mirror of https://github.com/pret/pokecrystal.git
54 lines
942 B
C
54 lines
942 B
C
#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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void usage(void) {
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fprintf(stderr, "Usage: png_dimensions infile outfile\n");
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exit(1);
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}
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void output_dimensions(char* png_filename, char* out_filename) {
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FILE* f;
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int width, height;
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int i;
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uint8_t bytes[4];
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uint8_t output;
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f = fopen(png_filename, "rb");
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if (f == NULL) {
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fprintf(stderr, "failed to open file %s\n", png_filename);
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exit(1);
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}
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// width
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fseek(f, 16, SEEK_SET);
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fread(bytes, 1, 4, f);
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fclose(f);
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width = 0;
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for (i = 0; i < 4; i++) {
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width |= bytes[i] << (8 * (3 - i));
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}
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width >>= 3;
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height = width;
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output = width & 0xf;
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output |= (height & 0xf) << 4;
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f = fopen(out_filename, "wb");
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if (f == NULL) {
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fprintf(stderr, "failed to open file %s\n", out_filename);
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exit(1);
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}
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fwrite(&output, 1, 1, f);
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fclose(f);
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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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usage();
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}
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output_dimensions(argv[1], argv[2]);
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return 0;
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}
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