/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.  For licensing terms and
** conditions see http://qt.digia.com/licensing.  For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights.  These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qlocale_tools_p.h"
#include "qlocale_p.h"
#include "qstring.h"

#include <ctype.h>
#include <float.h>
#include <limits.h>
#include <math.h>
#include <stdlib.h>
#include <time.h>

#ifdef Q_OS_WINCE
#   include "qfunctions_wince.h"    // for _control87
#endif

#if defined(Q_OS_LINUX) && !defined(__UCLIBC__)
#    include <fenv.h>
#endif

// Sizes as defined by the ISO C99 standard - fallback
#ifndef LLONG_MAX
#   define LLONG_MAX Q_INT64_C(0x7fffffffffffffff)
#endif
#ifndef LLONG_MIN
#   define LLONG_MIN (-LLONG_MAX - Q_INT64_C(1))
#endif
#ifndef ULLONG_MAX
#   define ULLONG_MAX Q_UINT64_C(0xffffffffffffffff)
#endif

QT_BEGIN_NAMESPACE

#ifndef QT_QLOCALE_USES_FCVT
static char *_qdtoa( NEEDS_VOLATILE double d, int mode, int ndigits, int *decpt,
                        int *sign, char **rve, char **digits_str);
#endif

QString qulltoa(qulonglong l, int base, const QChar _zero)
{
    ushort buff[65]; // length of MAX_ULLONG in base 2
    ushort *p = buff + 65;

    if (base != 10 || _zero.unicode() == '0') {
        while (l != 0) {
            int c = l % base;

            --p;

            if (c < 10)
                *p = '0' + c;
            else
                *p = c - 10 + 'a';

            l /= base;
        }
    }
    else {
        while (l != 0) {
            int c = l % base;

            *(--p) = _zero.unicode() + c;

            l /= base;
        }
    }

    return QString(reinterpret_cast<QChar *>(p), 65 - (p - buff));
}

QString qlltoa(qlonglong l, int base, const QChar zero)
{
    return qulltoa(l < 0 ? -l : l, base, zero);
}

QString &decimalForm(QChar zero, QChar decimal, QChar group,
                     QString &digits, int decpt, uint precision,
                     PrecisionMode pm,
                     bool always_show_decpt,
                     bool thousands_group)
{
    if (decpt < 0) {
        for (int i = 0; i < -decpt; ++i)
            digits.prepend(zero);
        decpt = 0;
    }
    else if (decpt > digits.length()) {
        for (int i = digits.length(); i < decpt; ++i)
            digits.append(zero);
    }

    if (pm == PMDecimalDigits) {
        uint decimal_digits = digits.length() - decpt;
        for (uint i = decimal_digits; i < precision; ++i)
            digits.append(zero);
    }
    else if (pm == PMSignificantDigits) {
        for (uint i = digits.length(); i < precision; ++i)
            digits.append(zero);
    }
    else { // pm == PMChopTrailingZeros
    }

    if (always_show_decpt || decpt < digits.length())
        digits.insert(decpt, decimal);

    if (thousands_group) {
        for (int i = decpt - 3; i > 0; i -= 3)
            digits.insert(i, group);
    }

    if (decpt == 0)
        digits.prepend(zero);

    return digits;
}

QString &exponentForm(QChar zero, QChar decimal, QChar exponential,
                      QChar group, QChar plus, QChar minus,
                      QString &digits, int decpt, uint precision,
                      PrecisionMode pm,
                      bool always_show_decpt)
{
    int exp = decpt - 1;

    if (pm == PMDecimalDigits) {
        for (uint i = digits.length(); i < precision + 1; ++i)
            digits.append(zero);
    }
    else if (pm == PMSignificantDigits) {
        for (uint i = digits.length(); i < precision; ++i)
            digits.append(zero);
    }
    else { // pm == PMChopTrailingZeros
    }

    if (always_show_decpt || digits.length() > 1)
        digits.insert(1, decimal);

    digits.append(exponential);
    digits.append(QLocalePrivate::longLongToString(zero, group, plus, minus,
                   exp, 2, 10, -1, QLocalePrivate::AlwaysShowSign));

    return digits;
}

// Removes thousand-group separators in "C" locale.
bool removeGroupSeparators(QLocalePrivate::CharBuff *num)
{
    int group_cnt = 0; // counts number of group chars
    int decpt_idx = -1;

    char *data = num->data();
    int l = qstrlen(data);

    // Find the decimal point and check if there are any group chars
    int i = 0;
    for (; i < l; ++i) {
        char c = data[i];

        if (c == ',') {
            if (i == 0 || data[i - 1] < '0' || data[i - 1] > '9')
                return false;
            if (i == l - 1 || data[i + 1] < '0' || data[i + 1] > '9')
                return false;
            ++group_cnt;
        }
        else if (c == '.') {
            // Fail if more than one decimal points
            if (decpt_idx != -1)
                return false;
            decpt_idx = i;
        } else if (c == 'e' || c == 'E') {
            // an 'e' or 'E' - if we have not encountered a decimal
            // point, this is where it "is".
            if (decpt_idx == -1)
                decpt_idx = i;
        }
    }

    // If no group chars, we're done
    if (group_cnt == 0)
        return true;

    // No decimal point means that it "is" at the end of the string
    if (decpt_idx == -1)
        decpt_idx = l;

    i = 0;
    while (i < l && group_cnt > 0) {
        char c = data[i];

        if (c == ',') {
            // Don't allow group chars after the decimal point
            if (i > decpt_idx)
                return false;

            // Check that it is placed correctly relative to the decpt
            if ((decpt_idx - i) % 4 != 0)
                return false;

            // Remove it
            memmove(data + i, data + i + 1, l - i - 1);
            data[--l] = '\0';

            --group_cnt;
            --decpt_idx;
        } else {
            // Check that we are not missing a separator
            if (i < decpt_idx
                    && (decpt_idx - i) % 4 == 0
                    && !(i == 0 && (c == '-' || c == '+'))) // check for negative or positive sign at start of string
                return false;
            ++i;
        }
    }

    return true;
}

/*-
 * Copyright (c) 1992, 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 acknowledgment:
 *        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.
 */

// static char sccsid[] = "@(#)strtouq.c        8.1 (Berkeley) 6/4/93";
//  "$FreeBSD: src/lib/libc/stdlib/strtoull.c,v 1.5.2.1 2001/03/02 09:45:20 obrien Exp $";

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

    if (ok != 0)
        *ok = true;

    /*
     * See strtoq for comments as to the logic used.
     */
    s = nptr;
    do {
        c = *s++;
    } while (isspace(c));
    if (c == '-') {
        if (ok != 0)
            *ok = false;
        if (endptr != 0)
            *endptr = s - 1;
        return 0;
    } else {
        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 = qulonglong(ULLONG_MAX) / qbase;
    cutlim = qulonglong(ULLONG_MAX) % qbase;
    for (acc = 0, any = 0;; c = *s++) {
        if (!isascii(c))
            break;
        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) {
        if (ok != 0)
            *ok = false;
    } else if (any < 0) {
        acc = ULLONG_MAX;
        if (ok != 0)
            *ok = false;
    }
    if (endptr != 0)
        *endptr = (any ? s - 1 : nptr);
    return acc;
}


//  "$FreeBSD: src/lib/libc/stdlib/strtoll.c,v 1.5.2.1 2001/03/02 09:45:20 obrien Exp $";


/*
 * Convert a string to a long long integer.
 *
 * Ignores `locale' stuff.  Assumes that the upper and lower case
 * alphabets and digits are each contiguous.
 */
qlonglong qstrtoll(const char *nptr, const char **endptr, int base, bool *ok)
{
    const char *s;
    qulonglong acc;
    unsigned char c;
    qulonglong 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 ? qulonglong(0-(LLONG_MIN + LLONG_MAX)) + LLONG_MAX : LLONG_MAX;
    cutlim = cutoff % qbase;
    cutoff /= qbase;
    for (acc = 0, any = 0;; c = *s++) {
        if (!isascii(c))
            break;
        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 ? LLONG_MIN : LLONG_MAX;
        if (ok != 0)
            *ok = false;
    } else if (neg) {
        acc = (~acc) + 1;
    }
    if (endptr != 0)
        *endptr = (any >= 0 ? s - 1 : nptr);

    if (ok != 0)
        *ok = any > 0;

    return acc;
}

#ifndef QT_QLOCALE_USES_FCVT

/*        From: NetBSD: strtod.c,v 1.26 1998/02/03 18:44:21 perry Exp */
/* $FreeBSD: src/lib/libc/stdlib/netbsd_strtod.c,v 1.2.2.2 2001/03/02 17:14:15 tegge Exp $        */

/* Please send bug reports to
        David M. Gay
        AT&T Bell Laboratories, Room 2C-463
        600 Mountain Avenue
        Murray Hill, NJ 07974-2070
        U.S.A.
        dmg@research.att.com or research!dmg
 */

/* strtod for IEEE-, VAX-, and IBM-arithmetic machines.
 *
 * This strtod returns a nearest machine number to the input decimal
 * string (or sets errno to ERANGE).  With IEEE arithmetic, ties are
 * broken by the IEEE round-even rule.  Otherwise ties are broken by
 * biased rounding (add half and chop).
 *
 * Inspired loosely by William D. Clinger's paper "How to Read Floating
 * Point Numbers Accurately" [Proc. ACM SIGPLAN '90, pp. 92-101].
 *
 * Modifications:
 *
 *        1. We only require IEEE, IBM, or VAX double-precision
 *                arithmetic (not IEEE double-extended).
 *        2. We get by with floating-point arithmetic in a case that
 *                Clinger missed -- when we're computing d * 10^n
 *                for a small integer d and the integer n is not too
 *                much larger than 22 (the maximum integer k for which
 *                we can represent 10^k exactly), we may be able to
 *                compute (d*10^k) * 10^(e-k) with just one roundoff.
 *        3. Rather than a bit-at-a-time adjustment of the binary
 *                result in the hard case, we use floating-point
 *                arithmetic to determine the adjustment to within
 *                one bit; only in really hard cases do we need to
 *                compute a second residual.
 *        4. Because of 3., we don't need a large table of powers of 10
 *                for ten-to-e (just some small tables, e.g. of 10^k
 *                for 0 <= k <= 22).
 */

/*
 * #define IEEE_LITTLE_ENDIAN for IEEE-arithmetic machines where the least
 *        significant byte has the lowest address.
 * #define IEEE_BIG_ENDIAN for IEEE-arithmetic machines where the most
 *        significant byte has the lowest address.
 * #define Long int on machines with 32-bit ints and 64-bit longs.
 * #define Sudden_Underflow for IEEE-format machines without gradual
 *        underflow (i.e., that flush to zero on underflow).
 * #define IBM for IBM mainframe-style floating-point arithmetic.
 * #define VAX for VAX-style floating-point arithmetic.
 * #define Unsigned_Shifts if >> does treats its left operand as unsigned.
 * #define No_leftright to omit left-right logic in fast floating-point
 *        computation of dtoa.
 * #define Check_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3.
 * #define RND_PRODQUOT to use rnd_prod and rnd_quot (assembly routines
 *        that use extended-precision instructions to compute rounded
 *        products and quotients) with IBM.
 * #define ROUND_BIASED for IEEE-format with biased rounding.
 * #define Inaccurate_Divide for IEEE-format with correctly rounded
 *        products but inaccurate quotients, e.g., for Intel i860.
 * #define Just_16 to store 16 bits per 32-bit Long when doing high-precision
 *        integer arithmetic.  Whether this speeds things up or slows things
 *        down depends on the machine and the number being converted.
 * #define KR_headers for old-style C function headers.
 * #define Bad_float_h if your system lacks a float.h or if it does not
 *        define some or all of DBL_DIG, DBL_MAX_10_EXP, DBL_MAX_EXP,
 *        FLT_RADIX, FLT_ROUNDS, and DBL_MAX.
 * #define MALLOC your_malloc, where your_malloc(n) acts like malloc(n)
 *        if memory is available and otherwise does something you deem
 *        appropriate.  If MALLOC is undefined, malloc will be invoked
 *        directly -- and assumed always to succeed.
 */

#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: strtod.c,v 1.26 1998/02/03 18:44:21 perry Exp $");
#endif /* LIBC_SCCS and not lint */

/*
#if defined(__m68k__)    || defined(__sparc__) || defined(__i386__) || \
     defined(__mips__)    || defined(__ns32k__) || defined(__alpha__) || \
     defined(__powerpc__) || defined(Q_OS_WIN) || defined(Q_OS_DARWIN) || defined(Q_OS_MAC) || \
     defined(mips) || defined(Q_OS_AIX) || defined(Q_OS_SOLARIS)
#           define IEEE_BIG_OR_LITTLE_ENDIAN 1
#endif
*/

// *All* of our architectures have IEEE arithmetic, don't they?
#define IEEE_BIG_OR_LITTLE_ENDIAN 1

#ifdef __arm32__
/*
 * Although the CPU is little endian the FP has different
 * byte and word endianness. The byte order is still little endian
 * but the word order is big endian.
 */
#define IEEE_BIG_OR_LITTLE_ENDIAN
#endif

#ifdef vax
#define VAX
#endif

#define Long        qint32
#define ULong        quint32

#define MALLOC malloc

#ifdef BSD_QDTOA_DEBUG
QT_BEGIN_INCLUDE_NAMESPACE
#include <stdio.h>
QT_END_INCLUDE_NAMESPACE

#define Bug(x) {fprintf(stderr, "%s\n", x); exit(1);}
#endif

#ifdef Unsigned_Shifts
#define Sign_Extend(a,b) if (b < 0) a |= 0xffff0000;
#else
#define Sign_Extend(a,b) /*no-op*/
#endif

#if (defined(IEEE_BIG_OR_LITTLE_ENDIAN) + defined(VAX) + defined(IBM)) != 1
#error Exactly one of IEEE_BIG_OR_LITTLE_ENDIAN, VAX, or IBM should be defined.
#endif

static inline ULong getWord0(const NEEDS_VOLATILE double x)
{
    const NEEDS_VOLATILE uchar *ptr = reinterpret_cast<const NEEDS_VOLATILE uchar *>(&x);
    if (QSysInfo::ByteOrder == QSysInfo::BigEndian) {
        return (ptr[0]<<24) + (ptr[1]<<16) + (ptr[2]<<8) + ptr[3];
    } else {
        return (ptr[7]<<24) + (ptr[6]<<16) + (ptr[5]<<8) + ptr[4];
    }
}

static inline void setWord0(NEEDS_VOLATILE double *x, ULong l)
{
    NEEDS_VOLATILE uchar *ptr = reinterpret_cast<NEEDS_VOLATILE uchar *>(x);
    if (QSysInfo::ByteOrder == QSysInfo::BigEndian) {
        ptr[0] = uchar(l>>24);
        ptr[1] = uchar(l>>16);
        ptr[2] = uchar(l>>8);
        ptr[3] = uchar(l);
    } else {
        ptr[7] = uchar(l>>24);
        ptr[6] = uchar(l>>16);
        ptr[5] = uchar(l>>8);
        ptr[4] = uchar(l);
    }
}

static inline ULong getWord1(const NEEDS_VOLATILE double x)
{
    const NEEDS_VOLATILE uchar *ptr = reinterpret_cast<const NEEDS_VOLATILE uchar *>(&x);
    if (QSysInfo::ByteOrder == QSysInfo::BigEndian) {
        return (ptr[4]<<24) + (ptr[5]<<16) + (ptr[6]<<8) + ptr[7];
    } else {
        return (ptr[3]<<24) + (ptr[2]<<16) + (ptr[1]<<8) + ptr[0];
    }
}
static inline void setWord1(NEEDS_VOLATILE double *x, ULong l)
{
    NEEDS_VOLATILE uchar *ptr = reinterpret_cast<uchar NEEDS_VOLATILE *>(x);
    if (QSysInfo::ByteOrder == QSysInfo::BigEndian) {
        ptr[4] = uchar(l>>24);
        ptr[5] = uchar(l>>16);
        ptr[6] = uchar(l>>8);
        ptr[7] = uchar(l);
    } else {
        ptr[3] = uchar(l>>24);
        ptr[2] = uchar(l>>16);
        ptr[1] = uchar(l>>8);
        ptr[0] = uchar(l);
    }
}

static inline void Storeinc(ULong *&a, const ULong &b, const ULong &c)
{

    *a = (ushort(b) << 16) | ushort(c);
    ++a;
}

/* #define P DBL_MANT_DIG */
/* Ten_pmax = floor(P*log(2)/log(5)) */
/* Bletch = (highest power of 2 < DBL_MAX_10_EXP) / 16 */
/* Quick_max = floor((P-1)*log(FLT_RADIX)/log(10) - 1) */
/* Int_max = floor(P*log(FLT_RADIX)/log(10) - 1) */

#if defined(IEEE_BIG_OR_LITTLE_ENDIAN)
#define Exp_shift  20
#define Exp_shift1 20
#define Exp_msk1    0x100000
#define Exp_msk11   0x100000
#define Exp_mask  0x7ff00000
#define P 53
#define Bias 1023
#define IEEE_Arith
#define Emin (-1022)
#define Exp_1  0x3ff00000
#define Exp_11 0x3ff00000
#define Ebits 11
#define Frac_mask  0xfffff
#define Frac_mask1 0xfffff
#define Ten_pmax 22
#define Bletch 0x10
#define Bndry_mask  0xfffff
#define Bndry_mask1 0xfffff
#if defined(LSB) && defined(Q_OS_VXWORKS)
#undef LSB
#endif
#define LSB 1
#define Sign_bit 0x80000000
#define Log2P 1
#define Tiny0 0
#define Tiny1 1
#define Quick_max 14
#define Int_max 14
#define Infinite(x) (getWord0(x) == 0x7ff00000) /* sufficient test for here */
#else
#undef  Sudden_Underflow
#define Sudden_Underflow
#ifdef IBM
#define Exp_shift  24
#define Exp_shift1 24
#define Exp_msk1   0x1000000
#define Exp_msk11  0x1000000
#define Exp_mask  0x7f000000
#define P 14
#define Bias 65
#define Exp_1  0x41000000
#define Exp_11 0x41000000
#define Ebits 8        /* exponent has 7 bits, but 8 is the right value in b2d */
#define Frac_mask  0xffffff
#define Frac_mask1 0xffffff
#define Bletch 4
#define Ten_pmax 22
#define Bndry_mask  0xefffff
#define Bndry_mask1 0xffffff
#define LSB 1
#define Sign_bit 0x80000000
#define Log2P 4
#define Tiny0 0x100000
#define Tiny1 0
#define Quick_max 14
#define Int_max 15
#else /* VAX */
#define Exp_shift  23
#define Exp_shift1 7
#define Exp_msk1    0x80
#define Exp_msk11   0x800000
#define Exp_mask  0x7f80
#define P 56
#define Bias 129
#define Exp_1  0x40800000
#define Exp_11 0x4080
#define Ebits 8
#define Frac_mask  0x7fffff
#define Frac_mask1 0xffff007f
#define Ten_pmax 24
#define Bletch 2
#define Bndry_mask  0xffff007f
#define Bndry_mask1 0xffff007f
#define LSB 0x10000
#define Sign_bit 0x8000
#define Log2P 1
#define Tiny0 0x80
#define Tiny1 0
#define Quick_max 15
#define Int_max 15
#endif
#endif

#ifndef IEEE_Arith
#define ROUND_BIASED
#endif

#ifdef RND_PRODQUOT
#define rounded_product(a,b) a = rnd_prod(a, b)
#define rounded_quotient(a,b) a = rnd_quot(a, b)
extern double rnd_prod(double, double), rnd_quot(double, double);
#else
#define rounded_product(a,b) a *= b
#define rounded_quotient(a,b) a /= b
#endif

#define Big0 (Frac_mask1 | Exp_msk1*(DBL_MAX_EXP+Bias-1))
#define Big1 0xffffffff

#ifndef Just_16
/* When Pack_32 is not defined, we store 16 bits per 32-bit Long.
 * This makes some inner loops simpler and sometimes saves work
 * during multiplications, but it often seems to make things slightly
 * slower.  Hence the default is now to store 32 bits per Long.
 */
#ifndef Pack_32
#define Pack_32
#endif
#endif

#define Kmax 15

struct
Bigint {
    struct Bigint *next;
    int k, maxwds, sign, wds;
    ULong x[1];
};

 typedef struct Bigint Bigint;

static Bigint *Balloc(int k)
{
    int x;
    Bigint *rv;

    x = 1 << k;
    rv = static_cast<Bigint *>(MALLOC(sizeof(Bigint) + (x-1)*sizeof(Long)));
    Q_CHECK_PTR(rv);
    rv->k = k;
    rv->maxwds = x;
    rv->sign = rv->wds = 0;
    return rv;
}

static void Bfree(Bigint *v)
{
    free(v);
}

#define Bcopy(x,y) memcpy(reinterpret_cast<char *>(&x->sign), reinterpret_cast<char *>(&y->sign), \
y->wds*sizeof(Long) + 2*sizeof(int))

/* multiply by m and add a */
static Bigint *multadd(Bigint *b, int m, int a)
{
    int i, wds;
    ULong *x, y;
#ifdef Pack_32
    ULong xi, z;
#endif
    Bigint *b1;

    wds = b->wds;
    x = b->x;
    i = 0;
    do {
#ifdef Pack_32
        xi = *x;
        y = (xi & 0xffff) * m + a;
        z = (xi >> 16) * m + (y >> 16);
        a = (z >> 16);
        *x++ = (z << 16) + (y & 0xffff);
#else
        y = *x * m + a;
        a = (y >> 16);
        *x++ = y & 0xffff;
#endif
    }
    while(++i < wds);
    if (a) {
        if (wds >= b->maxwds) {
            b1 = Balloc(b->k+1);
            Bcopy(b1, b);
            Bfree(b);
            b = b1;
        }
        b->x[wds++] = a;
        b->wds = wds;
    }
    return b;
}

static Bigint *s2b(const char *s, int nd0, int nd, ULong y9)
{
    Bigint *b;
    int i, k;
    Long x, y;

    x = (nd + 8) / 9;
    for(k = 0, y = 1; x > y; y <<= 1, k++) ;
#ifdef Pack_32
    b = Balloc(k);
    b->x[0] = y9;
    b->wds = 1;
#else
    b = Balloc(k+1);
    b->x[0] = y9 & 0xffff;
    b->wds = (b->x[1] = y9 >> 16) ? 2 : 1;
#endif

    i = 9;
    if (9 < nd0) {
        s += 9;
        do b = multadd(b, 10, *s++ - '0');
        while(++i < nd0);
        s++;
    }
    else
        s += 10;
    for(; i < nd; i++)
        b = multadd(b, 10, *s++ - '0');
    return b;
}

static int hi0bits(ULong x)
{
    int k = 0;

    if (!(x & 0xffff0000)) {
        k = 16;
        x <<= 16;
    }
    if (!(x & 0xff000000)) {
        k += 8;
        x <<= 8;
    }
    if (!(x & 0xf0000000)) {
        k += 4;
        x <<= 4;
    }
    if (!(x & 0xc0000000)) {
        k += 2;
        x <<= 2;
    }
    if (!(x & 0x80000000)) {
        k++;
        if (!(x & 0x40000000))
            return 32;
    }
    return k;
}

static int lo0bits(ULong *y)
{
    int k;
    ULong x = *y;

    if (x & 7) {
        if (x & 1)
            return 0;
        if (x & 2) {
            *y = x >> 1;
            return 1;
        }
        *y = x >> 2;
        return 2;
    }
    k = 0;
    if (!(x & 0xffff)) {
        k = 16;
        x >>= 16;
    }
    if (!(x & 0xff)) {
        k += 8;
        x >>= 8;
    }
    if (!(x & 0xf)) {
        k += 4;
        x >>= 4;
    }
    if (!(x & 0x3)) {
        k += 2;
        x >>= 2;
    }
    if (!(x & 1)) {
        k++;
        x >>= 1;
        if (!x & 1)
            return 32;
    }
    *y = x;
    return k;
}

static Bigint *i2b(int i)
{
    Bigint *b;

    b = Balloc(1);
    b->x[0] = i;
    b->wds = 1;
    return b;
}

static Bigint *mult(Bigint *a, Bigint *b)
{
    Bigint *c;
    int k, wa, wb, wc;
    ULong carry, y, z;
    ULong *x, *xa, *xae, *xb, *xbe, *xc, *xc0;
#ifdef Pack_32
    ULong z2;
#endif

    if (a->wds < b->wds) {
        c = a;
        a = b;
        b = c;
    }
    k = a->k;
    wa = a->wds;
    wb = b->wds;
    wc = wa + wb;
    if (wc > a->maxwds)
        k++;
    c = Balloc(k);
    for(x = c->x, xa = x + wc; x < xa; x++)
        *x = 0;
    xa = a->x;
    xae = xa + wa;
    xb = b->x;
    xbe = xb + wb;
    xc0 = c->x;
#ifdef Pack_32
    for(; xb < xbe; xb++, xc0++) {
        if ((y = *xb & 0xffff) != 0) {
            x = xa;
            xc = xc0;
            carry = 0;
            do {
                z = (*x & 0xffff) * y + (*xc & 0xffff) + carry;
                carry = z >> 16;
                z2 = (*x++ >> 16) * y + (*xc >> 16) + carry;
                carry = z2 >> 16;
                Storeinc(xc, z2, z);
            }
            while(x < xae);
            *xc = carry;
        }
        if ((y = *xb >> 16) != 0) {
            x = xa;
            xc = xc0;
            carry = 0;
            z2 = *xc;
            do {
                z = (*x & 0xffff) * y + (*xc >> 16) + carry;
                carry = z >> 16;
                Storeinc(xc, z, z2);
                z2 = (*x++ >> 16) * y + (*xc & 0xffff) + carry;
                carry = z2 >> 16;
            }
            while(x < xae);
            *xc = z2;
        }
    }
#else
    for(; xb < xbe; xc0++) {
        if (y = *xb++) {
            x = xa;
            xc = xc0;
            carry = 0;
            do {
                z = *x++ * y + *xc + carry;
                carry = z >> 16;
                *xc++ = z & 0xffff;
            }
            while(x < xae);
            *xc = carry;
        }
    }
#endif
    for(xc0 = c->x, xc = xc0 + wc; wc > 0 && !*--xc; --wc) ;
    c->wds = wc;
    return c;
}

static Bigint *p5s;

struct p5s_deleter
{
    ~p5s_deleter()
    {
        while (p5s) {
            Bigint *next = p5s->next;
            Bfree(p5s);
            p5s = next;
        }
    }
};

static Bigint *pow5mult(Bigint *b, int k)
{
    Bigint *b1, *p5, *p51;
    int i;
    static const int p05[3] = { 5, 25, 125 };

    if ((i = k & 3) != 0)
    b = multadd(b, p05[i-1], 0);

    if (!(k >>= 2))
        return b;
    if (!(p5 = p5s)) {
        /* first time */
        static p5s_deleter deleter;
        p5 = p5s = i2b(625);
        p5->next = 0;
    }
    for(;;) {
        if (k & 1) {
            b1 = mult(b, p5);
            Bfree(b);
            b = b1;
        }
        if (!(k >>= 1))
            break;
        if (!(p51 = p5->next)) {
            p51 = p5->next = mult(p5,p5);
            p51->next = 0;
        }
        p5 = p51;
    }
    return b;
}

static Bigint *lshift(Bigint *b, int k)
{
    int i, k1, n, n1;
    Bigint *b1;
    ULong *x, *x1, *xe, z;

#ifdef Pack_32
    n = k >> 5;
#else
    n = k >> 4;
#endif
    k1 = b->k;
    n1 = n + b->wds + 1;
    for(i = b->maxwds; n1 > i; i <<= 1)
        k1++;
    b1 = Balloc(k1);
    x1 = b1->x;
    for(i = 0; i < n; i++)
        *x1++ = 0;
    x = b->x;
    xe = x + b->wds;
#ifdef Pack_32
    if (k &= 0x1f) {
        k1 = 32 - k;
        z = 0;
        do {
            *x1++ = *x << k | z;
            z = *x++ >> k1;
        }
        while(x < xe);
        if ((*x1 = z) != 0)
            ++n1;
    }
#else
    if (k &= 0xf) {
        k1 = 16 - k;
        z = 0;
        do {
            *x1++ = *x << k  & 0xffff | z;
            z = *x++ >> k1;
        }
        while(x < xe);
        if (*x1 = z)
            ++n1;
    }
#endif
    else do
        *x1++ = *x++;
    while(x < xe);
    b1->wds = n1 - 1;
    Bfree(b);
    return b1;
}

static int cmp(Bigint *a, Bigint *b)
{
    ULong *xa, *xa0, *xb, *xb0;
    int i, j;

    i = a->wds;
    j = b->wds;
#ifdef BSD_QDTOA_DEBUG
    if (i > 1 && !a->x[i-1])
        Bug("cmp called with a->x[a->wds-1] == 0");
    if (j > 1 && !b->x[j-1])
        Bug("cmp called with b->x[b->wds-1] == 0");
#endif
    if (i -= j)
        return i;
    xa0 = a->x;
    xa = xa0 + j;
    xb0 = b->x;
    xb = xb0 + j;
    for(;;) {
        if (*--xa != *--xb)
            return *xa < *xb ? -1 : 1;
        if (xa <= xa0)
            break;
    }
    return 0;
}

static Bigint *diff(Bigint *a, Bigint *b)
{
    Bigint *c;
    int i, wa, wb;
    Long borrow, y;        /* We need signed shifts here. */
    ULong *xa, *xae, *xb, *xbe, *xc;
#ifdef Pack_32
    Long z;
#endif

    i = cmp(a,b);
    if (!i) {
        c = Balloc(0);
        c->wds = 1;
        c->x[0] = 0;
        return c;
    }
    if (i < 0) {
        c = a;
        a = b;
        b = c;
        i = 1;
    }
    else
        i = 0;
    c = Balloc(a->k);
    c->sign = i;
    wa = a->wds;
    xa = a->x;
    xae = xa + wa;
    wb = b->wds;
    xb = b->x;
    xbe = xb + wb;
    xc = c->x;
    borrow = 0;
#ifdef Pack_32
    do {
        y = (*xa & 0xffff) - (*xb & 0xffff) + borrow;
        borrow = y >> 16;
        Sign_Extend(borrow, y);
        z = (*xa++ >> 16) - (*xb++ >> 16) + borrow;
        borrow = z >> 16;
        Sign_Extend(borrow, z);
        Storeinc(xc, z, y);
    }
    while(xb < xbe);
    while(xa < xae) {
        y = (*xa & 0xffff) + borrow;
        borrow = y >> 16;
        Sign_Extend(borrow, y);
        z = (*xa++ >> 16) + borrow;
        borrow = z >> 16;
        Sign_Extend(borrow, z);
        Storeinc(xc, z, y);
    }
#else
    do {
        y = *xa++ - *xb++ + borrow;
        borrow = y >> 16;
        Sign_Extend(borrow, y);
        *xc++ = y & 0xffff;
    }
    while(xb < xbe);
    while(xa < xae) {
        y = *xa++ + borrow;
        borrow = y >> 16;
        Sign_Extend(borrow, y);
        *xc++ = y & 0xffff;
    }
#endif
    while(!*--xc)
        wa--;
    c->wds = wa;
    return c;
}

static double ulp(double x)
{
    Long L;
    double a;

    L = (getWord0(x) & Exp_mask) - (P-1)*Exp_msk1;
#ifndef Sudden_Underflow
    if (L > 0) {
#endif
#ifdef IBM
        L |= Exp_msk1 >> 4;
#endif
        setWord0(&a, L);
        setWord1(&a, 0);
#ifndef Sudden_Underflow
    }
    else {
        L = -L >> Exp_shift;
        if (L < Exp_shift) {
            setWord0(&a, 0x80000 >> L);
            setWord1(&a, 0);
        }
        else {
            setWord0(&a, 0);
            L -= Exp_shift;
            setWord1(&a, L >= 31 ? 1U : 1U << (31 - L));
        }
    }
#endif
    return a;
}

static double b2d(Bigint *a, int *e)
{
    ULong *xa, *xa0, w, y, z;
    int k;
    double d;

    xa0 = a->x;
    xa = xa0 + a->wds;
    y = *--xa;
#ifdef BSD_QDTOA_DEBUG
    if (!y) Bug("zero y in b2d");
#endif
    k = hi0bits(y);
    *e = 32 - k;
#ifdef Pack_32
    if (k < Ebits) {
        setWord0(&d, Exp_1 | y >> (Ebits - k));
        w = xa > xa0 ? *--xa : 0;
        setWord1(&d, y << ((32-Ebits) + k) | w >> (Ebits - k));
        goto ret_d;
    }
    z = xa > xa0 ? *--xa : 0;
    if (k -= Ebits) {
        setWord0(&d, Exp_1 | y << k | z >> (32 - k));
        y = xa > xa0 ? *--xa : 0;
        setWord1(&d, z << k | y >> (32 - k));
    }
    else {
        setWord0(&d, Exp_1 | y);
        setWord1(&d, z);
    }
#else
    if (k < Ebits + 16) {
        z = xa > xa0 ? *--xa : 0;
        setWord0(&d, Exp_1 | y << k - Ebits | z >> Ebits + 16 - k);
        w = xa > xa0 ? *--xa : 0;
        y = xa > xa0 ? *--xa : 0;
        setWord1(&d, z << k + 16 - Ebits | w << k - Ebits | y >> 16 + Ebits - k);
        goto ret_d;
    }
    z = xa > xa0 ? *--xa : 0;
    w = xa > xa0 ? *--xa : 0;
    k -= Ebits + 16;
    setWord0(&d, Exp_1 | y << k + 16 | z << k | w >> 16 - k);
    y = xa > xa0 ? *--xa : 0;
    setWord1(&d, w << k + 16 | y << k);
#endif
 ret_d:
    return d;
}

static Bigint *d2b(double d, int *e, int *bits)
{
    Bigint *b;
    int de, i, k;
    ULong *x, y, z;

#ifdef Pack_32
    b = Balloc(1);
#else
    b = Balloc(2);
#endif
    x = b->x;

    z = getWord0(d) & Frac_mask;
    setWord0(&d, getWord0(d) & 0x7fffffff);        /* clear sign bit, which we ignore */
#ifdef Sudden_Underflow
    de = (int)(getWord0(d) >> Exp_shift);
#ifndef IBM
    z |= Exp_msk11;
#endif
#else
    if ((de = int(getWord0(d) >> Exp_shift)) != 0)
        z |= Exp_msk1;
#endif
#ifdef Pack_32
    if ((y = getWord1(d)) != 0) {
        if ((k = lo0bits(&y)) != 0) {
            x[0] = y | z << (32 - k);
            z >>= k;
        }
        else
            x[0] = y;
        i = b->wds = (x[1] = z) ? 2 : 1;
    }
    else {
#ifdef BSD_QDTOA_DEBUG
        if (!z)
            Bug("Zero passed to d2b");
#endif
        k = lo0bits(&z);
        x[0] = z;
        i = b->wds = 1;
        k += 32;
    }
#else
    if (y = getWord1(d)) {
        if (k = lo0bits(&y))
            if (k >= 16) {
                x[0] = y | z << 32 - k & 0xffff;
                x[1] = z >> k - 16 & 0xffff;
                x[2] = z >> k;
                i = 2;
            }
            else {
                x[0] = y & 0xffff;
                x[1] = y >> 16 | z << 16 - k & 0xffff;
                x[2] = z >> k & 0xffff;
                x[3] = z >> k+16;
                i = 3;
            }
        else {
            x[0] = y & 0xffff;
            x[1] = y >> 16;
            x[2] = z & 0xffff;
            x[3] = z >> 16;
            i = 3;
        }
    }
    else {
#ifdef BSD_QDTOA_DEBUG
        if (!z)
            Bug("Zero passed to d2b");
#endif
        k = lo0bits(&z);
        if (k >= 16) {
            x[0] = z;
            i = 0;
        }
        else {
            x[0] = z & 0xffff;
            x[1] = z >> 16;
            i = 1;
        }
        k += 32;
    }
    while(!x[i])
        --i;
    b->wds = i + 1;
#endif
#ifndef Sudden_Underflow
    if (de) {
#endif
#ifdef IBM
        *e = (de - Bias - (P-1) << 2) + k;
        *bits = 4*P + 8 - k - hi0bits(getWord0(d) & Frac_mask);
#else
        *e = de - Bias - (P-1) + k;
        *bits = P - k;
#endif
#ifndef Sudden_Underflow
    }
    else {
        *e = de - Bias - (P-1) + 1 + k;
#ifdef Pack_32
        *bits = 32*i - hi0bits(x[i-1]);
#else
        *bits = (i+2)*16 - hi0bits(x[i]);
#endif
    }
#endif
    return b;
}

static double ratio(Bigint *a, Bigint *b)
{
    double da, db;
    int k, ka, kb;

    da = b2d(a, &ka);
    db = b2d(b, &kb);
#ifdef Pack_32
    k = ka - kb + 32*(a->wds - b->wds);
#else
    k = ka - kb + 16*(a->wds - b->wds);
#endif
#ifdef IBM
    if (k > 0) {
        setWord0(&da, getWord0(da) + (k >> 2)*Exp_msk1);
        if (k &= 3)
            da *= 1 << k;
    }
    else {
        k = -k;
        setWord0(&db, getWord0(db) + (k >> 2)*Exp_msk1);
        if (k &= 3)
            db *= 1 << k;
    }
#else
    if (k > 0)
        setWord0(&da, getWord0(da) + k*Exp_msk1);
    else {
        k = -k;
        setWord0(&db, getWord0(db) + k*Exp_msk1);
    }
#endif
    return da / db;
}

static const double tens[] = {
    1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9,
    1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19,
    1e20, 1e21, 1e22
#ifdef VAX
    , 1e23, 1e24
#endif
};

#ifdef IEEE_Arith
static const double bigtens[] = { 1e16, 1e32, 1e64, 1e128, 1e256 };
static const double tinytens[] = { 1e-16, 1e-32, 1e-64, 1e-128, 1e-256 };
#define n_bigtens 5
#else
#ifdef IBM
static const double bigtens[] = { 1e16, 1e32, 1e64 };
static const double tinytens[] = { 1e-16, 1e-32, 1e-64 };
#define n_bigtens 3
#else
static const double bigtens[] = { 1e16, 1e32 };
static const double tinytens[] = { 1e-16, 1e-32 };
#define n_bigtens 2
#endif
#endif

/*
  The pre-release gcc3.3 shipped with SuSE 8.2 has a bug which causes
  the comparison 1e-100 == 0.0 to return true. As a workaround, we
  compare it to a global variable containing 0.0, which produces
  correct assembler output.

  ### consider detecting the broken compilers and using the static
  ### double for these, and use a #define for all working compilers
*/
static double g_double_zero = 0.0;

Q_CORE_EXPORT double qstrtod(const char *s00, const char **se, bool *ok)
{
    int bb2, bb5, bbe, bd2, bd5, bbbits, bs2, c, dsign,
        e, e1, esign, i, j, k, nd, nd0, nf, nz, nz0, sign;
    const char *s, *s0, *s1;
    double aadj, aadj1, adj, rv, rv0;
    Long L;
    ULong y, z;
    Bigint *bb1, *bd0;
    Bigint *bb = NULL, *bd = NULL, *bs = NULL, *delta = NULL;/* pacify gcc */

    /*
      #ifndef KR_headers
      const char decimal_point = localeconv()->decimal_point[0];
      #else
      const char decimal_point = '.';
      #endif */
    if (ok != 0)
        *ok = true;

    const char decimal_point = '.';

    sign = nz0 = nz = 0;
    rv = 0.;


    for(s = s00; isspace(uchar(*s)); s++)
        ;

    if (*s == '-') {
        sign = 1;
        s++;
    } else if (*s == '+') {
        s++;
    }

    if (*s == '\0') {
        s = s00;
        goto ret;
    }

    if (*s == '0') {
        nz0 = 1;
        while(*++s == '0') ;
        if (!*s)
            goto ret;
    }
    s0 = s;
    y = z = 0;
    for(nd = nf = 0; (c = *s) >= '0' && c <= '9'; nd++, s++)
        if (nd < 9)
            y = 10*y + c - '0';
        else if (nd < 16)
            z = 10*z + c - '0';
    nd0 = nd;
    if (c == decimal_point) {
        c = *++s;
        if (!nd) {
            for(; c == '0'; c = *++s)
                nz++;
            if (c > '0' && c <= '9') {
                s0 = s;
                nf += nz;
                nz = 0;
                goto have_dig;
            }
            goto dig_done;
        }
        for(; c >= '0' && c <= '9'; c = *++s) {
        have_dig:
            nz++;
            if (c -= '0') {
                nf += nz;
                for(i = 1; i < nz; i++)
                    if (nd++ < 9)
                        y *= 10;
                    else if (nd <= DBL_DIG + 1)
                        z *= 10;
                if (nd++ < 9)
                    y = 10*y + c;
                else if (nd <= DBL_DIG + 1)
                    z = 10*z + c;
                nz = 0;
            }
        }
    }
 dig_done:
    e = 0;
    if (c == 'e' || c == 'E') {
        if (!nd && !nz && !nz0) {
            s = s00;
            goto ret;
        }
        s00 = s;
        esign = 0;
        switch(c = *++s) {
        case '-':
            esign = 1;
        case '+':
            c = *++s;
        }
        if (c >= '0' && c <= '9') {
            while(c == '0')
                c = *++s;
            if (c > '0' && c <= '9') {
                L = c - '0';
                s1 = s;
                while((c = *++s) >= '0' && c <= '9')
                    L = 10*L + c - '0';
                if (s - s1 > 8 || L > 19999)
                    /* Avoid confusion from exponents
                     * so large that e might overflow.
                     */
                    e = 19999; /* safe for 16 bit ints */
                else
                    e = int(L);
                if (esign)
                    e = -e;
            }
            else
                e = 0;
        }
        else
            s = s00;
    }
    if (!nd) {
        if (!nz && !nz0)
            s = s00;
        goto ret;
    }
    e1 = e -= nf;

    /* Now we have nd0 digits, starting at s0, followed by a
     * decimal point, followed by nd-nd0 digits.  The number we're
     * after is the integer represented by those digits times
     * 10**e */

    if (!nd0)
        nd0 = nd;
    k = nd < DBL_DIG + 1 ? nd : DBL_DIG + 1;
    rv = y;
    if (k > 9)
    rv = tens[k - 9] * rv + z;

    bd0 = 0;
    if (nd <= DBL_DIG
#ifndef RND_PRODQUOT
        && FLT_ROUNDS == 1
#endif
        ) {
        if (!e)
            goto ret;
        if (e > 0) {
            if (e <= Ten_pmax) {
#ifdef VAX
                goto vax_ovfl_check;
#else
                /* rv = */ rounded_product(rv, tens[e]);
                goto ret;
#endif
            }
            i = DBL_DIG - nd;
            if (e <= Ten_pmax + i) {
                /* A fancier test would sometimes let us do
                 * this for larger i values.
                 */
                e -= i;
                rv *= tens[i];
#ifdef VAX
                /* VAX exponent range is so narrow we must
                 * worry about overflow here...
                 */
            vax_ovfl_check:
                setWord0(&rv, getWord0(rv) - P*Exp_msk1);
                /* rv = */ rounded_product(rv, tens[e]);
                if ((getWord0(rv) & Exp_mask)
                    > Exp_msk1*(DBL_MAX_EXP+Bias-1-P))
                    goto ovfl;
                setWord0(&rv, getWord0(rv) + P*Exp_msk1);
#else
                /* rv = */ rounded_product(rv, tens[e]);
#endif
                goto ret;
            }
        }
#ifndef Inaccurate_Divide
        else if (e >= -Ten_pmax) {
            /* rv = */ rounded_quotient(rv, tens[-e]);
            goto ret;
        }
#endif
    }
    e1 += nd - k;

    /* Get starting approximation = rv * 10**e1 */

    if (e1 > 0) {
        if ((i = e1 & 15) != 0)
            rv *= tens[i];
        if (e1 &= ~15) {
            if (e1 > DBL_MAX_10_EXP) {
            ovfl:
                //                                errno = ERANGE;
                if (ok != 0)
                    *ok = false;
#ifdef __STDC__
                rv = HUGE_VAL;
#else
                /* Can't trust HUGE_VAL */
#ifdef IEEE_Arith
                setWord0(&rv, Exp_mask);
                setWord1(&rv, 0);
#else
                setWord0(&rv, Big0);
                setWord1(&rv, Big1);
#endif
#endif
                if (bd0)
                    goto retfree;
                goto ret;
            }
            if (e1 >>= 4) {
                for(j = 0; e1 > 1; j++, e1 >>= 1)
                    if (e1 & 1)
                        rv *= bigtens[j];
                /* The last multiplication could overflow. */
                setWord0(&rv, getWord0(rv) - P*Exp_msk1);
                rv *= bigtens[j];
                if ((z = getWord0(rv) & Exp_mask)
                    > Exp_msk1*(DBL_MAX_EXP+Bias-P))
                    goto ovfl;
                if (z > Exp_msk1*(DBL_MAX_EXP+Bias-1-P)) {
                    /* set to largest number */
                    /* (Can't trust DBL_MAX) */
                    setWord0(&rv, Big0);
                    setWord1(&rv, Big1);
                }
                else
                    setWord0(&rv, getWord0(rv) + P*Exp_msk1);
            }

        }
    }
    else if (e1 < 0) {
        e1 = -e1;
        if ((i = e1 & 15) != 0)
            rv /= tens[i];
        if (e1 &= ~15) {
            e1 >>= 4;
            if (e1 >= 1 << n_bigtens)
                goto undfl;
            for(j = 0; e1 > 1; j++, e1 >>= 1)
                if (e1 & 1)
                    rv *= tinytens[j];
            /* The last multiplication could underflow. */
            rv0 = rv;
            rv *= tinytens[j];
            if (rv == g_double_zero)
                {
                    rv = 2.*rv0;
                    rv *= tinytens[j];
                    if (rv == g_double_zero)
                        {
                        undfl:
                            rv = 0.;
                            //                                        errno = ERANGE;
                            if (ok != 0)
                                *ok = false;
                            if (bd0)
                                goto retfree;
                            goto ret;
                        }
                    setWord0(&rv, Tiny0);
                    setWord1(&rv, Tiny1);
                    /* The refinement below will clean
                     * this approximation up.
                     */
                }
        }
    }

    /* Now the hard part -- adjusting rv to the correct value.*/

    /* Put digits into bd: true value = bd * 10^e */

    bd0 = s2b(s0, nd0, nd, y);

    for(;;) {
        bd = Balloc(bd0->k);
        Bcopy(bd, bd0);
        bb = d2b(rv, &bbe, &bbbits);        /* rv = bb * 2^bbe */
        bs = i2b(1);

        if (e >= 0) {
            bb2 = bb5 = 0;
            bd2 = bd5 = e;
        }
        else {
            bb2 = bb5 = -e;
            bd2 = bd5 = 0;
        }
        if (bbe >= 0)
            bb2 += bbe;
        else
            bd2 -= bbe;
        bs2 = bb2;
#ifdef Sudden_Underflow
#ifdef IBM
        j = 1 + 4*P - 3 - bbbits + ((bbe + bbbits - 1) & 3);
#else
        j = P + 1 - bbbits;
#endif
#else
        i = bbe + bbbits - 1;        /* logb(rv) */
        if (i < Emin)        /* denormal */
            j = bbe + (P-Emin);
        else
            j = P + 1 - bbbits;
#endif
        bb2 += j;
        bd2 += j;
        i = bb2 < bd2 ? bb2 : bd2;
        if (i > bs2)
            i = bs2;
        if (i > 0) {
            bb2 -= i;
            bd2 -= i;
            bs2 -= i;
        }
        if (bb5 > 0) {
            bs = pow5mult(bs, bb5);
            bb1 = mult(bs, bb);
            Bfree(bb);
            bb = bb1;
        }
        if (bb2 > 0)
            bb = lshift(bb, bb2);
        if (bd5 > 0)
            bd = pow5mult(bd, bd5);
        if (bd2 > 0)
            bd = lshift(bd, bd2);
        if (bs2 > 0)
            bs = lshift(bs, bs2);
        delta = diff(bb, bd);
        dsign = delta->sign;
        delta->sign = 0;
        i = cmp(delta, bs);
        if (i < 0) {
            /* Error is less than half an ulp -- check for
             * special case of mantissa a power of two.
             */
            if (dsign || getWord1(rv) || getWord0(rv) & Bndry_mask)
                break;
            delta = lshift(delta,Log2P);
            if (cmp(delta, bs) > 0)
                goto drop_down;
            break;
        }
        if (i == 0) {
            /* exactly half-way between */
            if (dsign) {
                if ((getWord0(rv) & Bndry_mask1) == Bndry_mask1
                    &&  getWord1(rv) == 0xffffffff) {
                    /*boundary case -- increment exponent*/
                    setWord0(&rv, (getWord0(rv) & Exp_mask)
                                + Exp_msk1
#ifdef IBM
                                | Exp_msk1 >> 4
#endif
                                );
                    setWord1(&rv, 0);
                    break;
                }
            }
            else if (!(getWord0(rv) & Bndry_mask) && !getWord1(rv)) {
            drop_down:
                /* boundary case -- decrement exponent */
#ifdef Sudden_Underflow
                L = getWord0(rv) & Exp_mask;
#ifdef IBM
                if (L <  Exp_msk1)
#else
                    if (L <= Exp_msk1)
#endif
                        goto undfl;
                L -= Exp_msk1;
#else
                L = (getWord0(rv) & Exp_mask) - Exp_msk1;
#endif
                setWord0(&rv, L | Bndry_mask1);
                setWord1(&rv, 0xffffffff);
#ifdef IBM
                goto cont;
#else
                break;
#endif
            }
#ifndef ROUND_BIASED
            if (!(getWord1(rv) & LSB))
                break;
#endif
            if (dsign)
                rv += ulp(rv);
#ifndef ROUND_BIASED
            else {
                rv -= ulp(rv);
#ifndef Sudden_Underflow
                if (rv == g_double_zero)
                    goto undfl;
#endif
            }
#endif
            break;
        }
        if ((aadj = ratio(delta, bs)) <= 2.) {
            if (dsign)
                aadj = aadj1 = 1.;
            else if (getWord1(rv) || getWord0(rv) & Bndry_mask) {
#ifndef Sudden_Underflow
                if (getWord1(rv) == Tiny1 && !getWord0(rv))
                    goto undfl;
#endif
                aadj = 1.;
                aadj1 = -1.;
            }
            else {
                /* special case -- power of FLT_RADIX to be */
                /* rounded down... */

                if (aadj < 2./FLT_RADIX)
                    aadj = 1./FLT_RADIX;
                else
                    aadj *= 0.5;
                aadj1 = -aadj;
            }
        }
        else {
            aadj *= 0.5;
            aadj1 = dsign ? aadj : -aadj;
#ifdef Check_FLT_ROUNDS
            switch(FLT_ROUNDS) {
            case 2: /* towards +infinity */
                aadj1 -= 0.5;
                break;
            case 0: /* towards 0 */
            case 3: /* towards -infinity */
                aadj1 += 0.5;
            }
#else
            if (FLT_ROUNDS == 0)
                aadj1 += 0.5;
#endif
        }
        y = getWord0(rv) & Exp_mask;

        /* Check for overflow */

        if (y == Exp_msk1*(DBL_MAX_EXP+Bias-1)) {
            rv0 = rv;
            setWord0(&rv, getWord0(rv) - P*Exp_msk1);
            adj = aadj1 * ulp(rv);
            rv += adj;
            if ((getWord0(rv) & Exp_mask) >=
                Exp_msk1*(DBL_MAX_EXP+Bias-P)) {
                if (getWord0(rv0) == Big0 && getWord1(rv0) == Big1)
                    goto ovfl;
                setWord0(&rv, Big0);
                setWord1(&rv, Big1);
                goto cont;
            }
            else
                setWord0(&rv, getWord0(rv) + P*Exp_msk1);
        }
        else {
#ifdef Sudden_Underflow
            if ((getWord0(rv) & Exp_mask) <= P*Exp_msk1) {
                rv0 = rv;
                setWord0(&rv, getWord0(rv) + P*Exp_msk1);
                adj = aadj1 * ulp(rv);
                rv += adj;
#ifdef IBM
                if ((getWord0(rv) & Exp_mask) <  P*Exp_msk1)
#else
                    if ((getWord0(rv) & Exp_mask) <= P*Exp_msk1)
#endif
                        {
                            if (getWord0(rv0) == Tiny0
                                && getWord1(rv0) == Tiny1)
                                goto undfl;
                            setWord0(&rv, Tiny0);
                            setWord1(&rv, Tiny1);
                            goto cont;
                        }
                    else
                        setWord0(&rv, getWord0(rv) - P*Exp_msk1);
            }
            else {
                adj = aadj1 * ulp(rv);
                rv += adj;
            }
#else
            /* Compute adj so that the IEEE rounding rules will
             * correctly round rv + adj in some half-way cases.
             * If rv * ulp(rv) is denormalized (i.e.,
             * y <= (P-1)*Exp_msk1), we must adjust aadj to avoid
             * trouble from bits lost to denormalization;
             * example: 1.2e-307 .
             */
            if (y <= (P-1)*Exp_msk1 && aadj >= 1.) {
                aadj1 = int(aadj + 0.5);
                if (!dsign)
                    aadj1 = -aadj1;
            }
            adj = aadj1 * ulp(rv);
            rv += adj;
#endif
        }
        z = getWord0(rv) & Exp_mask;
        if (y == z) {
            /* Can we stop now? */
            L = Long(aadj);
            aadj -= L;
            /* The tolerances below are conservative. */
            if (dsign || getWord1(rv) || getWord0(rv) & Bndry_mask) {
                if (aadj < .4999999 || aadj > .5000001)
                    break;
            }
            else if (aadj < .4999999/FLT_RADIX)
                break;
        }
    cont:
        Bfree(bb);
        Bfree(bd);
        Bfree(bs);
        Bfree(delta);
    }
 retfree:
    Bfree(bb);
    Bfree(bd);
    Bfree(bs);
    Bfree(bd0);
    Bfree(delta);
 ret:
    if (se)
        *se = s;
    return sign ? -rv : rv;
}

static int quorem(Bigint *b, Bigint *S)
{
    int n;
    Long borrow, y;
    ULong carry, q, ys;
    ULong *bx, *bxe, *sx, *sxe;
#ifdef Pack_32
    Long z;
    ULong si, zs;
#endif

    n = S->wds;
#ifdef BSD_QDTOA_DEBUG
    /*debug*/ if (b->wds > n)
        /*debug*/        Bug("oversize b in quorem");
#endif
    if (b->wds < n)
        return 0;
    sx = S->x;
    sxe = sx + --n;
    bx = b->x;
    bxe = bx + n;
    q = *bxe / (*sxe + 1);        /* ensure q <= true quotient */
#ifdef BSD_QDTOA_DEBUG
    /*debug*/ if (q > 9)
        /*debug*/        Bug("oversized quotient in quorem");
#endif
    if (q) {
        borrow = 0;
        carry = 0;
        do {
#ifdef Pack_32
            si = *sx++;
            ys = (si & 0xffff) * q + carry;
            zs = (si >> 16) * q + (ys >> 16);
            carry = zs >> 16;
            y = (*bx & 0xffff) - (ys & 0xffff) + borrow;
            borrow = y >> 16;
            Sign_Extend(borrow, y);
            z = (*bx >> 16) - (zs & 0xffff) + borrow;
            borrow = z >> 16;
            Sign_Extend(borrow, z);
            Storeinc(bx, z, y);
#else
            ys = *sx++ * q + carry;
            carry = ys >> 16;
            y = *bx - (ys & 0xffff) + borrow;
            borrow = y >> 16;
            Sign_Extend(borrow, y);
            *bx++ = y & 0xffff;
#endif
        }
        while(sx <= sxe);
        if (!*bxe) {
            bx = b->x;
            while(--bxe > bx && !*bxe)
                --n;
            b->wds = n;
        }
    }
    if (cmp(b, S) >= 0) {
        q++;
        borrow = 0;
        carry = 0;
        bx = b->x;
        sx = S->x;
        do {
#ifdef Pack_32
            si = *sx++;
            ys = (si & 0xffff) + carry;
            zs = (si >> 16) + (ys >> 16);
            carry = zs >> 16;
            y = (*bx & 0xffff) - (ys & 0xffff) + borrow;
            borrow = y >> 16;
            Sign_Extend(borrow, y);
            z = (*bx >> 16) - (zs & 0xffff) + borrow;
            borrow = z >> 16;
            Sign_Extend(borrow, z);
            Storeinc(bx, z, y);
#else
            ys = *sx++ + carry;
            carry = ys >> 16;
            y = *bx - (ys & 0xffff) + borrow;
            borrow = y >> 16;
            Sign_Extend(borrow, y);
            *bx++ = y & 0xffff;
#endif
        }
        while(sx <= sxe);
        bx = b->x;
        bxe = bx + n;
        if (!*bxe) {
            while(--bxe > bx && !*bxe)
                --n;
            b->wds = n;
        }
    }
    return q;
}

/* dtoa for IEEE arithmetic (dmg): convert double to ASCII string.
 *
 * Inspired by "How to Print Floating-Point Numbers Accurately" by
 * Guy L. Steele, Jr. and Jon L. White [Proc. ACM SIGPLAN '90, pp. 92-101].
 *
 * Modifications:
 *        1. Rather than iterating, we use a simple numeric overestimate
 *           to determine k = floor(log10(d)).  We scale relevant
 *           quantities using O(log2(k)) rather than O(k) multiplications.
 *        2. For some modes > 2 (corresponding to ecvt and fcvt), we don't
 *           try to generate digits strictly left to right.  Instead, we
 *           compute with fewer bits and propagate the carry if necessary
 *           when rounding the final digit up.  This is often faster.
 *        3. Under the assumption that input will be rounded nearest,
 *           mode 0 renders 1e23 as 1e23 rather than 9.999999999999999e22.
 *           That is, we allow equality in stopping tests when the
 *           round-nearest rule will give the same floating-point value
 *           as would satisfaction of the stopping test with strict
 *           inequality.
 *        4. We remove common factors of powers of 2 from relevant
 *           quantities.
 *        5. When converting floating-point integers less than 1e16,
 *           we use floating-point arithmetic rather than resorting
 *           to multiple-precision integers.
 *        6. When asked to produce fewer than 15 digits, we first try
 *           to get by with floating-point arithmetic; we resort to
 *           multiple-precision integer arithmetic only if we cannot
 *           guarantee that the floating-point calculation has given
 *           the correctly rounded result.  For k requested digits and
 *           "uniformly" distributed input, the probability is
 *           something like 10^(k-15) that we must resort to the Long
 *           calculation.
 */

#if defined(Q_OS_WIN) && defined (Q_CC_GNU) && !defined(_clear87) // See QTBUG-7576
extern "C" {
__attribute__ ((dllimport)) unsigned int __cdecl __MINGW_NOTHROW _control87 (unsigned int unNew, unsigned int unMask);
__attribute__ ((dllimport)) unsigned int __cdecl __MINGW_NOTHROW _clearfp (void); /* Clear the FPU status word */
}
#  define _clear87 _clearfp
#endif

/* This actually sometimes returns a pointer to a string literal
   cast to a char*. Do NOT try to modify the return value. */

Q_CORE_EXPORT char *qdtoa ( double d, int mode, int ndigits, int *decpt, int *sign, char **rve, char **resultp)
{
    // Some values of the floating-point control word can cause _qdtoa to crash with an underflow.
    // We set a safe value here.
#ifdef Q_OS_WIN
    _clear87();
    unsigned int oldbits = _control87(0, 0);
#ifndef MCW_EM
#    ifdef _MCW_EM
#        define MCW_EM _MCW_EM
#    else
#        define MCW_EM 0x0008001F
#    endif
#endif
    _control87(MCW_EM, MCW_EM);
#endif

#if defined(Q_OS_LINUX) && !defined(__UCLIBC__)
    fenv_t envp;
    feholdexcept(&envp);
#endif

    char *s = _qdtoa(d, mode, ndigits, decpt, sign, rve, resultp);

#ifdef Q_OS_WIN
    _clear87();
#ifndef _M_X64
    _control87(oldbits, 0xFFFFF);
#else
#  ifndef _MCW_EM // Potentially missing on MinGW
#    define _MCW_EM         0x0008001f
#  endif
#  ifndef _MCW_RC
#    define _MCW_RC         0x00000300
#  endif
#  ifndef _MCW_DN
#    define _MCW_DN         0x03000000
#  endif
    _control87(oldbits, _MCW_EM|_MCW_DN|_MCW_RC);
#endif //_M_X64
#endif //Q_OS_WIN

#if defined(Q_OS_LINUX) && !defined(__UCLIBC__)
    fesetenv(&envp);
#endif

    return s;
}

static char *_qdtoa( NEEDS_VOLATILE double d, int mode, int ndigits, int *decpt, int *sign, char **rve, char **resultp)
{
    /*
      Arguments ndigits, decpt, sign are similar to those
      of ecvt and fcvt; trailing zeros are suppressed from
      the returned string.  If not null, *rve is set to point
      to the end of the return value.  If d is +-Infinity or NaN,
      then *decpt is set to 9999.

      mode:
      0 ==> shortest string that yields d when read in
      and rounded to nearest.
      1 ==> like 0, but with Steele & White stopping rule;
      e.g. with IEEE P754 arithmetic , mode 0 gives
      1e23 whereas mode 1 gives 9.999999999999999e22.
      2 ==> max(1,ndigits) significant digits.  This gives a
      return value similar to that of ecvt, except
      that trailing zeros are suppressed.
      3 ==> through ndigits past the decimal point.  This
      gives a return value similar to that from fcvt,
      except that trailing zeros are suppressed, and
      ndigits can be negative.
      4-9 should give the same return values as 2-3, i.e.,
      4 <= mode <= 9 ==> same return as mode
      2 + (mode & 1).  These modes are mainly for
      debugging; often they run slower but sometimes
      faster than modes 2-3.
      4,5,8,9 ==> left-to-right digit generation.
      6-9 ==> don't try fast floating-point estimate
      (if applicable).

      Values of mode other than 0-9 are treated as mode 0.

      Sufficient space is allocated to the return value
      to hold the suppressed trailing zeros.
    */

    int bbits, b2, b5, be, dig, i, ieps, ilim0,
        j, j1, k, k0, k_check, leftright, m2, m5, s2, s5,
        try_quick;
    int ilim = 0, ilim1 = 0, spec_case = 0;        /* pacify gcc */
    Long L;
#ifndef Sudden_Underflow
    int denorm;
    ULong x;
#endif
    Bigint *b, *b1, *delta, *mhi, *S;
    Bigint *mlo = NULL; /* pacify gcc */
    double d2;
    double ds, eps;
    char *s, *s0;

    if (getWord0(d) & Sign_bit) {
        /* set sign for everything, including 0's and NaNs */
        *sign = 1;
        setWord0(&d, getWord0(d) & ~Sign_bit);        /* clear sign bit */
    }
    else
        *sign = 0;

#if defined(IEEE_Arith) + defined(VAX)
#ifdef IEEE_Arith
    if ((getWord0(d) & Exp_mask) == Exp_mask)
#else
        if (getWord0(d)  == 0x8000)
#endif
            {
                /* Infinity or NaN */
                *decpt = 9999;
                s =
#ifdef IEEE_Arith
                    !getWord1(d) && !(getWord0(d) & 0xfffff) ? const_cast<char*>("Infinity") :
#endif
                    const_cast<char*>("NaN");
                if (rve)
                    *rve =
#ifdef IEEE_Arith
                        s[3] ? s + 8 :
#endif
                        s + 3;
                return s;
            }
#endif
#ifdef IBM
    d += 0; /* normalize */
#endif
    if (d == g_double_zero)
        {
            *decpt = 1;
            s = const_cast<char*>("0");
            if (rve)
                *rve = s + 1;
            return s;
        }

    b = d2b(d, &be, &bbits);
    i = (int)(getWord0(d) >> Exp_shift1 & (Exp_mask>>Exp_shift1));
#ifndef Sudden_Underflow
    if (i != 0) {
#endif
        d2 = d;
        setWord0(&d2, getWord0(d2) & Frac_mask1);
        setWord0(&d2, getWord0(d2) | Exp_11);
#ifdef IBM
        if (j = 11 - hi0bits(getWord0(d2) & Frac_mask))
            d2 /= 1 << j;
#endif

        /* log(x)        ~=~ log(1.5) + (x-1.5)/1.5
         * log10(x)         =  log(x) / log(10)
         *                ~=~ log(1.5)/log(10) + (x-1.5)/(1.5*log(10))
         * log10(d) = (i-Bias)*log(2)/log(10) + log10(d2)
         *
         * This suggests computing an approximation k to log10(d) by
         *
         * k = (i - Bias)*0.301029995663981
         *        + ( (d2-1.5)*0.289529654602168 + 0.176091259055681 );
         *
         * We want k to be too large rather than too small.
         * The error in the first-order Taylor series approximation
         * is in our favor, so we just round up the constant enough
         * to compensate for any error in the multiplication of
         * (i - Bias) by 0.301029995663981; since |i - Bias| <= 1077,
         * and 1077 * 0.30103 * 2^-52 ~=~ 7.2e-14,
         * adding 1e-13 to the constant term more than suffices.
         * Hence we adjust the constant term to 0.1760912590558.
         * (We could get a more accurate k by invoking log10,
         *  but this is probably not worthwhile.)
         */

        i -= Bias;
#ifdef IBM
        i <<= 2;
        i += j;
#endif
#ifndef Sudden_Underflow
        denorm = 0;
    }
    else {
        /* d is denormalized */

        i = bbits + be + (Bias + (P-1) - 1);
        x = i > 32  ? getWord0(d) << (64 - i) | getWord1(d) >> (i - 32)
            : getWord1(d) << (32 - i);
        d2 = x;
        setWord0(&d2, getWord0(d2) - 31*Exp_msk1); /* adjust exponent */
        i -= (Bias + (P-1) - 1) + 1;
        denorm = 1;
    }
#endif
    ds = (d2-1.5)*0.289529654602168 + 0.1760912590558 + i*0.301029995663981;
    k = int(ds);
    if (ds < 0. && ds != k)
        k--;        /* want k = floor(ds) */
    k_check = 1;
    if (k >= 0 && k <= Ten_pmax) {
        if (d < tens[k])
            k--;
        k_check = 0;
    }
    j = bbits - i - 1;
    if (j >= 0) {
        b2 = 0;
        s2 = j;
    }
    else {
        b2 = -j;
        s2 = 0;
    }
    if (k >= 0) {
        b5 = 0;
        s5 = k;
        s2 += k;
    }
    else {
        b2 -= k;
        b5 = -k;
        s5 = 0;
    }
    if (mode < 0 || mode > 9)
        mode = 0;
    try_quick = 1;
    if (mode > 5) {
        mode -= 4;
        try_quick = 0;
    }
    leftright = 1;
    switch(mode) {
    case 0:
    case 1:
        ilim = ilim1 = -1;
        i = 18;
        ndigits = 0;
        break;
    case 2:
        leftright = 0;
        /* no break */
    case 4:
        if (ndigits <= 0)
            ndigits = 1;
        ilim = ilim1 = i = ndigits;
        break;
    case 3:
        leftright = 0;
        /* no break */
    case 5:
        i = ndigits + k + 1;
        ilim = i;
        ilim1 = i - 1;
        if (i <= 0)
            i = 1;
    }
    QT_TRY {
        *resultp = static_cast<char *>(malloc(i + 1));
        Q_CHECK_PTR(*resultp);
    } QT_CATCH(...) {
        Bfree(b);
        QT_RETHROW;
    }
    s = s0 = *resultp;

    if (ilim >= 0 && ilim <= Quick_max && try_quick) {

        /* Try to get by with floating-point arithmetic. */

        i = 0;
        d2 = d;
        k0 = k;
        ilim0 = ilim;
        ieps = 2; /* conservative */
        if (k > 0) {
            ds = tens[k&0xf];
            j = k >> 4;
            if (j & Bletch) {
                /* prevent overflows */
                j &= Bletch - 1;
                d /= bigtens[n_bigtens-1];
                ieps++;
            }
            for(; j; j >>= 1, i++)
                if (j & 1) {
                    ieps++;
                    ds *= bigtens[i];
                }
            d /= ds;
        }
        else if ((j1 = -k) != 0) {
            d *= tens[j1 & 0xf];
            for(j = j1 >> 4; j; j >>= 1, i++)
                if (j & 1) {
                    ieps++;
                    d *= bigtens[i];
                }
        }
        if (k_check && d < 1. && ilim > 0) {
            if (ilim1 <= 0)
                goto fast_failed;
            ilim = ilim1;
            k--;
            d *= 10.;
            ieps++;
        }
        eps = ieps*d + 7.;
        setWord0(&eps, getWord0(eps) - (P-1)*Exp_msk1);
        if (ilim == 0) {
            S = mhi = 0;
            d -= 5.;
            if (d > eps)
                goto one_digit;
            if (d < -eps)
                goto no_digits;
            goto fast_failed;
        }
#ifndef No_leftright
        if (leftright) {
            /* Use Steele & White method of only
             * generating digits needed.
             */
            eps = 0.5/tens[ilim-1] - eps;
            for(i = 0;;) {
                L = Long(d);
                d -= L;
                *s++ = '0' + int(L);
                if (d < eps)
                    goto ret1;
                if (1. - d < eps)
                    goto bump_up;
                if (++i >= ilim)
                    break;
                eps *= 10.;
                d *= 10.;
            }
        }
        else {
#endif
            /* Generate ilim digits, then fix them up. */
            eps *= tens[ilim-1];
            for(i = 1;; i++, d *= 10.) {
                L = Long(d);
                d -= L;
                *s++ = '0' + int(L);
                if (i == ilim) {
                    if (d > 0.5 + eps)
                        goto bump_up;
                    else if (d < 0.5 - eps) {
                        while(*--s == '0') {}
                        s++;
                        goto ret1;
                    }
                    break;
                }
            }
#ifndef No_leftright
        }
#endif
    fast_failed:
        s = s0;
        d = d2;
        k = k0;
        ilim = ilim0;
    }

    /* Do we have a "small" integer? */

    if (be >= 0 && k <= Int_max) {
        /* Yes. */
        ds = tens[k];
        if (ndigits < 0 && ilim <= 0) {
            S = mhi = 0;
            if (ilim < 0 || d <= 5*ds)
                goto no_digits;
            goto one_digit;
        }
        for(i = 1;; i++) {
            L = Long(d / ds);
            d -= L*ds;
#ifdef Check_FLT_ROUNDS
            /* If FLT_ROUNDS == 2, L will usually be high by 1 */
            if (d < 0) {
                L--;
                d += ds;
            }
#endif
            *s++ = '0' + int(L);
            if (i == ilim) {
                d += d;
                if (d > ds || (d == ds && L & 1)) {
                bump_up:
                    while(*--s == '9')
                        if (s == s0) {
                            k++;
                            *s = '0';
                            break;
                        }
                    ++*s++;
                }
                break;
            }
            if ((d *= 10.) == g_double_zero)
                break;
        }
        goto ret1;
    }

    m2 = b2;
    m5 = b5;
    mhi = mlo = 0;
    if (leftright) {
        if (mode < 2) {
            i =
#ifndef Sudden_Underflow
                denorm ? be + (Bias + (P-1) - 1 + 1) :
#endif
#ifdef IBM
                1 + 4*P - 3 - bbits + ((bbits + be - 1) & 3);
#else
            1 + P - bbits;
#endif
        }
        else {
            j = ilim - 1;
            if (m5 >= j)
                m5 -= j;
            else {
                s5 += j -= m5;
                b5 += j;
                m5 = 0;
            }
            if ((i = ilim) < 0) {
                m2 -= i;
                i = 0;
            }
        }
        b2 += i;
        s2 += i;
        mhi = i2b(1);
    }
    if (m2 > 0 && s2 > 0) {
        i = m2 < s2 ? m2 : s2;
        b2 -= i;
        m2 -= i;
        s2 -= i;
    }
    if (b5 > 0) {
        if (leftright) {
            if (m5 > 0) {
                mhi = pow5mult(mhi, m5);
                b1 = mult(mhi, b);
                Bfree(b);
                b = b1;
            }
            if ((j = b5 - m5) != 0)
                b = pow5mult(b, j);
        }
        else
            b = pow5mult(b, b5);
    }
    S = i2b(1);
    if (s5 > 0)
        S = pow5mult(S, s5);

    /* Check for special case that d is a normalized power of 2. */

    if (mode < 2) {
        if (!getWord1(d) && !(getWord0(d) & Bndry_mask)
#ifndef Sudden_Underflow
            && getWord0(d) & Exp_mask
#endif
            ) {
            /* The special case */
            b2 += Log2P;
            s2 += Log2P;
            spec_case = 1;
        }
        else
            spec_case = 0;
    }

    /* Arrange for convenient computation of quotients:
     * shift left if necessary so divisor has 4 leading 0 bits.
     *
     * Perhaps we should just compute leading 28 bits of S once
     * and for all and pass them and a shift to quorem, so it
     * can do shifts and ors to compute the numerator for q.
     */
#ifdef Pack_32
    if ((i = ((s5 ? 32 - hi0bits(S->x[S->wds-1]) : 1) + s2) & 0x1f) != 0)
        i = 32 - i;
#else
    if (i = ((s5 ? 32 - hi0bits(S->x[S->wds-1]) : 1) + s2) & 0xf)
        i = 16 - i;
#endif
    if (i > 4) {
        i -= 4;
        b2 += i;
        m2 += i;
        s2 += i;
    }
    else if (i < 4) {
        i += 28;
        b2 += i;
        m2 += i;
        s2 += i;
    }
    if (b2 > 0)
        b = lshift(b, b2);
    if (s2 > 0)
        S = lshift(S, s2);
    if (k_check) {
        if (cmp(b,S) < 0) {
            k--;
            b = multadd(b, 10, 0);        /* we botched the k estimate */
            if (leftright)
                mhi = multadd(mhi, 10, 0);
            ilim = ilim1;
        }
    }
    if (ilim <= 0 && mode > 2) {
        if (ilim < 0 || cmp(b,S = multadd(S,5,0)) <= 0) {
            /* no digits, fcvt style */
        no_digits:
            k = -1 - ndigits;
            goto ret;
        }
    one_digit:
        *s++ = '1';
        k++;
        goto ret;
    }
    if (leftright) {
        if (m2 > 0)
            mhi = lshift(mhi, m2);

        /* Compute mlo -- check for special case
         * that d is a normalized power of 2.
         */

        mlo = mhi;
        if (spec_case) {
            mhi = Balloc(mhi->k);
            Bcopy(mhi, mlo);
            mhi = lshift(mhi, Log2P);
        }

        for(i = 1;;i++) {
            dig = quorem(b,S) + '0';
            /* Do we yet have the shortest decimal string
             * that will round to d?
             */
            j = cmp(b, mlo);
            delta = diff(S, mhi);
            j1 = delta->sign ? 1 : cmp(b, delta);
            Bfree(delta);
#ifndef ROUND_BIASED
            if (j1 == 0 && !mode && !(getWord1(d) & 1)) {
                if (dig == '9')
                    goto round_9_up;
                if (j > 0)
                    dig++;
                *s++ = dig;
                goto ret;
            }
#endif
            if (j < 0 || (j == 0 && !mode
#ifndef ROUND_BIASED
                          && !(getWord1(d) & 1)
#endif
                          )) {
                if (j1 > 0) {
                    b = lshift(b, 1);
                    j1 = cmp(b, S);
                    if ((j1 > 0 || (j1 == 0 && dig & 1))
                        && dig++ == '9')
                        goto round_9_up;
                }
                *s++ = dig;
                goto ret;
            }
            if (j1 > 0) {
                if (dig == '9') { /* possible if i == 1 */
                round_9_up:
                    *s++ = '9';
                    goto roundoff;
                }
                *s++ = dig + 1;
                goto ret;
            }
            *s++ = dig;
            if (i == ilim)
                break;
            b = multadd(b, 10, 0);
            if (mlo == mhi)
                mlo = mhi = multadd(mhi, 10, 0);
            else {
                mlo = multadd(mlo, 10, 0);
                mhi = multadd(mhi, 10, 0);
            }
        }
    }
    else
        for(i = 1;; i++) {
            *s++ = dig = quorem(b,S) + '0';
            if (i >= ilim)
                break;
            b = multadd(b, 10, 0);
        }

    /* Round off last digit */

    b = lshift(b, 1);
    j = cmp(b, S);
    if (j > 0 || (j == 0 && dig & 1)) {
    roundoff:
        while(*--s == '9')
            if (s == s0) {
                k++;
                *s++ = '1';
                goto ret;
            }
        ++*s++;
    }
    else {
        while(*--s == '0') {}
        s++;
    }
 ret:
    Bfree(S);
    if (mhi) {
        if (mlo && mlo != mhi)
            Bfree(mlo);
        Bfree(mhi);
    }
 ret1:
    Bfree(b);
    if (s == s0) {                                /* don't return empty string */
        *s++ = '0';
        k = 0;
    }
    *s = 0;
    *decpt = k + 1;
    if (rve)
        *rve = s;
    return s0;
}
#else
// NOT thread safe!

#include <errno.h>

Q_CORE_EXPORT char *qdtoa( double d, int mode, int ndigits, int *decpt, int *sign, char **rve, char **resultp)
{
    if(rve)
      *rve = 0;

    char *res;
    if (mode == 0)
        ndigits = 80;

    if (mode == 3)
        res = fcvt(d, ndigits, decpt, sign);
    else
        res = ecvt(d, ndigits, decpt, sign);

    int n = qstrlen(res);
    if (mode == 0) { // remove trailing 0's
        const int stop = qMax(1, *decpt);
        int i;
        for (i = n-1; i >= stop; --i) {
            if (res[i] != '0')
                break;
        }
        n = i + 1;
    }
    *resultp = static_cast<char*>(malloc(n + 1));
    Q_CHECK_PTR(resultp);
    qstrncpy(*resultp, res, n + 1);
    return *resultp;
}

Q_CORE_EXPORT double qstrtod(const char *s00, const char **se, bool *ok)
{
    double ret = strtod((char*)s00, (char**)se);
    if (ok) {
      if((ret == 0.0l && errno == ERANGE)
         || ret == HUGE_VAL || ret == -HUGE_VAL)
        *ok = false;
      else
        *ok = true; // the result will be that we don't report underflow in this case
    }
    return ret;
}

#endif // QT_QLOCALE_USES_FCVT

QT_END_NAMESPACE
