usr.bin/bsdiff/bsdiff/bsdiff.c

   1 /*-
   2  * Copyright 2003-2005 Colin Percival
   3  * All rights reserved
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted providing that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  16  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  18  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  22  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  23  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  24  * POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/types.h>
  31
  32 #include <bzlib.h>
  33 #include <err.h>
  34 #include <fcntl.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <unistd.h>
  39
  40 #ifndef O_BINARY
  41 #define O_BINARY 0
  42 #endif
  43
  44 #define MIN(x,y) (((x)<(y)) ? (x) : (y))
  45
  46 static void split(off_t *I,off_t *V,off_t start,off_t len,off_t h)
  47 {
  48         off_t i,j,k,x,tmp,jj,kk;
  49
  50         if(len<16) {
  51                 for(k=start;k<start+len;k+=j) {
  52                         j=1;x=V[I[k]+h];
  53                         for(i=1;k+i<start+len;i++) {
  54                                 if(V[I[k+i]+h]<x) {
  55                                         x=V[I[k+i]+h];
  56                                         j=0;
  57                                 };
  58                                 if(V[I[k+i]+h]==x) {
  59                                         tmp=I[k+j];I[k+j]=I[k+i];I[k+i]=tmp;
  60                                         j++;
  61                                 };
  62                         };
  63                         for(i=0;i<j;i++) V[I[k+i]]=k+j-1;
  64                         if(j==1) I[k]=-1;
  65                 };
  66                 return;
  67         };
  68
  69         x=V[I[start+len/2]+h];
  70         jj=0;kk=0;
  71         for(i=start;i<start+len;i++) {
  72                 if(V[I[i]+h]<x) jj++;
  73                 if(V[I[i]+h]==x) kk++;
  74         };
  75         jj+=start;kk+=jj;
  76
  77         i=start;j=0;k=0;
  78         while(i<jj) {
  79                 if(V[I[i]+h]<x) {
  80                         i++;
  81                 } else if(V[I[i]+h]==x) {
  82                         tmp=I[i];I[i]=I[jj+j];I[jj+j]=tmp;
  83                         j++;
  84                 } else {
  85                         tmp=I[i];I[i]=I[kk+k];I[kk+k]=tmp;
  86                         k++;
  87                 };
  88         };
  89
  90         while(jj+j<kk) {
  91                 if(V[I[jj+j]+h]==x) {
  92                         j++;
  93                 } else {
  94                         tmp=I[jj+j];I[jj+j]=I[kk+k];I[kk+k]=tmp;
  95                         k++;
  96                 };
  97         };
  98
  99         if(jj>start) split(I,V,start,jj-start,h);
 100
 101         for(i=0;i<kk-jj;i++) V[I[jj+i]]=kk-1;
 102         if(jj==kk-1) I[jj]=-1;
 103
 104         if(start+len>kk) split(I,V,kk,start+len-kk,h);
 105 }
 106
 107 static void qsufsort(off_t *I,off_t *V,u_char *old,off_t oldsize)
 108 {
 109         off_t buckets[256];
 110         off_t i,h,len;
 111
 112         for(i=0;i<256;i++) buckets[i]=0;
 113         for(i=0;i<oldsize;i++) buckets[old[i]]++;
 114         for(i=1;i<256;i++) buckets[i]+=buckets[i-1];
 115         for(i=255;i>0;i--) buckets[i]=buckets[i-1];
 116         buckets[0]=0;
 117
 118         for(i=0;i<oldsize;i++) I[++buckets[old[i]]]=i;
 119         I[0]=oldsize;
 120         for(i=0;i<oldsize;i++) V[i]=buckets[old[i]];
 121         V[oldsize]=0;
 122         for(i=1;i<256;i++) if(buckets[i]==buckets[i-1]+1) I[buckets[i]]=-1;
 123         I[0]=-1;
 124
 125         for(h=1;I[0]!=-(oldsize+1);h+=h) {
 126                 len=0;
 127                 for(i=0;i<oldsize+1;) {
 128                         if(I[i]<0) {
 129                                 len-=I[i];
 130                                 i-=I[i];
 131                         } else {
 132                                 if(len) I[i-len]=-len;
 133                                 len=V[I[i]]+1-i;
 134                                 split(I,V,i,len,h);
 135                                 i+=len;
 136                                 len=0;
 137                         };
 138                 };
 139                 if(len) I[i-len]=-len;
 140         };
 141
 142         for(i=0;i<oldsize+1;i++) I[V[i]]=i;
 143 }
 144
 145 static off_t matchlen(u_char *old,off_t oldsize,u_char *new,off_t newsize)
 146 {
 147         off_t i;
 148
 149         for(i=0;(i<oldsize)&&(i<newsize);i++)
 150                 if(old[i]!=new[i]) break;
 151
 152         return i;
 153 }
 154
 155 static off_t search(off_t *I,u_char *old,off_t oldsize,
 156                 u_char *new,off_t newsize,off_t st,off_t en,off_t *pos)
 157 {
 158         off_t x,y;
 159
 160         if(en-st<2) {
 161                 x=matchlen(old+I[st],oldsize-I[st],new,newsize);
 162                 y=matchlen(old+I[en],oldsize-I[en],new,newsize);
 163
 164                 if(x>y) {
 165                         *pos=I[st];
 166                         return x;
 167                 } else {
 168                         *pos=I[en];
 169                         return y;
 170                 }
 171         };
 172
 173         x=st+(en-st)/2;
 174         if(memcmp(old+I[x],new,MIN(oldsize-I[x],newsize))<0) {
 175                 return search(I,old,oldsize,new,newsize,x,en,pos);
 176         } else {
 177                 return search(I,old,oldsize,new,newsize,st,x,pos);
 178         };
 179 }
 180
 181 static void offtout(off_t x,u_char *buf)
 182 {
 183         off_t y;
 184
 185         if(x<0) y=-x; else y=x;
 186
 187                 buf[0]=y%256;y-=buf[0];
 188         y=y/256;buf[1]=y%256;y-=buf[1];
 189         y=y/256;buf[2]=y%256;y-=buf[2];
 190         y=y/256;buf[3]=y%256;y-=buf[3];
 191         y=y/256;buf[4]=y%256;y-=buf[4];
 192         y=y/256;buf[5]=y%256;y-=buf[5];
 193         y=y/256;buf[6]=y%256;y-=buf[6];
 194         y=y/256;buf[7]=y%256;
 195
 196         if(x<0) buf[7]|=0x80;
 197 }
 198
 199 static void
 200 usage(void)
 201 {
 202
 203         fprintf(stderr, "usage: bsdiff oldfile newfile patchfile\n");
 204         exit(1);
 205 }
 206
 207 int main(int argc,char *argv[])
 208 {
 209         int fd;
 210         u_char *old,*new;
 211         off_t oldsize,newsize;
 212         off_t *I,*V;
 213         off_t scan,pos,len;
 214         off_t lastscan,lastpos,lastoffset;
 215         off_t oldscore,scsc;
 216         off_t s,Sf,lenf,Sb,lenb;
 217         off_t overlap,Ss,lens;
 218         off_t i;
 219         off_t dblen,eblen;
 220         u_char *db,*eb;
 221         u_char buf[8];
 222         u_char header[32];
 223         FILE * pf;
 224         BZFILE * pfbz2;
 225         int bz2err;
 226
 227         if (argc != 4)
 228                 usage();
 229
 230         /* Allocate oldsize+1 bytes instead of oldsize bytes to ensure
 231                 that we never try to malloc(0) and get a NULL pointer */
 232         if(((fd=open(argv[1],O_RDONLY|O_BINARY,0))<0) ||
 233                 ((oldsize=lseek(fd,0,SEEK_END))==-1) ||
 234                 ((old=malloc(oldsize+1))==NULL) ||
 235                 (lseek(fd,0,SEEK_SET)!=0) ||
 236                 (read(fd,old,oldsize)!=oldsize) ||
 237                 (close(fd)==-1)) err(1,"%s",argv[1]);
 238
 239         if(((I=malloc((oldsize+1)*sizeof(off_t)))==NULL) ||
 240                 ((V=malloc((oldsize+1)*sizeof(off_t)))==NULL)) err(1,NULL);
 241
 242         qsufsort(I,V,old,oldsize);
 243
 244         free(V);
 245
 246         /* Allocate newsize+1 bytes instead of newsize bytes to ensure
 247                 that we never try to malloc(0) and get a NULL pointer */
 248         if(((fd=open(argv[2],O_RDONLY|O_BINARY,0))<0) ||
 249                 ((newsize=lseek(fd,0,SEEK_END))==-1) ||
 250                 ((new=malloc(newsize+1))==NULL) ||
 251                 (lseek(fd,0,SEEK_SET)!=0) ||
 252                 (read(fd,new,newsize)!=newsize) ||
 253                 (close(fd)==-1)) err(1,"%s",argv[2]);
 254
 255         if(((db=malloc(newsize+1))==NULL) ||
 256                 ((eb=malloc(newsize+1))==NULL)) err(1,NULL);
 257         dblen=0;
 258         eblen=0;
 259
 260         /* Create the patch file */
 261         if ((pf = fopen(argv[3], "wb")) == NULL)
 262                 err(1, "%s", argv[3]);
 263
 264         /* Header is
 265                 0       8        "BSDIFF40"
 266                 8       8       length of bzip2ed ctrl block
 267                 16      8       length of bzip2ed diff block
 268                 24      8       length of new file */
 269         /* File is
 270                 0       32      Header
 271                 32      ??      Bzip2ed ctrl block
 272                 ??      ??      Bzip2ed diff block
 273                 ??      ??      Bzip2ed extra block */
 274         memcpy(header,"BSDIFF40",8);
 275         offtout(0, header + 8);
 276         offtout(0, header + 16);
 277         offtout(newsize, header + 24);
 278         if (fwrite(header, 32, 1, pf) != 1)
 279                 err(1, "fwrite(%s)", argv[3]);
 280
 281         /* Compute the differences, writing ctrl as we go */
 282         if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
 283                 errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
 284         scan=0;len=0;pos=0;
 285         lastscan=0;lastpos=0;lastoffset=0;
 286         while(scan<newsize) {
 287                 oldscore=0;
 288
 289                 for(scsc=scan+=len;scan<newsize;scan++) {
 290                         len=search(I,old,oldsize,new+scan,newsize-scan,
 291                                         0,oldsize,&pos);
 292
 293                         for(;scsc<scan+len;scsc++)
 294                         if((scsc+lastoffset<oldsize) &&
 295                                 (old[scsc+lastoffset] == new[scsc]))
 296                                 oldscore++;
 297
 298                         if(((len==oldscore) && (len!=0)) ||
 299                                 (len>oldscore+8)) break;
 300
 301                         if((scan+lastoffset<oldsize) &&
 302                                 (old[scan+lastoffset] == new[scan]))
 303                                 oldscore--;
 304                 };
 305
 306                 if((len!=oldscore) || (scan==newsize)) {
 307                         s=0;Sf=0;lenf=0;
 308                         for(i=0;(lastscan+i<scan)&&(lastpos+i<oldsize);) {
 309                                 if(old[lastpos+i]==new[lastscan+i]) s++;
 310                                 i++;
 311                                 if(s*2-i>Sf*2-lenf) { Sf=s; lenf=i; };
 312                         };
 313
 314                         lenb=0;
 315                         if(scan<newsize) {
 316                                 s=0;Sb=0;
 317                                 for(i=1;(scan>=lastscan+i)&&(pos>=i);i++) {
 318                                         if(old[pos-i]==new[scan-i]) s++;
 319                                         if(s*2-i>Sb*2-lenb) { Sb=s; lenb=i; };
 320                                 };
 321                         };
 322
 323                         if(lastscan+lenf>scan-lenb) {
 324                                 overlap=(lastscan+lenf)-(scan-lenb);
 325                                 s=0;Ss=0;lens=0;
 326                                 for(i=0;i<overlap;i++) {
 327                                         if(new[lastscan+lenf-overlap+i]==
 328                                            old[lastpos+lenf-overlap+i]) s++;
 329                                         if(new[scan-lenb+i]==
 330                                            old[pos-lenb+i]) s--;
 331                                         if(s>Ss) { Ss=s; lens=i+1; };
 332                                 };
 333
 334                                 lenf+=lens-overlap;
 335                                 lenb-=lens;
 336                         };
 337
 338                         for(i=0;i<lenf;i++)
 339                                 db[dblen+i]=new[lastscan+i]-old[lastpos+i];
 340                         for(i=0;i<(scan-lenb)-(lastscan+lenf);i++)
 341                                 eb[eblen+i]=new[lastscan+lenf+i];
 342
 343                         dblen+=lenf;
 344                         eblen+=(scan-lenb)-(lastscan+lenf);
 345
 346                         offtout(lenf,buf);
 347                         BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
 348                         if (bz2err != BZ_OK)
 349                                 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
 350
 351                         offtout((scan-lenb)-(lastscan+lenf),buf);
 352                         BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
 353                         if (bz2err != BZ_OK)
 354                                 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
 355
 356                         offtout((pos-lenb)-(lastpos+lenf),buf);
 357                         BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
 358                         if (bz2err != BZ_OK)
 359                                 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
 360
 361                         lastscan=scan-lenb;
 362                         lastpos=pos-lenb;
 363                         lastoffset=pos-scan;
 364                 };
 365         };
 366         BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
 367         if (bz2err != BZ_OK)
 368                 errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
 369
 370         /* Compute size of compressed ctrl data */
 371         if ((len = ftello(pf)) == -1)
 372                 err(1, "ftello");
 373         offtout(len-32, header + 8);
 374
 375         /* Write compressed diff data */
 376         if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
 377                 errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
 378         BZ2_bzWrite(&bz2err, pfbz2, db, dblen);
 379         if (bz2err != BZ_OK)
 380                 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
 381         BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
 382         if (bz2err != BZ_OK)
 383                 errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
 384
 385         /* Compute size of compressed diff data */
 386         if ((newsize = ftello(pf)) == -1)
 387                 err(1, "ftello");
 388         offtout(newsize - len, header + 16);
 389
 390         /* Write compressed extra data */
 391         if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
 392                 errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
 393         BZ2_bzWrite(&bz2err, pfbz2, eb, eblen);
 394         if (bz2err != BZ_OK)
 395                 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
 396         BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
 397         if (bz2err != BZ_OK)
 398                 errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
 399
 400         /* Seek to the beginning, write the header, and close the file */
 401         if (fseeko(pf, 0, SEEK_SET))
 402                 err(1, "fseeko");
 403         if (fwrite(header, 32, 1, pf) != 1)
 404                 err(1, "fwrite(%s)", argv[3]);
 405         if (fclose(pf))
 406                 err(1, "fclose");
 407
 408         /* Free the memory we used */
 409         free(db);
 410         free(eb);
 411         free(I);
 412         free(old);
 413         free(new);
 414
 415         return 0;
 416 }