Foundation Sorting: Shellsort
/* Shell Sorting.
* Implemention history:.
* 2013-09-15, Mars Fu, first version.
*/
/* [Shell Sorting Algorithm].
* Published by Donald L. Shell [CACM 2, 7(July 1959), 30-32].
*/
#include "stdafx.h"
#include "shellsort.h"
#include <math.h>
static int
get_increment(int s)
{
int next_hs;
next_hs = (1 << s);
return next_hs;
}
int
do_shell_sort(void* src, int src_sz, int n, cmp_func cmp, exc_func exchange, dbg_func dbg)
{
int t;
int h;
int i,j;
float n2;
F_S();
if (src == NULL || cmp == NULL || exchange == NULL) return 0;
if (src_sz <= 0 || n <= 0) return 0;
/* get @t for aux table {h(t),...,h(0)}
*/
n2 = 2;
t = log((double)n) / log((double)n2) + (n%2 ? 1 : -1);
/* loop aux table for shell sorting
*/
while (t >= 0) {
h = get_increment(t); /* get h(t) */
/* loop all parts of @src, each part has @h items to be compared.
*/
for (i = 0; i < n/h; ++i) {
/* do the comparison and exchanging for each part.
*/
for ( j = i+h; j < n; j += h) {
if (cmp((char*)src + (j-h)*src_sz, (char*)src + j*src_sz) > 0) {
exchange((char*)src + (j-h) * src_sz, (char*)src + j * src_sz);
}
}
}
--t;
if (dbg != NULL) dbg(src, n, h);
}
F_E();
return 1;
}
#ifdef SHELL_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 shell 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_shell_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 shell sort].. done. \r\n");
END:
while(1);
return 0;
}
#endif /* SHELL_SORT_DEBUG */
#ifndef __SHELLSORT_H__ #define __SHELLSORT_H__ #define SHELL_SORT_DEBUG typedef int(*cmp_func)(void*, void*); typedef void (*exc_func)(void*, void*); typedef void (*dbg_func)(void*, int, int); int do_shell_sort(void* src, int src_sz, int n, cmp_func cmp, exc_func exchange, dbg_func dbg); #endif /* __SHELLSORT_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