Foundation Sorting: Quicksort

/* Quick Sorting.
 * Implementation history:.
 * 2013-09-15, Mars Fu, first version.
 */

/* [Quicksort Algorithm]
 * Published by C.A.R.Hoare,[Comp. J.5(1962),10-15].
 */

#include "stdafx.h"

#include "quicksort.h"

int
do_quick_sort(void* src, int src_sz, int n, cmp_func cmp, exc_func exchange, dbg_func dbg)
{
	const int M = 0;
	int i,j,k;
	int l,r;
	char *kv, *ki, *kj;
	static int h = 0;

	F_S();

	if (src == NULL || cmp == NULL || exchange == NULL) return 0;
	if (src_sz <= 0 || n <= 0) return 0;

Q1:
	/* initialize
	 */
	if (n <= M) {
		/* do straight insertion sort
		 */
		return 1;
	}
	else {
		l = 0;
		r = n-1;
	}

Q2:
	/* begine new stage
	 */
	i = l;
	j = r + 1;
	kv = (char*)src + l * src_sz;

Q3:
	do {
		/* compare @kv with @ki
		 */
		do {
			++i;
			if (i >= j) break;
			ki = (char*)src + i * src_sz;
		} while (cmp(ki, kv) < 0);

		/* compare @kv with @kj
		 */
		do {
			--j;
			if (j <= i) break;
			kj = (char*)src + j * src_sz;
		} while (cmp(kv, kj) < 0);

		/* test i:j
		 */
		if (j <= i) {

			/* found the absolute index @j for @kv,do exchanging here and break.
			 */
			if (j < i) {
				kj = (char*)src + j * src_sz;
				exchange(kv, kj);
			}
			else {
				/* @i == @j means no need to exchange,having been sorted already.
				 */
			}

			if (dbg) dbg(src, n, ++h);
			break;
		}
		else {
			ki = (char*)src + i * src_sz;
			kj = (char*)src + j * src_sz;
			exchange(ki, kj);

			if (dbg) dbg(src, n, ++h);
		}
	} while (1);

Q4:
	/* do the same procedure via recursion with the changed @left or @right.
	 */
	if(i == j) {
		/* the first item is sorted already, move forward 1 item, sort again.
		 */
		do_quick_sort((char*)src + 1*src_sz, src_sz, n-1, cmp, exchange, dbg);
	}
	else {
		if (j-l > 1) {
			do_quick_sort((char*)src + l*src_sz, src_sz, j-l, cmp, exchange, dbg);
		}

		if (r-j > 1) {
			do_quick_sort((char*)src + i*src_sz, src_sz, r-j, cmp, exchange, dbg);
		}
	}

END:
	F_E();
	return 1;
}

#ifdef QUICK_SORT_DEBUG

static int
int_increasing_cmp(void* lv, void* rv)
{
	int tmp_lv, tmp_rv;

	tmp_lv = *(int*)lv;
	tmp_rv = *(int*)rv;

	return (tmp_lv - tmp_rv);
}

static void
exchange_int_item(void* lv, void* rv)
{
	int tmp_lv, tmp_rv;

	tmp_lv = *(int*)lv;
	tmp_rv = *(int*)rv;

	*(int*)lv = *(int*)rv;
	*(int*)rv = tmp_lv;
}

static void
debug_func(void*src, int n, int h)
{
	int i;

	debug("%d-sort:\r\n----\r\n", h);
	for (i = 0; i < n; ++i) {
		debug("%d ", *((int*)src + i));
	}
	debug("\r\n----\r\n");
}

int
main(int argc, char* argv[])
{
	int i;
	int cnt;
	const int int_items[] = { 503, 87, 512, 61, 908, 170, 897, 275,
		                      653, 426, 154, 509, 612, 677, 765, 703
	                         };
	int ret;

	debug("[Testing quick sort].. \r\n");

	cnt = sizeof(int_items)/sizeof(int_items[0]);

	debug("src database:\r\n----\r\n");
	for (i = 0; i < cnt; ++i) {
		debug("%d ", int_items[i]);
	}
	debug("\r\n----\r\n");

	ret = do_quick_sort((void*)int_items, sizeof(int), cnt,
		                 int_increasing_cmp, exchange_int_item, debug_func);
	if (!ret) {
		debug("failed. \r\n");
		goto END;
	}

	debug("dst database:\r\n----\r\n");
	for (i = 0; i < cnt; ++i) {
		debug("%d ", int_items[i]);
	}
	debug("\r\n----\r\n");

	debug("\r\n");

	debug("[Testing quick sort].. done. \r\n");

END:
	while(1);
	return 0;
}

#endif /* QUICK_SORT_DEBUG */

#ifndef __QUICKSORT_H__
#define __QUICKSORT_H__

#define QUICK_SORT_DEBUG

typedef int(*cmp_func)(void*, void*);
typedef void (*exc_func)(void*, void*);
typedef void (*dbg_func)(void*, int, int);

int do_quick_sort(void* src, int src_sz, int n, cmp_func cmp, exc_func exchange, dbg_func dbg);

#endif /* __QUICKSORT_H__ */

#pragma once

#include <windows.h>
#ifdef _WIN32
#define msleep(x)  Sleep(x)
#endif

#include <stdio.h>
#include <tchar.h>
#include <stdlib.h>
#include <malloc.h>
#include <string.h>
#include <math.h>

#define MY_DEBUG
#ifdef MY_DEBUG
#define debug printf
#else
#define debug(x,argc, __VA_ARGS__)	;
#endif /* MY_DEBUG */

#define F_S() debug("[%s]..\r\n", __FUNCTION__)
#define F_E() debug("[%s]..done. \r\n", __FUNCTION__)

Mars

Sep 15th, 2013