ascii_strcasecmp.c revision 1.3
1/* 2 * Copyright (c) 1987 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that this notice is preserved and that due credit is given 7 * to the University of California at Berkeley. The name of the University 8 * may not be used to endorse or promote products derived from this 9 * software without specific written prior permission. This software 10 * is provided ``as is'' without express or implied warranty. 11 */ 12 13#include <sys/cdefs.h> 14#ifndef lint 15__RCSID("$NetBSD: ascii_strcasecmp.c,v 1.3 2023/08/17 20:19:39 christos Exp $"); 16#endif 17 18#include "ascii_strcasecmp.h" 19 20/* 21 * This array maps upper-case ASCII letters to their lower-case 22 * equivalents; all other byte values are mapped to themselves, 23 * so this is locale-independent and intended to be locale-independent, 24 * to avoid issues with, for example, "i" and "I" not being lower-case 25 * and upper-case versions of the same letter in Turkish, where 26 * there are separate "i with dot" and "i without dot" letters. 27 */ 28static const unsigned char charmap[] = { 29 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 30 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 31 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 32 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 33 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 34 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 35 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 36 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 37 0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 38 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 39 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 40 0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 41 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 42 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 43 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 44 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 45 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 46 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 47 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 48 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 49 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 50 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, 51 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 52 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, 53 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 54 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, 55 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 56 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, 57 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 58 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 59 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 60 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, 61}; 62 63int 64ascii_strcasecmp(const char *s1, const char *s2) 65{ 66 const unsigned char *cm = charmap, 67 *us1 = (const unsigned char *)s1, 68 *us2 = (const unsigned char *)s2; 69 70 while (cm[*us1] == cm[*us2++]) 71 if (*us1++ == '\0') 72 return(0); 73 return(cm[*us1] - cm[*--us2]); 74} 75 76int 77ascii_strncasecmp(const char *s1, const char *s2, size_t n) 78{ 79 const unsigned char *cm = charmap, 80 *us1 = (const unsigned char *)s1, 81 *us2 = (const unsigned char *)s2; 82 83 for (;;) { 84 if (n == 0) { 85 /* 86 * We've run out of characters that we should 87 * compare, and they've all been equal; return 88 * 0, to indicate that the prefixes are the 89 * same. 90 */ 91 return(0); 92 } 93 if (cm[*us1] != cm[*us2++]) { 94 /* 95 * We've found a mismatch. 96 */ 97 break; 98 } 99 if (*us1++ == '\0') { 100 /* 101 * We've run out of characters *to* compare, 102 * and they've all been equal; return 0, to 103 * indicate that the strings are the same. 104 */ 105 return(0); 106 } 107 n--; 108 } 109 return(cm[*us1] - cm[*--us2]); 110} 111