JUCE/modules/juce_core/text/juce_Base64.cpp

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

   This file is part of the JUCE library.
   Copyright (c) 2016 - ROLI Ltd.

   Permission is granted to use this software 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.

   THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD
   TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
   FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT,
   OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
   USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
   TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
   OF THIS SOFTWARE.

   -----------------------------------------------------------------------------

   To release a closed-source product which uses other parts of JUCE not
   licensed under the ISC terms, commercial licenses are available: visit
   www.juce.com for more information.

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

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

    while (sourceDataSize > 0)
    {
        char frame[4];
        const uint8 byte0 = *source++;
        frame[0] = lookup [(byte0 & 0xfcu) >> 2];
        uint32 bits = (byte0 & 0x03u) << 4;

        if (sourceDataSize > 1)
        {
            const uint8 byte1 = *source++;
            frame[1] = lookup[bits | ((byte1 & 0xf0u) >> 4)];
            bits = (byte1 & 0x0fu) << 2;

            if (sourceDataSize > 2)
            {
                const uint8 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 (String::CharPointerType s = base64TextInput.text; ! s.isEmpty();)
    {
        uint8 data[4];

        for (int i = 0; i < 4; ++i)
        {
            uint32 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);
    bool ok = convertToBase64 (m, sourceData, sourceDataSize);
    jassert (ok); // should always succeed for this simple case
    ignoreUnused (ok);
    return m.toString();
}

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


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

class Base64Tests  : public UnitTest
{
public:
    Base64Tests() : UnitTest ("Base64 class") {}

    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");

        Random r = getRandom();

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

static Base64Tests base64Tests;

#endif