/*- * 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. */ #if 0 __FBSDID("$FreeBSD: src/usr.bin/bsdiff/bsdiff/bsdiff.c,v 1.1 2005/08/06 01:59:05 cperciva Exp $"); #endif #include "bsdiff.h" #include <sys/types.h> #include <bzlib.h> #include <err.h> #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <algorithm> namespace bsdiff { static off_t matchlen(const u_char* old, off_t oldsize, const u_char* new_buf, off_t newsize) { off_t i; for(i=0;(i<oldsize)&&(i<newsize);i++) if(old[i]!=new_buf[i]) break; return i; } // This is a binary search of the string |new_buf| of size |newsize| (or a // prefix of it) in the |old| string with size |oldsize| using the suffix array // |I|. |st| and |en| is the start and end of the search range (inclusive). // Returns the length of the longest prefix found and stores the position of the // string found in |*pos|. static off_t search(saidx_t* I, const u_char* old, off_t oldsize, const u_char* new_buf, 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_buf,newsize); y=matchlen(old+I[en],oldsize-I[en],new_buf,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_buf,std::min(oldsize-I[x],newsize))<=0) { return search(I,old,oldsize,new_buf,newsize,x,en,pos); } else { return search(I,old,oldsize,new_buf,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 bsdiff(const char* old_filename, const char* new_filename, const char* patch_filename) { int fd; u_char *old_buf,*new_buf; off_t oldsize,newsize; /* 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(old_filename,O_RDONLY,0))<0) || ((oldsize=lseek(fd,0,SEEK_END))==-1) || ((old_buf=static_cast<u_char*>(malloc(oldsize+1)))==NULL) || (lseek(fd,0,SEEK_SET)!=0) || (read(fd,old_buf,oldsize)!=oldsize) || (close(fd)==-1)) err(1,"%s",old_filename); /* 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(new_filename,O_RDONLY,0))<0) || ((newsize=lseek(fd,0,SEEK_END))==-1) || ((new_buf = static_cast<u_char*>(malloc(newsize+1)))==NULL) || (lseek(fd,0,SEEK_SET)!=0) || (read(fd,new_buf,newsize)!=newsize) || (close(fd)==-1)) err(1,"%s",new_filename); int ret = bsdiff(old_buf, oldsize, new_buf, newsize, patch_filename, nullptr); free(old_buf); free(new_buf); return ret; } // Generate bsdiff patch from |old_buf| to |new_buf|, save the patch file to // |patch_filename|. Returns 0 on success. // |I_cache| can be used to cache the suffix array if the same |old_buf| is used // repeatedly, pass nullptr if not needed. int bsdiff(const u_char* old_buf, off_t oldsize, const u_char* new_buf, off_t newsize, const char* patch_filename, saidx_t** I_cache) { saidx_t *I; off_t scan,pos=0,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 (I_cache && *I_cache) { I = *I_cache; } else { if ((I=static_cast<saidx_t*>(malloc((oldsize+1)*sizeof(saidx_t))))==NULL) err(1,NULL); if (divsufsort(old_buf, I, oldsize)) err(1, "divsufsort"); if (I_cache) *I_cache = I; } if(((db=static_cast<u_char*>(malloc(newsize+1)))==NULL) || ((eb=static_cast<u_char*>(malloc(newsize+1)))==NULL)) err(1,NULL); dblen=0; eblen=0; /* Create the patch file */ if ((pf = fopen(patch_filename, "w")) == NULL) err(1, "%s", patch_filename); /* 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)", patch_filename); /* 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(scan<newsize) { oldscore=0; /* If we come across a large block of data that only differs * by less than 8 bytes, this loop will take a long time to * go past that block of data. We need to track the number of * times we're stuck in the block and break out of it. */ int num_less_than_eight = 0; off_t prev_len, prev_oldscore, prev_pos; for(scsc=scan+=len;scan<newsize;scan++) { prev_len=len; prev_oldscore=oldscore; prev_pos=pos; len=search(I,old_buf,oldsize,new_buf+scan,newsize-scan, 0,oldsize-1,&pos); for(;scsc<scan+len;scsc++) if((scsc+lastoffset<oldsize) && (old_buf[scsc+lastoffset] == new_buf[scsc])) oldscore++; if(((len==oldscore) && (len!=0)) || (len>oldscore+8)) break; if((scan+lastoffset<oldsize) && (old_buf[scan+lastoffset] == new_buf[scan])) oldscore--; const off_t fuzz = 8; if (prev_len-fuzz<=len && len<=prev_len && prev_oldscore-fuzz<=oldscore && oldscore<=prev_oldscore && prev_pos<=pos && pos <=prev_pos+fuzz && oldscore<=len && len<=oldscore+fuzz) ++num_less_than_eight; else num_less_than_eight=0; if (num_less_than_eight > 100) break; }; if((len!=oldscore) || (scan==newsize)) { s=0;Sf=0;lenf=0; for(i=0;(lastscan+i<scan)&&(lastpos+i<oldsize);) { if(old_buf[lastpos+i]==new_buf[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_buf[pos-i]==new_buf[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_buf[lastscan+lenf-overlap+i]== old_buf[lastpos+lenf-overlap+i]) s++; if(new_buf[scan-lenb+i]== old_buf[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_buf[lastscan+i]-old_buf[lastpos+i]; for(i=0;i<(scan-lenb)-(lastscan+lenf);i++) eb[eblen+i]=new_buf[lastscan+lenf+i]; dblen+=lenf; eblen+=(scan-lenb)-(lastscan+lenf); offtout(lenf,buf); BZ2_bzWrite(&bz2err, pfbz2, buf, 8); if (bz2err != BZ_OK) errx(1, "BZ2_bzWrite, bz2err = %d", bz2err); offtout((scan-lenb)-(lastscan+lenf),buf); BZ2_bzWrite(&bz2err, pfbz2, buf, 8); if (bz2err != BZ_OK) errx(1, "BZ2_bzWrite, bz2err = %d", bz2err); offtout((pos-lenb)-(lastpos+lenf),buf); BZ2_bzWrite(&bz2err, pfbz2, buf, 8); if (bz2err != BZ_OK) errx(1, "BZ2_bzWrite, bz2err = %d", bz2err); lastscan=scan-lenb; lastpos=pos-lenb; lastoffset=pos-scan; }; }; BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL); if (bz2err != BZ_OK) errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err); /* Compute size of compressed ctrl data */ if ((len = ftello(pf)) == -1) err(1, "ftello"); offtout(len-32, header + 8); /* Write compressed diff data */ if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL) errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err); BZ2_bzWrite(&bz2err, pfbz2, db, dblen); if (bz2err != BZ_OK) errx(1, "BZ2_bzWrite, bz2err = %d", bz2err); BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL); if (bz2err != BZ_OK) errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err); /* Compute size of compressed diff data */ if ((newsize = ftello(pf)) == -1) err(1, "ftello"); offtout(newsize - len, header + 16); /* Write compressed extra data */ if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL) errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err); BZ2_bzWrite(&bz2err, pfbz2, eb, eblen); if (bz2err != BZ_OK) errx(1, "BZ2_bzWrite, bz2err = %d", bz2err); BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL); if (bz2err != BZ_OK) errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err); /* Seek to the beginning, write the header, and close the file */ if (fseeko(pf, 0, SEEK_SET)) err(1, "fseeko"); if (fwrite(header, 32, 1, pf) != 1) err(1, "fwrite(%s)", patch_filename); if (fclose(pf)) err(1, "fclose"); /* Free the memory we used */ free(db); free(eb); if (I_cache == nullptr) free(I); return 0; } } // namespace bsdiff