04lst06.c

linux 24hours study source code chap01 - chap05

/* dos_cvrt.c */

static const char rcsid[] = 
    "$Id: dos_cvrt.c,v 1.8 1998/11/27 02:29:54 student1 Exp $";

/* REVISION HISTORY:
 * $Log: dos_cvrt.c,v $
 * Revision 1.8  1998/11/27 02:29:54  student1
 * Separated out the text conversion
 * functions to make this project
 * more modular.
 *
 * Revision 1.7  1998/11/27 01:31:39  student1
 * Now handles multiple input files, plus
 * put basename code into its own Basename() 
 * function.
 *
 * Revision 1.6  1998/11/27 01:01:28  student1
 * Separated conversions into unix2dos() and
 * dos2unix() functions.
 *
 * Revision 1.5  1998/11/23 05:32:21  student1
 * Completed utility & tested ok.
 *
 * Revision 1.4  1998/11/23 05:04:23  student1
 * Coded basename test
 *
 * Revision 1.3  1998/11/21 22:49:39  student1
 * Demonstration of RCS substitutions
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "dos_cvrt.h"

/*
 * Return the pointer to the basename component
 * of a pathname:
 */
static char *
Basename(const char *path) {
    char *base_name = 0;

    if ( ( base_name = strrchr(path,'/') ) != 0 )
        ++base_name;        		/* Skip over '/' */
    else
        base_name = (char *) path; 	/* No dir. */
    return base_name;
}

int
main(int argc,char **argv) {
    char *base_name = 0;    /* Basename of command */
    int rc = 0;             /* Command return code */
    int (*conv)(const char *pathname); /* Conv. Func. Ptr */
    int x;

    /*
     * Determine the basename of the command name. This
     * is necessary since this command could be invoked
     * with a pathname. For example, argv[0] could be
     * "/usr/local/bin/unix_cvrt" if it was installed
     * in the system that way.
     */
    base_name = Basename(argv[0]);

    /*
     * Check for missing input file:
     */
    if ( argc < 2 ) {
        fprintf(stderr,"Missing input file(s).\n");
        return 1;
    }

    /*
     * Now that we know the basename of the command
     * name used, we can determine which function we
     * must carry out here.
     */
    if ( !strcmp(base_name,"unix_cvrt") )
        conv = unix2dos;
    else
        conv = dos2unix;

    /*
     * Perform a text conversion
     */
    for ( x=1; x<argc; ++x )
        if ( (rc = conv(argv[x])) != 0 )
            break;      /* An error occured */

    return rc;
}