/*-
* Copyright 2003-2005 Colin Percival
* Copyright 2012 Matthew Endsley
* 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 "bsdiff.h"
#include <limits.h>
#include <string.h>
#define MIN(x,y) (((x)<(y)) ? (x) : (y))
static void split(int64_t *I,int64_t *V,int64_t start,int64_t len,int64_t h)
{
int64_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);
}
static void qsufsort(int64_t *I,int64_t *V,const uint8_t *old,int64_t oldsize)
{
int64_t buckets[256];
int64_t i,h,len;
for(i=0;i<256;i++) buckets[i]=0;
for(i=0;i<oldsize;i++) buckets[old[i]]++;
for(i=1;i<256;i++) buckets[i]+=buckets[i-1];
for(i=255;i>0;i--) buckets[i]=buckets[i-1];
buckets[0]=0;
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;
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;
}
static int64_t matchlen(const uint8_t *old,int64_t oldsize,const uint8_t *new,int64_t newsize)
{
int64_t i;
for(i=0;(i<oldsize)&&(i<newsize);i++)
if(old[i]!=new[i]) break;
return i;
}
static int64_t search(const int64_t *I,const uint8_t *old,int64_t oldsize,
const uint8_t *new,int64_t newsize,int64_t st,int64_t en,int64_t *pos)
{
int64_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);
};
}
static void offtout(int64_t x,uint8_t *buf)
{
int64_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;
}
static int64_t writedata(struct bsdiff_stream* stream, const void* buffer, int64_t length)
{
int64_t result = 0;
while (length > 0)
{
const int smallsize = (int)MIN(length, INT_MAX);
const int writeresult = stream->write(stream, buffer, smallsize);
if (writeresult == -1)
{
return -1;
}
result += writeresult;
length -= smallsize;
buffer = (uint8_t*)buffer + smallsize;
}
return result;
}
struct bsdiff_request
{
const uint8_t* old;
int64_t oldsize;
const uint8_t* new;
int64_t newsize;
struct bsdiff_stream* stream;
int64_t *I;
uint8_t *buffer;
};
static int bsdiff_internal(const struct bsdiff_request req)
{
int64_t *I,*V;
int64_t scan,pos,len;
int64_t lastscan,lastpos,lastoffset;
int64_t oldscore,scsc;
int64_t s,Sf,lenf,Sb,lenb;
int64_t overlap,Ss,lens;
int64_t i;
uint8_t *buffer;
uint8_t buf[8 * 3];
if((V=req.stream->malloc((req.oldsize+1)*sizeof(int64_t)))==NULL) return -1;
I = req.I;
qsufsort(I,V,req.old,req.oldsize);
req.stream->free(V);
buffer = req.buffer;
/* Compute the differences, writing ctrl as we go */
scan=0;len=0;pos=0;
lastscan=0;lastpos=0;lastoffset=0;
while(scan<req.newsize) {
oldscore=0;
for(scsc=scan+=len;scan<req.newsize;scan++) {
len=search(I,req.old,req.oldsize,req.new+scan,req.newsize-scan,
0,req.oldsize,&pos);
for(;scsc<scan+len;scsc++)
if((scsc+lastoffset<req.oldsize) &&
(req.old[scsc+lastoffset] == req.new[scsc]))
oldscore++;
if(((len==oldscore) && (len!=0)) ||
(len>oldscore+8)) break;
if((scan+lastoffset<req.oldsize) &&
(req.old[scan+lastoffset] == req.new[scan]))
oldscore--;
};
if((len!=oldscore) || (scan==req.newsize)) {
s=0;Sf=0;lenf=0;
for(i=0;(lastscan+i<scan)&&(lastpos+i<req.oldsize);) {
if(req.old[lastpos+i]==req.new[lastscan+i]) s++;
i++;
if(s*2-i>Sf*2-lenf) { Sf=s; lenf=i; };
};
lenb=0;
if(scan<req.newsize) {
s=0;Sb=0;
for(i=1;(scan>=lastscan+i)&&(pos>=i);i++) {
if(req.old[pos-i]==req.new[scan-i]) s++;
if(s*2-i>Sb*2-lenb) { Sb=s; lenb=i; };
};
};
if(lastscan+lenf>scan-lenb) {
overlap=(lastscan+lenf)-(scan-lenb);
s=0;Ss=0;lens=0;
for(i=0;i<overlap;i++) {
if(req.new[lastscan+lenf-overlap+i]==
req.old[lastpos+lenf-overlap+i]) s++;
if(req.new[scan-lenb+i]==
req.old[pos-lenb+i]) s--;
if(s>Ss) { Ss=s; lens=i+1; };
};
lenf+=lens-overlap;
lenb-=lens;
};
offtout(lenf,buf);
offtout((scan-lenb)-(lastscan+lenf),buf+8);
offtout((pos-lenb)-(lastpos+lenf),buf+16);
/* Write control data */
if (writedata(req.stream, buf, sizeof(buf)))
return -1;
/* Write diff data */
for(i=0;i<lenf;i++)
buffer[i]=req.new[lastscan+i]-req.old[lastpos+i];
if (writedata(req.stream, buffer, lenf))
return -1;
/* Write extra data */
for(i=0;i<(scan-lenb)-(lastscan+lenf);i++)
buffer[i]=req.new[lastscan+lenf+i];
if (writedata(req.stream, buffer, (scan-lenb)-(lastscan+lenf)))
return -1;
lastscan=scan-lenb;
lastpos=pos-lenb;
lastoffset=pos-scan;
};
};
return 0;
}
int bsdiff(const uint8_t* old, int64_t oldsize, const uint8_t* new, int64_t newsize, struct bsdiff_stream* stream)
{
int result;
struct bsdiff_request req;
if((req.I=stream->malloc((oldsize+1)*sizeof(int64_t)))==NULL)
return -1;
if((req.buffer=stream->malloc(newsize+1))==NULL)
{
stream->free(req.I);
return -1;
}
req.old = old;
req.oldsize = oldsize;
req.new = new;
req.newsize = newsize;
req.stream = stream;
result = bsdiff_internal(req);
stream->free(req.buffer);
stream->free(req.I);
return result;
}
#if defined(BSDIFF_EXECUTABLE)
#include <sys/types.h>
#include <bzlib.h>
#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
static int bz2_write(struct bsdiff_stream* stream, const void* buffer, int size)
{
int bz2err;
BZFILE* bz2;
bz2 = (BZFILE*)stream->opaque;
BZ2_bzWrite(&bz2err, bz2, (void*)buffer, size);
if (bz2err != BZ_STREAM_END && bz2err != BZ_OK)
return -1;
return 0;
}
int main(int argc,char *argv[])
{
int fd;
int bz2err;
uint8_t *old,*new;
off_t oldsize,newsize;
uint8_t buf[8];
FILE * pf;
struct bsdiff_stream stream;
BZFILE* bz2;
memset(&bz2, 0, sizeof(bz2));
stream.malloc = malloc;
stream.free = free;
stream.write = bz2_write;
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]);
/* 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]);
/* Create the patch file */
if ((pf = fopen(argv[3], "w")) == NULL)
err(1, "%s", argv[3]);
/* Write header (signature+newsize)*/
offtout(newsize, buf);
if (fwrite("ENDSLEY/BSDIFF43", 16, 1, pf) != 1 ||
fwrite(buf, sizeof(buf), 1, pf) != 1)
err(1, "Failed to write header");
if (NULL == (bz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)))
errx(1, "BZ2_bzWriteOpen, bz2err=%d", bz2err);
stream.opaque = bz2;
if (bsdiff(old, oldsize, new, newsize, &stream))
err(1, "bsdiff");
BZ2_bzWriteClose(&bz2err, bz2, 0, NULL, NULL);
if (bz2err != BZ_OK)
err(1, "BZ2_bzWriteClose, bz2err=%d", bz2err);
if (fclose(pf))
err(1, "fclose");
/* Free the memory we used */
free(old);
free(new);
return 0;
}
#endif