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path: root/test/span.cpp

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2021, Google Inc.
 *
 * mapped_framebuffer.cpp - Mapped Framebuffer support
 */

#include "libcamera/internal/mapped_framebuffer.h"

#include <algorithm>
#include <errno.h>
#include <map>
#include <sys/mman.h>
#include <unistd.h>

#include <libcamera/base/log.h>

/**
 * \file libcamera/internal/mapped_framebuffer.h
 * \brief Frame buffer memory mapping support
 */

namespace libcamera {

LOG_DECLARE_CATEGORY(Buffer)

/**
 * \class MappedBuffer
 * \brief Provide an interface to support managing memory mapped buffers
 *
 * The MappedBuffer interface provides access to a set of MappedPlanes which
 * are available for access by the CPU.
 *
 * This class is not meant to be constructed directly, but instead derived
 * classes should be used to implement the correct mapping of a source buffer.
 *
 * This allows treating CPU accessible memory through a generic interface
 * regardless of whether it originates from a libcamera FrameBuffer or other
 * source.
 */

/**
 * \typedef MappedBuffer::Plane
 * \brief A mapped region of memory accessible to the CPU
 *
 * The MappedBuffer::Plane uses the Span interface to describe the mapped memory
 * region.
 */

/**
 * \brief Construct an empty MappedBuffer
 */
MappedBuffer::MappedBuffer()
	: error_(0)
{
}

/**
 * \brief Move constructor, construct the MappedBuffer with the contents of \a
 * other using move semantics
 * \param[in] other The other MappedBuffer
 *
 * Moving a MappedBuffer moves the mappings contained in the \a other to the new
 * MappedBuffer and invalidates the \a other.
 *
 * No mappings are unmapped or destroyed in this process.
 */
MappedBuffer::MappedBuffer(MappedBuffer &&other)
{
	*this = std::move(other);
}

/**
 * \brief Move assignment operator, replace the mappings with those of \a other
* \param[in] other The other MappedBuffer
 *
 * Moving a MappedBuffer moves the mappings contained in the \a other to the new
 * MappedBuffer and invalidates the \a other.
 *
 * No mappings are unmapped or destroyed in this process.
 */
MappedBuffer &MappedBuffer::operator=(MappedBuffer &&other)
{
	error_ = other.error_;
	planes_ = std::move(other.planes_);
	maps_ = std::move(other.maps_);
	other.error_ = -ENOENT;

	return *this;
}

MappedBuffer::~MappedBuffer()
{
	for (Plane &map : maps_)
		munmap(map.data(), map.size());
}

/**
 * \fn MappedBuffer::isValid()
 * \brief Check if the MappedBuffer instance is valid
 * \return True if the MappedBuffer has valid mappings, false otherwise
 */

/**
 * \fn MappedBuffer::error()
 * \brief Retrieve the map error status
 *
 * This function retrieves the error status from the MappedBuffer.