bsdiff源码

bsdiff 源码

 /*-
 * 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 
#include "bzlib.h"
#include 
#include 
//#include 
//#include 
#include 
#include 
//#include 


#include 
#include 
#include 
typedef unsigned char u_char;
typedef long pid_t;

template
void err(int i, const char* str, T arg) {
        char lastErrorTxt[1024];
        FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,NULL,GetLastError(),0,lastErrorTxt,1024,NULL);
        printf("%s",lastErrorTxt);
        printf(str, arg);
        exit(i);
}
void err(int i, const char* str) {
        char lastErrorTxt[1024];
        FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,NULL,GetLastError(),0,lastErrorTxt,1024,NULL);
        printf("%s",lastErrorTxt);
        if (str!=NULL) {
                printf("%s",str);
        }
        exit(i);
}
template
void errx(int i, const char* str, T arg) {
        printf(str, arg);
        exit(i);
}
void errx(int i, const char* str) {
        printf("%s",str);
        exit(i);
}

#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;kstart) split(I,V,start,jj-start,h);

        for(i=0;ikk) split(I,V,kk,start+len-kk,h);
}

static 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;i0;i--) buckets[i]=buckets[i-1];
        buckets[0]=0;

        for(i=0;iy) {
                        *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(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;
        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];
        FILE * pf;
        BZFILE * pfbz2;
        int bz2err;

        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 */
        //org:
        //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]);
        //new:
        //Read in chunks, don't rely on read always returns full data!
        if(((fd=open(argv[1],O_RDONLY|O_BINARY|O_NOINHERIT,0))<0) ||
                ((oldsize=lseek(fd,0,SEEK_END))==-1) ||
                ((old=(u_char*)malloc(oldsize+1))==NULL) ||
                (lseek(fd,0,SEEK_SET)!=0))
                                err(1,"%s",argv[1]);
        int r=oldsize;
        while (r>0 && (i=read(fd,old+oldsize-r,r))>0) r-=i;
        if (r>0 || close(fd)==-1) err(1,"%s",argv[1]);


        if(((I=(off_t*)malloc((oldsize+1)*sizeof(off_t)))==NULL) ||
                ((V=(off_t*)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 */
        //org:
        //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]);
        //new:
        //Read in chunks, don't rely on read always returns full data!
        if(((fd=open(argv[2],O_RDONLY|O_BINARY|O_NOINHERIT,0))<0) ||
                ((newsize=lseek(fd,0,SEEK_END))==-1) ||
                ((_new=(u_char*)malloc(newsize+1))==NULL) ||
                (lseek(fd,0,SEEK_SET)!=0))
                                err(1,"%s",argv[2]);

        r=newsize;
        while (r>0 && (i=read(fd,_new+newsize-r,r))>0) r-=i;
        if (r>0 || close(fd)==-1) err(1,"%s",argv[1]);

        if(((db=(u_char*)malloc(newsize+1))==NULL) ||
                ((eb=(u_char*)malloc(newsize+1))==NULL)) err(1,NULL);
        dblen=0;
        eblen=0;

        /* Create the patch file */
        //org:
        //if ((pf = fopen(argv[3], "w")) == NULL)
        //new:
        //if((fd=open(argv[3],O_CREAT|O_TRUNC|O_WRONLY|O_BINARY|O_NOINHERIT,0666))<0)
        if ((pf = fopen(argv[3], "wb")) == NULL)
                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);
        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 */
        if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
                errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
        scan=0;len=0;
        lastscan=0;lastpos=0;lastoffset=0;
        while(scanoldscore+8)) break;

                        if((scan+lastoffsetSf*2-lenf) { Sf=s; lenf=i; };
                        };

                        lenb=0;
                        if(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;iSs) { Ss=s; lens=i+1; };
                                };

                                lenf+=lens-overlap;
                                lenb-=lens;
                        };

                        for(i=0;i

转载于：http://www.douban.com/note/189240301/