SpaceTab

/*
 * SpaceTab
 *
 * Created by Fabio de Albuquerque Dela Antonio
 *
 * fabio914 at gmail.com
 *
 */
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
unsigned char * toSpaceTab(unsigned char *, long int);
unsigned char * toText(unsigned char *, long int);
 
int main(int argc, char *argv[]) {
 
    FILE * in, * out;
 
    int option = 0;
 
    if(argc < 4) {
        fprintf(stderr, "Use: %s <input file> <output file> <option>\n", argv[0]);
        fprintf(stderr, "option: \"-1\" to convert from text to space-tab or \"-2\" to convert from space-tab to text\n");
        return 1;
    }
 
    if(!strcmp(argv[3], "-1"))
        option = 1;
    else if(!strcmp(argv[3], "-2"))
        option = 2;
    else {
        fprintf(stderr, "Invalid option.\n");
        return 1;
    }    
 
    if((in = fopen(argv[1], "r")) == NULL) {
        fprintf(stderr, "Could not open input file.\n");
        return 1;
    }
 
    fseek(in, 0, SEEK_END);
    long int fileSize = ftell(in);
    fseek(in, 0, SEEK_SET);
 
    unsigned char * inb, * outb;
 
    if((inb = (unsigned char *)malloc(fileSize*sizeof(unsigned char))) == NULL) {
        fprintf(stderr, "Could not allocate enough memory.\n");
        return 1;
    }
 
    if(fread(inb, sizeof(unsigned char), fileSize, in) < fileSize) {
        fprintf(stderr, "Could not read input file.\n");
        return 1;
    }
 
    outb = (option == 1) ? toSpaceTab(inb, fileSize):toText(inb, fileSize);
 
    fclose(in);
 
    if((out = fopen(argv[2], "w")) == NULL) {
        fprintf(stderr, "Could not open/create output file.\n");
        return 1;
    }
 
    if(fwrite(outb, sizeof(unsigned char), (option == 1) ? fileSize*8:fileSize/8, out) < ((option == 1) ? fileSize*8:fileSize/8)) {
        fprintf(stderr, "Could not write on output file.\n");
        return 1;
    }
 
    fclose(out);
    free(inb);
    free(outb);
 
    return 0;
}
 
unsigned char * toSpaceTab(unsigned char * text, long int fileSize) {
 
    unsigned char * outb;
    unsigned char current;
 
    if((outb = (unsigned char *)malloc(fileSize*sizeof(unsigned char)*8)) == NULL) {
        fprintf(stderr, "Could not allocate enough memory.\n");
        exit(1);
    }
 
    register long int i, k = 0;
    register unsigned char j;
 
    for(i = 0; i < fileSize; i++) {
        current = text[i];
 
        for(j = 0; j < 8; j++) {
 
            if((current & (1 << j)))
                outb[k] = ' ';
            else outb[k] = '\t';
 
            k++;
        }
    }
 
    return outb;
}
 
unsigned char * toText(unsigned char * spacetab, long int fileSize) {
 
    unsigned char * outb;
    unsigned char current;
 
    if((outb = (unsigned char *)malloc(fileSize*sizeof(unsigned char)/8)) == NULL) {
        fprintf(stderr, "Could not allocate enough memory.\n");
        exit(1);
    }
 
    register long int i, k = 0;
    register unsigned char j;
 
    for(i = 0; i < fileSize/8; i++) {
        current = 0;
 
        for(j = 0; j < 8; j++) {
 
            if(spacetab[k] == ' ')
                current |= (1 << j);
 
            k++;
        }
 
        outb[i] = current;
    }
 
    return outb;
}