/*

 * Copyright 2020 Google LLC

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#ifndef SkYUVAPixmaps_DEFINED

#define SkYUVAPixmaps_DEFINED

#include "include/core/SkData.h"

#include "include/core/SkImageInfo.h"

#include "include/core/SkPixmap.h"

#include "include/core/SkYUVAInfo.h"

#include "include/private/SkTo.h"

#include <array>

#include <bitset>

class GrImageContext;

/**

 * SkYUVAInfo combined with per-plane SkColorTypes and row bytes. Fully specifies the SkPixmaps

 * for a YUVA image without the actual pixel memory and data.

 */

class SK_API SkYUVAPixmapInfo {

public:

    static constexpr auto kMaxPlanes = SkYUVAInfo::kMaxPlanes;

    using PlaneConfig  = SkYUVAInfo::PlaneConfig;

    using Subsampling  = SkYUVAInfo::Subsampling;

    /**

     * Data type for Y, U, V, and possibly A channels independent of how values are packed into

     * planes.

     **/

    enum class DataType {

        kUnorm8,          ///< 8 bit unsigned normalized

        kUnorm16,         ///< 16 bit unsigned normalized

        kFloat16,         ///< 16 bit (half) floating point

        kUnorm10_Unorm2,  ///< 10 bit unorm for Y, U, and V. 2 bit unorm for alpha (if present).

        kLast = kUnorm10_Unorm2

    };

    static constexpr int kDataTypeCnt = static_cast<int>(DataType::kLast) + 1;

    class SK_API SupportedDataTypes {

    public:

        /** Defaults to nothing supported. */

        constexpr SupportedDataTypes() = default;

        /** Init based on texture formats supported by the context. */

        SupportedDataTypes(const GrImageContext&);

        /** All legal combinations of PlaneConfig and DataType are supported. */

        static constexpr SupportedDataTypes All();

        /**

         * Checks whether there is a supported combination of color types for planes structured

         * as indicated by PlaneConfig with channel data types as indicated by DataType.

         */

        constexpr bool supported(PlaneConfig, DataType) const;

        /**

         * Update to add support for pixmaps with numChannel channels where each channel is

         * represented as DataType.

         */

        void enableDataType(DataType, int numChannels);

    private:

        // The bit for DataType dt with n channels is at index kDataTypeCnt*(n-1) + dt.

        std::bitset<kDataTypeCnt*4> fDataTypeSupport = {};

    };

    /**

     * Gets the default SkColorType to use with numChannels channels, each represented as DataType.

     * Returns kUnknown_SkColorType if no such color type.

     */

    static constexpr SkColorType DefaultColorTypeForDataType(DataType dataType, int numChannels);

    /**

     * If the SkColorType is supported for YUVA pixmaps this will return the number of YUVA channels

     * that can be stored in a plane of this color type and what the DataType is of those channels.

     * If the SkColorType is not supported as a YUVA plane the number of channels is reported as 0

     * and the DataType returned should be ignored.

     */

    static std::tuple<int, DataType> NumChannelsAndDataType(SkColorType);

    /** Default SkYUVAPixmapInfo is invalid. */

    SkYUVAPixmapInfo() = default;

    /**

     * Initializes the SkYUVAPixmapInfo from a SkYUVAInfo with per-plane color types and row bytes.

     * This will be invalid if the colorTypes aren't compatible with the SkYUVAInfo or if a

     * rowBytes entry is not valid for the plane dimensions and color type. Color type and

     * row byte values beyond the number of planes in SkYUVAInfo are ignored. All SkColorTypes

     * must have the same DataType or this will be invalid.

     *

     * If rowBytes is nullptr then bpp*width is assumed for each plane.

     */

    SkYUVAPixmapInfo(const SkYUVAInfo&,

                     const SkColorType[kMaxPlanes],

                     const size_t rowBytes[kMaxPlanes]);

    /**

     * Like above but uses DefaultColorTypeForDataType to determine each plane's SkColorType. If

     * rowBytes is nullptr then bpp*width is assumed for each plane.

     */

    SkYUVAPixmapInfo(const SkYUVAInfo&, DataType, const size_t rowBytes[kMaxPlanes]);

    SkYUVAPixmapInfo(const SkYUVAPixmapInfo&) = default;

    SkYUVAPixmapInfo& operator=(const SkYUVAPixmapInfo&) = default;

    bool operator==(const SkYUVAPixmapInfo&) const;

    bool operator!=(const SkYUVAPixmapInfo& that) const { return !(*this == that); }

    const SkYUVAInfo& yuvaInfo() const { return fYUVAInfo; }

    SkYUVColorSpace yuvColorSpace() const { return fYUVAInfo.yuvColorSpace(); }

    /** The number of SkPixmap planes, 0 if this SkYUVAPixmapInfo is invalid. */

    int numPlanes() const { return fYUVAInfo.numPlanes(); }

    /** The per-YUV[A] channel data type. */

    DataType dataType() const { return fDataType; }

    /**

     * Row bytes for the ith plane. Returns zero if i >= numPlanes() or this SkYUVAPixmapInfo is

     * invalid.

     */

    size_t rowBytes(int i) const { return fRowBytes[static_cast<size_t>(i)]; }

    /** Image info for the ith plane, or default SkImageInfo if i >= numPlanes() */

    const SkImageInfo& planeInfo(int i) const { return fPlaneInfos[static_cast<size_t>(i)]; }

    /**

     * Determine size to allocate for all planes. Optionally retrieves the per-plane sizes in

     * planeSizes if not null. If total size overflows will return SIZE_MAX and set all planeSizes

     * to SIZE_MAX. Returns 0 and fills planesSizes with 0 if this SkYUVAPixmapInfo is not valid.

     */

    size_t computeTotalBytes(size_t planeSizes[kMaxPlanes] = nullptr) const;

    /**

     * Takes an allocation that is assumed to be at least computeTotalBytes() in size and configures

     * the first numPlanes() entries in pixmaps array to point into that memory. The remaining

     * entries of pixmaps are default initialized. Fails if this SkYUVAPixmapInfo not valid.

     */

    bool initPixmapsFromSingleAllocation(void* memory, SkPixmap pixmaps[kMaxPlanes]) const;

    /**

     * Returns true if this has been configured with a non-empty dimensioned SkYUVAInfo with

     * compatible color types and row bytes.

     */

    bool isValid() const { return fYUVAInfo.isValid(); }

    /** Is this valid and does it use color types allowed by the passed SupportedDataTypes? */

    bool isSupported(const SupportedDataTypes&) const;

private:

    SkYUVAInfo fYUVAInfo;

    std::array<SkImageInfo, kMaxPlanes> fPlaneInfos = {};

    std::array<size_t, kMaxPlanes> fRowBytes = {};

    DataType fDataType = DataType::kUnorm8;

    static_assert(kUnknown_SkColorType == 0, "default init isn't kUnknown");

};

/**

 * Helper to store SkPixmap planes as described by a SkYUVAPixmapInfo. Can be responsible for

 * allocating/freeing memory for pixmaps or use external memory.

 */

class SK_API SkYUVAPixmaps {

public:

    using DataType = SkYUVAPixmapInfo::DataType;

    static constexpr auto kMaxPlanes = SkYUVAPixmapInfo::kMaxPlanes;

    static SkColorType RecommendedRGBAColorType(DataType);

    /** Allocate space for pixmaps' pixels in the SkYUVAPixmaps. */

    static SkYUVAPixmaps Allocate(const SkYUVAPixmapInfo& yuvaPixmapInfo);

    /**

     * Use storage in SkData as backing store for pixmaps' pixels. SkData is retained by the

     * SkYUVAPixmaps.

     */

    static SkYUVAPixmaps FromData(const SkYUVAPixmapInfo&, sk_sp<SkData>);

    /**

     * Makes a deep copy of the src SkYUVAPixmaps. The returned SkYUVAPixmaps owns its planes'

     * backing stores.

     */

    static SkYUVAPixmaps MakeCopy(const SkYUVAPixmaps& src);

    /**

     * Use passed in memory as backing store for pixmaps' pixels. Caller must ensure memory remains

     * allocated while pixmaps are in use. There must be at least

     * SkYUVAPixmapInfo::computeTotalBytes() allocated starting at memory.

     */

    static SkYUVAPixmaps FromExternalMemory(const SkYUVAPixmapInfo&, void* memory);

    /**

     * Wraps existing SkPixmaps. The SkYUVAPixmaps will have no ownership of the SkPixmaps' pixel

     * memory so the caller must ensure it remains valid. Will return an invalid SkYUVAPixmaps if

     * the SkYUVAInfo isn't compatible with the SkPixmap array (number of planes, plane dimensions,

     * sufficient color channels in planes, ...).

     */

    static SkYUVAPixmaps FromExternalPixmaps(const SkYUVAInfo&, const SkPixmap[kMaxPlanes]);

    /** Default SkYUVAPixmaps is invalid. */

    SkYUVAPixmaps() = default;

    ~SkYUVAPixmaps() = default;

    SkYUVAPixmaps(SkYUVAPixmaps&& that) = default;

    SkYUVAPixmaps& operator=(SkYUVAPixmaps&& that) = default;

    SkYUVAPixmaps(const SkYUVAPixmaps&) = default;

    SkYUVAPixmaps& operator=(const SkYUVAPixmaps& that) = default;

    /** Does have initialized pixmaps compatible with its SkYUVAInfo. */

    bool isValid() const { return !fYUVAInfo.dimensions().isEmpty(); }

    const SkYUVAInfo& yuvaInfo() const { return fYUVAInfo; }

    DataType dataType() const { return fDataType; }

    SkYUVAPixmapInfo pixmapsInfo() const;

    /** Number of pixmap planes or 0 if this SkYUVAPixmaps is invalid. */

    int numPlanes() const { return this->isValid() ? fYUVAInfo.numPlanes() : 0; }

    /**

     * Access the SkPixmap planes. They are default initialized if this is not a valid

     * SkYUVAPixmaps.

     */

    const std::array<SkPixmap, kMaxPlanes>& planes() const { return fPlanes; }

    /**

     * Get the ith SkPixmap plane. SkPixmap will be default initialized if i >= numPlanes or this

     * SkYUVAPixmaps is invalid.

     */

    const SkPixmap& plane(int i) const { return fPlanes[SkToSizeT(i)]; }

    /**

     * Computes a YUVALocations representation of the planar layout. The result is guaranteed to be

     * valid if this->isValid().

     */

    SkYUVAInfo::YUVALocations toYUVALocations() const;

    /** Does this SkPixmaps own the backing store of the planes? */

    bool ownsStorage() const { return SkToBool(fData); }

private:

    SkYUVAPixmaps(const SkYUVAPixmapInfo&, sk_sp<SkData>);

    SkYUVAPixmaps(const SkYUVAInfo&, DataType, const SkPixmap[kMaxPlanes]);

    std::array<SkPixmap, kMaxPlanes> fPlanes = {};

    sk_sp<SkData> fData;

    SkYUVAInfo fYUVAInfo;

    DataType fDataType;

};

//////////////////////////////////////////////////////////////////////////////

constexpr SkYUVAPixmapInfo::SupportedDataTypes SkYUVAPixmapInfo::SupportedDataTypes::All() {

    using ULL = unsigned long long; // bitset cons. takes this.

    ULL bits = 0;

    for (ULL c = 1; c <= 4; ++c) {

        for (ULL dt = 0; dt <= ULL(kDataTypeCnt); ++dt) {

            if (DefaultColorTypeForDataType(static_cast<DataType>(dt),

                                            static_cast<int>(c)) != kUnknown_SkColorType) {

                bits |= ULL(1) << (dt + static_cast<ULL>(kDataTypeCnt)*(c - 1));

            }

        }

    }

    SupportedDataTypes combinations;

    combinations.fDataTypeSupport = bits;

    return combinations;

}

constexpr bool SkYUVAPixmapInfo::SupportedDataTypes::supported(PlaneConfig config,

                                                               DataType type) const {

    int n = SkYUVAInfo::NumPlanes(config);

    for (int i = 0; i < n; ++i) {

        auto c = static_cast<size_t>(SkYUVAInfo::NumChannelsInPlane(config, i));

        SkASSERT(c >= 1 && c <= 4);

        if (!fDataTypeSupport[static_cast<size_t>(type) +

                              (c - 1)*static_cast<size_t>(kDataTypeCnt)]) {

            return false;

        }

    }

    return true;

}

Unexecuted instantiation: SkYUVAPixmapInfo::SupportedDataTypes::supported(SkYUVAInfo::PlaneConfig, SkYUVAPixmapInfo::DataType) const

Unexecuted instantiation: SkYUVAPixmapInfo::SupportedDataTypes::supported(SkYUVAInfo::PlaneConfig, SkYUVAPixmapInfo::DataType) const

constexpr SkColorType SkYUVAPixmapInfo::DefaultColorTypeForDataType(DataType dataType,

                                                                    int numChannels) {

    switch (numChannels) {

        case 1:

            switch (dataType) {

                case DataType::kUnorm8:         return kGray_8_SkColorType;

                case DataType::kUnorm16:        return kA16_unorm_SkColorType;

                case DataType::kFloat16:        return kA16_float_SkColorType;

                case DataType::kUnorm10_Unorm2: return kUnknown_SkColorType;

            }

            break;

        case 2:

            switch (dataType) {

                case DataType::kUnorm8:         return kR8G8_unorm_SkColorType;

                case DataType::kUnorm16:        return kR16G16_unorm_SkColorType;

                case DataType::kFloat16:        return kR16G16_float_SkColorType;

                case DataType::kUnorm10_Unorm2: return kUnknown_SkColorType;

            }

            break;

        case 3:

            // None of these are tightly packed. The intended use case is for interleaved YUVA

            // planes where we're forcing opaqueness by ignoring the alpha values.

            // There are "x" rather than "A" variants for Unorm8 and Unorm10_Unorm2 but we don't

            // choose them because 1) there is no inherent advantage and 2) there is better support

            // in the GPU backend for the "A" versions.

            switch (dataType) {

                case DataType::kUnorm8:         return kRGBA_8888_SkColorType;

                case DataType::kUnorm16:        return kR16G16B16A16_unorm_SkColorType;

                case DataType::kFloat16:        return kRGBA_F16_SkColorType;

                case DataType::kUnorm10_Unorm2: return kRGBA_1010102_SkColorType;

            }

            break;

        case 4:

            switch (dataType) {

                case DataType::kUnorm8:         return kRGBA_8888_SkColorType;

                case DataType::kUnorm16:        return kR16G16B16A16_unorm_SkColorType;

                case DataType::kFloat16:        return kRGBA_F16_SkColorType;

                case DataType::kUnorm10_Unorm2: return kRGBA_1010102_SkColorType;

            }

            break;

    }

    return kUnknown_SkColorType;

}

#endif