JUCE/modules/juce_blocks_basics/protocol/juce_HostPacketBuilder.h

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

   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.

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


/**
    Helper class for constructing a packet for sending to a BLOCKS device
*/
template <int maxPacketBytes>
struct HostPacketBuilder
{
    HostPacketBuilder() noexcept {}
    HostPacketBuilder (const HostPacketBuilder&) = delete;
    HostPacketBuilder (HostPacketBuilder&&) = default;

    const void* getData() const noexcept        { return data.getData(); }
    int size() const noexcept                   { return data.size(); }

    //==============================================================================
    void writePacketSysexHeaderBytes (TopologyIndex deviceIndex) noexcept
    {
        static_assert (maxPacketBytes > 10, "Not enough bytes for a sensible message!");

        jassert ((deviceIndex & 64) == 0);

        data.writeHeaderSysexBytes (deviceIndex);
    }

    void writePacketSysexFooter() noexcept
    {
        data.writePacketSysexFooter();
    }

    //==============================================================================
    bool deviceControlMessage (DeviceCommand command) noexcept
    {
        if (! data.hasCapacity (MessageType::bits + DeviceCommand::bits))
            return false;

        writeMessageType (MessageFromHost::deviceCommandMessage);
        data << command;
        return true;
    }

    //==============================================================================
    bool beginDataChanges (PacketIndex packetIndex) noexcept
    {
        if (! data.hasCapacity (MessageType::bits + PacketIndex::bits + DataChangeCommand::bits))
            return false;

        writeMessageType (MessageFromHost::sharedDataChange);
        data << packetIndex;
        return true;
    }

    bool endDataChanges (bool isLastChange) noexcept
    {
        if (! data.hasCapacity (DataChangeCommand::bits))
            return false;

        data << DataChangeCommand ((uint32) isLastChange ? endOfChanges : endOfPacket);
        return true;
    }

    bool skipBytes (int numToSkip) noexcept
    {
        if (numToSkip <= 0)
            return true;

        auto state = data.getState();

        while (numToSkip > ByteCountMany::maxValue)
        {
            if (! skipBytes (ByteCountMany::maxValue))
            {
                data.restore (state);
                return false;
            }

            numToSkip -= ByteCountMany::maxValue;
        }

        if (numToSkip > ByteCountFew::maxValue)
        {
            if (! data.hasCapacity (DataChangeCommand::bits * 2 + ByteCountMany::bits))
            {
                data.restore (state);
                return false;
            }

            data << DataChangeCommand ((uint32) skipBytesMany) << ByteCountMany ((uint32) numToSkip);
            return true;
        }

        if (! data.hasCapacity (DataChangeCommand::bits * 2 + ByteCountFew::bits))
        {
            data.restore (state);
            return false;
        }

        data << DataChangeCommand ((uint32) skipBytesFew) << ByteCountFew ((uint32) numToSkip);
        return true;
    }

    bool setMultipleBytes (const uint8* values, int num) noexcept
    {
        if (num <= 0)
            return true;

        if (! data.hasCapacity (DataChangeCommand::bits * 2 + num * (1 + ByteValue::bits)))
            return false;

        data << DataChangeCommand ((uint32) setSequenceOfBytes);

        for (int i = 0; i < num; ++i)
            data << ByteValue ((uint32) values[i])
                 << ByteSequenceContinues (i < num - 1 ? 1 : 0);

        return true;
    }

    bool setMultipleBytes (uint8 value, uint8 lastValue, int num) noexcept
    {
        if (num <= 0)
            return true;

        if (num == 1)
            return setMultipleBytes (&value, 1); // (this is a more compact message)

        auto state = data.getState();

        if (num > ByteCountMany::maxValue)
        {
            if (! setMultipleBytes (value, lastValue, ByteCountMany::maxValue))
            {
                data.restore (state);
                return false;
            }

            return setMultipleBytes (value, lastValue, num - ByteCountMany::maxValue);
        }

        if (num > ByteCountFew::maxValue)
        {
            if (! data.hasCapacity (DataChangeCommand::bits * 2 + ByteCountMany::bits + ByteValue::bits))
            {
                data.restore (state);
                return false;
            }

            data << DataChangeCommand ((uint32) setManyBytesWithValue)
                 << ByteCountMany ((uint32) num)
                 << ByteValue ((uint32) value);

            return true;
        }

        if (value == lastValue)
        {
            if (! data.hasCapacity (DataChangeCommand::bits * 2 + ByteCountFew::bits))
            {
                data.restore (state);
                return false;
            }

            data << DataChangeCommand ((uint32) setFewBytesWithLastValue) << ByteCountFew ((uint32) num);
            return true;
        }

        if (! data.hasCapacity (DataChangeCommand::bits * 2 + ByteCountFew::bits + ByteValue::bits))
        {
            data.restore (state);
            return false;
        }

        data << DataChangeCommand ((uint32) setFewBytesWithValue) << ByteCountFew ((uint32) num)
             << ByteValue ((uint32) value);

        return true;
    }

    bool addProgramEventMessage (const int32* messageData)
    {
        if (! data.hasCapacity (BitSizes::programEventMessage))
            return false;

        writeMessageType (MessageFromHost::programEventMessage);

        for (uint32 i = 0; i < numProgramMessageInts; ++i)
            data << IntegerWithBitSize<32> ((uint32) messageData[i]);

        return true;
    }

    //==============================================================================
private:
    Packed7BitArrayBuilder<maxPacketBytes> data;

    void writeMessageType (MessageFromHost type) noexcept
    {
        data << MessageType ((uint32) type);
    }
};