| /*- |
| * 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 |