/*- * 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 #include #include #include #include #include #include #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); } /* qsufsort(I, V, old, oldsize) * * Computes the suffix sort of the string at 'old' and stores the resulting * indices in 'I', using 'V' as a temporary array for the computation. */ static void qsufsort(off_t *I, off_t *V, u_char *old, off_t oldsize) { off_t buckets[256]; off_t i, h, len; /* count number of each byte */ for (i = 0; i < 256; i++) buckets[i] = 0; for (i = 0; i < oldsize; i++) buckets[old[i]]++; /* make buckets cumulative */ for (i = 1; i < 256; i++) buckets[i] += buckets[i - 1]; /* shift right by one */ for (i = 255; i > 0; i--) buckets[i] = buckets[i - 1]; buckets[0] = 0; /* at this point, buckets[c] is the number of bytes in the old file with * value less than c. */ /* set up the sort order of the suffixes based solely on the first * character */ 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; /* forward any entries in the ordering which have the same initial * character */ 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; } /* matchlen(old, oldsize, new, newsize) * * Returns the length of the longest common prefix between 'old' and 'new'. */ 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; } /* search(I, old, oldsize, new, newsize, st, en, pos) * * Searches for the longest prefix of 'new' that occurs in 'old', stores its * offset in '*pos', and returns its length. 'I' should be the suffix sort of * 'old', and 'st' and 'en' are the lowest and highest indices in the suffix * sort to consider. If you're searching all suffixes, 'st = 0' and 'en = * oldsize - 1'. */ 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); }; } /* offtout(x, buf) * * Writes the off_t 'x' portably to the array 'buf'. */ static void offtout(off_t x, u_char *buf) { off_t y; if (x < 0) y = -x; else y = x; buf[0] = y % 256; y -= buf[0]; y = y/256; buf[1] = y%256; y -= buf[1]; y = y/256; buf[2] = y%256; y -= buf[2]; y = y/256; buf[3] = y%256; y -= buf[3]; y = y/256; buf[4] = y%256; y -= buf[4]; y = y/256; buf[5] = y%256; y -= buf[5]; y = y/256; buf[6] = y%256; y -= buf[6]; y = y/256; buf[7] = y%256; if (x < 0) buf[7] |= 0x80; } int bsdiff(int argc, char *argv[]); // Added by AMM: suppresses a warning about the following not having a prototype. int bsdiff(int argc, char *argv[]) { int fd; u_char *old,*new; /* contents of old, new files */ off_t oldsize, newsize; /* length of old, new files */ off_t *I,*V; /* arrays used for suffix sort; I is ordering */ off_t scan; /* position of current match in old file */ off_t pos; /* position of current match in new file */ off_t len; /* length of current match */ off_t lastscan; /* position of previous match in old file */ off_t lastpos; /* position of previous match in new file */ off_t lastoffset; /* lastpos - lastscan */ off_t oldscore, scsc; /* temp variables in match search */ off_t s, Sf, lenf, Sb, lenb; /* temp vars in match extension */ off_t overlap, Ss, lens; off_t i; off_t dblen, eblen; /* length of diff, extra sections */ u_char *db,*eb; /* contents of diff, extra sections */ u_char buf[8]; u_char header[32]; FILE * pf; if (argc != 4) errx(1,"usage: %s oldfile newfile patchfile\n", 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); /* Do a suffix sort on the old file. */ 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 (((db = malloc(newsize + 1)) == NULL) || ((eb = malloc(newsize + 1)) == NULL)) err(1, NULL); dblen = 0; eblen = 0; /* Create the patch file */ if ((pf = fopen(argv[3], "w")) == NULL) err(1, "%s", argv[3]); /* Header is 0 8 "BSDIFN40" 8 8 length of ctrl block 16 8 length of diff block 24 8 length of new file */ /* File is 0 32 Header 32 ?? ctrl block ?? ?? diff block ?? ?? extra block */ memcpy(header, "BSDIFN40", 8); offtout(0, header + 8); offtout(0, header + 16); offtout(newsize, header + 24); if (fwrite(header, 32, 1, pf) != 1) err(1, "fwrite(%s)", argv[3]); /* Compute the differences, writing ctrl as we go */ scan = 0; len = 0; lastscan = 0; lastpos = 0; lastoffset = 0; while (scan < newsize) { oldscore = 0; for (scsc = scan += len; scan < newsize; scan++) { /* 'oldscore' is the number of characters that match between the * substrings 'old[lastoffset + scan:lastoffset + scsc]' and * 'new[scan:scsc]'. */ len = search(I, old, oldsize, new + scan, newsize - scan, 0, oldsize, &pos); /* If this match extends further than the last one, add any new * matching characters to 'oldscore'. */ for (; scsc < scan + len; scsc++) { if ((scsc + lastoffset < oldsize) && (old[scsc + lastoffset] == new[scsc])) oldscore++; } /* Choose this as our match if it contains more than eight * characters that would be wrong if matched with a forward * extension of the previous match instead. */ if (((len == oldscore) && (len != 0)) || (len > oldscore + 8)) break; /* Since we're advancing 'scan' by 1, remove the character under it * from 'oldscore' if it matches. */ if ((scan + lastoffset < oldsize) && (old[scan + lastoffset] == new[scan])) oldscore--; } /* Skip this section if we found an exact match that would be * better serviced by a forward extension of the previous match. */ if ((len != oldscore) || (scan == newsize)) { /* Figure out how far forward the previous match should be * extended... */ 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; } } /* ... and how far backwards the next match should be extended. */ 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 there is an overlap between the extensions, find the best * dividing point in the middle and reset 'lenf' and 'lenb' * accordingly. */ 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; } /* Write the diff data for the last match to the diff section... */ for (i = 0; i < lenf; i++) db[dblen + i] = new[lastscan + i] - old[lastpos + i]; /* ... and, if there's a gap between the extensions just * calculated, write the data in that gap to the extra section. */ for (i = 0; i< (scan - lenb) - (lastscan + lenf); i++) eb[eblen + i] = new[lastscan + lenf + i]; /* Update the diff and extra section lengths accordingly. */ dblen += lenf; eblen += (scan - lenb) - (lastscan + lenf); /* Write the following triple of integers to the control section: * - length of the diff * - length of the extra section * - offset between the end of the diff and the start of the next * diff, in the old file */ offtout(lenf, buf); if (fwrite(buf, 8, 1, pf) != 1) errx(1, "fwrite"); offtout((scan - lenb) - (lastscan + lenf), buf); if (fwrite(buf, 8, 1, pf) != 1) err(1, "fwrite"); offtout((pos - lenb) - (lastpos + lenf), buf); if (fwrite(buf, 8, 1, pf) != 1) err(1, "fwrite"); /* Update the variables describing the last match. Note that * 'lastscan' is set to the start of the current match _after_ the * backwards extension; the data in that extension will be written * in the next pass. */ lastscan = scan - lenb; lastpos = pos - lenb; lastoffset = pos - scan; } } /* Compute size of compressed ctrl data */ if ((len = ftello(pf)) == -1) err(1, "ftello"); offtout(len - 32, header + 8); /* Write diff data */ if (dblen && fwrite(db, dblen, 1, pf) != 1) err(1, "fwrite"); /* Compute size of compressed diff data */ if ((newsize = ftello(pf)) == -1) err(1, "ftello"); offtout(newsize - len, header + 16); /* Write extra data */ if (eblen && fwrite(eb, eblen, 1, pf) != 1) err(1, "fwrite"); /* Seek to the beginning, write the header, and close the file */ if (fseeko(pf, 0, SEEK_SET)) err(1, "fseeko"); if (fwrite(header, 32, 1, pf) != 1) err(1, "fwrite(%s)", argv[3]); if (fclose(pf)) err(1, "fclose"); /* Free the memory we used */ free(db); free(eb); free(I); free(old); free(new); return 0; }