Source/WTF/wtf/text/StringConcatenateNumbers.h

/*
 * Copyright (C) 2017-2020 Apple Inc. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 */

#pragma once

#include <wtf/dtoa.h>
#include <wtf/text/IntegerToStringConversion.h>
#include <wtf/text/StringConcatenate.h>

namespace WTF {

template<typename Integer>
class StringTypeAdapter<Integer, typename std::enable_if_t<std::is_integral_v<Integer>>> {
public:
    StringTypeAdapter(Integer number)
        : m_number { number }
    {
    }

    unsigned length() const { return lengthOfIntegerAsString(m_number); }
    bool is8Bit() const { return true; }
    template<typename CharacterType>
    void writeTo(CharacterType* destination) const { writeIntegerToBuffer(m_number, destination); }

private:
    Integer m_number;
};

template<typename Enum>
class StringTypeAdapter<Enum, typename std::enable_if_t<std::is_enum_v<Enum>>> {
using UnderlyingType = typename std::underlying_type_t<Enum>;
public:
    StringTypeAdapter(Enum enumValue)
        : m_enum { enumValue }
    {
    }

    unsigned length() const { return lengthOfIntegerAsString(static_cast<UnderlyingType>(m_enum)); }
    bool is8Bit() const { return true; }
    template<typename CharacterType>
    void writeTo(CharacterType* destination) const { writeIntegerToBuffer(static_cast<UnderlyingType>(m_enum), destination); }

private:
    Enum m_enum;
};

template<typename FloatingPoint>
class StringTypeAdapter<FloatingPoint, typename std::enable_if_t<std::is_floating_point<FloatingPoint>::value>> {
public:
    StringTypeAdapter(FloatingPoint number)
    {
        numberToString(number, m_buffer);
        m_length = std::strlen(&m_buffer[0]);
    }

    unsigned length() const { return m_length; }
    bool is8Bit() const { return true; }
    template<typename CharacterType> void writeTo(CharacterType* destination) const { StringImpl::copyCharacters(destination, buffer(), m_length); }

private:
    const LChar* buffer() const { return reinterpret_cast<const LChar*>(&m_buffer[0]); }

    NumberToStringBuffer m_buffer;
    unsigned m_length;
};

class FormattedNumber {
    WTF_MAKE_FAST_ALLOCATED;
public:
    static FormattedNumber fixedPrecision(double number, unsigned significantFigures = 6, TrailingZerosTruncatingPolicy trailingZerosTruncatingPolicy = TruncateTrailingZeros)
    {
        FormattedNumber numberFormatter;
        numberToFixedPrecisionString(number, significantFigures, numberFormatter.m_buffer, trailingZerosTruncatingPolicy == TruncateTrailingZeros);
        numberFormatter.m_length = std::strlen(&numberFormatter.m_buffer[0]);
        return numberFormatter;
    }

    static FormattedNumber fixedWidth(double number, unsigned decimalPlaces)
    {
        FormattedNumber numberFormatter;
        numberToFixedWidthString(number, decimalPlaces, numberFormatter.m_buffer);
        numberFormatter.m_length = std::strlen(&numberFormatter.m_buffer[0]);
        return numberFormatter;
    }

    unsigned length() const { return m_length; }
    const LChar* buffer() const { return reinterpret_cast<const LChar*>(&m_buffer[0]); }

private:
    NumberToStringBuffer m_buffer;
    unsigned m_length;
};

template<> class StringTypeAdapter<FormattedNumber> {
public:
    StringTypeAdapter(const FormattedNumber& number)
        : m_number { number }
    {
    }

    unsigned length() const { return m_number.length(); }
    bool is8Bit() const { return true; }
    template<typename CharacterType> void writeTo(CharacterType* destination) const { StringImpl::copyCharacters(destination, m_number.buffer(), m_number.length()); }

private:
    const FormattedNumber& m_number;
};

}

using WTF::FormattedNumber;