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403 lines
8.8 KiB
C
403 lines
8.8 KiB
C
/* vim:set ts=8 sw=8 sts=8 noet: */
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/*
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bsdiff.c -- Binary patch generator.
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Copyright 2003 Colin Percival
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For the terms under which this work may be distributed, please see
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the adjoining file "LICENSE".
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ChangeLog:
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2005-05-05 - Use the modified header struct from bspatch.h; use 32-bit
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values throughout.
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--Benjamin Smedberg <benjamin@smedbergs.us>
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2005-05-18 - Use the same CRC algorithm as bzip2, and leverage the CRC table
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provided by libbz2.
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--Darin Fisher <darin@meer.net>
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*/
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#include "bspatch.h"
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <fcntl.h>
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#include <stdarg.h>
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#ifdef XP_WIN
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#include <io.h>
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#include <winsock2.h>
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#else
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#include <unistd.h>
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#include <arpa/inet.h>
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#define _O_BINARY 0
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#endif
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#undef MIN
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#define MIN(x,y) (((x)<(y)) ? (x) : (y))
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//-----------------------------------------------------------------------------
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// This variable lives in libbz2. It's declared in bzlib_private.h, so we just
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// declare it here to avoid including that entire header file.
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extern unsigned int BZ2_crc32Table[256];
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static unsigned int
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crc32(const unsigned char *buf, unsigned int len)
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{
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unsigned int crc = 0xffffffffL;
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const unsigned char *end = buf + len;
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for (; buf != end; ++buf)
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crc = (crc << 8) ^ BZ2_crc32Table[(crc >> 24) ^ *buf];
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crc = ~crc;
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return crc;
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}
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//-----------------------------------------------------------------------------
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static void
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reporterr(int e, const char *fmt, ...)
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{
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if (fmt) {
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va_list args;
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va_start(args, fmt);
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vfprintf(stderr, fmt, args);
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va_end(args);
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}
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exit(e);
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}
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static void
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split(PROffset32 *I,PROffset32 *V,PROffset32 start,PROffset32 len,PROffset32 h)
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{
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PROffset32 i,j,k,x,tmp,jj,kk;
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if(len<16) {
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for(k=start;k<start+len;k+=j) {
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j=1;x=V[I[k]+h];
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for(i=1;k+i<start+len;i++) {
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if(V[I[k+i]+h]<x) {
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x=V[I[k+i]+h];
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j=0;
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};
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if(V[I[k+i]+h]==x) {
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tmp=I[k+j];I[k+j]=I[k+i];I[k+i]=tmp;
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j++;
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};
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};
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for(i=0;i<j;i++) V[I[k+i]]=k+j-1;
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if(j==1) I[k]=-1;
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};
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return;
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};
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x=V[I[start+len/2]+h];
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jj=0;kk=0;
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for(i=start;i<start+len;i++) {
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if(V[I[i]+h]<x) jj++;
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if(V[I[i]+h]==x) kk++;
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};
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jj+=start;kk+=jj;
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i=start;j=0;k=0;
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while(i<jj) {
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if(V[I[i]+h]<x) {
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i++;
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} else if(V[I[i]+h]==x) {
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tmp=I[i];I[i]=I[jj+j];I[jj+j]=tmp;
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j++;
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} else {
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tmp=I[i];I[i]=I[kk+k];I[kk+k]=tmp;
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k++;
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};
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};
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while(jj+j<kk) {
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if(V[I[jj+j]+h]==x) {
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j++;
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} else {
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tmp=I[jj+j];I[jj+j]=I[kk+k];I[kk+k]=tmp;
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k++;
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};
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};
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if(jj>start) split(I,V,start,jj-start,h);
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for(i=0;i<kk-jj;i++) V[I[jj+i]]=kk-1;
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if(jj==kk-1) I[jj]=-1;
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if(start+len>kk) split(I,V,kk,start+len-kk,h);
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}
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static void
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qsufsort(PROffset32 *I,PROffset32 *V,unsigned char *old,PROffset32 oldsize)
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{
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PROffset32 buckets[256];
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PROffset32 i,h,len;
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for(i=0;i<256;i++) buckets[i]=0;
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for(i=0;i<oldsize;i++) buckets[old[i]]++;
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for(i=1;i<256;i++) buckets[i]+=buckets[i-1];
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for(i=255;i>0;i--) buckets[i]=buckets[i-1];
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buckets[0]=0;
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for(i=0;i<oldsize;i++) I[++buckets[old[i]]]=i;
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I[0]=oldsize;
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for(i=0;i<oldsize;i++) V[i]=buckets[old[i]];
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V[oldsize]=0;
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for(i=1;i<256;i++) if(buckets[i]==buckets[i-1]+1) I[buckets[i]]=-1;
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I[0]=-1;
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for(h=1;I[0]!=-(oldsize+1);h+=h) {
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len=0;
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for(i=0;i<oldsize+1;) {
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if(I[i]<0) {
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len-=I[i];
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i-=I[i];
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} else {
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if(len) I[i-len]=-len;
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len=V[I[i]]+1-i;
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split(I,V,i,len,h);
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i+=len;
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len=0;
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};
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};
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if(len) I[i-len]=-len;
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};
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for(i=0;i<oldsize+1;i++) I[V[i]]=i;
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}
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static PROffset32
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matchlen(unsigned char *old,PROffset32 oldsize,unsigned char *newbuf,PROffset32 newsize)
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{
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PROffset32 i;
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for(i=0;(i<oldsize)&&(i<newsize);i++)
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if(old[i]!=newbuf[i]) break;
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return i;
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}
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static PROffset32
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search(PROffset32 *I,unsigned char *old,PROffset32 oldsize,
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unsigned char *newbuf,PROffset32 newsize,PROffset32 st,PROffset32 en,PROffset32 *pos)
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{
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PROffset32 x,y;
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if(en-st<2) {
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x=matchlen(old+I[st],oldsize-I[st],newbuf,newsize);
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y=matchlen(old+I[en],oldsize-I[en],newbuf,newsize);
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if(x>y) {
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*pos=I[st];
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return x;
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} else {
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*pos=I[en];
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return y;
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}
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};
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x=st+(en-st)/2;
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if(memcmp(old+I[x],newbuf,MIN(oldsize-I[x],newsize))<0) {
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return search(I,old,oldsize,newbuf,newsize,x,en,pos);
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} else {
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return search(I,old,oldsize,newbuf,newsize,st,x,pos);
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};
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}
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int main(int argc,char *argv[])
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{
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int fd;
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unsigned char *old,*newbuf;
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PROffset32 oldsize,newsize;
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PROffset32 *I,*V;
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PROffset32 scan,pos,len;
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PROffset32 lastscan,lastpos,lastoffset;
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PROffset32 oldscore,scsc;
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PROffset32 s,Sf,lenf,Sb,lenb;
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PROffset32 overlap,Ss,lens;
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PROffset32 i;
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PROffset32 dblen,eblen;
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unsigned char *db,*eb;
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unsigned int scrc;
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MBSPatchHeader header = {
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{'M','B','D','I','F','F','1','0'},
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0, 0, 0, 0, 0, 0
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};
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PRUint32 numtriples;
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if(argc!=4)
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reporterr(1,"usage: %s <oldfile> <newfile> <patchfile>\n",argv[0]);
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/* Allocate oldsize+1 bytes instead of oldsize bytes to ensure
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that we never try to malloc(0) and get a NULL pointer */
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if(((fd=open(argv[1],O_RDONLY|_O_BINARY,0))<0) ||
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((oldsize=lseek(fd,0,SEEK_END))==-1) ||
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((old=(unsigned char*) malloc(oldsize+1))==NULL) ||
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(lseek(fd,0,SEEK_SET)!=0) ||
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(read(fd,old,oldsize)!=oldsize) ||
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(close(fd)==-1))
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reporterr(1,"%s\n",argv[1]);
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scrc = crc32(old, oldsize);
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if(((I=(PROffset32*) malloc((oldsize+1)*sizeof(PROffset32)))==NULL) ||
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((V=(PROffset32*) malloc((oldsize+1)*sizeof(PROffset32)))==NULL))
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reporterr(1,NULL);
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qsufsort(I,V,old,oldsize);
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free(V);
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/* Allocate newsize+1 bytes instead of newsize bytes to ensure
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that we never try to malloc(0) and get a NULL pointer */
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if(((fd=open(argv[2],O_RDONLY|_O_BINARY,0))<0) ||
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((newsize=lseek(fd,0,SEEK_END))==-1) ||
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((newbuf=(unsigned char*) malloc(newsize+1))==NULL) ||
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(lseek(fd,0,SEEK_SET)!=0) ||
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(read(fd,newbuf,newsize)!=newsize) ||
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(close(fd)==-1)) reporterr(1,"%s\n",argv[2]);
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if(((db=(unsigned char*) malloc(newsize+1))==NULL) ||
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((eb=(unsigned char*) malloc(newsize+1))==NULL))
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reporterr(1,NULL);
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dblen=0;
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eblen=0;
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if((fd=open(argv[3],O_CREAT|O_TRUNC|O_WRONLY|_O_BINARY,0666))<0)
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reporterr(1,"%s\n",argv[3]);
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/* start writing here */
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/* We don't know the lengths yet, so we will write the header again
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at the end */
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if(write(fd,&header,sizeof(MBSPatchHeader))!=sizeof(MBSPatchHeader))
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reporterr(1,"%s\n",argv[3]);
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scan=0;len=0;
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lastscan=0;lastpos=0;lastoffset=0;
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numtriples = 0;
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while(scan<newsize) {
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oldscore=0;
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for(scsc=scan+=len;scan<newsize;scan++) {
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len=search(I,old,oldsize,newbuf+scan,newsize-scan,
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0,oldsize,&pos);
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for(;scsc<scan+len;scsc++)
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if((scsc+lastoffset<oldsize) &&
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(old[scsc+lastoffset] == newbuf[scsc]))
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oldscore++;
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if(((len==oldscore) && (len!=0)) ||
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(len>oldscore+8)) break;
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if((scan+lastoffset<oldsize) &&
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(old[scan+lastoffset] == newbuf[scan]))
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oldscore--;
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};
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if((len!=oldscore) || (scan==newsize)) {
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MBSPatchTriple triple;
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s=0;Sf=0;lenf=0;
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for(i=0;(lastscan+i<scan)&&(lastpos+i<oldsize);) {
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if(old[lastpos+i]==newbuf[lastscan+i]) s++;
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i++;
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if(s*2-i>Sf*2-lenf) { Sf=s; lenf=i; };
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};
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lenb=0;
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if(scan<newsize) {
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s=0;Sb=0;
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for(i=1;(scan>=lastscan+i)&&(pos>=i);i++) {
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if(old[pos-i]==newbuf[scan-i]) s++;
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if(s*2-i>Sb*2-lenb) { Sb=s; lenb=i; };
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};
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};
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if(lastscan+lenf>scan-lenb) {
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overlap=(lastscan+lenf)-(scan-lenb);
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s=0;Ss=0;lens=0;
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for(i=0;i<overlap;i++) {
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if(newbuf[lastscan+lenf-overlap+i]==
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old[lastpos+lenf-overlap+i]) s++;
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if(newbuf[scan-lenb+i]==
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old[pos-lenb+i]) s--;
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if(s>Ss) { Ss=s; lens=i+1; };
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};
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lenf+=lens-overlap;
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lenb-=lens;
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};
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for(i=0;i<lenf;i++)
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db[dblen+i]=newbuf[lastscan+i]-old[lastpos+i];
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for(i=0;i<(scan-lenb)-(lastscan+lenf);i++)
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eb[eblen+i]=newbuf[lastscan+lenf+i];
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dblen+=lenf;
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eblen+=(scan-lenb)-(lastscan+lenf);
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triple.x = htonl(lenf);
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triple.y = htonl((scan-lenb)-(lastscan+lenf));
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triple.z = htonl((pos-lenb)-(lastpos+lenf));
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if (write(fd,&triple,sizeof(triple)) != sizeof(triple))
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reporterr(1,NULL);
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#ifdef DEBUG_bsmedberg
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printf("Writing a block:\n"
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" X: %u\n"
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" Y: %u\n"
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" Z: %i\n",
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(PRUint32) lenf,
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(PRUint32) ((scan-lenb)-(lastscan+lenf)),
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(PRUint32) ((pos-lenb)-(lastpos+lenf)));
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#endif
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++numtriples;
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lastscan=scan-lenb;
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lastpos=pos-lenb;
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lastoffset=pos-scan;
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};
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};
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if(write(fd,db,dblen)!=dblen)
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reporterr(1,NULL);
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if(write(fd,eb,eblen)!=eblen)
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reporterr(1,NULL);
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header.slen = htonl(oldsize);
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header.scrc32 = htonl(scrc);
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header.dlen = htonl(newsize);
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header.cblen = htonl(numtriples * sizeof(MBSPatchTriple));
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header.difflen = htonl(dblen);
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header.extralen = htonl(eblen);
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if (lseek(fd,0,SEEK_SET) == -1 ||
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write(fd,&header,sizeof(header)) != sizeof(header) ||
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close(fd) == -1)
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reporterr(1,NULL);
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free(db);
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free(eb);
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free(I);
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free(old);
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free(newbuf);
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return 0;
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}
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