79 lines
1.7 KiB
C
79 lines
1.7 KiB
C
#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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int main(int argc, char** argv) {
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if(argc<2) {
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printf("Usage: %s <input> <output>\nCurrently only 4-to-2-bit supported\n", argv[0]);
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}
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FILE *in, *out;
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size_t in_off = 0, out_off = 0;
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uint8_t pixperbyte, mask_shift, mask, depth, planeidx;
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uint8_t current_pixel, current_in_tile;
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int i,j;
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if((in=fopen(argv[1], "rb"))==NULL) {
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perror("Could not open input file");
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return 1;
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}
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if((out=fopen(argv[2], "wb"))==NULL) {
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perror("Could not open output file");
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return 1;
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}
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size_t fsize, dsize;
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fseek(in, 0, SEEK_END);
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fsize = ftell(in);
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fseek(in, 0, SEEK_SET);
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// pixperbyte = 2;
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// mask_shift = 4;
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// mask = 0x03;
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// depth = 2;
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// 4->2
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pixperbyte = 1;
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mask_shift = 0;
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mask = 0xff;
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depth = 8;
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// 8->8
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dsize = fsize / pixperbyte;
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uint16_t *obuf;
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if((obuf=malloc(dsize))==NULL) {
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perror("Could not reserve memory");
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fclose(out);
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fclose(in);
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return 1;
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}
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memset(obuf, 0, dsize);
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while (!feof(in)) {
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uint8_t chunk = fgetc(in);
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printf("%lX\n", out_off);
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for(i=0; i<pixperbyte; i++) {
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current_pixel = (in_off*pixperbyte+i)%8;
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current_in_tile = (in_off*pixperbyte+i)%64;
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if(!current_pixel && in_off) { // after 8 pixels:
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out_off++;
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}
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if(!current_in_tile && in_off) { // after 64 pixels:
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out_off += (depth/2-1) * 8;
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}
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uint8_t bits = (chunk&mask);
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chunk >>= mask_shift;
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for(planeidx=0; planeidx < depth/2; planeidx++) {
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for(j=0; j<2; j++) {
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obuf[out_off+planeidx*8] |= ((bits & (1<<(j+2*planeidx))) >> (j+2*planeidx) << ((8*j+7)-current_pixel));
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}
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}
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}
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in_off++;
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}
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free(obuf);
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fwrite(obuf, dsize, 1, out);
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fclose(out);
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fclose(in);
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}
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