JUCE/modules/juce_audio_basics/midi/ump/juce_UMPUtils.h

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

   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.

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

#ifndef DOXYGEN

namespace juce
{
namespace universal_midi_packets
{

/**
    Helpful types and functions for interacting with Universal MIDI Packets.

    @tags{Audio}
*/
struct Utils
{
    /** Joins 4 bytes into a single 32-bit word. */
    static constexpr uint32_t bytesToWord (std::byte a, std::byte b, std::byte c, std::byte d)
    {
        return uint32_t (a) << 0x18
             | uint32_t (b) << 0x10
             | uint32_t (c) << 0x08
             | uint32_t (d) << 0x00;
    }

    /** Returns the expected number of 32-bit words in a Universal MIDI Packet, given
        the first word of the packet.

        The result will be between 1 and 4 inclusive.
        A result of 1 means that the word is itself a complete packet.
    */
    static uint32_t getNumWordsForMessageType (uint32_t);

    /**
        Helper functions for setting/getting 4-bit ranges inside a 32-bit word.
    */
    template <size_t Index>
    struct U4
    {
        static constexpr uint32_t shift = (uint32_t) 0x1c - Index * 4;

        static constexpr uint32_t set (uint32_t word, uint8_t value)
        {
            return (word & ~((uint32_t) 0xf << shift)) | (uint32_t) ((value & 0xf) << shift);
        }

        static constexpr uint8_t get (uint32_t word)
        {
            return (uint8_t) ((word >> shift) & 0xf);
        }
    };

    /**
        Helper functions for setting/getting 8-bit ranges inside a 32-bit word.
    */
    template <size_t Index>
    struct U8
    {
        static constexpr uint32_t shift = (uint32_t) 0x18 - Index * 8;

        static constexpr uint32_t set (uint32_t word, uint8_t value)
        {
            return (word & ~((uint32_t) 0xff << shift)) | (uint32_t) (value << shift);
        }

        static constexpr uint8_t get (uint32_t word)
        {
            return (uint8_t) ((word >> shift) & 0xff);
        }
    };

    /**
        Helper functions for setting/getting 16-bit ranges inside a 32-bit word.
    */
    template <size_t Index>
    struct U16
    {
        static constexpr uint32_t shift = (uint32_t) 0x10 - Index * 16;

        static constexpr uint32_t set (uint32_t word, uint16_t value)
        {
            return (word & ~((uint32_t) 0xffff << shift)) | (uint32_t) (value << shift);
        }

        static constexpr uint16_t get (uint32_t word)
        {
            return (uint16_t) ((word >> shift) & 0xffff);
        }
    };

    static constexpr uint8_t getMessageType (uint32_t w) noexcept { return U4<0>::get (w); }
    static constexpr uint8_t getGroup       (uint32_t w) noexcept { return U4<1>::get (w); }
    static constexpr uint8_t getStatus      (uint32_t w) noexcept { return U4<2>::get (w); }
    static constexpr uint8_t getChannel     (uint32_t w) noexcept { return U4<3>::get (w); }
};

}
}

#endif