third_party/bsdiff/mbsdiff.cc

   1 /*
   2   bsdiff.c -- Binary patch generator.
   3
   4   Copyright 2003 Colin Percival
   5
   6   For the terms under which this work may be distributed, please see
   7   the adjoining file "LICENSE".
   8
   9   ChangeLog:
  10   2005-05-05 - Use the modified header struct from bspatch.h; use 32-bit
  11                values throughout.
  12                  --Benjamin Smedberg <benjamin@smedbergs.us>
  13   2005-05-18 - Use the same CRC algorithm as bzip2, and leverage the CRC table
  14                provided by libbz2.
  15                  --Darin Fisher <darin@meer.net>
  16   2007-11-14 - Changed to use Crc from Lzma library instead of Bzip library
  17                  --Rahul Kuchhal
  18 */
  19
  20 #include "mbspatch.h"
  21
  22 #include <stdlib.h>
  23 #include <stdio.h>
  24 #include <string.h>
  25 #include <fcntl.h>
  26 #include <stdarg.h>
  27 #ifdef _WIN32
  28 #include <io.h>
  29 #include <winsock2.h>
  30 #else
  31 #include <unistd.h>
  32 #include <arpa/inet.h>
  33 #define _O_BINARY 0
  34 #endif
  35
  36 #undef MIN
  37 #define MIN(x,y) (((x)<(y)) ? (x) : (y))
  38
  39 static void
  40 reporterr(int e, const char *fmt, ...)
  41 {
  42         if (fmt) {
  43                 va_list args;
  44                 va_start(args, fmt);
  45                 vfprintf(stderr, fmt, args);
  46                 va_end(args);
  47         }
  48
  49         exit(e);
  50 }
  51
  52 static void
  53 split(int *I,int *V,int start,int len,int h)
  54 {
  55         int i,j,k,x,tmp,jj,kk;
  56
  57         if(len<16) {
  58                 for(k=start;k<start+len;k+=j) {
  59                         j=1;x=V[I[k]+h];
  60                         for(i=1;k+i<start+len;i++) {
  61                                 if(V[I[k+i]+h]<x) {
  62                                         x=V[I[k+i]+h];
  63                                         j=0;
  64                                 };
  65                                 if(V[I[k+i]+h]==x) {
  66                                         tmp=I[k+j];I[k+j]=I[k+i];I[k+i]=tmp;
  67                                         j++;
  68                                 };
  69                         };
  70                         for(i=0;i<j;i++) V[I[k+i]]=k+j-1;
  71                         if(j==1) I[k]=-1;
  72                 };
  73                 return;
  74         };
  75
  76         x=V[I[start+len/2]+h];
  77         jj=0;kk=0;
  78         for(i=start;i<start+len;i++) {
  79                 if(V[I[i]+h]<x) jj++;
  80                 if(V[I[i]+h]==x) kk++;
  81         };
  82         jj+=start;kk+=jj;
  83
  84         i=start;j=0;k=0;
  85         while(i<jj) {
  86                 if(V[I[i]+h]<x) {
  87                         i++;
  88                 } else if(V[I[i]+h]==x) {
  89                         tmp=I[i];I[i]=I[jj+j];I[jj+j]=tmp;
  90                         j++;
  91                 } else {
  92                         tmp=I[i];I[i]=I[kk+k];I[kk+k]=tmp;
  93                         k++;
  94                 };
  95         };
  96
  97         while(jj+j<kk) {
  98                 if(V[I[jj+j]+h]==x) {
  99                         j++;
 100                 } else {
 101                         tmp=I[jj+j];I[jj+j]=I[kk+k];I[kk+k]=tmp;
 102                         k++;
 103                 };
 104         };
 105
 106         if(jj>start) split(I,V,start,jj-start,h);
 107
 108         for(i=0;i<kk-jj;i++) V[I[jj+i]]=kk-1;
 109         if(jj==kk-1) I[jj]=-1;
 110
 111         if(start+len>kk) split(I,V,kk,start+len-kk,h);
 112 }
 113
 114 static void
 115 qsufsort(int *I,int *V,unsigned char *old,int oldsize)
 116 {
 117         int buckets[256];
 118         int i,h,len;
 119
 120         for(i=0;i<256;i++) buckets[i]=0;
 121         for(i=0;i<oldsize;i++) buckets[old[i]]++;
 122         for(i=1;i<256;i++) buckets[i]+=buckets[i-1];
 123         for(i=255;i>0;i--) buckets[i]=buckets[i-1];
 124         buckets[0]=0;
 125
 126         for(i=0;i<oldsize;i++) I[++buckets[old[i]]]=i;
 127         I[0]=oldsize;
 128         for(i=0;i<oldsize;i++) V[i]=buckets[old[i]];
 129         V[oldsize]=0;
 130         for(i=1;i<256;i++) if(buckets[i]==buckets[i-1]+1) I[buckets[i]]=-1;
 131         I[0]=-1;
 132
 133         for(h=1;I[0]!=-(oldsize+1);h+=h) {
 134                 len=0;
 135                 for(i=0;i<oldsize+1;) {
 136                         if(I[i]<0) {
 137                                 len-=I[i];
 138                                 i-=I[i];
 139                         } else {
 140                                 if(len) I[i-len]=-len;
 141                                 len=V[I[i]]+1-i;
 142                                 split(I,V,i,len,h);
 143                                 i+=len;
 144                                 len=0;
 145                         };
 146                 };
 147                 if(len) I[i-len]=-len;
 148         };
 149
 150         for(i=0;i<oldsize+1;i++) I[V[i]]=i;
 151 }
 152
 153 static int
 154 matchlen(unsigned char *old,int oldsize,unsigned char *newbuf,int newsize)
 155 {
 156         int i;
 157
 158         for(i=0;(i<oldsize)&&(i<newsize);i++)
 159                 if(old[i]!=newbuf[i]) break;
 160
 161         return i;
 162 }
 163
 164 static int
 165 search(int *I,unsigned char *old,int oldsize,
 166        unsigned char *newbuf,int newsize,int st,int en,int *pos)
 167 {
 168         int x,y;
 169
 170         if(en-st<2) {
 171                 x=matchlen(old+I[st],oldsize-I[st],newbuf,newsize);
 172                 y=matchlen(old+I[en],oldsize-I[en],newbuf,newsize);
 173
 174                 if(x>y) {
 175                         *pos=I[st];
 176                         return x;
 177                 } else {
 178                         *pos=I[en];
 179                         return y;
 180                 }
 181         };
 182
 183         x=st+(en-st)/2;
 184         if(memcmp(old+I[x],newbuf,MIN(oldsize-I[x],newsize))<0) {
 185                 return search(I,old,oldsize,newbuf,newsize,x,en,pos);
 186         } else {
 187                 return search(I,old,oldsize,newbuf,newsize,st,x,pos);
 188         };
 189 }
 190
 191 int main(int argc,char *argv[])
 192 {
 193         int fd;
 194         unsigned char *old,*newbuf;
 195         int oldsize,newsize;
 196         int *I,*V;
 197
 198         int scan,pos,len;
 199         int lastscan,lastpos,lastoffset;
 200         int oldscore,scsc;
 201
 202         int s,Sf,lenf,Sb,lenb;
 203         int overlap,Ss,lens;
 204         int i;
 205
 206         int dblen,eblen;
 207         unsigned char *db,*eb;
 208
 209         unsigned int scrc;
 210
 211         MBSPatchHeader header = {
 212                 {'M','B','D','I','F','F','1','0'},
 213                 0, 0, 0, 0, 0, 0
 214         };
 215
 216         int numtriples;
 217
 218         if(argc!=4)
 219                 reporterr(1,"usage: %s <oldfile> <newfile> <patchfile>\n",argv[0]);
 220
 221         /* Allocate oldsize+1 bytes instead of oldsize bytes to ensure
 222                 that we never try to malloc(0) and get a NULL pointer */
 223         if(((fd=open(argv[1],O_RDONLY|_O_BINARY,0))<0) ||
 224                 ((oldsize=lseek(fd,0,SEEK_END))==-1) ||
 225                 ((old=(unsigned char*) malloc(oldsize+1))==NULL) ||
 226                 (lseek(fd,0,SEEK_SET)!=0) ||
 227                 (read(fd,old,oldsize)!=oldsize) ||
 228                 (close(fd)==-1))
 229                 reporterr(1,"%s\n",argv[1]);
 230
 231         scrc = CalculateCrc(old, oldsize);
 232
 233         if(((I=(int*) malloc((oldsize+1)*sizeof(int)))==NULL) ||
 234                 ((V=(int*) malloc((oldsize+1)*sizeof(int)))==NULL))
 235                 reporterr(1,NULL);
 236
 237         qsufsort(I,V,old,oldsize);
 238
 239         free(V);
 240
 241         /* Allocate newsize+1 bytes instead of newsize bytes to ensure
 242                 that we never try to malloc(0) and get a NULL pointer */
 243         if(((fd=open(argv[2],O_RDONLY|_O_BINARY,0))<0) ||
 244                 ((newsize=lseek(fd,0,SEEK_END))==-1) ||
 245                 ((newbuf=(unsigned char*) malloc(newsize+1))==NULL) ||
 246                 (lseek(fd,0,SEEK_SET)!=0) ||
 247                 (read(fd,newbuf,newsize)!=newsize) ||
 248                 (close(fd)==-1)) reporterr(1,"%s\n",argv[2]);
 249
 250         if(((db=(unsigned char*) malloc(newsize+1))==NULL) ||
 251                 ((eb=(unsigned char*) malloc(newsize+1))==NULL))
 252                 reporterr(1,NULL);
 253
 254         dblen=0;
 255         eblen=0;
 256
 257         if((fd=open(argv[3],O_CREAT|O_TRUNC|O_WRONLY|_O_BINARY,0666))<0)
 258                 reporterr(1,"%s\n",argv[3]);
 259
 260         /* start writing here */
 261
 262         /* We don't know the lengths yet, so we will write the header again
 263                  at the end */
 264
 265         if(write(fd,&header,sizeof(MBSPatchHeader))!=sizeof(MBSPatchHeader))
 266                 reporterr(1,"%s\n",argv[3]);
 267
 268         scan=0;len=0;
 269         lastscan=0;lastpos=0;lastoffset=0;
 270         numtriples = 0;
 271         while(scan<newsize) {
 272                 oldscore=0;
 273
 274                 for(scsc=scan+=len;scan<newsize;scan++) {
 275                         len=search(I,old,oldsize,newbuf+scan,newsize-scan,
 276                                         0,oldsize,&pos);
 277
 278                         for(;scsc<scan+len;scsc++)
 279                         if((scsc+lastoffset<oldsize) &&
 280                                 (old[scsc+lastoffset] == newbuf[scsc]))
 281                                 oldscore++;
 282
 283                         if(((len==oldscore) && (len!=0)) ||
 284                                 (len>oldscore+8)) break;
 285
 286                         if((scan+lastoffset<oldsize) &&
 287                                 (old[scan+lastoffset] == newbuf[scan]))
 288                                 oldscore--;
 289                 };
 290
 291                 if((len!=oldscore) || (scan==newsize)) {
 292                         MBSPatchTriple triple;
 293
 294                         s=0;Sf=0;lenf=0;
 295                         for(i=0;(lastscan+i<scan)&&(lastpos+i<oldsize);) {
 296                                 if(old[lastpos+i]==newbuf[lastscan+i]) s++;
 297                                 i++;
 298                                 if(s*2-i>Sf*2-lenf) { Sf=s; lenf=i; };
 299                         };
 300
 301                         lenb=0;
 302                         if(scan<newsize) {
 303                                 s=0;Sb=0;
 304                                 for(i=1;(scan>=lastscan+i)&&(pos>=i);i++) {
 305                                         if(old[pos-i]==newbuf[scan-i]) s++;
 306                                         if(s*2-i>Sb*2-lenb) { Sb=s; lenb=i; };
 307                                 };
 308                         };
 309
 310                         if(lastscan+lenf>scan-lenb) {
 311                                 overlap=(lastscan+lenf)-(scan-lenb);
 312                                 s=0;Ss=0;lens=0;
 313                                 for(i=0;i<overlap;i++) {
 314                                         if(newbuf[lastscan+lenf-overlap+i]==
 315                                            old[lastpos+lenf-overlap+i]) s++;
 316                                         if(newbuf[scan-lenb+i]==
 317                                            old[pos-lenb+i]) s--;
 318                                         if(s>Ss) { Ss=s; lens=i+1; };
 319                                 };
 320
 321                                 lenf+=lens-overlap;
 322                                 lenb-=lens;
 323                         };
 324
 325                         for(i=0;i<lenf;i++)
 326                                 db[dblen+i]=newbuf[lastscan+i]-old[lastpos+i];
 327                         for(i=0;i<(scan-lenb)-(lastscan+lenf);i++)
 328                                 eb[eblen+i]=newbuf[lastscan+lenf+i];
 329
 330                         dblen+=lenf;
 331                         eblen+=(scan-lenb)-(lastscan+lenf);
 332
 333                         triple.x = htonl(lenf);
 334                         triple.y = htonl((scan-lenb)-(lastscan+lenf));
 335                         triple.z = htonl((pos-lenb)-(lastpos+lenf));
 336                         if (write(fd,&triple,sizeof(triple)) != sizeof(triple))
 337                                 reporterr(1,NULL);
 338
 339 #ifdef DEBUG_bsmedberg
 340                         printf("Writing a block:\n"
 341                                "        X: %u\n"
 342                                "        Y: %u\n"
 343                                "        Z: %i\n",
 344                                (int) lenf,
 345                                (int) ((scan-lenb)-(lastscan+lenf)),
 346                                (int) ((pos-lenb)-(lastpos+lenf)));
 347 #endif
 348
 349                         ++numtriples;
 350
 351                         lastscan=scan-lenb;
 352                         lastpos=pos-lenb;
 353                         lastoffset=pos-scan;
 354                 };
 355         };
 356
 357         if(write(fd,db,dblen)!=dblen)
 358                 reporterr(1,NULL);
 359
 360         if(write(fd,eb,eblen)!=eblen)
 361                 reporterr(1,NULL);
 362
 363         header.slen     = htonl(oldsize);
 364         header.scrc32   = htonl(scrc);
 365         header.dlen     = htonl(newsize);
 366         header.cblen    = htonl(numtriples * sizeof(MBSPatchTriple));
 367         header.difflen  = htonl(dblen);
 368         header.extralen = htonl(eblen);
 369
 370         if (lseek(fd,0,SEEK_SET) == -1 ||
 371             write(fd,&header,sizeof(header)) != sizeof(header) ||
 372             close(fd) == -1)
 373                 reporterr(1,NULL);
 374
 375         free(db);
 376         free(eb);
 377         free(I);
 378         free(old);
 379         free(newbuf);
 380
 381         return 0;
 382 }