getopt.c

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/* getopt.c
 *
 * Copyright (c) 1992-2001 by Mike Gleason.
 * All rights reserved.
 *
 */
 
#include <stdio.h>
#include <string.h>
 
#include "getopt.h"
 
int gOptErr = 1;                    /* if error message should be printed */
int gOptInd = 1;                    /* index into parent argv vector */
int gOptOpt;                        /* character checked for validity */
const char *gOptArg;                        /* argument associated with option */
const char *gOptPlace = kGetoptErrMsg;  /* saved position in an arg */
 
/* This must be called before each Getopt. */
void
GetoptReset(void)
{
    gOptInd = 1;
    gOptPlace = kGetoptErrMsg;
}   /* GetoptReset */
 
 
 
 
static char *
NextOption(const char *const ostr)
{
    if ((gOptOpt = (int) *gOptPlace++) == (int) ':')
        return 0;
    return strchr(ostr, gOptOpt);
}   /* NextOption */
 
 
 
 
int
Getopt(int nargc, const char **const nargv, const char *const ostr)
{
    const char *oli;                   /* Option letter list index */
 
    if (!*gOptPlace) {                     /* update scanning pointer */
        if (gOptInd >= nargc || *(gOptPlace = nargv[gOptInd]) != '-')
            return (EOF);
        if (gOptPlace[1] && *++gOptPlace == '-') {  /* found "--" */
            ++gOptInd;
            return (EOF);
        }
    }                                  /* Option letter okay? */
    oli = NextOption(ostr);
    if (oli == NULL) {
        if (!*gOptPlace)
            ++gOptInd;
        if (gOptErr)
            (void) fprintf(stderr, "%s%s%c\n", *nargv, ": illegal option -- ", gOptOpt);
        return(kGetoptBadChar);
    }
    if (*++oli != ':') {               /* don't need argument */
        gOptArg = NULL;
        if (!*gOptPlace)
            ++gOptInd;
    } else {                           /* need an argument */
        if (*gOptPlace)                    /* no white space */
            gOptArg = gOptPlace;
        else if (nargc <= ++gOptInd) {  /* no arg */
            gOptPlace = kGetoptErrMsg;
            if (gOptErr)
                (void) fprintf(stderr, "%s%s%c\n", *nargv, ": option requires an argument -- ", gOptOpt);
            return(kGetoptBadChar);
        } else                         /* white space */
            gOptArg = nargv[gOptInd];
        gOptPlace = kGetoptErrMsg;
        ++gOptInd;
    }
    return (gOptOpt);                  /* dump back Option letter */
}                                      /* Getopt */
 
/* eof */