tab2spc.c

/*
    Copyright 2004,2005,2006 Luigi Auriemma

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA

    http://www.gnu.org/licenses/gpl.txt
*/

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



#define VER     "0.1"
#define BUFFSZ  16384



void std_err(void);



int main(int argc, char *argv[]) {
    FILE            *fd,
                    *fdout;
    unsigned char   *buff,
                    *ptr;
    unsigned int   numspc,
                    pos,
                    tmp;
    int             err;


    setbuf(stdout, NULL);

    fputs("\n"
        "Formatted tabs to spaces "VER"\n"
        "by Luigi Auriemma\n"
        "e-mail: [email protected]\n"
        "web:    aluigi.org\n"
        "\n", stdout);

    if(argc < 3) {
        printf("\nUsage: %s <num_of_spaces*> <input_file> [output_file(stdout)]\n"
            "\n"
            "* a normal TAB is composed by 8 \"spaces\", however be free to choose\n"
            "  what size you want. This program doesn't make a simple substitution\n"
            "  but a real conversion from tab to spaces\n"
            "\n", argv[0]);
        exit(1);
    }


    if(argc > 3) {
        fdout = fopen(argv[3], "wb");
        if(!fdout) std_err();
    } else fdout = stdout;
    numspc = atoi(argv[1]);


    fd = fopen(argv[2], "rb");
    if(!fd) std_err();


    buff = malloc(BUFFSZ + 1);
    if(!buff) std_err();


    pos = 0;
    while(!feof(fd)) {
        err = fread(buff, 1, BUFFSZ, fd);
        if(!err) break;

        ptr = buff;
        for(; err > 0; err--, ptr++) {
            if(*ptr == 0x9) {
                tmp = numspc - (pos % numspc);   // optimization impossibile
                pos += tmp;                      // with custom values
                for(; tmp > 0; tmp--) fputc(0x20, fdout);
            } else {
                fputc(*ptr, fdout);
                pos++;
                if(*ptr == 0xa) pos = 0;
            }
        }
    }

    fclose(fd);
    if(fdout != stdout) {
        fputs("\nDone\n", stdout);
        fclose(fdout);
    }

    return(0);
}






void std_err(void) {
    perror("\nError");
    exit(1);
}