[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 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->blength, (double)len);

	/* cast is to make s->blength signed; it should always be reasonably
	 * small */
	k = 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=%d\n", sum, k);
	
	offset = 0;
	
	end = len + 1 - s->sums[s->count-1].len;
	
	if (verbose > 3)
		rprintf(FINFO, "hash search s->blength=%ld len=%.0f count=%ld\n",
			(long) s->blength, (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->blength,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,s->s2length) != 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,s->s2length) != 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->blength);
			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->blength && 
		    (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[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
	22	extern int verbose;
	23	extern int am_server;
	24
	25	typedef unsigned short tag;
	26
	27	#define TABLESIZE (1<<16)
100e5241	28	#define NULL_TAG (-1)
c627d613 AT	29
	30	static int false_alarms;
	31	static int tag_hits;
	32	static int matches;
a800434a	33	static int64 data_transfer;
c627d613	34
3a6a366f AT	35	static int total_false_alarms;
	36	static int total_tag_hits;
	37	static int total_matches;
c627d613	38
a800434a	39	extern struct stats stats;
c627d613 AT	40
	41	struct target {
	42	tag t;
	43	int i;
	44	};
	45
3a6a366f	46	static struct target *targets;
c627d613	47
100e5241	48	static int *tag_table;
c627d613 AT	49
	50	#define gettag2(s1,s2) (((s1) + (s2)) & 0xFFFF)
	51	#define gettag(sum) gettag2((sum)&0xFFFF,(sum)>>16)
	52
	53	static int compare_targets(struct target t1,struct target t2)
	54	{
a16bbc39	55	return((int)t1->t - (int)t2->t);
c627d613 AT	56	}
	57
	58
	59	static void build_hash_table(struct sum_struct *s)
	60	{
	61	int i;
	62
	63	if (!tag_table)
100e5241	64	tag_table = (int )malloc(sizeof(tag_table[0])TABLESIZE);
c627d613 AT	65
	66	targets = (struct target )malloc(sizeof(targets[0])s->count);
	67	if (!tag_table \|\| !targets)
	68	out_of_memory("build_hash_table");
	69
a261989c	70	for (i=0;i<(int) s->count;i++) {
c627d613 AT	71	targets[i].i = i;
	72	targets[i].t = gettag(s->sums[i].sum1);
	73	}
	74
	75	qsort(targets,s->count,sizeof(targets[0]),(int (*)())compare_targets);
	76
	77	for (i=0;i<TABLESIZE;i++)
	78	tag_table[i] = NULL_TAG;
	79
	80	for (i=s->count-1;i>=0;i--) {
	81	tag_table[targets[i].t] = i;
	82	}
	83	}
	84
	85
bcacc18b	86	static OFF_T last_match;
c627d613 AT	87
c627d613 AT	88
f5f95a38 MP	89	/**
	90	* Transmit a literal and/or match token.
	91	*
	92	* This delightfully-named function is called either when we find a
	93	* match and need to transmit all the unmatched data leading up to it,
	94	* or when we get bored of accumulating literal data and just need to
	95	* transmit it. As a result of this second case, it is called even if
	96	* we have not matched at all!
	97	*
	98	* @param i If >0, the number of a matched token. If 0, indicates we
	99	* have only literal data.
	100	**/
c6e7fcb4	101	static void matched(int f,struct sum_struct s,struct map_struct buf,
bcacc18b	102	OFF_T offset,int i)
c627d613	103	{
bcacc18b	104	OFF_T n = offset - last_match;
1309d90d	105	OFF_T j;
9e31c482	106
0d0e2e93	107	if (verbose > 2 && i >= 0)
5f808dfb AT	108	rprintf(FINFO,"match at %.0f last_match=%.0f j=%d len=%d n=%.0f\n",
5f808dfb AT	109	(double)offset,(double)last_match,i,s->sums[i].len,(double)n);
c627d613	110
45f133b9	111	send_token(f,i,buf,last_match,n,i<0?0:s->sums[i].len);
e7ebc36c	112	data_transfer += n;
70d794dc	113
a800434a AT	114	if (i >= 0) {
a800434a AT	115	stats.matched_data += s->sums[i].len;
e7ebc36c	116	n += s->sums[i].len;
a800434a	117	}
70d794dc	118
e7ebc36c AT	119	for (j=0;j<n;j+=CHUNK_SIZE) {
	120	int n1 = MIN(CHUNK_SIZE,n-j);
	121	sum_update(map_ptr(buf,last_match+j,n1),n1);
	122	}
9e31c482	123
9e31c482	124
0d0e2e93	125	if (i >= 0)
e7ebc36c	126	last_match = offset + s->sums[i].len;
0d0e2e93 AT	127	else
0d0e2e93 AT	128	last_match = offset;
eb86d661	129
5e12ce11	130	if (buf) {
4440b8aa	131	show_progress(last_match, buf->file_size);
eb86d661	132
5e12ce11 AT	133	if (i == -1) end_progress(buf->file_size);
5e12ce11 AT	134	}
9e31c482 AT	135	}
	136
	137
c6e7fcb4	138	static void hash_search(int f,struct sum_struct *s,
bcacc18b	139	struct map_struct *buf,OFF_T len)
c627d613	140	{
5f808dfb	141	OFF_T offset, end;
923fa978	142	int j,k, last_i;
e7ebc36c AT	143	char sum2[SUM_LENGTH];
e7ebc36c AT	144	uint32 s1, s2, sum;
debb4505	145	schar *map;
e7ebc36c	146
923fa978 AT	147	/* last_i is used to encourage adjacent matches, allowing the RLL coding of the
	148	output to work more efficiently */
	149	last_i = -1;
	150
e7ebc36c	151	if (verbose > 2)
e35080ce	152	rprintf(FINFO,"hash search b=%ld len=%.0f\n",
fc0257c9	153	(long) s->blength, (double)len);
e7ebc36c	154
fc0257c9	155	/* cast is to make s->blength signed; it should always be reasonably
e35080ce	156	* small */
fc0257c9	157	k = MIN(len, (OFF_T) s->blength);
e7ebc36c	158
debb4505	159	map = (schar *)map_ptr(buf,0,k);
e7ebc36c AT	160
	161	sum = get_checksum1((char *)map, k);
	162	s1 = sum & 0xFFFF;
	163	s2 = sum >> 16;
	164	if (verbose > 3)
9486289c	165	rprintf(FINFO, "sum=%.8x k=%d\n", sum, k);
e7ebc36c AT	166
	167	offset = 0;
	168
	169	end = len + 1 - s->sums[s->count-1].len;
	170
	171	if (verbose > 3)
fc0257c9 S	172	rprintf(FINFO, "hash search s->blength=%ld len=%.0f count=%ld\n",
fc0257c9 S	173	(long) s->blength, (double) len, (long) s->count);
e7ebc36c AT	174
	175	do {
	176	tag t = gettag2(s1,s2);
	177	int done_csum2 = 0;
	178
	179	j = tag_table[t];
	180	if (verbose > 4)
5f808dfb	181	rprintf(FINFO,"offset=%.0f sum=%08x\n",(double)offset,sum);
e7ebc36c AT	182
	183	if (j == NULL_TAG) {
	184	goto null_tag;
	185	}
	186
	187	sum = (s1 & 0xffff) \| (s2 << 16);
	188	tag_hits++;
a261989c	189	for (; j < (int) s->count && targets[j].t == t; j++) {
536541d5	190	int l, i = targets[j].i;
e7ebc36c	191
536541d5	192	if (sum != s->sums[i].sum1) continue;
e7ebc36c	193
536541d5	194	/* also make sure the two blocks are the same length */
fc0257c9	195	l = MIN(s->blength,len-offset);
536541d5 AT	196	if (l != s->sums[i].len) continue;
536541d5 AT	197
e7ebc36c	198	if (verbose > 3)
5f808dfb AT	199	rprintf(FINFO,"potential match at %.0f target=%d %d sum=%08x\n",
5f808dfb AT	200	(double)offset,j,i,sum);
e7ebc36c AT	201
e7ebc36c AT	202	if (!done_csum2) {
debb4505	203	map = (schar *)map_ptr(buf,offset,l);
e7ebc36c AT	204	get_checksum2((char *)map,l,sum2);
	205	done_csum2 = 1;
	206	}
	207
fc0257c9	208	if (memcmp(sum2,s->sums[i].sum2,s->s2length) != 0) {
e7ebc36c AT	209	false_alarms++;
	210	continue;
	211	}
923fa978 AT	212
	213	/* we've found a match, but now check to see
	214	if last_i can hint at a better match */
a261989c	215	for (j++; j < (int) s->count && targets[j].t == t; j++) {
34d3eed4	216	int i2 = targets[j].i;
923fa978 AT	217	if (i2 == last_i + 1) {
923fa978 AT	218	if (sum != s->sums[i2].sum1) break;
fc0257c9	219	if (memcmp(sum2,s->sums[i2].sum2,s->s2length) != 0) break;
923fa978 AT	220	/* we've found an adjacent match - the RLL coder
	221	will be happy */
	222	i = i2;
	223	break;
	224	}
	225	}
	226
	227	last_i = i;
e7ebc36c AT	228
	229	matched(f,s,buf,offset,i);
	230	offset += s->sums[i].len - 1;
fc0257c9	231	k = MIN((len-offset), s->blength);
debb4505	232	map = (schar *)map_ptr(buf,offset,k);
e7ebc36c AT	233	sum = get_checksum1((char *)map, k);
	234	s1 = sum & 0xFFFF;
	235	s2 = sum >> 16;
	236	matches++;
	237	break;
	238	}
	239
	240	null_tag:
	241	/* Trim off the first byte from the checksum */
debb4505	242	map = (schar *)map_ptr(buf,offset,k+1);
e7ebc36c AT	243	s1 -= map[0] + CHAR_OFFSET;
	244	s2 -= k * (map[0]+CHAR_OFFSET);
	245
	246	/* Add on the next byte (if there is one) to the checksum */
	247	if (k < (len-offset)) {
	248	s1 += (map[k]+CHAR_OFFSET);
	249	s2 += s1;
	250	} else {
	251	--k;
	252	}
45f133b9	253
5914bf15 PM	254	/* By matching early we avoid re-reading the
	255	data 3 times in the case where a token
	256	match comes a long way after last
	257	match. The 3 reads are caused by the
	258	running match, the checksum update and the
	259	literal send. */
0e948031	260	if (offset > last_match &&
fc0257c9	261	offset-last_match >= CHUNK_SIZE+s->blength &&
5914bf15	262	(end-offset > CHUNK_SIZE)) {
fc0257c9	263	matched(f,s,buf,offset - s->blength, -2);
45f133b9	264	}
e7ebc36c AT	265	} while (++offset < end);
	266
	267	matched(f,s,buf,len,-1);
	268	map_ptr(buf,len-1,1);
c627d613 AT	269	}
	270
	271
f5f95a38 MP	272	/**
	273	* Scan through a origin file, looking for sections that match
	274	* checksums from the generator, and transmit either literal or token
	275	* data.
	276	*
538ba24f MP	277	* Also calculates the MD4 checksum of the whole file, using the md
	278	* accumulator. This is transmitted with the file as protection
	279	* against corruption on the wire.
	280	*
f5f95a38 MP	281	* @param s Checksums received from the generator. If <tt>s->count ==
	282	* 0</tt>, then there are actually no checksums for this file.
	283	*
	284	* @param len Length of the file to send.
	285	**/
	286	void match_sums(int f, struct sum_struct s, struct map_struct buf, OFF_T len)
c627d613	287	{
e7ebc36c	288	char file_sum[MD4_SUM_LENGTH];
6902ed17	289	extern int write_batch; /* dw */
e7ebc36c AT	290
	291	last_match = 0;
	292	false_alarms = 0;
	293	tag_hits = 0;
	294	matches=0;
	295	data_transfer=0;
	296
	297	sum_init();
	298
	299	if (len > 0 && s->count>0) {
	300	build_hash_table(s);
	301
	302	if (verbose > 2)
9486289c	303	rprintf(FINFO,"built hash table\n");
e7ebc36c AT	304
	305	hash_search(f,s,buf,len);
	306
	307	if (verbose > 2)
9486289c	308	rprintf(FINFO,"done hash search\n");
e7ebc36c	309	} else {
eb86d661 AT	310	OFF_T j;
	311	/* by doing this in pieces we avoid too many seeks */
	312	for (j=0;j<(len-CHUNK_SIZE);j+=CHUNK_SIZE) {
	313	int n1 = MIN(CHUNK_SIZE,(len-CHUNK_SIZE)-j);
	314	matched(f,s,buf,j+n1,-2);
	315	}
e7ebc36c AT	316	matched(f,s,buf,len,-1);
e7ebc36c AT	317	}
9e31c482	318
e7ebc36c	319	sum_end(file_sum);
c627d613	320
bc63ae3f S	321	if (verbose > 2)
	322	rprintf(FINFO,"sending file_sum\n");
	323	write_buf(f,file_sum,MD4_SUM_LENGTH);
	324	if (write_batch) /* dw */
	325	write_batch_delta_file(file_sum, MD4_SUM_LENGTH);
c627d613	326
e7ebc36c AT	327	if (targets) {
	328	free(targets);
	329	targets=NULL;
	330	}
	331
	332	if (verbose > 2)
9486289c	333	rprintf(FINFO, "false_alarms=%d tag_hits=%d matches=%d\n",
e7ebc36c AT	334	false_alarms, tag_hits, matches);
	335
	336	total_tag_hits += tag_hits;
	337	total_false_alarms += false_alarms;
	338	total_matches += matches;
a800434a	339	stats.literal_data += data_transfer;
c627d613 AT	340	}
	341
	342	void match_report(void)
	343	{
e7ebc36c AT	344	if (verbose <= 1)
e7ebc36c AT	345	return;
c627d613	346
9486289c	347	rprintf(FINFO,
a800434a	348	"total: matches=%d tag_hits=%d false_alarms=%d data=%.0f\n",
e7ebc36c	349	total_matches,total_tag_hits,
a800434a AT	350	total_false_alarms,
a800434a AT	351	(double)stats.literal_data);
c627d613	352	}