xref: /PHP-5.3/Zend/zend_qsort.c (revision 831fbcf3)
1 /*
2    +----------------------------------------------------------------------+
3    | Zend Engine                                                          |
4    +----------------------------------------------------------------------+
5    | Copyright (c) 1998-2013 Zend Technologies Ltd. (http://www.zend.com) |
6    +----------------------------------------------------------------------+
7    | This source file is subject to version 2.00 of the Zend license,     |
8    | that is bundled with this package in the file LICENSE, and is        |
9    | available through the world-wide-web at the following url:           |
10    | http://www.zend.com/license/2_00.txt.                                |
11    | If you did not receive a copy of the Zend license and are unable to  |
12    | obtain it through the world-wide-web, please send a note to          |
13    | license@zend.com so we can mail you a copy immediately.              |
14    +----------------------------------------------------------------------+
15    | Authors: Sterling Hughes <sterling@php.net>                          |
16    +----------------------------------------------------------------------+
17 */
18 
19 /* $Id$ */
20 
21 #include "zend.h"
22 
23 #include <limits.h>
24 
25 #define QSORT_STACK_SIZE (sizeof(size_t) * CHAR_BIT)
26 
_zend_qsort_swap(void * a,void * b,size_t siz)27 static void _zend_qsort_swap(void *a, void *b, size_t siz)
28 {
29 	register char  *tmp_a_char;
30 	register char  *tmp_b_char;
31 	register int   *tmp_a_int;
32 	register int   *tmp_b_int;
33 	register size_t i;
34 	int             t_i;
35 	char            t_c;
36 
37 	tmp_a_int = (int *) a;
38 	tmp_b_int = (int *) b;
39 
40 	for (i = sizeof(int); i <= siz; i += sizeof(int)) {
41 		t_i = *tmp_a_int;
42 		*tmp_a_int++ = *tmp_b_int;
43 		*tmp_b_int++ = t_i;
44 	}
45 
46 	tmp_a_char = (char *) tmp_a_int;
47 	tmp_b_char = (char *) tmp_b_int;
48 
49 	for (i = i - sizeof(int) + 1; i <= siz; ++i) {
50 		t_c = *tmp_a_char;
51 		*tmp_a_char++ = *tmp_b_char;
52 		*tmp_b_char++ = t_c;
53 	}
54 }
55 
zend_qsort(void * base,size_t nmemb,size_t siz,compare_func_t compare TSRMLS_DC)56 ZEND_API void zend_qsort(void *base, size_t nmemb, size_t siz, compare_func_t compare TSRMLS_DC)
57 {
58 	void           *begin_stack[QSORT_STACK_SIZE];
59 	void           *end_stack[QSORT_STACK_SIZE];
60 	register char  *begin;
61 	register char  *end;
62 	register char  *seg1;
63 	register char  *seg2;
64 	register char  *seg2p;
65 	register int    loop;
66 	uint            offset;
67 
68 	begin_stack[0] = (char *) base;
69 	end_stack[0]   = (char *) base + ((nmemb - 1) * siz);
70 
71 	for (loop = 0; loop >= 0; --loop) {
72 		begin = begin_stack[loop];
73 		end   = end_stack[loop];
74 
75 		while (begin < end) {
76 			offset = (end - begin) >> 1;
77 			_zend_qsort_swap(begin, begin + (offset - (offset % siz)), siz);
78 
79 			seg1 = begin + siz;
80 			seg2 = end;
81 
82 			while (1) {
83 				for (; seg1 < seg2 && compare(begin, seg1 TSRMLS_CC) > 0;
84 				     seg1 += siz);
85 
86 				for (; seg2 >= seg1 && compare(seg2, begin TSRMLS_CC) > 0;
87 				     seg2 -= siz);
88 
89 				if (seg1 >= seg2)
90 					break;
91 
92 				_zend_qsort_swap(seg1, seg2, siz);
93 
94 				seg1 += siz;
95 				seg2 -= siz;
96 			}
97 
98 			_zend_qsort_swap(begin, seg2, siz);
99 
100 			seg2p = seg2;
101 
102 			if ((seg2p - begin) <= (end - seg2p)) {
103 				if ((seg2p + siz) < end) {
104 					begin_stack[loop] = seg2p + siz;
105 					end_stack[loop++] = end;
106 				}
107 				end = seg2p - siz;
108 			}
109 			else {
110 				if ((seg2p - siz) > begin) {
111 					begin_stack[loop] = begin;
112 					end_stack[loop++] = seg2p - siz;
113 				}
114 				begin = seg2p + siz;
115 			}
116 		}
117 	}
118 }
119 
120 /*
121  * Local Variables:
122  * c-basic-offset: 4
123  * tab-width: 4
124  * End:
125  * vim600: fdm=marker
126  * vim: noet sw=4 ts=4
127  */
128