root/Zend/zend_qsort.c

DEFINITIONS

1. _zend_qsort_swap
2. zend_qsort

/*
   +----------------------------------------------------------------------+
   | Zend Engine                                                          |
   +----------------------------------------------------------------------+
   | Copyright (c) 1998-2008 Zend Technologies Ltd. (http://www.zend.com) |
   +----------------------------------------------------------------------+
   | This source file is subject to version 2.00 of the Zend license,     |
   | that is bundled with this package in the file LICENSE, and is        | 
   | available through the world-wide-web at the following url:           |
   | http://www.zend.com/license/2_00.txt.                                |
   | If you did not receive a copy of the Zend license and are unable to  |
   | obtain it through the world-wide-web, please send a note to          |
   | license@zend.com so we can mail you a copy immediately.              |
   +----------------------------------------------------------------------+
   | Authors: Sterling Hughes <sterling@php.net>                          |
   +----------------------------------------------------------------------+
*/

/* $Id: zend_qsort.c,v 1.8.2.1.2.2 2007/12/31 07:20:03 sebastian Exp $ */

#include "zend.h"

#include <limits.h>

#define QSORT_STACK_SIZE (sizeof(size_t) * CHAR_BIT)

static void _zend_qsort_swap(void *a, void *b, size_t siz)
{
        register char  *tmp_a_char;
        register char  *tmp_b_char;
        register int   *tmp_a_int;
        register int   *tmp_b_int;
        register size_t i;
        int             t_i;
        char            t_c;

        tmp_a_int = (int *) a;
        tmp_b_int = (int *) b;

        for (i = sizeof(int); i <= siz; i += sizeof(int)) {
                t_i = *tmp_a_int;
                *tmp_a_int++ = *tmp_b_int;
                *tmp_b_int++ = t_i;
        }

        tmp_a_char = (char *) tmp_a_int;
        tmp_b_char = (char *) tmp_b_int;

        for (i = i - sizeof(int) + 1; i <= siz; ++i) {
                t_c = *tmp_a_char;
                *tmp_a_char++ = *tmp_b_char;
                *tmp_b_char++ = t_c;
        }
}

ZEND_API void zend_qsort(void *base, size_t nmemb, size_t siz, compare_func_t compare TSRMLS_DC)
{
        void           *begin_stack[QSORT_STACK_SIZE];
        void           *end_stack[QSORT_STACK_SIZE];
        register char  *begin;
        register char  *end;
        register char  *seg1;
        register char  *seg2;
        register char  *seg2p;
        register int    loop;
        uint            offset;

        begin_stack[0] = (char *) base;
        end_stack[0]   = (char *) base + ((nmemb - 1) * siz);

        for (loop = 0; loop >= 0; --loop) {
                begin = begin_stack[loop];
                end   = end_stack[loop];

                while (begin < end) {
                        offset = (end - begin) >> 1;
                        _zend_qsort_swap(begin, begin + (offset - (offset % siz)), siz);

                        seg1 = begin + siz;
                        seg2 = end;

                        while (1) {
                                for (; seg1 < seg2 && compare(begin, seg1 TSRMLS_CC) > 0;
                                     seg1 += siz);

                                for (; seg2 >= seg1 && compare(seg2, begin TSRMLS_CC) > 0;
                                     seg2 -= siz);
                                
                                if (seg1 >= seg2)
                                        break;
                                
                                _zend_qsort_swap(seg1, seg2, siz);

                                seg1 += siz;
                                seg2 -= siz;
                        }

                        _zend_qsort_swap(begin, seg2, siz);

                        seg2p = seg2;
                        
                        if ((seg2p - begin) <= (end - seg2p)) {
                                if ((seg2p + siz) < end) {
                                        begin_stack[loop] = seg2p + siz;
                                        end_stack[loop++] = end;
                                }
                                end = seg2p - siz;
                        }
                        else {
                                if ((seg2p - siz) > begin) {
                                        begin_stack[loop] = begin;
                                        end_stack[loop++] = seg2p - siz;
                                }
                                begin = seg2p + siz;
                        }
                }
        }
}

/* 
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 * tab-width: 4
 * End:
 * vim600: fdm=marker
 * vim: noet sw=4 ts=4
 */