160x200 4bpp Windows BMP to CPC MODE 0 converter.

cpcconvert.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
    unsigned char *file_buf, bmp_buf[16000], cpc_buf[16000];
    FILE *fp_in, *fp_out;
    unsigned int bmp_offset, bmp_size, file_size;
    int i;
 
    if (argc != 3) { fprintf(stdout, "Usage: %s bitmap.bmp output.src\n", argv[0]); return 0;}

    fp_in = fopen(argv[1], "r");
    if ( (fp_in = fopen(argv[1], "r")) == NULL ){ fprintf(stdout, "Can't open file %s\n", argv[1]); return 0;}       

    fseek(fp_in, 0L, SEEK_END);
    file_size = ftell(fp_in);
    rewind(fp_in); 

    printf("file size: %d bytes\n", file_size); 
    if ( (file_buf = malloc(file_size * sizeof(char))) == NULL) {
        fprintf(stderr, "Cannot allocate memory for %d bytes.\n", file_size*sizeof(char));
        abort();
    }
    if ( (i = fread(file_buf, sizeof(char), file_size, fp_in)) == 0) 
        fprintf(stderr, "0 byte was read from file %s.\n", argv[1]);
    fclose(fp_in); 

    bmp_offset = *((unsigned int *) (file_buf + 0x0a)); /* Image offset relative to file */
    bmp_size   = *((unsigned int *) (file_buf + 0x22)); /* Image size */ 
    printf("bmp_offset = %d\nbmp_size = %d\n", bmp_offset, bmp_size); 
    
    /* Turn the image upside down */
    for (i = 0; i < bmp_size/2; i++)
        file_buf[bmp_offset+i] = file_buf[bmp_offset+bmp_size-1-i];
    
    if ( (fp_out = fopen(argv[2], "w")) == NULL ) {
        fprintf(stderr, "Can't open file: %d\n", argv[2]);
        abort();
    }
    fwrite(file_buf, sizeof(char), file_size, fp_out);
    fclose(fp_out);
    free(file_buf);
 
  return 0;
}