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