astoll.c

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/* @(#)astoll.c 1.5 15/12/10 Copyright 1985, 2000-2015 J. Schilling */
/*
 *  astoll() converts a string to long long
 *
 *  Leading tabs and spaces are ignored.
 *  Both return pointer to the first char that has not been used.
 *  Caller must check if this means a bad conversion.
 *
 *  leading "+" is ignored
 *  leading "0"  makes conversion octal (base 8)
 *  leading "0x" makes conversion hex   (base 16)
 *
 *  Llong is silently reverted to long if the compiler does not
 *  support long long.
 *
 *  Copyright (c) 1985, 2000-2015 J. Schilling
 */
/*
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * See the file CDDL.Schily.txt in this distribution for details.
 * A copy of the CDDL is also available via the Internet at
 * http://www.opensource.org/licenses/cddl1.txt
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file CDDL.Schily.txt from this distribution.
 */
 
#include <schily/mconfig.h>
#include <schily/standard.h>
#include <schily/utypes.h>
#include <schily/schily.h>
#include <schily/errno.h>
 
#define is_space(c)  ((c) == ' ' || (c) == '\t')
#define is_digit(c)  ((c) >= '0' && (c) <= '9')
#define is_hex(c)   (\
            ((c) >= 'a' && (c) <= 'f') || \
            ((c) >= 'A' && (c) <= 'F'))
 
#define is_lower(c) ((c) >= 'a' && (c) <= 'z')
#define is_upper(c) ((c) >= 'A' && (c) <= 'Z')
#define to_lower(c) (((c) >= 'A' && (c) <= 'Z') ? (c) - 'A'+'a' : (c))
 
#if ('i' + 1) < 'j'
#define BASE_MAX    ('i' - 'a' + 10 + 1)    /* This is EBCDIC */
#else
#define BASE_MAX    ('z' - 'a' + 10 + 1)    /* This is ASCII */
#endif
 
 
char *
astoll(s, l)
    register const char *s;
    Llong *l;
{
    return (astollb(s, l, 0));
}
 
char *
astollb(s, l, base)
    register const char *s;
    Llong *l;
    register int base;
{
    int neg = 0;
    register ULlong ret = (ULlong)0;
        ULlong maxmult;
        ULlong maxval;
    register int digit;
    register char c;
 
    if (base > BASE_MAX || base == 1 || base < 0) {
        seterrno(EINVAL);
        return ((char *)s);
    }
 
    while (is_space(*s))
        s++;
 
    if (*s == '+') {
        s++;
    } else if (*s == '-') {
        s++;
        neg++;
    }
 
    if (base == 0) {
        if (*s == '0') {
            base = 8;
            s++;
            if (*s == 'x' || *s == 'X') {
                s++;
                base = 16;
            }
        } else {
            base = 10;
        }
    }
    if (neg) {
        /*
         * Portable way to compute the positive value of "min-Llong"
         * as -TYPE_MINVAL(Llong) does not work.
         */
        maxval = ((ULlong)(-1 * (TYPE_MINVAL(Llong)+1))) + 1;
    } else {
        maxval = TYPE_MAXVAL(Llong);
    }
    maxmult = maxval / base;
    for (; (c = *s) != 0; s++) {
 
        if (is_digit(c)) {
            digit = c - '0';
        } else if (is_lower(c)) {
            digit = c - 'a' + 10;
        } else if (is_upper(c)) {
            digit = c - 'A' + 10;
        } else {
            break;
        }
 
        if (digit < base) {
            if (ret > maxmult)
                goto overflow;
            ret *= base;
            if (maxval - ret < digit)
                goto overflow;
            ret += digit;
        } else {
            break;
        }
    }
    if (neg) {
        *l = (Llong)-1 * ret;
    } else {
        *l = (Llong)ret;
    }
    return ((char *)s);
overflow:
    for (; (c = *s) != 0; s++) {
 
        if (is_digit(c)) {
            digit = c - '0';
        } else if (is_lower(c)) {
            digit = c - 'a' + 10;
        } else if (is_upper(c)) {
            digit = c - 'A' + 10;
        } else {
            break;
        }
        if (digit >= base)
            break;
    }
    if (neg) {
        *l = TYPE_MINVAL(Llong);
    } else {
        *l = TYPE_MAXVAL(Llong);
    }
    seterrno(ERANGE);
    return ((char *)s);
}