wmii/libcext/strtonum.c

/*
 * Copyright (c) 2004 Ted Unangst and Todd Miller
 * All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <errno.h>
#include <limits.h>
#include <stdlib.h>

#define INVALID 	1
#define TOOSMALL 	2
#define TOOLARGE 	3

long long
cext_strtonum(const char *numstr, long long minval, long long maxval,
              const char **errstrp)
{
    long long ll = 0;
    char *ep;
    int error = 0;
    struct errval {
        const char *errstr;
        int err;
    } ev[4] = {
        {
        NULL, 0}, {
        "invalid", EINVAL}, {
        "too small", ERANGE}, {
    "too large", ERANGE},};

    ev[0].err = errno;
    errno = 0;
    if(minval > maxval)
        error = INVALID;
    else {
        ll = strtoll(numstr, &ep, 10);
        if(numstr == ep || *ep != 0)
            error = INVALID;
        else if(errno == ERANGE || ll < minval)
            error = TOOSMALL;
        else if(errno == ERANGE || ll > maxval)
            error = TOOLARGE;
    }
    if(errstrp != NULL)
        *errstrp = ev[error].errstr;
    errno = ev[error].err;
    if(error)
        ll = 0;

    return (ll);
}