StringConverter.h

// Copyright (c) Stefano Cristiano
// SPDX-License-Identifier: MIT
#pragma once
#include "../Strings/StringView.h"
 
namespace SC
{
struct Buffer;
struct SC_COMPILER_EXPORT StringConverter;
struct String;
} // namespace SC
 
 
struct SC::StringConverter
{
    enum NullTermination
    {
        AddZeroTerminator,     
        DoNotAddZeroTerminator 
    };
 
    [[nodiscard]] static bool convertEncodingToUTF8(StringSpan text, Buffer& buffer, StringSpan* encodedText = nullptr,
                                                    NullTermination nullTerminate = AddZeroTerminator);
 
    [[nodiscard]] static bool convertEncodingToUTF16(StringSpan text, Buffer& buffer, StringSpan* encodedText = nullptr,
                                                     NullTermination nullTerminate = AddZeroTerminator);
 
    [[nodiscard]] static bool convertEncodingTo(StringEncoding encoding, StringSpan text, Buffer& buffer,
                                                StringSpan*     encodedText   = nullptr,
                                                NullTermination nullTerminate = AddZeroTerminator);
 
    enum Flags
    {
        Clear,     
        DoNotClear 
    };
 
    StringConverter(String& text, Flags flags = DoNotClear);
 
    StringConverter(Buffer& text, StringEncoding encoding);
 
    [[nodiscard]] bool convertNullTerminateFastPath(StringSpan input, StringSpan& encodedText);
 
    [[nodiscard]] bool appendNullTerminated(StringSpan input, bool popExistingNullTerminator = true);
 
  private:
    [[nodiscard]] static bool popNullTermIfNotEmpty(Buffer& stringData, StringEncoding encoding);
 
    [[nodiscard]] static bool pushNullTerm(Buffer& stringData, StringEncoding encoding);
 
    static void ensureZeroTermination(Buffer& data, StringEncoding encoding);
 
    void internalClear();
    // TODO: FileSystemIterator should just use a Buffer
    friend struct FileSystemIterator;
    friend struct String;
    template <int N>
    friend struct SmallString;
    friend struct StringBuilder;
    friend struct File;
 
    [[nodiscard]] bool        setTextLengthInBytesIncludingTerminator(size_t newDataSize);
    [[nodiscard]] static bool convertSameEncoding(StringSpan text, Buffer& buffer, StringSpan* encodedText,
                                                  NullTermination terminate);
    static void eventuallyNullTerminate(Buffer& buffer, StringEncoding destinationEncoding, StringSpan* encodedText,
                                        NullTermination terminate);
 
    StringEncoding encoding;
    Buffer&        data;
    // Appends the input string null terminated
    [[nodiscard]] bool internalAppend(StringSpan input, StringSpan* encodedText);
 
    // Fallbacks for platforms without an API to do the conversion out of the box (Linux)
    [[nodiscard]] static bool convertUTF16LE_to_UTF8(const StringSpan sourceUtf16, Buffer& destination,
                                                     int& writtenCodeUnits);
    [[nodiscard]] static bool convertUTF8_to_UTF16LE(const StringSpan sourceUtf8, Buffer& destination,
                                                     int& writtenCodeUnits);
};