root/chrome/installer/mac/third_party/bsdiff/goobsdiff.c

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DEFINITIONS

This source file includes following definitions.
  1. split
  2. qsufsort
  3. matchlen
  4. search
  5. offtout
  6. compress2gzip
  7. make_small
  8. main

/*-
 * 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 <sys/types.h>

#include <bzlib.h>
#include <err.h>
#include <fcntl.h>
#include <lzma.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <zlib.h>

#if defined(__APPLE__)
#include <libkern/OSByteOrder.h>
#define htole64(x) OSSwapHostToLittleInt64(x)
#elif defined(__linux__)
#include <endian.h>
#elif defined(_WIN32) && (defined(_M_IX86) || defined(_M_X64))
#define htole64(x) (x)
#else
#error Provide htole64 for this platform
#endif

#include "chrome/installer/mac/third_party/bsdiff/sha1_adapter.h"

#define MIN(x,y) (((x)<(y)) ? (x) : (y))

static void split(off_t *I,off_t *V,off_t start,off_t len,off_t h)
{
        off_t i,j,k,x,tmp,jj,kk;

        if(len<16) {
                for(k=start;k<start+len;k+=j) {
                        j=1;x=V[I[k]+h];
                        for(i=1;k+i<start+len;i++) {
                                if(V[I[k+i]+h]<x) {
                                        x=V[I[k+i]+h];
                                        j=0;
                                };
                                if(V[I[k+i]+h]==x) {
                                        tmp=I[k+j];I[k+j]=I[k+i];I[k+i]=tmp;
                                        j++;
                                };
                        };
                        for(i=0;i<j;i++) V[I[k+i]]=k+j-1;
                        if(j==1) I[k]=-1;
                };
                return;
        };

        x=V[I[start+len/2]+h];
        jj=0;kk=0;
        for(i=start;i<start+len;i++) {
                if(V[I[i]+h]<x) jj++;
                if(V[I[i]+h]==x) kk++;
        };
        jj+=start;kk+=jj;

        i=start;j=0;k=0;
        while(i<jj) {
                if(V[I[i]+h]<x) {
                        i++;
                } else if(V[I[i]+h]==x) {
                        tmp=I[i];I[i]=I[jj+j];I[jj+j]=tmp;
                        j++;
                } else {
                        tmp=I[i];I[i]=I[kk+k];I[kk+k]=tmp;
                        k++;
                };
        };

        while(jj+j<kk) {
                if(V[I[jj+j]+h]==x) {
                        j++;
                } else {
                        tmp=I[jj+j];I[jj+j]=I[kk+k];I[kk+k]=tmp;
                        k++;
                };
        };

        if(jj>start) split(I,V,start,jj-start,h);

        for(i=0;i<kk-jj;i++) V[I[jj+i]]=kk-1;
        if(jj==kk-1) I[jj]=-1;

        if(start+len>kk) split(I,V,kk,start+len-kk,h);
}

static void qsufsort(off_t *I,off_t *V,u_char *old,off_t oldsize)
{
        off_t buckets[256];
        off_t i,h,len;

        for(i=0;i<256;i++) buckets[i]=0;
        for(i=0;i<oldsize;i++) buckets[old[i]]++;
        for(i=1;i<256;i++) buckets[i]+=buckets[i-1];
        for(i=255;i>0;i--) buckets[i]=buckets[i-1];
        buckets[0]=0;

        for(i=0;i<oldsize;i++) I[++buckets[old[i]]]=i;
        I[0]=oldsize;
        for(i=0;i<oldsize;i++) V[i]=buckets[old[i]];
        V[oldsize]=0;
        for(i=1;i<256;i++) if(buckets[i]==buckets[i-1]+1) I[buckets[i]]=-1;
        I[0]=-1;

        for(h=1;I[0]!=-(oldsize+1);h+=h) {
                len=0;
                for(i=0;i<oldsize+1;) {
                        if(I[i]<0) {
                                len-=I[i];
                                i-=I[i];
                        } else {
                                if(len) I[i-len]=-len;
                                len=V[I[i]]+1-i;
                                split(I,V,i,len,h);
                                i+=len;
                                len=0;
                        };
                };
                if(len) I[i-len]=-len;
        };

        for(i=0;i<oldsize+1;i++) I[V[i]]=i;
}

static off_t matchlen(u_char *old,off_t oldsize,u_char *new,off_t newsize)
{
        off_t i;

        for(i=0;(i<oldsize)&&(i<newsize);i++)
                if(old[i]!=new[i]) break;

        return i;
}

static off_t search(off_t *I,u_char *old,off_t oldsize,
                u_char *new,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,newsize);
                y=matchlen(old+I[en],oldsize-I[en],new,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,MIN(oldsize-I[x],newsize))<0) {
                return search(I,old,oldsize,new,newsize,x,en,pos);
        } else {
                return search(I,old,oldsize,new,newsize,st,x,pos);
        };
}

static inline void offtout(off_t x,u_char *buf)
{
        *((off_t*)buf) = htole64(x);
}

/* zlib provides compress2, which deflates to deflate (zlib) format. This is
 * unfortunately distinct from gzip format in that the headers wrapping the
 * decompressed data are different. gbspatch reads gzip-compressed data using
 * the file-oriented gzread interface, which only supports gzip format.
 * compress2gzip is identical to zlib's compress2 except that it produces gzip
 * output compatible with gzread. This change is achieved by calling
 * deflateInit2 instead of deflateInit and specifying 31 for windowBits;
 * numbers greater than 15 cause the addition of a gzip wrapper. */
static int compress2gzip(Bytef *dest, uLongf *destLen,
                         const Bytef *source, uLong sourceLen, int level)
{
        z_stream stream;
        int err;

        stream.next_in = (Bytef*)source;
        stream.avail_in = (uInt)sourceLen;

        stream.next_out = dest;
        stream.avail_out = (uInt)*destLen;
        if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR;

        stream.zalloc = (alloc_func)0;
        stream.zfree = (free_func)0;
        stream.opaque = (voidpf)0;

        err = deflateInit2(&stream,
                           level, Z_DEFLATED, 31, 8, Z_DEFAULT_STRATEGY);
        if (err != Z_OK) return err;

        err = deflate(&stream, Z_FINISH);
        if (err != Z_STREAM_END) {
                deflateEnd(&stream);
                return err == Z_OK ? Z_BUF_ERROR : err;
        }
        *destLen = stream.total_out;

        err = deflateEnd(&stream);
        return err;
}

/* Recompress buf of size buf_len using bzip2 or gzip. The smallest version is
 * used. The original uncompressed variant may be the smallest. Returns a
 * number identifying the encoding, 1 for uncompressed, 2 for bzip2, 3 for
 * gzip, and 4 for xz/lzma2. If the original uncompressed variant is not
 * smallest, it is freed. The caller must free any buf after this function
 * returns. */
static char make_small(u_char **buf, off_t *buf_len)
{
        u_char *source = *buf;
        off_t source_len = *buf_len;
        u_char *bz2, *gz, *lzma;
        unsigned int bz2_len;
        size_t gz_len, lzma_len, lzma_pos;
        int bz2_err, gz_err;
        lzma_ret lzma_err;
        lzma_check lzma_ck;
        char smallest;

        smallest = 1;

        bz2_len = source_len + 1;
        bz2 = malloc(bz2_len);
        bz2_err = BZ2_bzBuffToBuffCompress((char*)bz2, &bz2_len, (char*)source,
                                           source_len, 9, 0, 0);
        if (bz2_err == BZ_OK) {
                if (bz2_len < *buf_len) {
                        smallest = 2;
                        *buf = bz2;
                        *buf_len = bz2_len;
                } else {
                        free(bz2);
                        bz2 = NULL;
                }
        } else if (bz2_err == BZ_OUTBUFF_FULL) {
                free(bz2);
                bz2 = NULL;
        } else {
                errx(1, "BZ2_bzBuffToBuffCompress: %d", bz2_err);
        }

        gz_len = source_len + 1;
        gz = malloc(gz_len);
        gz_err = compress2gzip(gz, &gz_len, source, source_len, 9);
        if (gz_err == Z_OK) {
                if (gz_len < *buf_len) {
                        smallest = 3;
                        *buf = gz;
                        *buf_len = gz_len;
                } else {
                        free(gz);
                        gz = NULL;
                }
        } else if (gz_err == Z_BUF_ERROR) {
                free(gz);
                gz = NULL;
        } else {
                errx(1, "compress2gzip: %d", gz_err);
        }

        lzma_len = source_len + 1;
        lzma = malloc(lzma_len);
        lzma_pos = 0;

        /* Equivalent to the options used by xz -9 -e. */
        lzma_ck = LZMA_CHECK_CRC64;
        if (!lzma_check_is_supported(lzma_ck))
                lzma_ck = LZMA_CHECK_CRC32;
        lzma_err = lzma_easy_buffer_encode(9 | LZMA_PRESET_EXTREME,
                                           lzma_ck, NULL,
                                           source, source_len,
                                           lzma, &lzma_pos, lzma_len);
        if (lzma_err == LZMA_OK) {
                if (lzma_pos < *buf_len) {
                        smallest = 4;
                        *buf = lzma;
                        *buf_len = lzma_pos;
                } else {
                        free(lzma);
                        lzma = NULL;
                }
        } else if (lzma_err == LZMA_BUF_ERROR) {
                free(lzma);
                lzma = NULL;
        } else {
                errx(1, "lzma_easy_buffer_encode: %d", lzma_err);
        }

        if (smallest != 1) {
                free(source);
        }

        return smallest;
}

int main(int argc,char *argv[])
{
        int fd;
        u_char *old,*new;
        off_t oldsize,newsize;
        off_t *I,*V;
        off_t scan,pos,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 cblen, dblen, eblen;
        u_char *cb, *db, *eb;
        u_char header[96];
        FILE * pf;

        if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile",argv[0]);

        /* 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(argv[1],O_RDONLY,0))<0) ||
                ((oldsize=lseek(fd,0,SEEK_END))==-1) ||
                ((old=malloc(oldsize+1))==NULL) ||
                (lseek(fd,0,SEEK_SET)!=0) ||
                (read(fd,old,oldsize)!=oldsize) ||
                (close(fd)==-1)) err(1,"%s",argv[1]);

        if(((I=malloc((oldsize+1)*sizeof(off_t)))==NULL) ||
                ((V=malloc((oldsize+1)*sizeof(off_t)))==NULL)) err(1,NULL);

        qsufsort(I,V,old,oldsize);

        free(V);

        /* 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(argv[2],O_RDONLY,0))<0) ||
                ((newsize=lseek(fd,0,SEEK_END))==-1) ||
                ((new=malloc(newsize+1))==NULL) ||
                (lseek(fd,0,SEEK_SET)!=0) ||
                (read(fd,new,newsize)!=newsize) ||
                (close(fd)==-1)) err(1,"%s",argv[2]);

        if(((cb=malloc(newsize+1))==NULL) ||
                ((db=malloc(newsize+1))==NULL) ||
                ((eb=malloc(newsize+1))==NULL)) err(1,NULL);
        cblen=0;
        dblen=0;
        eblen=0;

        /* Create the patch file */
        if ((pf = fopen(argv[3], "wb")) == NULL)
                err(1, "%s", argv[3]);

        /* File format:
                0       8       "BSDIFF4G"
                8       8       length of compressed control block (x)
                16      8       length of compressed diff block (y)
                24      8       length of compressed extra block (z)
                32      8       length of old file
                40      8       length of new file
                48      20      SHA1 of old file
                68      20      SHA1 of new file
                88      1       encoding of control block
                89      1       encoding of diff block
                90      1       encoding of extra block
                91      5       unused
                96      x       compressed control block
                96+x    y       compressed diff block
                96+x+y  z       compressed extra block
        Encodings are 1 (uncompressed), 2 (bzip2), 3 (gzip), and 4 (xz/lzma2).
        */

        memset(header, 0, sizeof(header));
        if (fwrite(header, sizeof(header), 1, pf) != 1)
                err(1, "fwrite(%s)", argv[3]);
        memcpy(header, "BSDIFF4G", 8);
        offtout(oldsize, header + 32);
        offtout(newsize, header + 40);
        SHA1(old, oldsize, header + 48);
        SHA1(new, newsize, header + 68);

        /* Compute the differences */
        scan=0;len=0;
        lastscan=0;lastpos=0;lastoffset=0;
        while(scan<newsize) {
                oldscore=0;

                for(scsc=scan+=len;scan<newsize;scan++) {
                        len=search(I,old,oldsize,new+scan,newsize-scan,
                                        0,oldsize,&pos);

                        for(;scsc<scan+len;scsc++)
                        if((scsc+lastoffset<oldsize) &&
                                (old[scsc+lastoffset] == new[scsc]))
                                oldscore++;

                        if(((len==oldscore) && (len!=0)) || 
                                (len>oldscore+8)) break;

                        if((scan+lastoffset<oldsize) &&
                                (old[scan+lastoffset] == new[scan]))
                                oldscore--;
                };

                if((len!=oldscore) || (scan==newsize)) {
                        s=0;Sf=0;lenf=0;
                        for(i=0;(lastscan+i<scan)&&(lastpos+i<oldsize);) {
                                if(old[lastpos+i]==new[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[pos-i]==new[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[lastscan+lenf-overlap+i]==
                                           old[lastpos+lenf-overlap+i]) s++;
                                        if(new[scan-lenb+i]==
                                           old[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[lastscan+i]-old[lastpos+i];
                        for(i=0;i<(scan-lenb)-(lastscan+lenf);i++)
                                eb[eblen+i]=new[lastscan+lenf+i];

                        dblen+=lenf;
                        eblen+=(scan-lenb)-(lastscan+lenf);

                        offtout(lenf, cb + cblen);
                        cblen += 8;

                        offtout((scan - lenb) - (lastscan + lenf), cb + cblen);
                        cblen += 8;

                        offtout((pos - lenb) - (lastpos + lenf), cb + cblen);
                        cblen += 8;

                        lastscan=scan-lenb;
                        lastpos=pos-lenb;
                        lastoffset=pos-scan;
                };
        };

        header[88] = make_small(&cb, &cblen);
        header[89] = make_small(&db, &dblen);
        header[90] = make_small(&eb, &eblen);

        if (fwrite(cb, 1, cblen, pf) != cblen)
                err(1, "fwrite");
        if (fwrite(db, 1, dblen, pf) != dblen)
                err(1, "fwrite");
        if (fwrite(eb, 1, eblen, pf) != eblen)
                err(1, "fwrite");

        offtout(cblen, header + 8);
        offtout(dblen, header + 16);
        offtout(eblen, header + 24);

        /* Seek to the beginning, write the header, and close the file */
        if (fseeko(pf, 0, SEEK_SET))
                err(1, "fseeko");
        if (fwrite(header, sizeof(header), 1, pf) != 1)
                err(1, "fwrite(%s)", argv[3]);
        if (fclose(pf))
                err(1, "fclose");

        /* Free the memory we used */
        free(cb);
        free(db);
        free(eb);
        free(I);
        free(old);
        free(new);

        return 0;
}

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