1 /*
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 <stdio.h>
28
29 #include "php.h"
30 #include "php_string.h"
31
32 /* {{{ compare_right */
33 static int
compare_right(char const ** a,char const * aend,char const ** b,char const * bend)34 compare_right(char const **a, char const *aend, char const **b, char const *bend)
35 {
36 int bias = 0;
37
38 /* The longest run of digits wins. That aside, the greatest
39 value wins, but we can't know that it will until we've scanned
40 both numbers to know that they have the same magnitude, so we
41 remember it in BIAS. */
42 for(;; (*a)++, (*b)++) {
43 if ((*a == aend || !isdigit((int)(unsigned char)**a)) &&
44 (*b == bend || !isdigit((int)(unsigned char)**b)))
45 return bias;
46 else if (*a == aend || !isdigit((int)(unsigned char)**a))
47 return -1;
48 else if (*b == bend || !isdigit((int)(unsigned char)**b))
49 return +1;
50 else if (**a < **b) {
51 if (!bias)
52 bias = -1;
53 } else if (**a > **b) {
54 if (!bias)
55 bias = +1;
56 }
57 }
58
59 return 0;
60 }
61 /* }}} */
62
63 /* {{{ compare_left */
64 static int
compare_left(char const ** a,char const * aend,char const ** b,char const * bend)65 compare_left(char const **a, char const *aend, char const **b, char const *bend)
66 {
67 /* Compare two left-aligned numbers: the first to have a
68 different value wins. */
69 for(;; (*a)++, (*b)++) {
70 if ((*a == aend || !isdigit((int)(unsigned char)**a)) &&
71 (*b == bend || !isdigit((int)(unsigned char)**b)))
72 return 0;
73 else if (*a == aend || !isdigit((int)(unsigned char)**a))
74 return -1;
75 else if (*b == bend || !isdigit((int)(unsigned char)**b))
76 return +1;
77 else if (**a < **b)
78 return -1;
79 else if (**a > **b)
80 return +1;
81 }
82
83 return 0;
84 }
85 /* }}} */
86
87 /* {{{ strnatcmp_ex */
strnatcmp_ex(char const * a,size_t a_len,char const * b,size_t b_len,bool is_case_insensitive)88 PHPAPI int strnatcmp_ex(char const *a, size_t a_len, char const *b, size_t b_len, bool is_case_insensitive)
89 {
90 unsigned char ca, cb;
91 char const *ap, *bp;
92 char const *aend = a + a_len,
93 *bend = b + b_len;
94 int fractional, result;
95
96 if (a_len == 0 || b_len == 0) {
97 return (a_len == b_len ? 0 : (a_len > b_len ? 1 : -1));
98 }
99
100 ap = a;
101 bp = b;
102
103 ca = *ap; cb = *bp;
104
105 /* skip over leading zeros */
106 while (ca == '0' && (ap+1 < aend) && isdigit((int)(unsigned char)*(ap+1))) {
107 ca = *++ap;
108 }
109
110 while (cb == '0' && (bp+1 < bend) && isdigit((int)(unsigned char)*(bp+1))) {
111 cb = *++bp;
112 }
113
114 while (1) {
115
116 /* Skip consecutive whitespace */
117 while (isspace((int)(unsigned char)ca)) {
118 ca = *++ap;
119 }
120
121 while (isspace((int)(unsigned char)cb)) {
122 cb = *++bp;
123 }
124
125 /* process run of digits */
126 if (isdigit((int)(unsigned char)ca) && isdigit((int)(unsigned char)cb)) {
127 fractional = (ca == '0' || cb == '0');
128
129 if (fractional)
130 result = compare_left(&ap, aend, &bp, bend);
131 else
132 result = compare_right(&ap, aend, &bp, bend);
133
134 if (result != 0)
135 return result;
136 else if (ap == aend && bp == bend)
137 /* End of the strings. Let caller sort them out. */
138 return 0;
139 else if (ap == aend)
140 return -1;
141 else if (bp == bend)
142 return 1;
143 else {
144 /* Keep on comparing from the current point. */
145 ca = *ap; cb = *bp;
146 }
147 }
148
149 if (is_case_insensitive) {
150 ca = toupper((int)(unsigned char)ca);
151 cb = toupper((int)(unsigned char)cb);
152 }
153
154 if (ca < cb)
155 return -1;
156 else if (ca > cb)
157 return +1;
158
159 ++ap; ++bp;
160 if (ap >= aend && bp >= bend)
161 /* The strings compare the same. Perhaps the caller
162 will want to call strcmp to break the tie. */
163 return 0;
164 else if (ap >= aend)
165 return -1;
166 else if (bp >= bend)
167 return 1;
168
169 ca = *ap; cb = *bp;
170 }
171 }
172 /* }}} */
173
