targets);
	331	targets=NULL;
	332	}
	333
	334	if (verbose > 2)
9486289c	335	rprintf(FINFO, "false_alarms=%d tag_hits=%d matches=%d\n",
e7ebc36c AT	336	false_alarms, tag_hits, matches);
	337
	338	total_tag_hits += tag_hits;
	339	total_false_alarms += false_alarms;
	340	total_matches += matches;
a800434a	341	stats.literal_data += data_transfer;
c627d613 AT	342	}
	343
	344	void match_report(void)
	345	{
e7ebc36c AT	346	if (verbose <= 1)
e7ebc36c AT	347	return;
c627d613	348
9486289c	349	rprintf(FINFO,
a800434a	350	"total: matches=%d tag_hits=%d false_alarms=%d data=%.0f\n",
e7ebc36c	351	total_matches,total_tag_hits,
a800434a AT	352	total_false_alarms,
a800434a AT	353	(double)stats.literal_data);
c627d613	354	}