dexed/JuceLibraryCode/modules/juce_graphics/images/juce_ImageFileFormat.cpp

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

   This file is part of the JUCE library.
   Copyright (c) 2015 - ROLI Ltd.

   Permission is granted to use this software under the terms of either:
   a) the GPL v2 (or any later version)
   b) the Affero GPL v3

   Details of these licenses can be found at: www.gnu.org/licenses

   JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

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

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.juce.com for more information.

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

struct DefaultImageFormats
{
    static ImageFileFormat** get()
    {
        static DefaultImageFormats formats;
        return formats.formats;
    }

private:
    DefaultImageFormats() noexcept
    {
        formats[0] = &png;
        formats[1] = &jpg;
        formats[2] = &gif;
        formats[3] = nullptr;
    }

    PNGImageFormat  png;
    JPEGImageFormat jpg;
    GIFImageFormat  gif;

    ImageFileFormat* formats[4];
};

ImageFileFormat* ImageFileFormat::findImageFormatForStream (InputStream& input)
{
    const int64 streamPos = input.getPosition();

    for (ImageFileFormat** i = DefaultImageFormats::get(); *i != nullptr; ++i)
    {
        const bool found = (*i)->canUnderstand (input);
        input.setPosition (streamPos);

        if (found)
            return *i;
    }

    return nullptr;
}

ImageFileFormat* ImageFileFormat::findImageFormatForFileExtension (const File& file)
{
    for (ImageFileFormat** i = DefaultImageFormats::get(); *i != nullptr; ++i)
        if ((*i)->usesFileExtension (file))
            return *i;

    return nullptr;
}

//==============================================================================
Image ImageFileFormat::loadFrom (InputStream& input)
{
    ImageFileFormat* const format = findImageFormatForStream (input);

    if (format != nullptr)
        return format->decodeImage (input);

    return Image::null;
}

Image ImageFileFormat::loadFrom (const File& file)
{
    FileInputStream stream (file);

    if (stream.openedOk())
    {
        BufferedInputStream b (stream, 8192);
        return loadFrom (b);
    }

    return Image::null;
}

Image ImageFileFormat::loadFrom (const void* rawData, const size_t numBytes)
{
    if (rawData != nullptr && numBytes > 4)
    {
        MemoryInputStream stream (rawData, numBytes, false);
        return loadFrom (stream);
    }

    return Image::null;
}