source: liacs/da/opdr2b/fileio.cc@ 11

/* Author    : Rick van der Zwet
 * S-number  : 0433373
 * Version   : $Id: compressie.cc 330 2007-11-25 23:31:30Z rick $
 * Copyright : FreeBSD Licence
 */
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <sysexits.h>

#include "fileio.h"



int
fetchnumber(FILE * input) {
    static bool odd = true;
    static int buffer[3];
    int number;

    if (feof(input))
        return(FILE_END);

    if (odd == true) {
        buffer[0] = fgetc(input);
        buffer[1] = fgetc(input);
        buffer[2] = fgetc(input);
        number = (buffer[0] << 4) | (buffer[1] >> 4);
        odd = false;
    } else {
        number = ((buffer[1] & 0xF) << 8) | buffer[2];
        odd = true;
    }

    if (number == FILE_END | number == EOF)
        return(FILE_END);

    return(number);
}

/* XXX: Check fread/fwrite instead of hacking around like this */
void
tofile(FILE * output, const int input) {
    static int stored = 0;
    static bool instore = false;

    if (not instore) {
        stored = input << 12;
        instore = true;
    } else {
        stored = stored | input;
        fprintf(output,"%c%c%c", ((0x00FF0000 & stored) >> 16),
                                 ((0x0000FF00 & stored) >> 8),
                                  (0x000000FF & stored));
        instore = false;
    }
}

/* set closing point, to really make sure we hit the end of the file */
void
closefile(FILE * output) {
    tofile(output, FILE_END);
    tofile(output, FILE_END);
}