7389928d89
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@20183 a1c6a512-1295-4272-9138-f99709370657
162 lines
3.8 KiB
C
162 lines
3.8 KiB
C
/* Based on:
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strnatcmp.c -- Perform 'natural order' comparisons of strings in C.
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Copyright (C) 2000, 2004 by Martin Pool <mbp sourcefrog net>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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/* partial change history:
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*
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* 2004-10-10 mbp: Lift out character type dependencies into macros.
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*
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* Eric Sosman pointed out that ctype functions take a parameter whose
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* value must be that of an unsigned int, even on platforms that have
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* negative chars in their default char type.
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*
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*
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* This version is changed to ignore leading zeros, it does not equal to the
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* original software.
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*/
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#include <ctype.h>
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#include <string.h>
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#include <stdio.h>
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#include "strnatcmp.h"
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#define assert(x) /* nothing */
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/* Convert char to int regardless of whether char is signed or not */
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static inline int
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to_int(char c)
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{
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return (int) ((unsigned char) c);
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}
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/* These are defined as macros to make it easier to adapt this code to
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* different characters types or comparison functions. */
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static inline int
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nat_isdigit(int a)
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{
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return isdigit(a);
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}
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static inline int
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nat_isspace(int a)
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{
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return a == '0' || isspace(a);
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}
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static inline int
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nat_toupper(int a)
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{
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return toupper(a);
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}
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static int
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compare_right(char const *a, char const *b)
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{
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int bias = 0;
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int ca, cb;
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/* The longest run of digits wins. That aside, the greatest
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value wins, but we can't know that it will until we've scanned
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both numbers to know that they have the same magnitude, so we
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remember it in BIAS. */
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for (;; a++, b++) {
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ca = to_int(*a);
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cb = to_int(*b);
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if (!nat_isdigit(ca) && !nat_isdigit(cb))
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return bias;
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else if (!nat_isdigit(ca))
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return -1;
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else if (!nat_isdigit(cb))
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return +1;
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else if (ca < cb) {
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if (!bias)
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bias = -1;
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} else if (ca > cb) {
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if (!bias)
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bias = +1;
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} else if (!ca && !cb)
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return bias;
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}
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return 0;
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}
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static int strnatcmp0(char const *a, char const *b, int fold_case)
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{
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int ai, bi;
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int ca, cb;
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int result;
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assert(a && b);
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ai = bi = 0;
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while (1) {
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ca = to_int(a[ai]);
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cb = to_int(b[bi]);
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/* skip over leading spaces or zeros */
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while (nat_isspace(ca))
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ca = to_int(a[++ai]);
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while (nat_isspace(cb))
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cb = to_int(b[++bi]);
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/* process run of digits */
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if (nat_isdigit(ca) && nat_isdigit(cb)) {
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if ((result = compare_right(a+ai, b+bi)) != 0)
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return result;
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}
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if (!ca && !cb) {
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/* The strings compare the same. Perhaps the caller
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will want to call strcmp to break the tie. */
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return 0;
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}
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if (fold_case) {
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ca = nat_toupper(ca);
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cb = nat_toupper(cb);
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}
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if (ca < cb)
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return -1;
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else if (ca > cb)
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return +1;
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++ai; ++bi;
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}
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}
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int strnatcmp(const char *a, const char *b) {
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return strnatcmp0(a, b, 0);
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}
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/* Compare, recognizing numeric string and ignoring case. */
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int strnatcasecmp(const char *a, const char *b) {
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return strnatcmp0(a, b, 1);
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}
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