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/*-
* Copyright 2003 - 2005 Colin Percival
* All rights reserved
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted providing that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#if 0
__FBSDID("$FreeBSD: src/usr.bin/bsdiff/bsdiff/bsdiff.c, v 1.1 2005/08/06 01:59:05 cperciva Exp $");
#endif
#include <sys/types.h>
#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define MIN(x, y) (((x)<(y)) ? (x) : (y))
static void split(off_t *I, off_t *V, off_t start, off_t len, off_t h)
{
off_t i, j, k, x, tmp, jj, kk;
if (len < 16) {
for (k = start; k < start + len; k += j) {
j = 1; x = V[I[k] + h];
for (i = 1; k + i < start + len; i++) {
if (V[I[k + i] + h] < x) {
x = V[I[k + i] + h];
j = 0;
};
if (V[I[k + i] + h] == x) {
tmp = I[k + j]; I[k + j] = I[k + i]; I[k + i] = tmp;
j++;
};
};
for (i = 0; i < j; i++)
V[I[k + i]] = k + j - 1;
if (j == 1)
I[k] = -1;
};
return;
};
x = V[I[start + len/2] + h];
jj = 0; kk = 0;
for (i = start; i < start + len; i++) {
if (V[I[i] + h] < x)
jj++;
if (V[I[i] + h] == x)
kk++;
};
jj += start; kk += jj;
i = start; j = 0; k = 0;
while (i < jj) {
if (V[I[i] + h] < x) {
i++;
} else if (V[I[i] + h] == x) {
tmp = I[i]; I[i] = I[jj + j]; I[jj + j] = tmp;
j++;
} else {
tmp = I[i]; I[i] = I[kk + k]; I[kk + k] = tmp;
k++;
};
};
while (jj + j < kk) {
if (V[I[jj + j] + h] == x) {
j++;
} else {
tmp = I[jj + j]; I[jj + j] = I[kk + k]; I[kk + k] = tmp;
k++;
};
};
if (jj > start)
split(I, V, start, jj - start, h);
for (i = 0; i < kk - jj; i++)
V[I[jj + i]] = kk - 1;
if (jj == kk - 1)
I[jj] = -1;
if (start + len > kk)
split(I, V, kk, start + len - kk, h);
}
/* qsufsort(I, V, old, oldsize)
*
* Computes the suffix sort of the string at 'old' and stores the resulting
* indices in 'I', using 'V' as a temporary array for the computation. */
static void qsufsort(off_t *I, off_t *V, u_char *old, off_t oldsize)
{
off_t buckets[256];
off_t i, h, len;
/* count number of each byte */
for (i = 0; i < 256; i++)
buckets[i] = 0;
for (i = 0; i < oldsize; i++)
buckets[old[i]]++;
/* make buckets cumulative */
for (i = 1; i < 256; i++)
buckets[i] += buckets[i - 1];
/* shift right by one */
for (i = 255; i > 0; i--)
buckets[i] = buckets[i - 1];
buckets[0] = 0;
/* at this point, buckets[c] is the number of bytes in the old file with
* value less than c. */
/* set up the sort order of the suffixes based solely on the first
* character */
for (i = 0; i < oldsize; i++)
I[++buckets[old[i]]] = i;
I[0] = oldsize;
/* ? */
for (i = 0; i < oldsize; i++)
V[i] = buckets[old[i]];
V[oldsize] = 0;
/* forward any entries in the ordering which have the same initial
* character */
for (i = 1; i < 256; i++) {
if (buckets[i] == buckets[i - 1] + 1)
I[buckets[i]] = -1;
}
I[0] = -1;
for (h = 1; I[0] != -(oldsize + 1); h += h) {
len = 0;
for (i = 0; i < oldsize + 1;) {
if (I[i] < 0) {
len -= I[i];
i -= I[i];
} else {
if (len)
I[i - len] = -len;
len = V[I[i]] + 1 - i;
split(I, V, i, len, h);
i += len;
len = 0;
}
}
if (len)
I[i - len] = -len;
};
for (i = 0; i < oldsize + 1; i++) I[V[i]] = i;
}
/* matchlen(old, oldsize, new, newsize)
*
* Returns the length of the longest common prefix between 'old' and 'new'. */
static off_t matchlen(u_char *old, off_t oldsize, u_char *new, off_t newsize)
{
off_t i;
for (i = 0; (i < oldsize) && (i < newsize); i++)
{
if (old[i] != new[i])
break;
}
return i;
}
/* search(I, old, oldsize, new, newsize, st, en, pos)
*
* Searches for the longest prefix of 'new' that occurs in 'old', stores its
* offset in '*pos', and returns its length. 'I' should be the suffix sort of
* 'old', and 'st' and 'en' are the lowest and highest indices in the suffix
* sort to consider. If you're searching all suffixes, 'st = 0' and 'en =
* oldsize - 1'. */
static off_t search(off_t *I, u_char *old, off_t oldsize,
u_char *new, off_t newsize, off_t st, off_t en, off_t *pos)
{
off_t x, y;
if (en - st < 2) {
x = matchlen(old + I[st], oldsize - I[st], new, newsize);
y = matchlen(old + I[en], oldsize - I[en], new, newsize);
if (x > y) {
*pos = I[st];
return x;
} else {
*pos = I[en];
return y;
}
}
x = st + (en - st)/2;
if (memcmp(old + I[x], new, MIN(oldsize - I[x], newsize)) < 0) {
return search(I, old, oldsize, new, newsize, x, en, pos);
} else {
return search(I, old, oldsize, new, newsize, st, x, pos);
};
}
/* offtout(x, buf)
*
* Writes the off_t 'x' portably to the array 'buf'. */
static void offtout(off_t x, u_char *buf)
{
off_t y;
if (x < 0)
y = -x;
else
y = x;
buf[0] = y % 256;
y -= buf[0];
y = y/256; buf[1] = y%256; y -= buf[1];
y = y/256; buf[2] = y%256; y -= buf[2];
y = y/256; buf[3] = y%256; y -= buf[3];
y = y/256; buf[4] = y%256; y -= buf[4];
y = y/256; buf[5] = y%256; y -= buf[5];
y = y/256; buf[6] = y%256; y -= buf[6];
y = y/256; buf[7] = y%256;
if (x < 0)
buf[7] |= 0x80;
}
int bsdiff(int argc, char *argv[]); // Added by AMM: suppresses a warning about the following not having a prototype.
int bsdiff(int argc, char *argv[])
{
int fd;
u_char *old,*new; /* contents of old, new files */
off_t oldsize, newsize; /* length of old, new files */
off_t *I,*V; /* arrays used for suffix sort; I is ordering */
off_t scan; /* position of current match in old file */
off_t pos; /* position of current match in new file */
off_t len; /* length of current match */
off_t lastscan; /* position of previous match in old file */
off_t lastpos; /* position of previous match in new file */
off_t lastoffset; /* lastpos - lastscan */
off_t oldscore, scsc; /* temp variables in match search */
off_t s, Sf, lenf, Sb, lenb; /* temp vars in match extension */
off_t overlap, Ss, lens;
off_t i;
off_t dblen, eblen; /* length of diff, extra sections */
u_char *db,*eb; /* contents of diff, extra sections */
u_char buf[8];
u_char header[32];
FILE * pf;
if (argc != 4)
errx(1,"usage: %s oldfile newfile patchfile\n", argv[0]);
/* Allocate oldsize + 1 bytes instead of oldsize bytes to ensure
that we never try to malloc(0) and get a NULL pointer */
if (((fd = open(argv[1], O_RDONLY, 0)) < 0) ||
((oldsize = lseek(fd, 0, SEEK_END)) == -1) ||
((old = malloc(oldsize + 1)) == NULL) ||
(lseek(fd, 0, SEEK_SET) != 0) ||
(read(fd, old, oldsize) != oldsize) ||
(close(fd) == -1))
err(1,"%s", argv[1]);
if (((I = malloc((oldsize + 1) * sizeof(off_t))) == NULL) ||
((V = malloc((oldsize + 1) * sizeof(off_t))) == NULL))
err(1, NULL);
/* Do a suffix sort on the old file. */
qsufsort(I, V, old, oldsize);
free(V);
/* Allocate newsize + 1 bytes instead of newsize bytes to ensure
that we never try to malloc(0) and get a NULL pointer */
if (((fd = open(argv[2], O_RDONLY, 0)) < 0) ||
((newsize = lseek(fd, 0, SEEK_END)) == -1) ||
((new = malloc(newsize + 1)) == NULL) ||
(lseek(fd, 0, SEEK_SET) != 0) ||
(read(fd, new, newsize) != newsize) ||
(close(fd) == -1))
err(1,"%s", argv[2]);
if (((db = malloc(newsize + 1)) == NULL) ||
((eb = malloc(newsize + 1)) == NULL))
err(1, NULL);
dblen = 0;
eblen = 0;
/* Create the patch file */
if ((pf = fopen(argv[3], "w")) == NULL)
err(1, "%s", argv[3]);
/* Header is
0 8 "BSDIFN40"
8 8 length of ctrl block
16 8 length of diff block
24 8 length of new file */
/* File is
0 32 Header
32 ?? ctrl block
?? ?? diff block
?? ?? extra block */
memcpy(header, "BSDIFN40", 8);
offtout(0, header + 8);
offtout(0, header + 16);
offtout(newsize, header + 24);
if (fwrite(header, 32, 1, pf) != 1)
err(1, "fwrite(%s)", argv[3]);
/* Compute the differences, writing ctrl as we go */
scan = 0;
len = 0;
lastscan = 0;
lastpos = 0;
lastoffset = 0;
while (scan < newsize) {
oldscore = 0;
for (scsc = scan += len; scan < newsize; scan++) {
/* 'oldscore' is the number of characters that match between the
* substrings 'old[lastoffset + scan:lastoffset + scsc]' and
* 'new[scan:scsc]'. */
len = search(I, old, oldsize, new + scan, newsize - scan,
0, oldsize, &pos);
/* If this match extends further than the last one, add any new
* matching characters to 'oldscore'. */
for (; scsc < scan + len; scsc++) {
if ((scsc + lastoffset < oldsize) &&
(old[scsc + lastoffset] == new[scsc]))
oldscore++;
}
/* Choose this as our match if it contains more than eight
* characters that would be wrong if matched with a forward
* extension of the previous match instead. */
if (((len == oldscore) && (len != 0)) ||
(len > oldscore + 8))
break;
/* Since we're advancing 'scan' by 1, remove the character under it
* from 'oldscore' if it matches. */
if ((scan + lastoffset < oldsize) &&
(old[scan + lastoffset] == new[scan]))
oldscore--;
}
/* Skip this section if we found an exact match that would be
* better serviced by a forward extension of the previous match. */
if ((len != oldscore) || (scan == newsize)) {
/* Figure out how far forward the previous match should be
* extended... */
s = 0;
Sf = 0;
lenf = 0;
for (i = 0; (lastscan + i < scan) && (lastpos + i < oldsize);) {
if (old[lastpos + i] == new[lastscan + i])
s++;
i++;
if (s * 2 - i > Sf * 2 - lenf) {
Sf = s;
lenf = i;
}
}
/* ... and how far backwards the next match should be extended. */
lenb = 0;
if (scan < newsize) {
s = 0;
Sb = 0;
for (i = 1; (scan >= lastscan + i) && (pos >= i); i++) {
if (old[pos - i] == new[scan - i])
s++;
if (s * 2 - i > Sb * 2 - lenb) {
Sb = s;
lenb = i;
}
}
}
/* If there is an overlap between the extensions, find the best
* dividing point in the middle and reset 'lenf' and 'lenb'
* accordingly. */
if (lastscan + lenf > scan - lenb) {
overlap = (lastscan + lenf) - (scan - lenb);
s = 0;
Ss = 0;
lens = 0;
for (i = 0; i < overlap; i++) {
if (new[lastscan + lenf - overlap + i] ==
old[lastpos + lenf - overlap + i])
s++;
if (new[scan - lenb + i] == old[pos - lenb + i])
s--;
if (s > Ss) {
Ss = s;
lens = i + 1;
}
}
lenf += lens - overlap;
lenb -= lens;
}
/* Write the diff data for the last match to the diff section... */
for (i = 0; i < lenf; i++)
db[dblen + i] = new[lastscan + i] - old[lastpos + i];
/* ... and, if there's a gap between the extensions just
* calculated, write the data in that gap to the extra section. */
for (i = 0; i< (scan - lenb) - (lastscan + lenf); i++)
eb[eblen + i] = new[lastscan + lenf + i];
/* Update the diff and extra section lengths accordingly. */
dblen += lenf;
eblen += (scan - lenb) - (lastscan + lenf);
/* Write the following triple of integers to the control section:
* - length of the diff
* - length of the extra section
* - offset between the end of the diff and the start of the next
* diff, in the old file
*/
offtout(lenf, buf);
if (fwrite(buf, 8, 1, pf) != 1)
errx(1, "fwrite");
offtout((scan - lenb) - (lastscan + lenf), buf);
if (fwrite(buf, 8, 1, pf) != 1)
err(1, "fwrite");
offtout((pos - lenb) - (lastpos + lenf), buf);
if (fwrite(buf, 8, 1, pf) != 1)
err(1, "fwrite");
/* Update the variables describing the last match. Note that
* 'lastscan' is set to the start of the current match _after_ the
* backwards extension; the data in that extension will be written
* in the next pass. */
lastscan = scan - lenb;
lastpos = pos - lenb;
lastoffset = pos - scan;
}
}
/* Compute size of compressed ctrl data */
if ((len = ftello(pf)) == -1)
err(1, "ftello");
offtout(len - 32, header + 8);
/* Write diff data */
if (dblen && fwrite(db, dblen, 1, pf) != 1)
err(1, "fwrite");
/* Compute size of compressed diff data */
if ((newsize = ftello(pf)) == -1)
err(1, "ftello");
offtout(newsize - len, header + 16);
/* Write extra data */
if (eblen && fwrite(eb, eblen, 1, pf) != 1)
err(1, "fwrite");
/* Seek to the beginning, write the header, and close the file */
if (fseeko(pf, 0, SEEK_SET))
err(1, "fseeko");
if (fwrite(header, 32, 1, pf) != 1)
err(1, "fwrite(%s)", argv[3]);
if (fclose(pf))
err(1, "fclose");
/* Free the memory we used */
free(db);
free(eb);
free(I);
free(old);
free(new);
return 0;
}
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