fcds-lab-2015/c_sequential/haar/haar.c

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2015-04-25 13:31:21 +00:00
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#include <stdint.h>
#define pixel(x,y) pixels[((y)*size)+(x)]
//#define DEBUG
void print(int *pixels, int size) {
int x, y;
for (y = 0; y < size; y++) {
for (x = 0; x < size; x++) {
printf("%10d ", pixel(x,y));
}
printf("\n");
fflush(stdout);
}
}
int main(int argc, char *argv[]) {
if (argc != 3) {
printf("usage: %s [input_file] [output_file]\n", argv[0]);
return 0;
}
FILE *in;
FILE *out;
clock_t start;
clock_t end;
in = fopen(argv[1], "rb");
if (in == NULL) {
perror(argv[1]);
exit(EXIT_FAILURE);
}
out = fopen(argv[2], "wb");
if (out == NULL) {
perror(argv[2]);
exit(EXIT_FAILURE);
}
long long int s, size, mid;
int x, y;
long long int a, d;
double SQRT_2;
fread(&size, sizeof(size), 1, in);
fwrite(&size, sizeof(size), 1, out);
int *pixels = (int *) malloc(size * size * sizeof(int));
start = clock();
if (!fread(pixels, size * size * sizeof(int), 1, in)) {
perror("read error");
exit(EXIT_FAILURE);
}
end = clock();
printf("time to read: %ju (%f s)\n", (uintmax_t)(end - start), (float)(end - start) / CLOCKS_PER_SEC);
#ifdef DEBUG
printf("origin: %lld\n", size);
print(pixels, size);
#endif
// haar
start = clock();
SQRT_2 = sqrt(2);
for (s = size; s > 1; s /= 2) {
mid = s / 2;
// row-transformation
for (y = 0; y < mid; y++) {
for (x = 0; x < mid; x++) {
a = pixel(x,y);
a = (a+pixel(mid+x,y))/SQRT_2;
d = pixel(x,y);
d = (d-pixel(mid+x,y))/SQRT_2;
pixel(x,y) = a;
pixel(mid+x,y) = d;
}
}
#ifdef DEBUG
printf("after row-transformation: %lld\n", mid);
print(pixels, size);
#endif
// column-transformation
for (y = 0; y < mid; y++) {
for (x = 0; x < mid; x++) {
a = pixel(x,y);
a = (a+pixel(x,mid+y))/SQRT_2;
d = pixel(x,y);
d = (d-pixel(x,mid+y))/SQRT_2;
pixel(x,y) = a;
pixel(x,mid+y) = d;
}
}
#ifdef DEBUG
printf("after column-transformation: %lld\n", mid);
print(pixels, size);
#endif
}
end = clock();
printf("time to haar: %ju (%f s)\n", (uintmax_t)(end - start), (float)(end - start) / CLOCKS_PER_SEC);
start = clock();
fwrite(pixels, size * size * sizeof(int), 1, out);
end = clock();
printf("time to write: %ju (%f s)\n", (uintmax_t)(end - start), (float)(end - start) / CLOCKS_PER_SEC);
free(pixels);
fclose(out);
fclose(in);
return EXIT_SUCCESS;
}