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delta.c
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delta.c
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/*
diff.c -- binary diff generator
Copyright 2004,2005 Michael Schroeder
rewritten from bsdiff.c,
http://www.freebsd.org/cgi/cvsweb.cgi/src/usr.bin/bsdiff
added library interface and hash method, enhanced suffix method.
*/
/*-
* 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.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <bzlib.h>
#include "delta.h"
struct bzblock {
unsigned char *data;
unsigned int len;
bz_stream strm;
};
static struct bzblock *blockopen()
{
struct bzblock *bzf;
int ret;
bzf = malloc(sizeof(*bzf));
if (!bzf)
return 0;
bzf->strm.bzalloc = 0;
bzf->strm.bzfree = 0;
bzf->strm.opaque = 0;
bzf->len = 0;
ret = BZ2_bzCompressInit(&bzf->strm, 9, 0, 30);
if (ret != BZ_OK)
{
free(bzf);
return 0;
}
bzf->data = 0;
bzf->strm.avail_in = 0;
bzf->strm.next_in = 0;
bzf->strm.avail_out = 0;
bzf->strm.next_out = 0;
return bzf;
}
static int blockwrite(struct bzblock *bzf, void *buf, int len)
{
int ret;
if (len <= 0)
return len < 0 ? -1 : 0;
bzf->strm.avail_in = len;
bzf->strm.next_in = buf;
for (;;)
{
if (bzf->strm.avail_out < 4096)
{
if (bzf->len + 8192 < bzf->len)
return -1;
if (bzf->data)
bzf->data = realloc(bzf->data, bzf->len + 8192);
else
bzf->data = malloc(bzf->len + 8192);
if (!bzf->data)
return -1;
bzf->strm.avail_out = 8192;
}
bzf->strm.next_out = (char *)bzf->data + bzf->len;
ret = BZ2_bzCompress(&bzf->strm, BZ_RUN);
if (ret != BZ_RUN_OK)
return -1;
bzf->len = (unsigned char *)bzf->strm.next_out - bzf->data;
if (bzf->strm.avail_in == 0)
return len;
}
}
static int blockclose(struct bzblock *bzf, unsigned char **datap, unsigned int *lenp)
{
int ret;
bzf->strm.avail_in = 0;
bzf->strm.next_in = 0;
for (;;)
{
if (bzf->strm.avail_out < 4096)
{
if (bzf->len + 8192 < bzf->len)
return -1;
if (bzf->data)
bzf->data = realloc(bzf->data, bzf->len + 8192);
else
bzf->data = malloc(bzf->len + 8192);
if (!bzf->data)
return -1;
bzf->strm.avail_out = 8192;
}
bzf->strm.next_out = (char *)bzf->data + bzf->len;
ret = BZ2_bzCompress(&bzf->strm, BZ_FINISH);
if (ret != BZ_FINISH_OK && ret != BZ_STREAM_END)
return -1;
bzf->len = (unsigned char *)bzf->strm.next_out - bzf->data;
if (ret == BZ_STREAM_END)
break;
}
BZ2_bzCompressEnd (&bzf->strm);
*datap = bzf->data;
*lenp = bzf->len;
free(bzf);
return 0;
}
static inline bsuint matchlen(unsigned char *old, bsuint oldlen, unsigned char *new, bsuint newlen)
{
unsigned char *oldsave;
bsuint max;
oldsave = old;
max = oldlen > newlen ? newlen : oldlen;
while (max-- > 0)
if (*old++ != *new++)
return old - oldsave - 1;
return old - oldsave;
}
#ifndef BSDIFF_NO_HASH
/******************************************************************/
/* */
/* hash method */
/* */
/******************************************************************/
#define HSIZESHIFT 4
#define HSIZE (1 << HSIZESHIFT)
/* 256 random numbers generated by a quantum source */
static unsigned int noise[256] =
{
0x9be502a4U, 0xba7180eaU, 0x324e474fU, 0x0aab8451U, 0x0ced3810U,
0x2158a968U, 0x6bbd3771U, 0x75a02529U, 0x41f05c14U, 0xc2264b87U,
0x1f67b359U, 0xcd2d031dU, 0x49dc0c04U, 0xa04ae45cU, 0x6ade28a7U,
0x2d0254ffU, 0xdec60c7cU, 0xdef5c084U, 0x0f77ffc8U, 0x112021f6U,
0x5f6d581eU, 0xe35ea3dfU, 0x3216bfb4U, 0xd5a3083dU, 0x7e63e9cdU,
0xaa9208f6U, 0xda3f3978U, 0xfe0e2547U, 0x09dfb020U, 0xd97472c5U,
0xbbce2edeU, 0x121aebd2U, 0x0e9fdbebU, 0x7b6f5d9cU, 0x84938e43U,
0x30694f2dU, 0x86b7a7f8U, 0xefaf5876U, 0x263812e6U, 0xb6e48ddfU,
0xce8ed980U, 0x4df591e1U, 0x75257b35U, 0x2f88dcffU, 0xa461fe44U,
0xca613b4dU, 0xd9803f73U, 0xea056205U, 0xccca7a89U, 0x0f2dbb07U,
0xc53e359eU, 0xe80d0137U, 0x2b2d2a5dU, 0xcfc1391aU, 0x2bb3b6c5U,
0xb66aea3cU, 0x00ea419eU, 0xce5ada84U, 0xae1d6712U, 0x12f576baU,
0x117fcbc4U, 0xa9d4c775U, 0x25b3d616U, 0xefda65a8U, 0xaff3ef5bU,
0x00627e68U, 0x668d1e99U, 0x088d0eefU, 0xf8fac24dU, 0xe77457c7U,
0x68d3beb4U, 0x921d2acbU, 0x9410eac9U, 0xd7f24399U, 0xcbdec497U,
0x98c99ae1U, 0x65802b2cU, 0x81e1c3c4U, 0xa130bb09U, 0x17a87badU,
0xa70367d6U, 0x148658d4U, 0x02f33377U, 0x8620d8b6U, 0xbdac25bdU,
0xb0a6de51U, 0xd64c4571U, 0xa4185ba0U, 0xa342d70fU, 0x3f1dc4c1U,
0x042dc3ceU, 0x0de89f43U, 0xa69b1867U, 0x3c064e11U, 0xad1e2c3eU,
0x9660e8cdU, 0xd36b09caU, 0x4888f228U, 0x61a9ac3cU, 0xd9561118U,
0x3532797eU, 0x71a35c22U, 0xecc1376cU, 0xab31e656U, 0x88bd0d35U,
0x423b20ddU, 0x38e4651cU, 0x3c6397a4U, 0x4a7b12d9U, 0x08b1cf33U,
0xd0604137U, 0xb035fdb8U, 0x4916da23U, 0xa9349493U, 0xd83daa9bU,
0x145f7d95U, 0x868531d6U, 0xacb18f17U, 0x9cd33b6fU, 0x193e42b9U,
0x26dfdc42U, 0x5069d8faU, 0x5bee24eeU, 0x5475d4c6U, 0x315b2c0cU,
0xf764ef45U, 0x01b6f4ebU, 0x60ba3225U, 0x8a16777cU, 0x4c05cd28U,
0x53e8c1d2U, 0xc8a76ce5U, 0x8045c1e6U, 0x61328752U, 0x2ebad322U,
0x3444f3e2U, 0x91b8af11U, 0xb0cee675U, 0x55dbff5aU, 0xf7061ee0U,
0x27d7d639U, 0xa4aef8c9U, 0x42ff0e4fU, 0x62755468U, 0x1c6ca3f3U,
0xe4f522d1U, 0x2765fcb3U, 0xe20c8a95U, 0x3a69aea7U, 0x56ab2c4fU,
0x8551e688U, 0xe0bc14c2U, 0x278676bfU, 0x893b6102U, 0xb4f0ab3bU,
0xb55ddda9U, 0xa04c521fU, 0xc980088eU, 0x912aeac1U, 0x08519badU,
0x991302d3U, 0x5b91a25bU, 0x696d9854U, 0x9ad8b4bfU, 0x41cb7e21U,
0xa65d1e03U, 0x85791d29U, 0x89478aa7U, 0x4581e337U, 0x59bae0b1U,
0xe0fc9df3U, 0x45d9002cU, 0x7837464fU, 0xda22de3aU, 0x1dc544bdU,
0x601d8badU, 0x668b0abcU, 0x7a5ebfb1U, 0x3ac0b624U, 0x5ee16d7dU,
0x9bfac387U, 0xbe8ef20cU, 0x8d2ae384U, 0x819dc7d5U, 0x7c4951e7U,
0xe60da716U, 0x0c5b0073U, 0xb43b3d97U, 0xce9974edU, 0x0f691da9U,
0x4b616d60U, 0x8fa9e819U, 0x3f390333U, 0x6f62fad6U, 0x5a32b67cU,
0x3be6f1c3U, 0x05851103U, 0xff28828dU, 0xaa43a56aU, 0x075d7dd5U,
0x248c4b7eU, 0x52fde3ebU, 0xf72e2edaU, 0x5da6f75fU, 0x2f5148d9U,
0xcae2aeaeU, 0xfda6f3e5U, 0xff60d8ffU, 0x2adc02d2U, 0x1dbdbd4cU,
0xd410ad7cU, 0x8c284aaeU, 0x392ef8e0U, 0x37d48b3aU, 0x6792fe9dU,
0xad32ddfaU, 0x1545f24eU, 0x3a260f73U, 0xb724ca36U, 0xc510d751U,
0x4f8df992U, 0x000b8b37U, 0x292e9b3dU, 0xa32f250fU, 0x8263d144U,
0xfcae0516U, 0x1eae2183U, 0xd4af2027U, 0xc64afae3U, 0xe7b34fe4U,
0xdf864aeaU, 0x80cc71c5U, 0x0e814df3U, 0x66cc5f41U, 0x853a497aU,
0xa2886213U, 0x5e34a2eaU, 0x0f53ba47U, 0x718c484aU, 0xfa0f0b12U,
0x33cc59ffU, 0x72b48e07U, 0x8b6f57bcU, 0x29cf886dU, 0x1950955bU,
0xcd52910cU, 0x4cecef65U, 0x05c2cbfeU, 0x49df4f6aU, 0x1f4c3f34U,
0xfadc1a09U, 0xf2d65a24U, 0x117f5594U, 0xde3a84e6U, 0x48db3024U,
0xd10ca9b5U
};
/* buzhash by Robert C. Uzgalis */
/* General hash functions. Technical Report TR-92-01, The University
of Hong Kong, 1993 */
static unsigned int buzhash(unsigned char *buf)
{
unsigned int x = 0x83d31df4U;
int i;
for (i = HSIZE; i != 0; i--)
x = (x << 1) ^ (x & (1u << 31) ? 1 : 0) ^ noise[*buf++];
return x;
}
static unsigned int primes[] =
{
65537, 98317, 147481, 221227, 331841, 497771, 746659, 1120001,
1680013, 2520031, 3780053, 5670089, 8505137, 12757739, 19136609,
28704913, 43057369, 64586087, 96879131, 145318741, 217978121,
326967209, 490450837, 735676303, 1103514463, 1655271719,
0xffffffff
};
struct hash_data {
bsuint *hash;
unsigned int prime;
};
static void *hash_create(unsigned char *buf, bsuint len)
{
struct hash_data *hd;
bsuint *hash;
unsigned char *bp = buf;
bsuint off;
unsigned int s;
unsigned int prime;
unsigned int num;
#ifdef BSDIFF_64BIT
/* this is a 16GB limit for HSIZESHIFT == 4 */
if (len >= (bsuint)(0xffffffff / 4) << HSIZESHIFT)
return 0;
#endif
hd = malloc(sizeof(*hd));
if (!hd)
return 0;
num = (len + HSIZE - 1) >> HSIZESHIFT;
prime = num * 4;
for (s = 0; s < sizeof(primes)/sizeof(*primes) - 1; s++)
if (prime < primes[s])
break;
prime = primes[s];
hash = calloc(prime, sizeof(*hash));
if (!hash)
{
free(hd);
return 0;
}
for (off = 0; len >= HSIZE; off += HSIZE, buf += HSIZE, len -= HSIZE)
{
s = buzhash(buf) % prime;
if (hash[s])
{
if (hash[(s == prime - 1) ? 0 : s + 1])
continue;
if (!memcmp(buf, bp + hash[s], HSIZE))
continue;
s = (s == prime - 1) ? 0 : s + 1;
}
hash[s] = off + 1;
}
hd->hash = hash;
hd->prime = prime;
return hd;
}
static void hash_free(void *data)
{
struct hash_data *hd = data;
free(hd->hash);
free(hd);
}
static bsuint hash_findnext(void *data, unsigned char *old, bsuint oldlen, unsigned char *new, bsuint newlen, bsuint lastoffset, bsuint scan, bsuint *posp, bsuint *lenp)
{
struct hash_data *hd = data;
bsuint scanstart, oldscore, oldscorenum, oldscorestart;
bsuint pos, len;
bsuint lscan, lpos, llen;
bsuint i, ss, scsc;
unsigned int ssx;
unsigned int prime;
bsuint *hash;
hash = hd->hash;
prime = hd->prime;
scanstart = scan;
oldscore = oldscorenum = oldscorestart = 0;
ssx = scan <= newlen - HSIZE ? buzhash(new + scan) : 0;
pos = 0;
len = 0;
lpos = lscan = llen = 0;
for (;;)
{
if (scan >= newlen - HSIZE)
{
if (llen >= 32)
goto gotit;
break;
}
ss = ssx % prime;
pos = hash[ss];
if (!pos)
{
unsigned int oldc;
scannext:
if (llen >= 32 && scan - lscan >= HSIZE)
goto gotit;
ssx = (ssx << 1) ^ (ssx & (1u << 31) ? 1 : 0) ^ noise[new[scan + HSIZE]];
oldc = noise[new[scan]] ^ (0x83d31df4U ^ 0x07a63be9U);
#if HSIZE % 32 != 0
ssx ^= (oldc << (HSIZE % 32)) ^ (oldc >> (32 - (HSIZE % 32)));
#else
ssx ^= oldc;
#endif
scan++;
continue;
}
pos--;
if (memcmp(old + pos, new + scan, HSIZE))
{
pos = hash[ss == prime - 1 ? 0 : ss + 1];
if (!pos)
goto scannext;
pos--;
if (memcmp(old + pos, new + scan, HSIZE))
goto scannext;
}
len = matchlen(old + pos + HSIZE, oldlen - pos - HSIZE, new + scan + HSIZE, newlen - scan - HSIZE) + HSIZE;
if (scan + HSIZE * 4 <= newlen)
{
unsigned int ssx2;
bsuint len2, pos2;
ssx2 = buzhash(new + scan + HSIZE * 3) % prime;
pos2 = hash[ssx2];
if (pos2)
{
if (memcmp(new + scan + HSIZE *3, old + pos2 - 1, HSIZE))
{
ssx2 = (ssx2 == prime - 1) ? 0 : ssx2 + 1;
pos2 = hash[ssx2];
}
}
if (pos2 > 1 + HSIZE*3)
{
pos2 = pos2 - 1 - HSIZE*3;
if (pos2 != pos)
{
len2 = matchlen(old + pos2, oldlen - pos2, new + scan, newlen - scan);
if (len2 > len)
{
pos = pos2;
len = len2;
}
}
}
}
if (len > llen)
{
llen = len;
lpos = pos;
lscan = scan;
}
goto scannext;
gotit:
scan = lscan;
len = llen;
pos = lpos;
if (scan + lastoffset == pos)
{
scan += len;
scanstart = scan;
if (scan + HSIZE < newlen)
ssx = buzhash(new + scan);
llen = 0;
continue;
}
for (i = scan - scanstart; i && pos && scan && old[pos - 1] == new[scan - 1]; i--)
{
len++;
pos--;
scan--;
}
if (oldscorestart + 1 != scan || oldscorenum == 0 || oldscorenum - 1 > len)
{
oldscore = 0;
for (scsc = scan; scsc<scan+len; scsc++)
if ((scsc+lastoffset<oldlen) && (old[scsc+lastoffset] == new[scsc]))
oldscore++;
oldscorestart = scan;
oldscorenum = len;
}
else
{
if (oldscorestart + lastoffset < oldlen && old[oldscorestart + lastoffset] == new[oldscorestart])
oldscore--;
oldscorestart++;
oldscorenum--;
for (scsc = oldscorestart + oldscorenum; oldscorenum < len; scsc++)
{
if ((scsc+lastoffset<oldlen) && (old[scsc+lastoffset] == new[scsc]))
oldscore++;
oldscorenum++;
}
}
if (len - oldscore >= 32)
break;
if (len > HSIZE * 3 + 32)
scan += len - (HSIZE * 3 + 32);
if (scan <= lscan)
scan = lscan + 1;
scanstart = scan;
if (scan + HSIZE < newlen)
ssx = buzhash(new + scan);
llen = 0;
}
if (scan >= newlen - HSIZE)
{
scan = newlen;
pos = 0;
len = 0;
}
*posp = pos;
*lenp = len;
return scan;
}
#endif /* BSDIFF_NO_HASH */
#ifndef BSDIFF_NO_SUF
/******************************************************************/
/* */
/* suffix list method */
/* */
/******************************************************************/
struct suf_data {
bsint *I;
bsint F[257];
};
static void suf_split(bsint *I, bsint *V, bsint start, bsint len, bsint h)
{
bsint 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)
suf_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)
suf_split(I, V, kk, start + len - kk, h);
}
static bsint suf_bucketsort(bsint *V, bsint *I, bsint n, bsint s)
{
bsint c, d, g, i, j;
bsint *B;
B = calloc(s, sizeof(bsint));
if (!B)
return 0;
for (i = n - 1; i >= 0; i--)
{
c = V[i];
V[i] = B[c];
B[c] = i + 1;
}
for (j = s - 1, i = n; i; j--)
{
for (d = B[j], g = i; d; i--)
{
c = d - 1;
d = V[c];
V[c] = g;
I[i] = !d && g == i ? -1 : c;
}
}
V[n] = 0;
I[0] = -1;
free(B);
return 1;
}
static void *suf_create(unsigned char *buf, bsuint ulen)
{
struct suf_data *sd;
bsint *V, *I;
bsint i, h, l, oldv, s, len;
len = ulen;
if (len < 0)
return 0;
sd = malloc(sizeof(*sd));
if (!sd)
return 0;
V = malloc(sizeof(bsint) * (len + 3));
if (!V)
{
free(sd);
return 0;
}
I = malloc(sizeof(bsint) * (len + 3));
if (!I)
{
free(V);
free(sd);
return 0;
}
memset(sd->F, 0, sizeof(sd->F));
if (len >= 0x1000000)
{
s = 0x1000002;
sd->F[buf[0]]++;
sd->F[buf[1]]++;
oldv = buf[0] << 8 | buf[1];
for (i = 2; i < len; i++)
{
sd->F[buf[i]]++;
oldv = (oldv & 0xffff) << 8 | buf[i];
V[i - 2] = oldv + 2;
}
oldv = (oldv & 0xffff) << 8;
V[len - 2] = oldv + 2;
oldv = (oldv & 0xffff) << 8;
V[len - 1] = oldv + 2;
len += 2;
V[len - 2] = 1;
V[len - 1] = 0;
h = 3;
}
else
{
s = 0x10001;
sd->F[buf[0]]++;
oldv = buf[0];
for (i = 1; i < len; i++)
{
sd->F[buf[i]]++;
oldv = (oldv & 0xff) << 8 | buf[i];
V[i - 1] = oldv + 1;
}
oldv = (oldv & 0xff) << 8;
V[len - 1] = oldv + 1;
len += 1;
V[len - 1] = 0;
h = 2;
}
oldv = len;
for (i = 256; i > 0; i--)
{
sd->F[i] = oldv;
oldv -= sd->F[i - 1];
}
sd->F[0] = oldv;
if (!suf_bucketsort(V, I, len, s))
{
free(I);
free(V);
free(sd);
return 0;
}
for(; I[0] != -(len + 1); h += h)
{
l=0;
for (i = 0; i < len + 1; )
{
if (I[i] < 0)
{
l -= I[i];
i -= I[i];
}
else
{
if(l)
I[i - l] = -l;
l = V[I[i]] + 1 - i;
suf_split(I, V, i, l, h);
i += l;
l = 0;
}
}
if (l)
I[i - l] = -l;
}
for (i = 0; i < len + 1; i++)
I[V[i]] = i;
free(V);
sd->I = I;
return sd;
}
static void suf_free(void *data)
{
struct suf_data *sd = data;
free(sd->I);
free(sd);
}
static bsuint suf_bsearch(bsint *I, unsigned char *old, bsuint oldlen, unsigned char *new, bsuint newlen, bsuint st, bsuint en, bsuint *posp)
{
bsuint x, y;
if (st > en)
return 0;
while (en - st >= 2)
{
x = st + (en - st) / 2;
if (memcmp(old + I[x], new, oldlen - I[x] < newlen ? oldlen - I[x] : newlen) < 0)
st = x;
else
en = x;
}
x = matchlen(old + I[st], oldlen - I[st], new, newlen);
y = matchlen(old + I[en], oldlen - I[en], new, newlen);
*posp = x > y ? I[st] : I[en];
return x > y ? x : y;
}
static bsuint suf_findnext(void *data, unsigned char *old, bsuint oldlen, unsigned char *new, bsuint newlen, bsuint lastoffset, bsuint scan, bsuint *posp, bsuint *lenp)
{
bsuint scsc, oldscore, len;
struct suf_data *sd = data;
len = 0;
*posp = 0;
scsc = scan;
oldscore = 0;
while (scan < newlen)
{
len = suf_bsearch(sd->I, old, oldlen, new + scan, newlen - scan, sd->F[new[scan]] + 1, sd->F[new[scan] + 1], posp);
for (; scsc < scan + len; scsc++)
if (scsc + lastoffset < oldlen && old[scsc + lastoffset] == new[scsc])
oldscore++;
if (len && len == oldscore)
{
scan += len;
scsc = scan;
oldscore = 0;
continue;
}
if (len > oldscore + 32)
break;
if (scan + lastoffset < oldlen && old[scan + lastoffset] == new[scan])
oldscore--;
scan++;
}
*lenp = len;
return scan;
}
#endif /* BSDIFF_NO_SUF */
/******************************************************************/
struct deltamode {
int mode;
void *(*create)(unsigned char *buf, bsuint len);
bsuint (*findnext)(void *data, unsigned char *old, bsuint oldlen, unsigned char *new, bsuint newlen, bsuint lastoffset, bsuint scan, bsuint *posp, bsuint *lenp);
void (*free)(void *data);
};
struct deltamode deltamodes[] =
{
#ifndef BSDIFF_NO_SUF
{DELTAMODE_SUF, suf_create, suf_findnext, suf_free},
#endif
#ifndef BSDIFF_NO_HASH
{DELTAMODE_HASH, hash_create, hash_findnext, hash_free},
#endif
};
static void addoff(struct bzblock *bzi, bsint off)
{
int i, sign = 0;
unsigned char b[8];
if (off < 0)
{
sign = 0x80;
off = -off;
}
for (i = 0; i < 7; i++)
{
b[i] = off & 0xff;
off >>= 8;
}
b[7] = sign | (off & 0xff);
blockwrite(bzi, b, 8);
}
void mkdiff(int mode,
unsigned char *old, bsuint oldlen,
unsigned char *new, bsuint newlen,
struct instr **instrp, int *instrlenp,
unsigned char **instrblkp, unsigned int *instrblklenp,
unsigned char **addblkp, unsigned int *addblklenp,
unsigned char **extrablkp, unsigned int *extrablklenp)
{
struct instr *instr = 0;
int instrlen = 0;
bsuint i, scan, pos, len;
bsuint lastscan, lastpos, lastoffset;
bsuint s, Sf, lenf, Sb, lenb;
bsuint overlap, Ss, lens;
struct bzblock *bza = 0;
struct bzblock *bze = 0;
struct bzblock *bzi = 0;
void *data;
struct deltamode *dm;
int noaddblk = 0;
if ((mode & DELTAMODE_NOADDBLK) != 0)
{
mode ^= DELTAMODE_NOADDBLK;
noaddblk = 1;
}
dm = 0;
for (i = 0; i < sizeof(deltamodes)/sizeof(*deltamodes); i++)
{
dm = deltamodes + i;
if (deltamodes[i].mode == mode)
break;
}
if (!dm)
{
fprintf(stderr, "mkdiff: no mode installed\n");
exit(1);
}
if (addblkp)
{
*addblkp = 0;
*addblklenp = 0;
}
if (extrablkp)
{
*extrablkp = 0;
*extrablklenp = 0;
}
if (instrblkp)
{
*instrblkp = 0;
*instrblklenp = 0;
}
if (!noaddblk && addblkp && (bza = blockopen()) == 0)
{
fprintf(stderr, "mkdiff: could not create compression stream\n");
exit(1);
}
if (extrablkp && (bze = blockopen()) == 0)
{
fprintf(stderr, "mkdiff: could not create compression stream\n");
exit(1);
}
if (instrblkp && (bzi = blockopen()) == 0)
{
fprintf(stderr, "mkdiff: could not create compression stream\n");
exit(1);
}
data = dm->create(old, oldlen);
if (!data)
{
fprintf(stderr, "mkdiff: could not create data\n");
exit(1);
}
scan = 0; len = 0; lenf = 0;
lastscan = 0; lastpos = 0;
while (lastscan < newlen)
{
/* search for data matching something in new[scan...]
* input:
* old/oldlen, new/newlen: search data
* lastoffset: lastpos - lastscan (because we want to find a different match)
* returns:
* scan: start of match in new[]
* pos: start of match in old[]
* len: length of match
* (if no match is found, scan = newlen, len = 0)
*/
lastoffset = noaddblk ? oldlen : lastpos - lastscan;
scan = dm->findnext(data, old, oldlen, new, newlen, lastoffset, scan, &pos, &len);
/* extand old match forward */
if (!noaddblk)
{
s = Sf = lenf = 0;
for (i = 0; lastscan + i < scan && lastpos + i < oldlen; )
{
if (old[lastpos+i] == new[lastscan+i])
{
s++;
i++;
if (s >= Sf + i - s)
{
Sf = 2 * s - i;
lenf = i;
}
}
else
i++;
}
}
else
{
for (i = 0; lastscan + i < scan && lastpos + i < oldlen; i++)
if (old[lastpos+i] != new[lastscan+i])
break;
lenf = i;
}
lenb = 0;
/* extand new match backward, scan == newlen means we're going to finish */
if (!noaddblk && scan < newlen)
{
s = Sb = 0;
for(i = 1; scan >= lastscan + i && pos >= i; i++)
{
if (old[pos-i] == new[scan-i])
{
s++;
if(s >= Sb + i - s)
{
Sb = 2 * s - i;
lenb = i;
}
}
}
}
/* if there is an overlap find good place to split */
if (lastscan + lenf > scan - lenb)
{
overlap = (lastscan + lenf) - (scan - lenb);
s = Sb = Ss = 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])
Sb++;
if (s > Sb && s - Sb > Ss)
{
Ss = s - Sb;
lens = i + 1;
}
}
lenf -= overlap - lens;
lenb -= lens;
}
/*
* lastscan scan
* |--- lenf ---| |- lenb -|-- len --|
* | | | | |
* new: ------+=======-----+----+--------+=========+--
* / \
* / |
* old: ---+=======-----------------------+=========---
* | |
* lastpos pos
*/
if (instrp)
{
if ((instrlen & 31) == 0)
{
if (instr)
instr = realloc(instr, sizeof(*instr) * (instrlen + 32));
else
instr = malloc(sizeof(*instr) * (instrlen + 32));
if (!instr)
{
fprintf(stderr, "out of memory\n");
exit(1);
}
}
instr[instrlen].copyout = lenf;
instr[instrlen].copyin = (scan - lenb) - (lastscan + lenf);
instr[instrlen].copyinoff = lastscan + lenf;
instr[instrlen].copyoutoff = lastpos;
instrlen++;
}
if (bzi)
{
addoff(bzi, lenf);