firmware/common/strnatcmp.c

   1 /* Based on:
   2   strnatcmp.c -- Perform 'natural order' comparisons of strings in C.
   3   Copyright (C) 2000, 2004 by Martin Pool <mbp sourcefrog net>
   4
   5   This software is provided 'as-is', without any express or implied
   6   warranty.  In no event will the authors be held liable for any damages
   7   arising from the use of this software.
   8
   9   Permission is granted to anyone to use this software for any purpose,
  10   including commercial applications, and to alter it and redistribute it
  11   freely, subject to the following restrictions:
  12
  13   1. The origin of this software must not be misrepresented; you must not
  14      claim that you wrote the original software. If you use this software
  15      in a product, an acknowledgment in the product documentation would be
  16      appreciated but is not required.
  17   2. Altered source versions must be plainly marked as such, and must not be
  18      misrepresented as being the original software.
  19   3. This notice may not be removed or altered from any source distribution.
  20 */
  21
  22
  23 /* partial change history:
  24  *
  25  * 2004-10-10 mbp: Lift out character type dependencies into macros.
  26  *
  27  * Eric Sosman pointed out that ctype functions take a parameter whose
  28  * value must be that of an unsigned int, even on platforms that have
  29  * negative chars in their default char type.
  30  *
  31  *
  32  * This version is changed to ignore leading zeros, it does not equal to the
  33  * original software.
  34  */
  35
  36 #include <ctype.h>
  37 #include <string.h>
  38 #include <stdio.h>
  39
  40 #include "strnatcmp.h"
  41
  42 #define assert(x)   /* nothing */
  43
  44
  45 /* These are defined as macros to make it easier to adapt this code to
  46  * different characters types or comparison functions. */
  47 static inline int
  48 nat_isdigit(char a)
  49 {
  50      return isdigit((unsigned char) a);
  51 }
  52
  53
  54 static inline int
  55 nat_isspace(char a)
  56 {
  57      return a == '0' || isspace((unsigned char) a);
  58 }
  59
  60
  61 static inline char
  62 nat_toupper(char a)
  63 {
  64      return toupper((unsigned char) a);
  65 }
  66
  67
  68
  69 static int
  70 compare_right(char const *a, char const *b)
  71 {
  72      int bias = 0;
  73
  74      /* The longest run of digits wins.  That aside, the greatest
  75         value wins, but we can't know that it will until we've scanned
  76         both numbers to know that they have the same magnitude, so we
  77         remember it in BIAS. */
  78      for (;; a++, b++) {
  79           if (!nat_isdigit(*a)  &&  !nat_isdigit(*b))
  80                return bias;
  81           else if (!nat_isdigit(*a))
  82                return -1;
  83           else if (!nat_isdigit(*b))
  84                return +1;
  85           else if (*a < *b) {
  86                if (!bias)
  87                     bias = -1;
  88           } else if (*a > *b) {
  89                if (!bias)
  90                     bias = +1;
  91           } else if (!*a  &&  !*b)
  92                return bias;
  93      }
  94
  95      return 0;
  96 }
  97
  98 static int strnatcmp0(char const *a, char const *b, int fold_case)
  99 {
 100      int ai, bi;
 101      char ca, cb;
 102      int result;
 103
 104      assert(a && b);
 105      ai = bi = 0;
 106      while (1) {
 107           ca = a[ai]; cb = b[bi];
 108
 109           /* skip over leading spaces or zeros */
 110           while (nat_isspace(ca))
 111                ca = a[++ai];
 112
 113           while (nat_isspace(cb))
 114                cb = b[++bi];
 115
 116           /* process run of digits */
 117           if (nat_isdigit(ca)  &&  nat_isdigit(cb)) {
 118                 if ((result = compare_right(a+ai, b+bi)) != 0)
 119                         return result;
 120           }
 121
 122           if (!ca && !cb) {
 123                /* The strings compare the same.  Perhaps the caller
 124                   will want to call strcmp to break the tie. */
 125                return 0;
 126           }
 127
 128           if (fold_case) {
 129                ca = nat_toupper(ca);
 130                cb = nat_toupper(cb);
 131           }
 132
 133           if (ca < cb)
 134                return -1;
 135           else if (ca > cb)
 136                return +1;
 137
 138           ++ai; ++bi;
 139      }
 140 }
 141
 142
 143
 144 int strnatcmp(const char *a, const char *b) {
 145      return strnatcmp0(a, b, 0);
 146 }
 147
 148
 149 /* Compare, recognizing numeric string and ignoring case. */
 150 int strnatcasecmp(const char *a, const char *b) {
 151      return strnatcmp0(a, b, 1);
 152 }