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guix/src/bsdiff-4.2/bsdiff.c

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8.6 KiB
C
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/*
bsdiff.c -- Binary patch generator.
Copyright 2003 Colin Percival
For the terms under which this work may be distributed, please see
the adjoining file "LICENSE".
*/
#ifndef BZIP2
#define BZIP2 "/usr/bin/bzip2"
#endif
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <err.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/wait.h>
#define MIN(x,y) (((x)<(y)) ? (x) : (y))
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);
}
void qsufsort(off_t *I,off_t *V,u_char *old,off_t oldsize)
{
off_t buckets[256];
off_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;
}
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;
}
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);
};
}
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 main(int argc,char *argv[])
{
int fd,p[2];
pid_t pid;
u_char *old,*new;
off_t oldsize,newsize;
off_t *I,*V;
off_t scan,pos,len;
off_t lastscan,lastpos,lastoffset;
off_t oldscore,scsc;
off_t s,Sf,lenf,Sb,lenb;
off_t overlap,Ss,lens;
off_t i;
off_t dblen,eblen;
u_char *db,*eb;
u_char buf[8];
u_char header[32];
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);
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;
if((fd=open(argv[3],O_CREAT|O_TRUNC|O_WRONLY,0666))<0)
err(1,"%s",argv[3]);
/* Header is
0 8 "BSDIFF40"
8 8 length of bzip2ed ctrl block
16 8 length of bzip2ed diff block
24 8 length of new file */
/* File is
0 32 Header
32 ?? Bzip2ed ctrl block
?? ?? Bzip2ed diff block
?? ?? Bzip2ed extra block */
memcpy(header,"BSDIFF40",8);
memset(header+8,0,24);
if(write(fd,header,32)!=32) err(1,"%s",argv[3]);
if((pipe(p)==-1) || ((pid=fork())==-1)) err(1,NULL);
if(pid==0) {
if((close(0)==-1) || (close(1)==-1) || (dup2(fd,1)==-1) ||
(dup2(p[0],0)==-1) || (close(fd)==-1) ||
(close(p[0])==-1) || (close(p[1])==-1))
err(1,NULL);
execl(BZIP2,BZIP2,"-zc",NULL);
err(1,"%s",BZIP2);
};
if(close(p[0])==-1) err(1,NULL);
scan=0;len=0;
lastscan=0;lastpos=0;lastoffset=0;
while(scan<newsize) {
oldscore=0;
for(scsc=scan+=len;scan<newsize;scan++) {
len=search(I,old,oldsize,new+scan,newsize-scan,
0,oldsize,&pos);
for(;scsc<scan+len;scsc++)
if((scsc+lastoffset<oldsize) &&
(old[scsc+lastoffset] == new[scsc]))
oldscore++;
if(((len==oldscore) && (len!=0)) ||
(len>oldscore+8)) break;
if((scan+lastoffset<oldsize) &&
(old[scan+lastoffset] == new[scan]))
oldscore--;
};
if((len!=oldscore) || (scan==newsize)) {
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; };
};
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(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;
};
for(i=0;i<lenf;i++)
db[dblen+i]=new[lastscan+i]-old[lastpos+i];
for(i=0;i<(scan-lenb)-(lastscan+lenf);i++)
eb[eblen+i]=new[lastscan+lenf+i];
dblen+=lenf;
eblen+=(scan-lenb)-(lastscan+lenf);
offtout(lenf,buf);
if(write(p[1],buf,8)!=8) err(1,NULL);
offtout((scan-lenb)-(lastscan+lenf),buf);
if(write(p[1],buf,8)!=8) err(1,NULL);
offtout((pos-lenb)-(lastpos+lenf),buf);
if(write(p[1],buf,8)!=8) err(1,NULL);
lastscan=scan-lenb;
lastpos=pos-lenb;
lastoffset=pos-scan;
};
};
if((close(p[1])==-1) || (waitpid(pid,NULL,0)!=pid)) err(1,NULL);
if((len=lseek(fd,0,SEEK_END))==-1) err(1,"%s",argv[3]);
offtout(len-32,buf);
if((lseek(fd,8,SEEK_SET)!=8) || (write(fd,buf,8)!=8))
err(1,"%s",argv[3]);
offtout(newsize,buf);
if((lseek(fd,24,SEEK_SET)!=24) || (write(fd,buf,8)!=8))
err(1,"%s",argv[3]);
if(lseek(fd,0,SEEK_END)==-1) err(1,"%s",argv[3]);
if((pipe(p)==-1) || ((pid=fork())==-1)) err(1,NULL);
if(pid==0) {
if((close(0)==-1) || (close(1)==-1) || (dup2(fd,1)==-1) ||
(dup2(p[0],0)==-1) || (close(fd)==-1) ||
(close(p[0])==-1) || (close(p[1])==-1))
err(1,NULL);
execl(BZIP2,BZIP2,"-zc",NULL);
err(1,"%s",BZIP2);
};
if(close(p[0])==-1) err(1,NULL);
if(write(p[1],db,dblen)!=dblen) err(1,NULL);
if((close(p[1])==-1) || (waitpid(pid,NULL,0)!=pid)) err(1,NULL);
if((newsize=lseek(fd,0,SEEK_END))==-1) err(1,"%s",argv[3]);
offtout(newsize-len,buf);
if((lseek(fd,16,SEEK_SET)!=16) || (write(fd,buf,8)!=8))
err(1,"%s",argv[3]);
if(lseek(fd,0,SEEK_END)==-1) err(1,"%s",argv[3]);
if((pipe(p)==-1) || ((pid=fork())==-1)) err(1,NULL);
if(pid==0) {
if((close(0)==-1) || (close(1)==-1) || (dup2(fd,1)==-1) ||
(dup2(p[0],0)==-1) || (close(fd)==-1) ||
(close(p[0])==-1) || (close(p[1])==-1))
err(1,NULL);
execl(BZIP2,BZIP2,"-zc",NULL);
err(1,"%s",BZIP2);
};
if(close(p[0])==-1) err(1,NULL);
if(write(p[1],eb,eblen)!=eblen) err(1,NULL);
if((close(p[1])==-1) || (waitpid(pid,NULL,0)!=pid)) err(1,NULL);
if(close(fd)==-1) err(1,"%s",argv[3]);
free(db);
free(eb);
free(I);
free(old);
free(new);
return 0;
}
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