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