juce_CharacterFunctions.h

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 /*
  ==============================================================================
 
   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited
 
   JUCE is an open source library subject to commercial or open-source
   licensing.
 
   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.
 
   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.
 
  ==============================================================================
*/
 
namespace juce
{
 
//==============================================================================
#if JUCE_WINDOWS && ! defined (DOXYGEN)
 #define JUCE_NATIVE_WCHAR_IS_UTF8      0
 #define JUCE_NATIVE_WCHAR_IS_UTF16     1
 #define JUCE_NATIVE_WCHAR_IS_UTF32     0
#else
 #define JUCE_NATIVE_WCHAR_IS_UTF8      0
 #define JUCE_NATIVE_WCHAR_IS_UTF16     0
 #define JUCE_NATIVE_WCHAR_IS_UTF32     1
#endif
 
#if JUCE_NATIVE_WCHAR_IS_UTF32 || DOXYGEN
 using juce_wchar = wchar_t;
#else
 using juce_wchar = uint32;
#endif
 
#ifndef DOXYGEN
 #define JUCE_T(stringLiteral)   (L##stringLiteral)
#endif
 
#if JUCE_DEFINE_T_MACRO
 #define T(stringLiteral)   JUCE_T(stringLiteral)
#endif
 
#ifndef DOXYGEN
 
//==============================================================================
// GNU libstdc++ does not have std::make_unsigned
namespace internal
{
    template <typename Type> struct make_unsigned               { using type = Type; };
    template <> struct make_unsigned<signed char>               { using type = unsigned char; };
    template <> struct make_unsigned<char>                      { using type = unsigned char; };
    template <> struct make_unsigned<short>                     { using type = unsigned short; };
    template <> struct make_unsigned<int>                       { using type = unsigned int; };
    template <> struct make_unsigned<long>                      { using type = unsigned long; };
    template <> struct make_unsigned<long long>                 { using type = unsigned long long; };
}
 
#endif
 
//==============================================================================
class JUCE_API  CharacterFunctions
{
public:
    //==============================================================================
    static juce_wchar toUpperCase (juce_wchar character) noexcept;
    static juce_wchar toLowerCase (juce_wchar character) noexcept;
 
    static bool isUpperCase (juce_wchar character) noexcept;
    static bool isLowerCase (juce_wchar character) noexcept;
 
    static bool isWhitespace (char character) noexcept;
    static bool isWhitespace (juce_wchar character) noexcept;
 
    static bool isDigit (char character) noexcept;
    static bool isDigit (juce_wchar character) noexcept;
 
    static bool isLetter (char character) noexcept;
    static bool isLetter (juce_wchar character) noexcept;
 
    static bool isLetterOrDigit (char character) noexcept;
    static bool isLetterOrDigit (juce_wchar character) noexcept;
 
    static bool isPrintable (char character) noexcept;
 
    static bool isPrintable (juce_wchar character) noexcept;
 
    static int getHexDigitValue (juce_wchar digit) noexcept;
 
    static juce_wchar getUnicodeCharFromWindows1252Codepage (uint8 windows1252Char) noexcept;
 
    //==============================================================================
    template <typename CharPointerType>
    static double readDoubleValue (CharPointerType& text) noexcept
    {
        constexpr auto inf = std::numeric_limits<double>::infinity();
 
        bool isNegative = false;
       #if ! JUCE_MINGW
        constexpr const int maxSignificantDigits = 17 + 1; // An additional digit for rounding
        constexpr const int bufferSize = maxSignificantDigits + 7 + 1; // -.E-XXX and a trailing null-terminator
        char buffer[(size_t) bufferSize] = {};
        char* writePtr = &(buffer[0]);
       #endif
 
        const auto endOfWhitspace = text.findEndOfWhitespace();
        text = endOfWhitspace;
 
        auto c = *text;
 
        switch (c)
        {
            case '-':
                isNegative = true;
               #if ! JUCE_MINGW
                *writePtr++ = '-';
               #endif
                JUCE_FALLTHROUGH
            case '+':
                c = *++text;
                break;
            default:
                break;
        }
 
        switch (c)
        {
            case 'n':
            case 'N':
            {
                if ((text[1] == 'a' || text[1] == 'A') && (text[2] == 'n' || text[2] == 'N'))
                {
                    text += 3;
                    return std::numeric_limits<double>::quiet_NaN();
                }
 
                text = endOfWhitspace;
                return 0.0;
            }
 
            case 'i':
            case 'I':
            {
                if ((text[1] == 'n' || text[1] == 'N') && (text[2] == 'f' || text[2] == 'F'))
                {
                    text += 3;
                    return isNegative ? -inf : inf;
                }
 
                text = endOfWhitspace;
                return 0.0;
            }
 
            default:
                break;
        }
 
       #if JUCE_MINGW
        // MinGW does not have access to the locale functions required for strtold, so we parse the doubles
        // ourselves. There are some edge cases where the least significant digit will be wrong!
        double result[3] = { 0 }, accumulator[2] = { 0 };
        int exponentAdjustment[2] = { 0 }, exponentAccumulator[2] = { -1, -1 };
        int exponent = 0, decPointIndex = 0, digit = 0;
        int lastDigit = 0, numSignificantDigits = 0;
        bool digitsFound = false;
        constexpr const int maxSignificantDigits = 17 + 1;
 
        for (;;)
        {
            if (text.isDigit())
            {
                lastDigit = digit;
                digit = (int) text.getAndAdvance() - '0';
                digitsFound = true;
 
                if (decPointIndex != 0)
                    exponentAdjustment[1]++;
 
                if (numSignificantDigits == 0 && digit == 0)
                    continue;
 
                if (++numSignificantDigits > maxSignificantDigits)
                {
                    if (digit > 5)
                        ++accumulator [decPointIndex];
                    else if (digit == 5 && (lastDigit & 1) != 0)
                        ++accumulator [decPointIndex];
 
                    if (decPointIndex > 0)
                        exponentAdjustment[1]--;
                    else
                        exponentAdjustment[0]++;
 
                    while (text.isDigit())
                    {
                        ++text;
                        if (decPointIndex == 0)
                            exponentAdjustment[0]++;
                    }
                }
                else
                {
                    const auto maxAccumulatorValue = (double) ((std::numeric_limits<unsigned int>::max() - 9) / 10);
                    if (accumulator [decPointIndex] > maxAccumulatorValue)
                    {
                        result [decPointIndex] = mulexp10 (result [decPointIndex], exponentAccumulator [decPointIndex])
                                                 + accumulator [decPointIndex];
                        accumulator [decPointIndex] = 0;
                        exponentAccumulator [decPointIndex] = 0;
                    }
 
                    accumulator [decPointIndex] = accumulator[decPointIndex] * 10 + digit;
                    exponentAccumulator [decPointIndex]++;
                }
            }
            else if (decPointIndex == 0 && *text == '.')
            {
                ++text;
                decPointIndex = 1;
 
                if (numSignificantDigits > maxSignificantDigits)
                {
                    while (text.isDigit())
                        ++text;
                    break;
                }
            }
            else
            {
                break;
            }
        }
 
        result[0] = mulexp10 (result[0], exponentAccumulator[0]) + accumulator[0];
 
        if (decPointIndex != 0)
            result[1] = mulexp10 (result[1], exponentAccumulator[1]) + accumulator[1];
 
        c = *text;
        if ((c == 'e' || c == 'E') && digitsFound)
        {
            auto negativeExponent = false;
 
            switch (*++text)
            {
                case '-':   negativeExponent = true; JUCE_FALLTHROUGH
                case '+':   ++text;
            }
 
            while (text.isDigit())
                exponent = (exponent * 10) + ((int) text.getAndAdvance() - '0');
 
            if (negativeExponent)
                exponent = -exponent;
        }
 
        auto r = mulexp10 (result[0], exponent + exponentAdjustment[0]);
        if (decPointIndex != 0)
            r += mulexp10 (result[1], exponent - exponentAdjustment[1]);
 
        return isNegative ? -r : r;
 
       #else   // ! JUCE_MINGW
 
        int numSigFigs = 0, extraExponent = 0;
        bool decimalPointFound = false, leadingZeros = false;
 
        for (;;)
        {
            if (text.isDigit())
            {
                auto digit = (int) text.getAndAdvance() - '0';
 
                if (decimalPointFound)
                {
                    if (numSigFigs >= maxSignificantDigits)
                        continue;
                }
                else
                {
                    if (numSigFigs >= maxSignificantDigits)
                    {
                        ++extraExponent;
                        continue;
                    }
 
                    if (numSigFigs == 0 && digit == 0)
                    {
                        leadingZeros = true;
                        continue;
                    }
                }
 
                *writePtr++ = (char) ('0' + (char) digit);
                numSigFigs++;
            }
            else if ((! decimalPointFound) && *text == '.')
            {
                ++text;
                *writePtr++ = '.';
                decimalPointFound = true;
            }
            else
            {
                break;
            }
        }
 
        if ((! leadingZeros) && (numSigFigs == 0))
        {
            text = endOfWhitspace;
            return 0.0;
        }
 
        auto writeExponentDigits = [] (int exponent, char* destination)
        {
            auto exponentDivisor = 100;
 
            while (exponentDivisor > 1)
            {
                auto digit = exponent / exponentDivisor;
                *destination++ = (char) ('0' + (char) digit);
                exponent -= digit * exponentDivisor;
                exponentDivisor /= 10;
            }
 
            *destination++ = (char) ('0' + (char) exponent);
        };
 
        c = *text;
 
        if (c == 'e' || c == 'E')
        {
            const auto startOfExponent = text;
            *writePtr++ = 'e';
            bool parsedExponentIsPositive = true;
 
            switch (*++text)
            {
                case '-':
                    parsedExponentIsPositive = false;
                    JUCE_FALLTHROUGH
                case '+':
                    ++text;
                    break;
                default:
                    break;
            }
 
            int exponent = 0;
            const auto startOfExponentDigits = text;
 
            while (text.isDigit())
            {
                auto digit = (int) text.getAndAdvance() - '0';
 
                if (digit != 0 || exponent != 0)
                    exponent = (exponent * 10) + digit;
            }
 
            if (text == startOfExponentDigits)
                text = startOfExponent;
 
            exponent = extraExponent + (parsedExponentIsPositive ? exponent : -exponent);
 
            if (exponent < 0)
            {
                if (exponent < std::numeric_limits<double>::min_exponent10 - 1)
                    return isNegative ? -0.0 : 0.0;
 
                *writePtr++ = '-';
                exponent = -exponent;
            }
            else if (exponent > std::numeric_limits<double>::max_exponent10 + 1)
            {
                return isNegative ? -inf : inf;
            }
 
            writeExponentDigits (exponent, writePtr);
        }
        else if (extraExponent > 0)
        {
            *writePtr++ = 'e';
            writeExponentDigits (extraExponent, writePtr);
        }
 
       #if JUCE_WINDOWS
        static _locale_t locale = _create_locale (LC_ALL, "C");
        return _strtod_l (&buffer[0], nullptr, locale);
       #else
        static locale_t locale = newlocale (LC_ALL_MASK, "C", nullptr);
        #if JUCE_ANDROID
        return (double) strtold_l (&buffer[0], nullptr, locale);
        #else
        return strtod_l (&buffer[0], nullptr, locale);
        #endif
       #endif
 
       #endif   // JUCE_MINGW
    }
 
    template <typename CharPointerType>
    static double getDoubleValue (CharPointerType text) noexcept
    {
        return readDoubleValue (text);
    }
 
    //==============================================================================
    template <typename IntType, typename CharPointerType>
    static IntType getIntValue (const CharPointerType text) noexcept
    {
        using UIntType = typename internal::make_unsigned<IntType>::type;
 
        UIntType v = 0;
        auto s = text.findEndOfWhitespace();
        const bool isNeg = *s == '-';
 
        if (isNeg)
            ++s;
 
        for (;;)
        {
            auto c = s.getAndAdvance();
 
            if (c >= '0' && c <= '9')
                v = v * 10 + (UIntType) (c - '0');
            else
                break;
        }
 
        return isNeg ? - (IntType) v : (IntType) v;
    }
 
    template <typename ResultType>
    struct HexParser
    {
        static_assert (std::is_unsigned_v<ResultType>, "ResultType must be unsigned because "
                                                       "left-shifting a negative value is UB");
 
        template <typename CharPointerType>
        static ResultType parse (CharPointerType t) noexcept
        {
            ResultType result = 0;
 
            while (! t.isEmpty())
            {
                auto hexValue = CharacterFunctions::getHexDigitValue (t.getAndAdvance());
 
                if (hexValue >= 0)
                    result = static_cast<ResultType> (result << 4) | static_cast<ResultType> (hexValue);
            }
 
            return result;
        }
    };
 
    //==============================================================================
    template <typename CharPointerType>
    static size_t lengthUpTo (CharPointerType text, const size_t maxCharsToCount) noexcept
    {
        size_t len = 0;
 
        while (len < maxCharsToCount && text.getAndAdvance() != 0)
            ++len;
 
        return len;
    }
 
    template <typename CharPointerType>
    static size_t lengthUpTo (CharPointerType start, const CharPointerType end) noexcept
    {
        size_t len = 0;
 
        while (start < end && start.getAndAdvance() != 0)
            ++len;
 
        return len;
    }
 
    template <typename DestCharPointerType, typename SrcCharPointerType>
    static void copyAll (DestCharPointerType& dest, SrcCharPointerType src) noexcept
    {
        while (auto c = src.getAndAdvance())
            dest.write (c);
 
        dest.writeNull();
    }
 
    template <typename DestCharPointerType, typename SrcCharPointerType>
    static size_t copyWithDestByteLimit (DestCharPointerType& dest, SrcCharPointerType src, size_t maxBytesToWrite) noexcept
    {
        auto startAddress = dest.getAddress();
        auto maxBytes = (ssize_t) maxBytesToWrite;
        maxBytes -= (ssize_t) sizeof (typename DestCharPointerType::CharType); // (allow for a terminating null)
 
        for (;;)
        {
            auto c = src.getAndAdvance();
            auto bytesNeeded = (ssize_t) DestCharPointerType::getBytesRequiredFor (c);
            maxBytes -= bytesNeeded;
 
            if (c == 0 || maxBytes < 0)
                break;
 
            dest.write (c);
        }
 
        dest.writeNull();
 
        return (size_t) getAddressDifference (dest.getAddress(), startAddress)
                 + sizeof (typename DestCharPointerType::CharType);
    }
 
    template <typename DestCharPointerType, typename SrcCharPointerType>
    static void copyWithCharLimit (DestCharPointerType& dest, SrcCharPointerType src, int maxChars) noexcept
    {
        while (--maxChars > 0)
        {
            auto c = src.getAndAdvance();
 
            if (c == 0)
                break;
 
            dest.write (c);
        }
 
        dest.writeNull();
    }
 
    static int compare (juce_wchar char1, juce_wchar char2) noexcept
    {
        if (auto diff = static_cast<int> (char1) - static_cast<int> (char2))
            return diff < 0 ? -1 : 1;
 
        return 0;
    }
 
    template <typename CharPointerType1, typename CharPointerType2>
    static int compare (CharPointerType1 s1, CharPointerType2 s2) noexcept
    {
        for (;;)
        {
            auto c1 = s1.getAndAdvance();
 
            if (auto diff = compare (c1, s2.getAndAdvance()))
                return diff;
 
            if (c1 == 0)
                break;
        }
 
        return 0;
    }
 
    template <typename CharPointerType1, typename CharPointerType2>
    static int compareUpTo (CharPointerType1 s1, CharPointerType2 s2, int maxChars) noexcept
    {
        while (--maxChars >= 0)
        {
            auto c1 = s1.getAndAdvance();
 
            if (auto diff = compare (c1, s2.getAndAdvance()))
                return diff;
 
            if (c1 == 0)
                break;
        }
 
        return 0;
    }
 
    static int compareIgnoreCase (juce_wchar char1, juce_wchar char2) noexcept
    {
        return char1 != char2 ? compare (toUpperCase (char1), toUpperCase (char2)) : 0;
    }
 
    template <typename CharPointerType1, typename CharPointerType2>
    static int compareIgnoreCase (CharPointerType1 s1, CharPointerType2 s2) noexcept
    {
        for (;;)
        {
            auto c1 = s1.getAndAdvance();
 
            if (auto diff = compareIgnoreCase (c1, s2.getAndAdvance()))
                return diff;
 
            if (c1 == 0)
                break;
        }
 
        return 0;
    }
 
    template <typename CharPointerType1, typename CharPointerType2>
    static int compareIgnoreCaseUpTo (CharPointerType1 s1, CharPointerType2 s2, int maxChars) noexcept
    {
        while (--maxChars >= 0)
        {
            auto c1 = s1.getAndAdvance();
 
            if (auto diff = compareIgnoreCase (c1, s2.getAndAdvance()))
                return diff;
 
            if (c1 == 0)
                break;
        }
 
        return 0;
    }
 
    template <typename CharPointerType1, typename CharPointerType2>
    static int indexOf (CharPointerType1 textToSearch, const CharPointerType2 substringToLookFor) noexcept
    {
        int index = 0;
        auto substringLength = (int) substringToLookFor.length();
 
        for (;;)
        {
            if (textToSearch.compareUpTo (substringToLookFor, substringLength) == 0)
                return index;
 
            if (textToSearch.getAndAdvance() == 0)
                return -1;
 
            ++index;
        }
    }
 
    template <typename CharPointerType1, typename CharPointerType2>
    static CharPointerType1 find (CharPointerType1 textToSearch, const CharPointerType2 substringToLookFor) noexcept
    {
        auto substringLength = (int) substringToLookFor.length();
 
        while (textToSearch.compareUpTo (substringToLookFor, substringLength) != 0
                 && ! textToSearch.isEmpty())
            ++textToSearch;
 
        return textToSearch;
    }
 
    template <typename CharPointerType>
    static CharPointerType find (CharPointerType textToSearch, const juce_wchar charToLookFor) noexcept
    {
        for (;; ++textToSearch)
        {
            auto c = *textToSearch;
 
            if (c == charToLookFor || c == 0)
                break;
        }
 
        return textToSearch;
    }
 
    template <typename CharPointerType1, typename CharPointerType2>
    static int indexOfIgnoreCase (CharPointerType1 haystack, const CharPointerType2 needle) noexcept
    {
        int index = 0;
        auto needleLength = (int) needle.length();
 
        for (;;)
        {
            if (haystack.compareIgnoreCaseUpTo (needle, needleLength) == 0)
                return index;
 
            if (haystack.getAndAdvance() == 0)
                return -1;
 
            ++index;
        }
    }
 
    template <typename Type>
    static int indexOfChar (Type text, const juce_wchar charToFind) noexcept
    {
        int i = 0;
 
        while (! text.isEmpty())
        {
            if (text.getAndAdvance() == charToFind)
                return i;
 
            ++i;
        }
 
        return -1;
    }
 
    template <typename Type>
    static int indexOfCharIgnoreCase (Type text, juce_wchar charToFind) noexcept
    {
        charToFind = CharacterFunctions::toLowerCase (charToFind);
        int i = 0;
 
        while (! text.isEmpty())
        {
            if (text.toLowerCase() == charToFind)
                return i;
 
            ++text;
            ++i;
        }
 
        return -1;
    }
 
    template <typename Type>
    static void incrementToEndOfWhitespace (Type& text) noexcept
    {
        while (text.isWhitespace())
            ++text;
    }
 
    template <typename Type>
    static Type findEndOfWhitespace (Type text) noexcept
    {
        incrementToEndOfWhitespace (text);
        return text;
    }
 
    template <typename Type, typename BreakType>
    static Type findEndOfToken (Type text, BreakType breakCharacters, Type quoteCharacters)
    {
        juce_wchar currentQuoteChar = 0;
 
        while (! text.isEmpty())
        {
            auto c = text.getAndAdvance();
 
            if (currentQuoteChar == 0 && breakCharacters.indexOf (c) >= 0)
            {
                --text;
                break;
            }
 
            if (quoteCharacters.indexOf (c) >= 0)
            {
                if (currentQuoteChar == 0)
                    currentQuoteChar = c;
                else if (currentQuoteChar == c)
                    currentQuoteChar = 0;
            }
        }
 
        return text;
    }
 
private:
    static double mulexp10 (double value, int exponent) noexcept;
};
 
} // namespace juce