Created
September 8, 2011 18:10
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Generic array shuffle and unshuffle
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#include <stdio.h> | |
#include <string.h> | |
#include <stdlib.h> | |
#define Shuffle(A, B, C) shuffle(A, B, 0, C, sizeof(*A)) | |
#define Unshuffle(A, B, C) unshuffle(A, B, 0, C, sizeof(*A)) | |
typedef struct | |
{ | |
int x; | |
int y; | |
} Point; | |
void * shuffle(void * array, int seed, int index, int len, size_t size); | |
void * unshuffle(void * array, int seed, int index, int len, size_t size); | |
void swap(void * num1, void * num2, size_t size); | |
void printArray(void * array, int len, size_t size, void(*print)(void * item)); | |
void printPoint(void * item); | |
int main() | |
{ | |
Point array[4] = {{0, 1}, {2, 3}, {4, 5}, {6, 7}}; | |
Shuffle(array, 1, 4); | |
printArray(array, 4, sizeof(Point), printPoint); | |
puts("\n"); | |
Unshuffle(array, 1, 4); | |
printArray(array, 4, sizeof(Point), printPoint); | |
return 0; | |
} | |
void * shuffle(void * array, int seed, int index, int len, size_t size) | |
{ | |
int result; | |
if(index == len) | |
return array; | |
srand(seed); | |
result = rand(); | |
swap((array + index * size), (array + result%len * size), size); | |
return shuffle(array, result, index + 1, len, size); | |
} | |
void * unshuffle(void * array, int seed, int index, int len, size_t size) | |
{ | |
int result; | |
if(index == len) | |
return array; | |
srand(seed); | |
result = rand(); | |
array = unshuffle(array, result, index + 1, len, size); | |
swap((array + index * size), (array + result%len * size), size); | |
return array; | |
} | |
void swap(void * a, void * b, size_t size) | |
{ | |
void * temp = malloc(size); | |
memcpy(temp, a, size); | |
memcpy(a, b, size); | |
memcpy(b, temp, size); | |
free(temp); | |
} | |
void printArray(void * array, int len, size_t size, void(*print)(void * item)) | |
{ | |
int i; | |
for(i = 0; i < len; i++) | |
print((array + i * size)); | |
} | |
void printPoint(void * item) | |
{ | |
Point * pitem = (Point*)item; | |
printf("x = %d, y = %d\n", pitem->x, pitem->y); | |
} |
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