//
// Copyright (c) 2014-2015 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

#include "common/mathutil.h"

namespace rx
{

template <typename T>
inline T *OffsetDataPointer(uint8_t *data, size_t y, size_t z, size_t rowPitch, size_t depthPitch)
{
    return reinterpret_cast<T*>(data + (y * rowPitch) + (z * depthPitch));
}

template <typename T>
inline const T *OffsetDataPointer(const uint8_t *data, size_t y, size_t z, size_t rowPitch, size_t depthPitch)
{
    return reinterpret_cast<const T*>(data + (y * rowPitch) + (z * depthPitch));
}

template <typename type, size_t componentCount>
inline void LoadToNative(size_t width, size_t height, size_t depth,
                         const uint8_t *input, size_t inputRowPitch, size_t inputDepthPitch,
                         uint8_t *output, size_t outputRowPitch, size_t outputDepthPitch)
{
    const size_t rowSize = width * sizeof(type) * componentCount;
    const size_t layerSize = rowSize * height;
    const size_t imageSize = layerSize * depth;

    if (layerSize == inputDepthPitch && layerSize == outputDepthPitch)
    {
        ASSERT(rowSize == inputRowPitch && rowSize == outputRowPitch);
        memcpy(output, input, imageSize);
    }
    else if (rowSize == inputRowPitch && rowSize == outputRowPitch)
    {
        for (size_t z = 0; z < depth; z++)
        {
            const type *source = OffsetDataPointer<type>(input, 0, z, inputRowPitch, inputDepthPitch);
            type *dest = OffsetDataPointer<type>(output, 0, z, outputRowPitch, outputDepthPitch);

            memcpy(dest, source, layerSize);
        }
    }
    else
    {
        for (size_t z = 0; z < depth; z++)
        {
            for (size_t y = 0; y < height; y++)
            {
                const type *source = OffsetDataPointer<type>(input, y, z, inputRowPitch, inputDepthPitch);
                type *dest = OffsetDataPointer<type>(output, y, z, outputRowPitch, outputDepthPitch);
                memcpy(dest, source, width * sizeof(type) * componentCount);
            }
        }
    }
}

template <typename type, uint32_t fourthComponentBits>
inline void LoadToNative3To4(size_t width, size_t height, size_t depth,
                             const uint8_t *input, size_t inputRowPitch, size_t inputDepthPitch,
                             uint8_t *output, size_t outputRowPitch, size_t outputDepthPitch)
{
    const type fourthValue = gl::bitCast<type>(fourthComponentBits);

    for (size_t z = 0; z < depth; z++)
    {
        for (size_t y = 0; y < height; y++)
        {
            const type *source = OffsetDataPointer<type>(input, y, z, inputRowPitch, inputDepthPitch);
            type *dest = OffsetDataPointer<type>(output, y, z, outputRowPitch, outputDepthPitch);
            for (size_t x = 0; x < width; x++)
            {
                dest[x * 4 + 0] = source[x * 3 + 0];
                dest[x * 4 + 1] = source[x * 3 + 1];
                dest[x * 4 + 2] = source[x * 3 + 2];
                dest[x * 4 + 3] = fourthValue;
            }
        }
    }
}

template <size_t componentCount>
inline void Load32FTo16F(size_t width, size_t height, size_t depth,
                         const uint8_t *input, size_t inputRowPitch, size_t inputDepthPitch,
                         uint8_t *output, size_t outputRowPitch, size_t outputDepthPitch)
{
    const size_t elementWidth = componentCount * width;

    for (size_t z = 0; z < depth; z++)
    {
        for (size_t y = 0; y < height; y++)
        {
            const float *source = OffsetDataPointer<float>(input, y, z, inputRowPitch, inputDepthPitch);
            uint16_t *dest = OffsetDataPointer<uint16_t>(output, y, z, outputRowPitch, outputDepthPitch);

            for (size_t x = 0; x < elementWidth; x++)
            {
                dest[x] = gl::float32ToFloat16(source[x]);
            }
        }
    }
}

template <size_t blockWidth, size_t blockHeight, size_t blockSize>
inline void LoadCompressedToNative(size_t width, size_t height, size_t depth,
                                   const uint8_t *input, size_t inputRowPitch, size_t inputDepthPitch,
                                   uint8_t *output, size_t outputRowPitch, size_t outputDepthPitch)
{
    const size_t columns = (width + (blockWidth - 1)) / blockWidth;
    const size_t rows = (height + (blockHeight - 1)) / blockHeight;

    for (size_t z = 0; z < depth; ++z)
    {
        for (size_t y = 0; y < rows; ++y)
        {
            const uint8_t *source = OffsetDataPointer<uint8_t>(input, y, z, inputRowPitch, inputDepthPitch);
            uint8_t *dest = OffsetDataPointer<uint8_t>(output, y, z, outputRowPitch, outputDepthPitch);
            memcpy(dest, source, columns * blockSize);
        }
    }
}

template <typename type, uint32_t firstBits, uint32_t secondBits, uint32_t thirdBits, uint32_t fourthBits>
inline void Initialize4ComponentData(size_t width, size_t height, size_t depth,
                                     uint8_t *output, size_t outputRowPitch, size_t outputDepthPitch)
{
    type writeValues[4] =
    {
        gl::bitCast<type>(firstBits),
        gl::bitCast<type>(secondBits),
        gl::bitCast<type>(thirdBits),
        gl::bitCast<type>(fourthBits),
    };

    for (size_t z = 0; z < depth; z++)
    {
        for (size_t y = 0; y < height; y++)
        {
            type *destRow = OffsetDataPointer<type>(output, y, z, outputRowPitch, outputDepthPitch);
            for (size_t x = 0; x < width; x++)
            {
                type* destPixel = destRow + x * 4;

                // This could potentially be optimized by generating an entire row of initialization
                // data and copying row by row instead of pixel by pixel.
                memcpy(destPixel, writeValues, sizeof(type) * 4);
            }
        }
    }
}

}
