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

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

   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.

   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.

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

namespace juce
{
namespace universal_midi_packets
{

/**
    Enables iteration over a collection of Universal MIDI Packets stored as
    a contiguous range of 32-bit words.

    This iterator is used by Packets to allow access to the messages
    that it contains.

    @tags{Audio}
*/
class Iterator
{
public:
    /** Creates an invalid (singular) iterator. */
    Iterator() noexcept = default;

    /** Creates an iterator pointing at `ptr`. */
    explicit Iterator (const uint32_t* ptr, size_t bytes) noexcept
        : view (ptr)
       #if JUCE_DEBUG
        , bytesRemaining (bytes)
       #endif
    {
        ignoreUnused (bytes);
    }

    using difference_type    = std::iterator_traits<const uint32_t*>::difference_type;
    using value_type         = View;
    using reference          = const View&;
    using pointer            = const View*;
    using iterator_category  = std::forward_iterator_tag;

    /** Moves this iterator to the next packet in the range. */
    Iterator& operator++() noexcept
    {
        const auto increment = view.size();

       #if JUCE_DEBUG
        // If you hit this, the memory region contained a truncated or otherwise
        // malformed Universal MIDI Packet.
        // The Iterator can only be used on regions containing complete packets!
        jassert (increment <= bytesRemaining);
        bytesRemaining -= increment;
       #endif

        view = View (view.data() + increment);
        return *this;
    }

    /** Moves this iterator to the next packet in the range,
        returning the value of the iterator before it was
        incremented.
    */
    Iterator operator++ (int) noexcept
    {
        auto copy = *this;
        ++(*this);
        return copy;
    }

    /** Returns true if this iterator points to the same address
        as another iterator.
    */
    bool operator== (const Iterator& other) const noexcept
    {
        return view == other.view;
    }

    /** Returns false if this iterator points to the same address
        as another iterator.
    */
    bool operator!= (const Iterator& other) const noexcept
    {
        return ! operator== (other);
    }

    /** Returns a reference to a View of the packet currently
        pointed-to by this iterator.

        The View can be queried for its size and content.
    */
    reference operator*() noexcept { return view; }

    /** Returns a pointer to a View of the packet currently
        pointed-to by this iterator.

        The View can be queried for its size and content.
    */
    pointer operator->() noexcept { return &view; }

private:
    View view;

   #if JUCE_DEBUG
    size_t bytesRemaining = 0;
   #endif
};

}
}