#ifndef Magnum_Vk_Memory_h
#define Magnum_Vk_Memory_h
/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
                2020 Vladimír Vondruš <mosra@centrum.cz>

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
*/

/** @file
 * @brief Class @ref Magnum::Vk::MemoryRequirements, @ref Magnum::Vk::MemoryAllocateInfo, @ref Magnum::Vk::Memory, enum @ref Magnum::Vk::MemoryFlag, enum set @ref Magnum::Vk::MemoryFlags
 */

#include <Corrade/Containers/EnumSet.h>

#include "Magnum/Magnum.h"
#include "Magnum/Tags.h"
#include "Magnum/Vk/Vk.h"
#include "Magnum/Vk/Vulkan.h"
#include "Magnum/Vk/visibility.h"

namespace Magnum { namespace Vk {

class MemoryMapDeleter;

/**
@brief Memory type flag
@m_since_latest

Wraps a @type_vk_keyword{MemoryPropertyFlagBits}.
@see @ref MemoryFlags, @ref DeviceProperties::memoryFlags()
@m_enum_values_as_keywords
*/
enum class MemoryFlag: UnsignedInt {
    /**
     * Device local. Always corresponds to a heap with
     * @ref MemoryHeapFlag::DeviceLocal.
     *
     * @m_class{m-note m-success}
     *
     * @par
     *      This memory is the most efficient for device access.
     */
    DeviceLocal = VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT,

    /** Memory that can be mapped for host access */
    HostVisible = VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT,

    /** Memory with coherent access on the host */
    HostCoherent = VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,

    /**
     * Memory that is cached on the host. Host memory accesses to uncached
     * memory are slower than to cached memory, however uncached memory is
     * always @ref MemoryFlag::HostCoherent.
     */
    HostCached = VK_MEMORY_PROPERTY_HOST_CACHED_BIT,

    /**
     * Lazily allocated memory. Allows only device access (i.e., there's no
     * memory that has both this and @ref MemoryFlag::HostVisible set).
     *
     * @m_class{m-note m-success}
     *
     * @par
     *      The device is allowed (but not required) to allocate the memory
     *      as-needed and thus is useful for example for temporary framebuffer
     *      attachments --- certain tiled architectures might not even need to
     *      allocate the memory in that case.
     */
    LazilyAllocated = VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT,

    /** @todo Protected, VK 1.1 */
};

/**
@debugoperatorclassenum{DeviceProperties,MemoryFlag}
@m_since_latest
*/
MAGNUM_VK_EXPORT Debug& operator<<(Debug& debug, MemoryFlag value);

/**
@brief Memory type flags
@m_since_latest

@see @ref DeviceProperties::memoryFlags()
*/
typedef Containers::EnumSet<MemoryFlag> MemoryFlags;

CORRADE_ENUMSET_OPERATORS(MemoryFlags)

/**
@debugoperatorclassenum{DeviceProperties,MemoryFlags}
@m_since_latest
*/
MAGNUM_VK_EXPORT Debug& operator<<(Debug& debug, MemoryFlags value);

/**
@brief Device memory
@m_since_latest

Wraps a @type_vk_keyword{DeviceMemory} and handles its allocation and mapping.

@section Vk-Memory-allocation Memory allocation

By default, the memory will get allocated for you during the creation of
@ref Buffer, @ref Image and other objects. In case you want to handle the
allocation yourself instead (which you indicate by passing the @ref NoAllocate
tag to constructors of these objects), it consists of these steps:

1.  Querying memory requirements of a particular object, for example using
    @ref Buffer::memoryRequirements() or @ref Image::memoryRequirements()
2.  Picking a memory type satisfying requirements of the object it's being
    allocated for (such as allowed memory types) and user requirements (whether
    it should be device-local, host-mappable etc.) using
    @ref DeviceProperties::pickMemory()
3.  Allocating a new @ref Memory or taking a (correctly aligned) sub-range of
    an existing allocation from given memory type
4.  Binding the memory (sub-range) to the object, using
    @ref Buffer::bindMemory(), @ref Image::bindMemory() and others

The following example allocates a single block memory for two buffers, one
containing vertex and the other index data:

@snippet MagnumVk.cpp Memory-allocation

@section Vk-Memory-mapping Memory mapping

If the memory is created with the @ref MemoryFlag::HostVisible flag, it can be
mapped on the host via @ref map(). The unmapping is then taken care of by a
custom deleter in the returned @ref Corrade::Containers::Array. It's possible
to map either the whole range or a sub-range, however note that one @ref Memory
object can't be mapped twice at the same time --- in the code snippet above, it
means that in order to upload vertex and index data, there are two options:

-   One is to first map the vertex buffer sub-range, upload the data, unmap it,
    and then do the same process for the index buffer sub-range. This way is
    more encapsulated without having to worry if there's already a mapping and
    who owns it, but means more work for the driver.
-   Another option is to map the whole memory at once and then upload data of
    particular buffers to correct subranges. Here the mapping has to be owned
    by some external entity which ensures it's valid for as long as any buffer
    wants to map its memory sub-range.

The following example maps the memory allocated above and copies index and
vertex data to it:

@snippet MagnumVk.cpp Memory-mapping

<b></b>

@m_class{m-note m-success}

@par Map temporarily or forever?
    Mapping smaller ranges and unmapping again after makes sense on 32-bit
    systems where the amount of virtual memory is limited --- otherwise it may
    happen that the system won't be able to find a sufficiently large block of
    virtual memory, causing the next mapping to fail. On 64-bit systems the
    virtual address space is sufficiently large for most use cases and it's
    common to just map the whole memory block for its whole lifetime.
*/
class MAGNUM_VK_EXPORT Memory {
    public:
        /**
         * @brief Wrap existing Vulkan handle
         * @param device    Vulkan device the memory is allocated on
         * @param handle    The @type_vk{DeviceMemory} handle
         * @param size      Memory size
         * @param flags     Handle flags
         *
         * The @p handle is expected to be originating from @p device. The
         * @p size parameter will be used to properly size the output array
         * coming from @ref map(). If a concrete @p size is unknown, use a
         * zero --- you will then be able to only use the @ref map(UnsignedLong, UnsignedLong)
         * overload.
         *
         * Unlike a memory allocated using a constructor, the Vulkan memory is
         * by default not freed on destruction, use @p flags for different
         * behavior.
         * @see @ref release()
         */
        static Memory wrap(Device& device, VkDeviceMemory handle, UnsignedLong size, HandleFlags flags = {});

        /**
         * @brief Constructor
         * @param device    Vulkan device to allocate the memory on
         * @param info      Memory allocation info
         *
         * @see @fn_vk_keyword{AllocateMemory}
         */
        explicit Memory(Device& device, const MemoryAllocateInfo& info);

        /**
         * @brief Construct without allocating the memory
         *
         * The constructed instance is equivalent to moved-from state. Useful
         * in cases where you will overwrite the instance later anyway. Move
         * another object over it to make it useful.
         */
        explicit Memory(NoCreateT);

        /** @brief Copying is not allowed */
        Memory(const Memory&) = delete;

        /** @brief Move constructor */
        Memory(Memory&& other) noexcept;

        /**
         * @brief Destructor
         *
         * Frees associated @type_vk{DeviceMemory} handle, unless the instance
         * was created using @ref wrap() without @ref HandleFlag::DestroyOnDestruction
         * specified.
         * @see @fn_vk_keyword{FreeMemory}, @ref release()
         */
        ~Memory();

        /** @brief Copying is not allowed */
        Memory& operator=(const Memory&) = delete;

        /** @brief Move assignment */
        Memory& operator=(Memory&& other) noexcept;

        /** @brief Underlying @type_vk{DeviceMemory} handle */
        VkDeviceMemory handle() { return _handle; }
        /** @overload */
        operator VkDeviceMemory() { return _handle; }

        /** @brief Handle flags */
        HandleFlags handleFlags() const { return _flags; }

        /** @brief Memory allocation size */
        UnsignedLong size() const { return _size; }

        /**
         * @brief Map a memory range
         * @param offset    Byte offset
         * @param size      Memory size
         *
         * The returned array size is @p size and the deleter performs an
         * unmap. For this operation to work, the memory has to be allocated
         * with @ref MemoryFlag::HostVisible and the @p offset and @p size be
         * in bounds for @ref size().
         * @see @fn_vk_keyword{MapMemory}, @fn_vk{UnmapMemory}
         */
        Containers::Array<char, MemoryMapDeleter> map(UnsignedLong offset, UnsignedLong size);

        /**
         * @brief Map the whole memory
         *
         * Equivalent to calling @ref map(UnsignedLong, UnsignedLong) with
         * @cpp 0 @ce and @ref size().
         */
        Containers::Array<char, MemoryMapDeleter> map();

        /**
         * @brief Map a memory range read-only
         *
         * Like @ref map(UnsignedLong, UnsignedLong) but returning a
         * @cpp const @ce array. Currently Vulkan doesn't have any flags to
         * control read/write access, so apart from a different return type the
         * behavior is equivalent.
         */
        Containers::Array<const char, MemoryMapDeleter> mapRead(UnsignedLong offset, UnsignedLong size);

        /**
         * @brief Map the whole memory read-only
         *
         * Equivalent to calling @ref mapRead(UnsignedLong, UnsignedLong) with
         * @cpp 0 @ce and @ref size().
         */
        Containers::Array<const char, MemoryMapDeleter> mapRead();

        /**
         * @brief Release the underlying Vulkan memory
         *
         * Releases ownership of the Vulkan memory and returns its handle so
         * @fn_vk{FreeMemory} is not called on destruction. The internal state
         * is then equivalent to moved-from state.
         * @see @ref wrap()
         */
        VkDeviceMemory release();

    private:
        /* Can't be a reference because of the NoCreate constructor */
        Device* _device;

        VkDeviceMemory _handle;
        HandleFlags _flags;
        UnsignedLong _size;
};

/** @relates Memory
@brief Deleter for mapped memory
@m_since_latest

Deleter for the array returned from @ref Memory::map(). Calls
@fn_vk_keyword{UnmapMemory}.
*/
class MAGNUM_VK_EXPORT MemoryMapDeleter {
    #ifndef DOXYGEN_GENERATING_OUTPUT
    public:
        explicit MemoryMapDeleter(): _unmap{}, _device{}, _memory{} {}
        explicit MemoryMapDeleter(void(*unmap)(VkDevice, VkDeviceMemory), VkDevice device, VkDeviceMemory memory): _unmap{unmap}, _device{device}, _memory{memory} {}
        void operator()(const char*, std::size_t) {
            if(_unmap) _unmap(_device, _memory);
        }

    private:
        void(*_unmap)(VkDevice, VkDeviceMemory);
        VkDevice _device;
        VkDeviceMemory _memory;
    #endif
};

}}

#endif