/* bsearch.c -- binary search newline-separated fields in memory $Id: bsearch.c,v 1.19 2003/02/13 20:15:39 rjs3 Exp $ * Copyright (c) 1998-2003 Carnegie Mellon University. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided 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. * * 3. The name "Carnegie Mellon University" must not be used to * endorse or promote products derived from this software without * prior written permission. For permission or any other legal * details, please contact * Office of Technology Transfer * Carnegie Mellon University * 5000 Forbes Avenue * Pittsburgh, PA 15213-3890 * (412) 268-4387, fax: (412) 268-7395 * tech-transfer@andrew.cmu.edu * * 4. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by Computing Services * at Carnegie Mellon University (http://www.cmu.edu/computing/)." * * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * * */ #include #include #include "bsearch.h" #include "util.h" /* TOLOWER and convert_to_lowercase */ /* Case-dependent comparison converter. * Treats \r and \t as end-of-string and treats '.' lower than * everything else. */ #define TOCOMPARE(c) (convert_to_compare[(unsigned char)(c)]) static unsigned char convert_to_compare[256] = { 0x00, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x01, 0x01, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x02, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 0x40, 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 0x60, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff }; /* * Search for a line starting with 'word'. The search ignores case if * 'caseSensitive' is nonzero. The search is performed in 'base', * which is of length 'len'. 'hint' gives a idea of where to start * looking. * * On success, the offset in 'base' of the found line is returned and * the length of the found line is put in the unsigned long pointed to * by 'linelenp'. On failure, the offset in 'base' of where a new line should * be inserted is returned and zero is put in the unsigned long pointed to * by 'linelenp'. */ int bsearch_mem(const char *word, int caseSensitive, const char *base, unsigned long len, unsigned long hint, unsigned long *linelenp) { int firstsearch = 1; unsigned long start = 0, end = len - 1, mid, offset; unsigned long linelen; long n; int cmp = 0; const char *wordp, *p; while (start < end + 1) { if (firstsearch) { /* Use hint supplied by caller */ firstsearch = 0; mid = offset = hint; if (mid <= start || mid > end) mid = offset = start; } else { /* Calculate position of middle of this range */ offset = mid = (start + end)/2; } if (mid) { p = memchr(base+mid, '\n', (end + 1) - mid); if (!p) { end = mid - 1; continue; } offset = p - base + 1; } p = memchr(base+offset, '\n', len-offset); if (p) { linelen = p - (base+offset) + 1; } else { end = mid - 1; continue; } n = linelen; wordp = word; p = base+offset; if (caseSensitive) { while (n-- > 0 && (cmp = TOCOMPARE(*wordp) - TOCOMPARE(*p)) == 0) { wordp++; p++; } if (n >= 0 && !*wordp) { cmp = TOCOMPARE('\t') - TOCOMPARE(*p); } else if (!cmp) { cmp = 1; } } else { while (n-- > 0 && (cmp = TOLOWER(*wordp) - TOLOWER(*p)) == 0) { wordp++; p++; } if (n >= 0 && !*wordp) { cmp = TOLOWER('\t') - TOLOWER(*p); } else if (!cmp) { cmp = 1; } } if (!cmp) { if (linelenp) *linelenp = linelen; return offset; } if (cmp < 0) { if (mid == 0) break; end = mid - 1; } else { start = offset + 1; } } /* Word was not found. Return offset where word should be inserted */ if (linelenp) *linelenp = 0; if (start > len) return len; if (!start) return 0; p = memchr(base+start, '\n', len-start); return p - base + 1; } int bsearch_compare(const char *s1, const char *s2) { int cmp; char c2; for (;;) { if ((c2 = *s2) == 0) { return (unsigned char)*s1; } cmp = TOCOMPARE(*s1) - TOCOMPARE(c2); if (cmp) return cmp; if (TOCOMPARE(c2) == TOCOMPARE('\t')) { return 0; } s1++; s2++; } }