1 /* Compare strings while treating digits characters numerically. 2 Copyright (C) 1997, 2000, 2002, 2004 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 Contributed by Jean-Franois Bignolles <bignolle (at) ecoledoc.ibp.fr>, 1997. 5 6 This program is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License along 17 with this program; if not, write to the Free Software Foundation, 18 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ 19 20 #ifdef HAVE_CONFIG_H 21 # include <config.h> 22 #endif 23 24 #include <string.h> 25 #include <ctype.h> 26 27 /* states: S_N: normal, S_I: comparing integral part, S_F: comparing 28 fractional parts, S_Z: idem but with leading Zeroes only */ 29 #define S_N 0x0 30 #define S_I 0x4 31 #define S_F 0x8 32 #define S_Z 0xC 33 34 /* result_type: CMP: return diff; LEN: compare using len_diff/diff */ 35 #define CMP 2 36 #define LEN 3 37 38 39 /* ISDIGIT differs from isdigit, as follows: 40 - Its arg may be any int or unsigned int; it need not be an unsigned char. 41 - It's guaranteed to evaluate its argument exactly once. 42 - It's typically faster. 43 POSIX says that only '0' through '9' are digits. Prefer ISDIGIT to 44 ISDIGIT_LOCALE unless it's important to use the locale's definition 45 of `digit' even when the host does not conform to POSIX. */ 46 #define ISDIGIT(c) ((unsigned int) (c) - '0' <= 9) 47 48 #undef __strverscmp 49 #undef strverscmp 50 51 #ifndef weak_alias 52 # define __strverscmp strverscmp 53 #endif 54 55 /* Compare S1 and S2 as strings holding indices/version numbers, 56 returning less than, equal to or greater than zero if S1 is less than, 57 equal to or greater than S2 (for more info, see the texinfo doc). 58 */ 59 60 int 61 __strverscmp (const char *s1, const char *s2) 62 { 63 const unsigned char *p1 = (const unsigned char *) s1; 64 const unsigned char *p2 = (const unsigned char *) s2; 65 unsigned char c1, c2; 66 int state; 67 int diff; 68 69 /* Symbol(s) 0 [1-9] others (padding) 70 Transition (10) 0 (01) d (00) x (11) - */ 71 static const unsigned int next_state[] = 72 { 73 /* state x d 0 - */ 74 /* S_N */ S_N, S_I, S_Z, S_N, 75 /* S_I */ S_N, S_I, S_I, S_I, 76 /* S_F */ S_N, S_F, S_F, S_F, 77 /* S_Z */ S_N, S_F, S_Z, S_Z 78 }; 79 80 static const int result_type[] = 81 { 82 /* state x/x x/d x/0 x/- d/x d/d d/0 d/- 83 0/x 0/d 0/0 0/- -/x -/d -/0 -/- */ 84 85 /* S_N */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP, 86 CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, 87 /* S_I */ CMP, -1, -1, CMP, 1, LEN, LEN, CMP, 88 1, LEN, LEN, CMP, CMP, CMP, CMP, CMP, 89 /* S_F */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP, 90 CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, 91 /* S_Z */ CMP, 1, 1, CMP, -1, CMP, CMP, CMP, 92 -1, CMP, CMP, CMP 93 }; 94 95 if (p1 == p2) 96 return 0; 97 98 c1 = *p1++; 99 c2 = *p2++; 100 /* Hint: '0' is a digit too. */ 101 state = S_N | ((c1 == '0') + (ISDIGIT (c1) != 0)); 102 103 while ((diff = c1 - c2) == 0 && c1 != '\0') 104 { 105 state = next_state[state]; 106 c1 = *p1++; 107 c2 = *p2++; 108 state |= (c1 == '0') + (ISDIGIT (c1) != 0); 109 } 110 111 state = result_type[state << 2 | ((c2 == '0') + (ISDIGIT (c2) != 0))]; 112 113 switch (state) 114 { 115 case CMP: 116 return diff; 117 118 case LEN: 119 while (ISDIGIT (*p1++)) 120 if (!ISDIGIT (*p2++)) 121 return 1; 122 123 return ISDIGIT (*p2) ? -1 : diff; 124 125 default: 126 return state; 127 } 128 } 129 #ifdef weak_alias 130 weak_alias (__strverscmp, strverscmp) 131 #endif 132
