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 <errno.h>
  35 #include <fcntl.h>
  36 #include <limits.h>
  37 #include <stdint.h>
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41 #include <unistd.h>
  42
  43 #ifndef O_BINARY
  44 #define O_BINARY 0
  45 #endif
  46
  47 #define MIN(x,y) (((x)<(y)) ? (x) : (y))
  48
  49 static void split(off_t *I,off_t *V,off_t start,off_t len,off_t h)
  50 {
  51         off_t i,j,k,x,tmp,jj,kk;
  52
  53         if(len<16) {
  54                 for(k=start;k<start+len;k+=j) {
  55                         j=1;x=V[I[k]+h];
  56                         for(i=1;k+i<start+len;i++) {
  57                                 if(V[I[k+i]+h]<x) {
  58                                         x=V[I[k+i]+h];
  59                                         j=0;
  60                                 };
  61                                 if(V[I[k+i]+h]==x) {
  62                                         tmp=I[k+j];I[k+j]=I[k+i];I[k+i]=tmp;
  63                                         j++;
  64                                 };
  65                         };
  66                         for(i=0;i<j;i++) V[I[k+i]]=k+j-1;
  67                         if(j==1) I[k]=-1;
  68                 };
  69                 return;
  70         };
  71
  72         x=V[I[start+len/2]+h];
  73         jj=0;kk=0;
  74         for(i=start;i<start+len;i++) {
  75                 if(V[I[i]+h]<x) jj++;
  76                 if(V[I[i]+h]==x) kk++;
  77         };
  78         jj+=start;kk+=jj;
  79
  80         i=start;j=0;k=0;
  81         while(i<jj) {
  82                 if(V[I[i]+h]<x) {
  83                         i++;
  84                 } else if(V[I[i]+h]==x) {
  85                         tmp=I[i];I[i]=I[jj+j];I[jj+j]=tmp;
  86                         j++;
  87                 } else {
  88                         tmp=I[i];I[i]=I[kk+k];I[kk+k]=tmp;
  89                         k++;
  90                 };
  91         };
  92
  93         while(jj+j<kk) {
  94                 if(V[I[jj+j]+h]==x) {
  95                         j++;
  96                 } else {
  97                         tmp=I[jj+j];I[jj+j]=I[kk+k];I[kk+k]=tmp;
  98                         k++;
  99                 };
 100         };
 101
 102         if(jj>start) split(I,V,start,jj-start,h);
 103
 104         for(i=0;i<kk-jj;i++) V[I[jj+i]]=kk-1;
 105         if(jj==kk-1) I[jj]=-1;
 106
 107         if(start+len>kk) split(I,V,kk,start+len-kk,h);
 108 }
 109
 110 static void qsufsort(off_t *I,off_t *V,u_char *old,off_t oldsize)
 111 {
 112         off_t buckets[256];
 113         off_t i,h,len;
 114
 115         for(i=0;i<256;i++) buckets[i]=0;
 116         for(i=0;i<oldsize;i++) buckets[old[i]]++;
 117         for(i=1;i<256;i++) buckets[i]+=buckets[i-1];
 118         for(i=255;i>0;i--) buckets[i]=buckets[i-1];
 119         buckets[0]=0;
 120
 121         for(i=0;i<oldsize;i++) I[++buckets[old[i]]]=i;
 122         I[0]=oldsize;
 123         for(i=0;i<oldsize;i++) V[i]=buckets[old[i]];
 124         V[oldsize]=0;
 125         for(i=1;i<256;i++) if(buckets[i]==buckets[i-1]+1) I[buckets[i]]=-1;
 126         I[0]=-1;
 127
 128         for(h=1;I[0]!=-(oldsize+1);h+=h) {
 129                 len=0;
 130                 for(i=0;i<oldsize+1;) {
 131                         if(I[i]<0) {
 132                                 len-=I[i];
 133                                 i-=I[i];
 134                         } else {
 135                                 if(len) I[i-len]=-len;
 136                                 len=V[I[i]]+1-i;
 137                                 split(I,V,i,len,h);
 138                                 i+=len;
 139                                 len=0;
 140                         };
 141                 };
 142                 if(len) I[i-len]=-len;
 143         };
 144
 145         for(i=0;i<oldsize+1;i++) I[V[i]]=i;
 146 }
 147
 148 static off_t matchlen(u_char *old,off_t oldsize,u_char *new,off_t newsize)
 149 {
 150         off_t i;
 151
 152         for(i=0;(i<oldsize)&&(i<newsize);i++)
 153                 if(old[i]!=new[i]) break;
 154
 155         return i;
 156 }
 157
 158 static off_t search(off_t *I,u_char *old,off_t oldsize,
 159                 u_char *new,off_t newsize,off_t st,off_t en,off_t *pos)
 160 {
 161         off_t x,y;
 162
 163         if(en-st<2) {
 164                 x=matchlen(old+I[st],oldsize-I[st],new,newsize);
 165                 y=matchlen(old+I[en],oldsize-I[en],new,newsize);
 166
 167                 if(x>y) {
 168                         *pos=I[st];
 169                         return x;
 170                 } else {
 171                         *pos=I[en];
 172                         return y;
 173                 }
 174         };
 175
 176         x=st+(en-st)/2;
 177         if(memcmp(old+I[x],new,MIN(oldsize-I[x],newsize))<0) {
 178                 return search(I,old,oldsize,new,newsize,x,en,pos);
 179         } else {
 180                 return search(I,old,oldsize,new,newsize,st,x,pos);
 181         };
 182 }
 183
 184 static void offtout(off_t x,u_char *buf)
 185 {
 186         off_t y;
 187
 188         if(x<0) y=-x; else y=x;
 189
 190                 buf[0]=y%256;y-=buf[0];
 191         y=y/256;buf[1]=y%256;y-=buf[1];
 192         y=y/256;buf[2]=y%256;y-=buf[2];
 193         y=y/256;buf[3]=y%256;y-=buf[3];
 194         y=y/256;buf[4]=y%256;y-=buf[4];
 195         y=y/256;buf[5]=y%256;y-=buf[5];
 196         y=y/256;buf[6]=y%256;y-=buf[6];
 197         y=y/256;buf[7]=y%256;
 198
 199         if(x<0) buf[7]|=0x80;
 200 }
 201
 202 int main(int argc,char *argv[])
 203 {
 204         int fd;
 205         u_char *old,*new;
 206         off_t oldsize,newsize;
 207         off_t *I,*V;
 208         off_t scan,pos,len;
 209         off_t lastscan,lastpos,lastoffset;
 210         off_t oldscore,scsc;
 211         off_t s,Sf,lenf,Sb,lenb;
 212         off_t overlap,Ss,lens;
 213         off_t i;
 214         off_t dblen,eblen;
 215         u_char *db,*eb;
 216         u_char buf[8];
 217         u_char header[32];
 218         FILE * pf;
 219         BZFILE * pfbz2;
 220         int bz2err;
 221
 222         if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);
 223
 224         /* Allocate oldsize+1 bytes instead of oldsize bytes to ensure
 225                 that we never try to malloc(0) and get a NULL pointer */
 226         if(((fd=open(argv[1],O_RDONLY|O_BINARY,0))<0) ||
 227             ((oldsize=lseek(fd,0,SEEK_END))==-1))
 228                 err(1, "%s", argv[1]);
 229
 230         if (oldsize > SSIZE_MAX ||
 231             (uintmax_t)oldsize >= SIZE_T_MAX / sizeof(off_t) ||
 232             oldsize == OFF_MAX) {
 233                 errno = EFBIG;
 234                 err(1, "%s", argv[1]);
 235         }
 236
 237         if (((old=malloc(oldsize+1))==NULL) ||
 238                 (lseek(fd,0,SEEK_SET)!=0) ||
 239                 (read(fd,old,oldsize)!=oldsize) ||
 240                 (close(fd)==-1)) err(1,"%s",argv[1]);
 241
 242         if(((I=malloc((oldsize+1)*sizeof(off_t)))==NULL) ||
 243                 ((V=malloc((oldsize+1)*sizeof(off_t)))==NULL)) err(1,NULL);
 244
 245         qsufsort(I,V,old,oldsize);
 246
 247         free(V);
 248
 249         /* Allocate newsize+1 bytes instead of newsize bytes to ensure
 250                 that we never try to malloc(0) and get a NULL pointer */
 251         if(((fd=open(argv[2],O_RDONLY|O_BINARY,0))<0) ||
 252             ((newsize=lseek(fd,0,SEEK_END))==-1))
 253                 err(1, "%s", argv[2]);
 254
 255         if (newsize > SSIZE_MAX || (uintmax_t)newsize >= SIZE_T_MAX ||
 256             newsize == OFF_MAX) {
 257                 errno = EFBIG;
 258                 err(1, "%s", argv[2]);
 259         }
 260
 261         if (((new=malloc(newsize+1))==NULL) ||
 262                 (lseek(fd,0,SEEK_SET)!=0) ||
 263                 (read(fd,new,newsize)!=newsize) ||
 264                 (close(fd)==-1)) err(1,"%s",argv[2]);
 265
 266         if(((db=malloc(newsize+1))==NULL) ||
 267                 ((eb=malloc(newsize+1))==NULL)) err(1,NULL);
 268         dblen=0;
 269         eblen=0;
 270
 271         /* Create the patch file */
 272         if ((pf = fopen(argv[3], "wb")) == NULL)
 273                 err(1, "%s", argv[3]);
 274
 275         /* Header is
 276                 0       8        "BSDIFF40"
 277                 8       8       length of bzip2ed ctrl block
 278                 16      8       length of bzip2ed diff block
 279                 24      8       length of new file */
 280         /* File is
 281                 0       32      Header
 282                 32      ??      Bzip2ed ctrl block
 283                 ??      ??      Bzip2ed diff block
 284                 ??      ??      Bzip2ed extra block */
 285         memcpy(header,"BSDIFF40",8);
 286         offtout(0, header + 8);
 287         offtout(0, header + 16);
 288         offtout(newsize, header + 24);
 289         if (fwrite(header, 32, 1, pf) != 1)
 290                 err(1, "fwrite(%s)", argv[3]);
 291
 292         /* Compute the differences, writing ctrl as we go */
 293         if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
 294                 errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
 295         scan=0;len=0;pos=0;
 296         lastscan=0;lastpos=0;lastoffset=0;
 297         while(scan<newsize) {
 298                 oldscore=0;
 299
 300                 for(scsc=scan+=len;scan<newsize;scan++) {
 301                         len=search(I,old,oldsize,new+scan,newsize-scan,
 302                                         0,oldsize,&pos);
 303
 304                         for(;scsc<scan+len;scsc++)
 305                         if((scsc+lastoffset<oldsize) &&
 306                                 (old[scsc+lastoffset] == new[scsc]))
 307                                 oldscore++;
 308
 309                         if(((len==oldscore) && (len!=0)) ||
 310                                 (len>oldscore+8)) break;
 311
 312                         if((scan+lastoffset<oldsize) &&
 313                                 (old[scan+lastoffset] == new[scan]))
 314                                 oldscore--;
 315                 };
 316
 317                 if((len!=oldscore) || (scan==newsize)) {
 318                         s=0;Sf=0;lenf=0;
 319                         for(i=0;(lastscan+i<scan)&&(lastpos+i<oldsize);) {
 320                                 if(old[lastpos+i]==new[lastscan+i]) s++;
 321                                 i++;
 322                                 if(s*2-i>Sf*2-lenf) { Sf=s; lenf=i; };
 323                         };
 324
 325                         lenb=0;
 326                         if(scan<newsize) {
 327                                 s=0;Sb=0;
 328                                 for(i=1;(scan>=lastscan+i)&&(pos>=i);i++) {
 329                                         if(old[pos-i]==new[scan-i]) s++;
 330                                         if(s*2-i>Sb*2-lenb) { Sb=s; lenb=i; };
 331                                 };
 332                         };
 333
 334                         if(lastscan+lenf>scan-lenb) {
 335                                 overlap=(lastscan+lenf)-(scan-lenb);
 336                                 s=0;Ss=0;lens=0;
 337                                 for(i=0;i<overlap;i++) {
 338                                         if(new[lastscan+lenf-overlap+i]==
 339                                            old[lastpos+lenf-overlap+i]) s++;
 340                                         if(new[scan-lenb+i]==
 341                                            old[pos-lenb+i]) s--;
 342                                         if(s>Ss) { Ss=s; lens=i+1; };
 343                                 };
 344
 345                                 lenf+=lens-overlap;
 346                                 lenb-=lens;
 347                         };
 348
 349                         for(i=0;i<lenf;i++)
 350                                 db[dblen+i]=new[lastscan+i]-old[lastpos+i];
 351                         for(i=0;i<(scan-lenb)-(lastscan+lenf);i++)
 352                                 eb[eblen+i]=new[lastscan+lenf+i];
 353
 354                         dblen+=lenf;
 355                         eblen+=(scan-lenb)-(lastscan+lenf);
 356
 357                         offtout(lenf,buf);
 358                         BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
 359                         if (bz2err != BZ_OK)
 360                                 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
 361
 362                         offtout((scan-lenb)-(lastscan+lenf),buf);
 363                         BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
 364                         if (bz2err != BZ_OK)
 365                                 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
 366
 367                         offtout((pos-lenb)-(lastpos+lenf),buf);
 368                         BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
 369                         if (bz2err != BZ_OK)
 370                                 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
 371
 372                         lastscan=scan-lenb;
 373                         lastpos=pos-lenb;
 374                         lastoffset=pos-scan;
 375                 };
 376         };
 377         BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
 378         if (bz2err != BZ_OK)
 379                 errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
 380
 381         /* Compute size of compressed ctrl data */
 382         if ((len = ftello(pf)) == -1)
 383                 err(1, "ftello");
 384         offtout(len-32, header + 8);
 385
 386         /* Write compressed diff data */
 387         if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
 388                 errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
 389         BZ2_bzWrite(&bz2err, pfbz2, db, dblen);
 390         if (bz2err != BZ_OK)
 391                 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
 392         BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
 393         if (bz2err != BZ_OK)
 394                 errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
 395
 396         /* Compute size of compressed diff data */
 397         if ((newsize = ftello(pf)) == -1)
 398                 err(1, "ftello");
 399         offtout(newsize - len, header + 16);
 400
 401         /* Write compressed extra data */
 402         if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
 403                 errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
 404         BZ2_bzWrite(&bz2err, pfbz2, eb, eblen);
 405         if (bz2err != BZ_OK)
 406                 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
 407         BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
 408         if (bz2err != BZ_OK)
 409                 errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
 410
 411         /* Seek to the beginning, write the header, and close the file */
 412         if (fseeko(pf, 0, SEEK_SET))
 413                 err(1, "fseeko");
 414         if (fwrite(header, 32, 1, pf) != 1)
 415                 err(1, "fwrite(%s)", argv[3]);
 416         if (fclose(pf))
 417                 err(1, "fclose");
 418
 419         /* Free the memory we used */
 420         free(db);
 421         free(eb);
 422         free(I);
 423         free(old);
 424         free(new);
 425
 426         return 0;
 427 }