JUCE/modules/juce_core/text/juce_Base64.cpp

/*
  ==============================================================================

   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
{

bool Base64::convertToBase64 (OutputStream& base64Result, const void* sourceData, size_t sourceDataSize)
{
    static const char lookup[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    auto* source = static_cast<const uint8*> (sourceData);

    while (sourceDataSize > 0)
    {
        char frame[4];
        auto byte0 = *source++;
        frame[0] = lookup [(byte0 & 0xfcu) >> 2];
        uint32 bits = (byte0 & 0x03u) << 4;

        if (sourceDataSize > 1)
        {
            auto byte1 = *source++;
            frame[1] = lookup[bits | ((byte1 & 0xf0u) >> 4)];
            bits = (byte1 & 0x0fu) << 2;

            if (sourceDataSize > 2)
            {
                auto byte2 = *source++;
                frame[2] = lookup[bits | ((byte2 & 0xc0u) >> 6)];
                frame[3] = lookup[byte2 & 0x3fu];
                sourceDataSize -= 3;
            }
            else
            {
                frame[2] = lookup[bits];
                frame[3] = '=';
                sourceDataSize = 0;
            }
        }
        else
        {
            frame[1] = lookup[bits];
            frame[2] = '=';
            frame[3] = '=';
            sourceDataSize = 0;
        }

        if (! base64Result.write (frame, 4))
            return false;
    }

    return true;
}

bool Base64::convertFromBase64 (OutputStream& binaryOutput, StringRef base64TextInput)
{
    for (auto s = base64TextInput.text; ! s.isEmpty();)
    {
        uint8 data[4];

        for (int i = 0; i < 4; ++i)
        {
            auto c = (uint32) s.getAndAdvance();

            if (c >= 'A' && c <= 'Z')         c -= 'A';
            else if (c >= 'a' && c <= 'z')    c -= 'a' - 26;
            else if (c >= '0' && c <= '9')    c += 52 - '0';
            else if (c == '+')                c = 62;
            else if (c == '/')                c = 63;
            else if (c == '=')                { c = 64; if (i <= 1) return false; }
            else                              return false;

            data[i] = (uint8) c;
        }

        binaryOutput.writeByte ((char) ((data[0] << 2) | (data[1] >> 4)));

        if (data[2] < 64)
        {
            binaryOutput.writeByte ((char) ((data[1] << 4) | (data[2] >> 2)));

            if (data[3] < 64)
                binaryOutput.writeByte ((char) ((data[2] << 6) | data[3]));
        }
    }

    return true;
}

String Base64::toBase64 (const void* sourceData, size_t sourceDataSize)
{
    MemoryOutputStream m ((sourceDataSize * 4) / 3 + 3);
    [[maybe_unused]] bool ok = convertToBase64 (m, sourceData, sourceDataSize);
    jassert (ok); // should always succeed for this simple case
    return m.toString();
}

String Base64::toBase64 (const String& text)
{
    return toBase64 (text.toRawUTF8(), strlen (text.toRawUTF8()));
}


//==============================================================================
//==============================================================================
#if JUCE_UNIT_TESTS

class Base64Tests final : public UnitTest
{
public:
    Base64Tests()
        : UnitTest ("Base64 class", UnitTestCategories::text)
    {}

    static MemoryBlock createRandomData (Random& r)
    {
        MemoryOutputStream m;

        for (int i = r.nextInt (400); --i >= 0;)
            m.writeByte ((char) r.nextInt (256));

        return m.getMemoryBlock();
    }

    void runTest() override
    {
        beginTest ("Base64");

        auto r = getRandom();

        for (int i = 1000; --i >= 0;)
        {
            auto original = createRandomData (r);
            auto asBase64 = Base64::toBase64 (original.getData(), original.getSize());
            MemoryOutputStream out;
            expect (Base64::convertFromBase64 (out, asBase64));
            auto result = out.getMemoryBlock();
            expect (result == original);
        }
    }
};

static Base64Tests base64Tests;

#endif

} // namespace juce