source: liacs/da/opdr2b/compressie.cc@ 104

/* Author    : Rick van der Zwet
 * S-number  : 0433373
 * Version   : $Id: compressie.cc 457 2008-01-08 22:24:08Z rick $
 * Copyright : FreeBSD Licence
 */
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <sysexits.h>
#include "trie.cc"
#include "fileio.h"
#include "constants.h"

/* XXX: File are only checked at creation time, not during execution */
int
main(int argc, char ** argv) {
    FILE * input;
    FILE * output;
    int knob = START_KNOB;
    int code = 0;
    // character storage
    /* input Letter */
    int c;
    Trie<int> * lwz;

    if (argc < 2) {
        fprintf(stderr, "Usage: %s <infile> [<outfile>]\n",argv[0]);
        return(EX_USAGE);
    }

    input = fopen(argv[1], "r");
    if (input == NULL) {
        fprintf(stderr,"Error: Unable to use `%s', errno: %i\n", 
            argv[1], errno);
        return(EX_NOINPUT);
    }

    if (argc == 3) {
        output = fopen(argv[2], "w");
        if (output == NULL) {
            fprintf(stderr,"Error: Unable to use `%s', errno: %i\n",
                argv[2], errno);
            return(EX_CANTCREAT);
        }
    } else
        output = stdout;

    /* initialiseer Trie voor ZLW codering */
    lwz = new Trie<int>;
    for (code = 0; code <= 0xFF; code++) {
        lwz->GoRoot();
        lwz->AddChild(code);
        lwz->GoChild(code);
        lwz->PutInfo(knob);
        knob++;
    }
    lwz->GoRoot();

    /* while not eof (SourceFile) */
    while ((c = fgetc(input)) != EOF) {
        if (not lwz->ExistsChild(c)) {
            tofile(output, lwz->GetInfo());
            /* if not (maximaal aantal strings in Trie) */
            if (knob < MAX_KNOB) {
                /* voes nieuwe code via tak Letter and Trie toe */
                lwz->AddChild(c);
                lwz->GoChild(c);
                lwz->PutInfo(knob);
                knob++;
            }
            /* ga naar wortel Trie */
            lwz->GoRoot();
        }
        /* ga naar kind Letter in Trie */
        lwz->GoChild(c);
    }
    tofile(output, lwz->GetInfo());

    /* flush buffer */
    closefile(output);

    /* delete trie */
    delete lwz;

    fclose(input);
    fclose(output);
    return(EX_OK);
}