61 lines
1.5 KiB
C
61 lines
1.5 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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typedef struct bmp_header bmp_header;
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struct bmp_header {
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uint8_t id[2];
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uint8_t size[4];
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uint8_t r1[2];
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uint8_t r2[2];
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uint8_t offset[4];
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};
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int32_t little_endian(uint8_t bytes[4]) {
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int32_t le = bytes[0] | (bytes[1] << 8) | (bytes[2] << 16) | (bytes[3] << 24);
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return le;
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}
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int main(int argc, char **argv) {
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if (argc != 2) {
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fprintf(stderr, "extractor [usage]: input_file");
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return EXIT_FAILURE;
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}
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bmp_header header;
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char search;
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int count = 0;
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char out_name[128] = {0};
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char *in = argv[1];
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FILE *fin = fopen(in, "r");
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fseek(fin, 0, SEEK_SET);
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while (fread(&search, sizeof(char), 1, fin) > 0) {
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if (search != 'B')
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continue;
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if (fread(&search, sizeof(char), 1, fin) <= 0)
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continue;
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if (search != 'M')
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continue;
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fpos_t pos;
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fseek(fin, -2 * sizeof(char), SEEK_CUR);
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fgetpos(fin, &pos);
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fread(&header, sizeof(bmp_header), 1, fin);
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if (header.r1[0] == 0 && header.r1[1] == 0 && header.r2[0] == 0 &&
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header.r2[1] == 0) {
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fseek(fin, pos, SEEK_SET);
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int32_t size = little_endian(header.size);
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char *data = (char *)malloc((size + 1) * sizeof(char));
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fread(data, sizeof(char), size, fin);
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data[size + 1] = 0;
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snprintf(out_name, sizeof out_name, "%s_%d.bmp", in, ++count);
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FILE *fout = fopen(out_name, "w");
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fwrite(data, sizeof(char), size, fout);
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fclose(fout);
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free(data);
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}
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}
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fclose(fin);
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return EXIT_SUCCESS;
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}
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