JUCE/extras/Build/juce_build_tools/utils/juce_ResourceFileHelpers.cpp

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

   This file is part of the JUCE library.
   Copyright (c) 2020 - Raw Material Software Limited

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 6 End-User License
   Agreement and JUCE Privacy Policy (both effective as of the 16th June 2020).

   End User License Agreement: www.juce.com/juce-6-licence
   Privacy Policy: www.juce.com/juce-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   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
{
namespace build_tools
{
    uint64 calculateStreamHashCode (InputStream& in)
    {
        uint64 t = 0;

        const int bufferSize = 4096;
        HeapBlock<uint8> buffer;
        buffer.malloc (bufferSize);

        for (;;)
        {
            auto num = in.read (buffer, bufferSize);

            if (num <= 0)
                break;

            for (int i = 0; i < num; ++i)
                t = t * 65599 + buffer[i];
        }

        return t;
    }

    uint64 calculateFileHashCode (const File& file)
    {
        std::unique_ptr<FileInputStream> stream (file.createInputStream());
        return stream != nullptr ? calculateStreamHashCode (*stream) : 0;
    }

    uint64 calculateMemoryHashCode (const void* data, size_t numBytes)
    {
        uint64 t = 0;

        for (size_t i = 0; i < numBytes; ++i)
            t = t * 65599 + static_cast<const uint8*> (data)[i];

        return t;
    }

    bool overwriteFileWithNewDataIfDifferent (const File& file, const void* data, size_t numBytes)
    {
        if (file.getSize() == (int64) numBytes
            && calculateMemoryHashCode (data, numBytes) == calculateFileHashCode (file))
            return true;

        if (file.exists())
            return file.replaceWithData (data, numBytes);

        return file.getParentDirectory().createDirectory() && file.appendData (data, numBytes);
    }

    bool overwriteFileWithNewDataIfDifferent (const File& file, const MemoryOutputStream& newData)
    {
        return overwriteFileWithNewDataIfDifferent (file, newData.getData(), newData.getDataSize());
    }

    bool overwriteFileWithNewDataIfDifferent (const File& file, const String& newData)
    {
        const char* const utf8 = newData.toUTF8();
        return overwriteFileWithNewDataIfDifferent (file, utf8, strlen (utf8));
    }
}
}