[apple/xnu.git] / iokit / Kernel / IOStringFuncs.c

/*
 * Copyright (c) 1998-2016 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

/*
 *      Copyright (c) 1995 NeXT Computer, Inc.  All rights reserved.
 *
 * strol.c - The functions strtol() & strtoul() are exported as public API
 *           via the header file ~driverkit/generalFuncs.h
 *
 * HISTORY
 * 25-Oct-1995    Dean Reece at NeXT
 *      Created based on BSD4.4's strtol.c & strtoul.c.
 *      Removed dependency on _ctype_ by static versions of isupper()...
 *      Added support for "0b101..." binary constants.
 *      Commented out references to errno.
 */

/*
 * Copyright (c) 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 #include <string.h>
 #include <stdlib.h>
 #include <limits.h>
 */
#include <sys/types.h>
#include <machine/limits.h>


long strtol(const char *nptr, char **endptr, int base);
unsigned long strtoul(const char *nptr, char **endptr, int base);
quad_t strtoq(const char *nptr, char **endptr, int base);
u_quad_t strtouq(const char *nptr, char **endptr, int base);
char *strncat(char *s1, const char *s2, unsigned long n);


typedef int BOOL;

static inline BOOL
isupper(char c)
{
        return c >= 'A' && c <= 'Z';
}

static inline BOOL
isalpha(char c)
{
        return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
}


static inline BOOL
isspace(char c)
{
        return c == ' ' || c == '\t' || c == '\n' || c == '\12';
}

static inline BOOL
isdigit(char c)
{
        return c >= '0' && c <= '9';
}

/*
 * Convert a string to a long integer.
 *
 * Ignores `locale' stuff.  Assumes that the upper and lower case
 * alphabets and digits are each contiguous.
 */
long
strtol(const char *nptr, char **endptr, int base)
{
        const char *s = nptr;
        unsigned long acc;
        char c;
        unsigned long cutoff;
        int neg = 0, any, cutlim;

        /*
         * Skip white space and pick up leading +/- sign if any.
         * If base is 0, allow 0x for hex and 0 for octal, else
         * assume decimal; if base is already 16, allow 0x.
         */
        do {
                c = *s++;
        } while (isspace(c));
        if (c == '-') {
                neg = 1;
                c = *s++;
        } else if (c == '+') {
                c = *s++;
        }
        if ((base == 0 || base == 16) &&
            c == '0' && (*s == 'x' || *s == 'X')) {
                c = s[1];
                s += 2;
                base = 16;
        } else if ((base == 0 || base == 2) &&
            c == '0' && (*s == 'b' || *s == 'B')) {
                c = s[1];
                s += 2;
                base = 2;
        }
        if (base == 0) {
                base = c == '0' ? 8 : 10;
        }

        /*
         * Compute the cutoff value between legal numbers and illegal
         * numbers.  That is the largest legal value, divided by the
         * base.  An input number that is greater than this value, if
         * followed by a legal input character, is too big.  One that
         * is equal to this value may be valid or not; the limit
         * between valid and invalid numbers is then based on the last
         * digit.  For instance, if the range for longs is
         * [-2147483648..2147483647] and the input base is 10,
         * cutoff will be set to 214748364 and cutlim to either
         * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
         * a value > 214748364, or equal but the next digit is > 7 (or 8),
         * the number is too big, and we will return a range error.
         *
         * Set any if any `digits' consumed; make it negative to indicate
         * overflow.
         */
        cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
        cutlim = ((int)(cutoff % (unsigned long)base));
        cutoff /= (unsigned long)base;
        for (acc = 0, any = 0;; c = *s++) {
                if (isdigit(c)) {
                        c -= '0';
                } else if (isalpha(c)) {
                        c -= isupper(c) ? 'A' - 10 : 'a' - 10;
                } else {
                        break;
                }
                if (c >= base) {
                        break;
                }
                if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) {
                        any = -1;
                } else {
                        any = 1;
                        acc *= base;
                        acc += c;
                }
        }
        if (any < 0) {
                acc = neg ? LONG_MIN : LONG_MAX;
//              errno = ERANGE;
        } else if (neg) {
                acc = -acc;
        }
        if (endptr != 0) {
                if (any) {
                        *endptr = __CAST_AWAY_QUALIFIER(s - 1, const, char *);
                } else {
                        *endptr = __CAST_AWAY_QUALIFIER(nptr, const, char *);
                }
        }
        return acc;
}

unsigned long
strtoul(const char *nptr, char **endptr, int base)
{
        const char *s = nptr;
        unsigned long acc;
        char c;
        unsigned long cutoff;
        int neg = 0, any, cutlim;

        /*
         * See strtol for comments as to the logic used.
         */
        do {
                c = *s++;
        } while (isspace(c));
        if (c == '-') {
                neg = 1;
                c = *s++;
        } else if (c == '+') {
                c = *s++;
        }
        if ((base == 0 || base == 16) &&
            c == '0' && (*s == 'x' || *s == 'X')) {
                c = s[1];
                s += 2;
                base = 16;
        } else if ((base == 0 || base == 2) &&
            c == '0' && (*s == 'b' || *s == 'B')) {
                c = s[1];
                s += 2;
                base = 2;
        }
        if (base == 0) {
                base = c == '0' ? 8 : 10;
        }
        cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
        cutlim = ((int)((unsigned long)ULONG_MAX % (unsigned long)base));
        for (acc = 0, any = 0;; c = *s++) {
                if (isdigit(c)) {
                        c -= '0';
                } else if (isalpha(c)) {
                        c -= isupper(c) ? 'A' - 10 : 'a' - 10;
                } else {
                        break;
                }
                if (c >= base) {
                        break;
                }
                if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) {
                        any = -1;
                } else {
                        any = 1;
                        acc *= base;
                        acc += c;
                }
        }
        if (any < 0) {
                acc = ULONG_MAX;
//              errno = ERANGE;
        } else if (neg) {
                acc = -acc;
        }
        if (endptr != 0) {
                if (any) {
                        *endptr = __CAST_AWAY_QUALIFIER(s - 1, const, char *);
                } else {
                        *endptr = __CAST_AWAY_QUALIFIER(nptr, const, char *);
                }
        }

        return acc;
}

/*
 * Convert a string to a quad integer.
 *
 * Ignores `locale' stuff.  Assumes that the upper and lower case
 * alphabets and digits are each contiguous.
 */
quad_t
strtoq(const char *nptr, char **endptr, int base)
{
        const char *s;
        u_quad_t acc;
        char c;
        u_quad_t qbase, cutoff;
        int neg, any, cutlim;

        /*
         * Skip white space and pick up leading +/- sign if any.
         * If base is 0, allow 0x for hex and 0 for octal, else
         * assume decimal; if base is already 16, allow 0x.
         */
        s = nptr;
        do {
                c = *s++;
        } while (isspace(c));
        if (c == '-') {
                neg = 1;
                c = *s++;
        } else {
                neg = 0;
                if (c == '+') {
                        c = *s++;
                }
        }
        if ((base == 0 || base == 16) &&
            c == '0' && (*s == 'x' || *s == 'X')) {
                c = s[1];
                s += 2;
                base = 16;
        }
        if (base == 0) {
                base = c == '0' ? 8 : 10;
        }

        /*
         * Compute the cutoff value between legal numbers and illegal
         * numbers.  That is the largest legal value, divided by the
         * base.  An input number that is greater than this value, if
         * followed by a legal input character, is too big.  One that
         * is equal to this value may be valid or not; the limit
         * between valid and invalid numbers is then based on the last
         * digit.  For instance, if the range for quads is
         * [-9223372036854775808..9223372036854775807] and the input base
         * is 10, cutoff will be set to 922337203685477580 and cutlim to
         * either 7 (neg==0) or 8 (neg==1), meaning that if we have
         * accumulated a value > 922337203685477580, or equal but the
         * next digit is > 7 (or 8), the number is too big, and we will
         * return a range error.
         *
         * Set any if any `digits' consumed; make it negative to indicate
         * overflow.
         */
        qbase = (unsigned)base;
        cutoff = neg ? -(u_quad_t)QUAD_MIN : QUAD_MAX;
        cutlim = ((int)(cutoff % qbase));
        cutoff /= qbase;
        for (acc = 0, any = 0;; c = *s++) {
                if (isdigit(c)) {
                        c -= '0';
                } else if (isalpha(c)) {
                        c -= isupper(c) ? 'A' - 10 : 'a' - 10;
                } else {
                        break;
                }
                if (c >= base) {
                        break;
                }
                if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) {
                        any = -1;
                } else {
                        any = 1;
                        acc *= qbase;
                        acc += c;
                }
        }
        if (any < 0) {
                acc = neg ? QUAD_MIN : QUAD_MAX;
//              errno = ERANGE;
        } else if (neg) {
                acc = -acc;
        }
        if (endptr != 0) {
                if (any) {
                        *endptr = __CAST_AWAY_QUALIFIER(s - 1, const, char *);
                } else {
                        *endptr = __CAST_AWAY_QUALIFIER(nptr, const, char *);
                }
        }

        return acc;
}


/*
 * Convert a string to an unsigned quad integer.
 *
 * Ignores `locale' stuff.  Assumes that the upper and lower case
 * alphabets and digits are each contiguous.
 */
u_quad_t
strtouq(const char *nptr,
    char **endptr,
    int base)
{
        const char *s = nptr;
        u_quad_t acc;
        char c;
        u_quad_t qbase, cutoff;
        int neg, any, cutlim;

        /*
         * See strtoq for comments as to the logic used.
         */
        s = nptr;
        do {
                c = *s++;
        } while (isspace(c));
        if (c == '-') {
                neg = 1;
                c = *s++;
        } else {
                neg = 0;
                if (c == '+') {
                        c = *s++;
                }
        }
        if ((base == 0 || base == 16) &&
            c == '0' && (*s == 'x' || *s == 'X')) {
                c = s[1];
                s += 2;
                base = 16;
        }
        if (base == 0) {
                base = c == '0' ? 8 : 10;
        }
        qbase = (unsigned)base;
        cutoff = (u_quad_t)UQUAD_MAX / qbase;
        cutlim = ((int)((u_quad_t)UQUAD_MAX % qbase));
        for (acc = 0, any = 0;; c = *s++) {
                if (isdigit(c)) {
                        c -= '0';
                } else if (isalpha(c)) {
                        c -= isupper(c) ? 'A' - 10 : 'a' - 10;
                } else {
                        break;
                }
                if (c >= base) {
                        break;
                }
                if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) {
                        any = -1;
                } else {
                        any = 1;
                        acc *= qbase;
                        acc += c;
                }
        }
        if (any < 0) {
                acc = UQUAD_MAX;
//              errno = ERANGE;
        } else if (neg) {
                acc = -acc;
        }
        if (endptr != 0) {
                if (any) {
                        *endptr = __CAST_AWAY_QUALIFIER(s - 1, const, char *);
                } else {
                        *endptr = __CAST_AWAY_QUALIFIER(nptr, const, char *);
                }
        }

        return acc;
}


/*
 *
 */

char *
strncat(char *s1, const char *s2, unsigned long n)
{
        if (n != 0) {
                char *d = s1;
                const char *s = s2;

                while (*d != 0) {
                        d++;
                }
                do {
                        if ((*d = *s++) == '\0') {
                                break;
                        }
                        d++;
                } while (--n != 0);
                *d = '\0';
        }
        return s1;
}