match.c - android_external_rsync - Gitiles

 /*
    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;
 extern int do_progress;

 typedef unsigned short tag;

 #define TABLESIZE (1<<16)
 #define NULL_TAG ((size_t)-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;
 	size_t i;
 };

 static struct target *targets;

 static size_t *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)
 {
 	size_t i;

 	if (!tag_table)
 		tag_table = new_array(size_t, TABLESIZE);

 	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);
 	}

 	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; i-- > 0; )
 		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=%u 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 && do_progress) {
 		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;
 	unsigned int k;
 	size_t 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 = (size_t)-1;

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

 	k = MIN(len, 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=%u\n", sum, k);

 	offset = 0;

 	end = len + 1 - s->sums[s->count-1].len;

 	if (verbose > 3) {
 		rprintf(FINFO, "hash search s->blength=%u len=%.0f count=%.0f\n",
 			s->blength, (double)len, (double)s->count);
 	}

 	do {
 		tag t = gettag2(s1,s2);
 		int done_csum2 = 0;
 		size_t 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 < s->count && targets[j].t == t; j++) {
 			unsigned int l;
 			size_t i = targets[j].i;

 			if (sum != s->sums[i].sum1)
 				continue;

 			/* also make sure the two blocks are the same length */
 			l = MIN((OFF_T)s->blength, len-offset);
 			if (l != s->sums[i].len)
 				continue;

 			if (verbose > 3)
 				rprintf(FINFO,"potential match at %.0f target=%.0f %.0f sum=%08x\n",
 					(double)offset,(double)j,(double)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 < s->count && targets[j].t == t; j++) {
 				size_t 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(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;
 		}

 	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;

 	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)
 		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);
 }
	/*
	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;
	extern int do_progress;

	typedef unsigned short tag;

	#define TABLESIZE (1<<16)
	#define NULL_TAG ((size_t)-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;
	size_t i;
	};

	static struct target *targets;

	static size_t *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)
	{
	size_t i;

	if (!tag_table)
	tag_table = new_array(size_t, TABLESIZE);

	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);
	}

	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; i-- > 0; )
	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=%u 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 && do_progress) {
	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;
	unsigned int k;
	size_t 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 = (size_t)-1;

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

	k = MIN(len, 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=%u\n", sum, k);

	offset = 0;

	end = len + 1 - s->sums[s->count-1].len;

	if (verbose > 3) {
	rprintf(FINFO, "hash search s->blength=%u len=%.0f count=%.0f\n",
	s->blength, (double)len, (double)s->count);
	}

	do {
	tag t = gettag2(s1,s2);
	int done_csum2 = 0;
	size_t 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 < s->count && targets[j].t == t; j++) {
	unsigned int l;
	size_t i = targets[j].i;

	if (sum != s->sums[i].sum1)
	continue;

	/* also make sure the two blocks are the same length */
	l = MIN((OFF_T)s->blength, len-offset);
	if (l != s->sums[i].len)
	continue;

	if (verbose > 3)
	rprintf(FINFO,"potential match at %.0f target=%.0f %.0f sum=%08x\n",
	(double)offset,(double)j,(double)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 < s->count && targets[j].t == t; j++) {
	size_t 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(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;
	}

	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;

	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)
	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);
	}