1 /* -*- mode: c; c-file-style: "k&r" -*-
2
3 Modified for PHP by Andrei Zmievski <andrei@ispi.net>
4
5 strnatcmp.c -- Perform 'natural order' comparisons of strings in C.
6 Copyright (C) 2000 by Martin Pool <mbp@humbug.org.au>
7
8 This software is provided 'as-is', without any express or implied
9 warranty. In no event will the authors be held liable for any damages
10 arising from the use of this software.
11
12 Permission is granted to anyone to use this software for any purpose,
13 including commercial applications, and to alter it and redistribute it
14 freely, subject to the following restrictions:
15
16 1. The origin of this software must not be misrepresented; you must not
17 claim that you wrote the original software. If you use this software
18 in a product, an acknowledgment in the product documentation would be
19 appreciated but is not required.
20 2. Altered source versions must be plainly marked as such, and must not be
21 misrepresented as being the original software.
22 3. This notice may not be removed or altered from any source distribution.
23 */
24
25 #include <ctype.h>
26 #include <string.h>
27 #include <assert.h>
28 #include <stdio.h>
29
30 #include "php.h"
31 #include "php_string.h"
32
33 #if defined(__GNUC__)
34 # define UNUSED __attribute__((__unused__))
35 #else
36 # define UNUSED
37 #endif
38
39 #if 0
40 static char const *version UNUSED =
41 "$Id$";
42 #endif
43 /* {{{ compare_right
44 */
45 static int
46 compare_right(char const **a, char const *aend, char const **b, char const *bend)
47 {
48 int bias = 0;
49
50 /* The longest run of digits wins. That aside, the greatest
51 value wins, but we can't know that it will until we've scanned
52 both numbers to know that they have the same magnitude, so we
53 remember it in BIAS. */
54 for(;; (*a)++, (*b)++) {
55 if ((*a == aend || !isdigit((int)(unsigned char)**a)) &&
56 (*b == bend || !isdigit((int)(unsigned char)**b)))
57 return bias;
58 else if (*a == aend || !isdigit((int)(unsigned char)**a))
59 return -1;
60 else if (*b == bend || !isdigit((int)(unsigned char)**b))
61 return +1;
62 else if (**a < **b) {
63 if (!bias)
64 bias = -1;
65 } else if (**a > **b) {
66 if (!bias)
67 bias = +1;
68 }
69 }
70
71 return 0;
72 }
73 /* }}} */
74
75 /* {{{ compare_left
76 */
77 static int
78 compare_left(char const **a, char const *aend, char const **b, char const *bend)
79 {
80 /* Compare two left-aligned numbers: the first to have a
81 different value wins. */
82 for(;; (*a)++, (*b)++) {
83 if ((*a == aend || !isdigit((int)(unsigned char)**a)) &&
84 (*b == bend || !isdigit((int)(unsigned char)**b)))
85 return 0;
86 else if (*a == aend || !isdigit((int)(unsigned char)**a))
87 return -1;
88 else if (*b == bend || !isdigit((int)(unsigned char)**b))
89 return +1;
90 else if (**a < **b)
91 return -1;
92 else if (**a > **b)
93 return +1;
94 }
95
96 return 0;
97 }
98 /* }}} */
99
100 /* {{{ strnatcmp_ex
101 */
102 PHPAPI int strnatcmp_ex(char const *a, size_t a_len, char const *b, size_t b_len, int fold_case)
103 {
104 unsigned char ca, cb;
105 char const *ap, *bp;
106 char const *aend = a + a_len,
107 *bend = b + b_len;
108 int fractional, result;
109 short leading = 1;
110
111 if (a_len == 0 || b_len == 0)
112 return a_len - b_len;
113
114 ap = a;
115 bp = b;
116 while (1) {
117 ca = *ap; cb = *bp;
118
119 /* skip over leading zeros */
120 while (leading && ca == '0' && (ap+1 < aend) && isdigit((int)(unsigned char)*(ap+1))) {
121 ca = *++ap;
122 }
123
124 while (leading && cb == '0' && (bp+1 < bend) && isdigit((int)(unsigned char)*(bp+1))) {
125 cb = *++bp;
126 }
127
128 leading = 0;
129
130 /* Skip consecutive whitespace */
131 while (isspace((int)(unsigned char)ca)) {
132 ca = *++ap;
133 }
134
135 while (isspace((int)(unsigned char)cb)) {
136 cb = *++bp;
137 }
138
139 /* process run of digits */
140 if (isdigit((int)(unsigned char)ca) && isdigit((int)(unsigned char)cb)) {
141 fractional = (ca == '0' || cb == '0');
142
143 if (fractional)
144 result = compare_left(&ap, aend, &bp, bend);
145 else
146 result = compare_right(&ap, aend, &bp, bend);
147
148 if (result != 0)
149 return result;
150 else if (ap == aend && bp == bend)
151 /* End of the strings. Let caller sort them out. */
152 return 0;
153 else {
154 /* Keep on comparing from the current point. */
155 ca = *ap; cb = *bp;
156 }
157 }
158
159 if (fold_case) {
160 ca = toupper((int)(unsigned char)ca);
161 cb = toupper((int)(unsigned char)cb);
162 }
163
164 if (ca < cb)
165 return -1;
166 else if (ca > cb)
167 return +1;
168
169 ++ap; ++bp;
170 if (ap >= aend && bp >= bend)
171 /* The strings compare the same. Perhaps the caller
172 will want to call strcmp to break the tie. */
173 return 0;
174 else if (ap >= aend)
175 return -1;
176 else if (bp >= bend)
177 return 1;
178 }
179 }
180 /* }}} */
181
182 /*
183 * Local variables:
184 * tab-width: 4
185 * c-basic-offset: 4
186 * End:
187 * vim600: sw=4 ts=4 fdm=marker
188 * vim<600: sw=4 ts=4
189 */