/*
 * Copyright 2006 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */


#include "SkSpriteBlitter.h"
#include "SkArenaAlloc.h"
#include "SkBlitRow.h"
#include "SkTemplates.h"
#include "SkUtils.h"
#include "SkColorPriv.h"

#define D16_S32A_Opaque_Pixel(dst, sc)                                        \
do {                                                                          \
    if (sc) {                                                                 \
        *dst = SkSrcOver32To16(sc, *dst);                                     \
    }                                                                         \
} while (0)

static inline void D16_S32A_Blend_Pixel_helper(uint16_t* dst, SkPMColor sc,
                                               unsigned src_scale) {
    uint16_t dc = *dst;
    unsigned sa = SkGetPackedA32(sc);
    unsigned dr, dg, db;

    if (255 == sa) {
        dr = SkAlphaBlend(SkPacked32ToR16(sc), SkGetPackedR16(dc), src_scale);
        dg = SkAlphaBlend(SkPacked32ToG16(sc), SkGetPackedG16(dc), src_scale);
        db = SkAlphaBlend(SkPacked32ToB16(sc), SkGetPackedB16(dc), src_scale);
    } else {
#ifdef SK_SUPPORT_LEGACY_BROKEN_LERP
        unsigned dst_scale = 255 - SkAlphaMul(sa, src_scale);
#else
        unsigned dst_scale = SkAlphaMulInv256(sa, src_scale);
#endif
        dr = (SkPacked32ToR16(sc) * src_scale + SkGetPackedR16(dc) * dst_scale) >> 8;
        dg = (SkPacked32ToG16(sc) * src_scale + SkGetPackedG16(dc) * dst_scale) >> 8;
        db = (SkPacked32ToB16(sc) * src_scale + SkGetPackedB16(dc) * dst_scale) >> 8;
    }
    *dst = SkPackRGB16(dr, dg, db);
}

#define D16_S32A_Blend_Pixel(dst, sc, src_scale) \
    do { if (sc) D16_S32A_Blend_Pixel_helper(dst, sc, src_scale); } while (0)


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

class Sprite_D16_S16_Opaque : public SkSpriteBlitter {
public:
    Sprite_D16_S16_Opaque(const SkPixmap& source) : SkSpriteBlitter(source) {}

    // overrides
    void blitRect(int x, int y, int width, int height) override {
        uint16_t* SK_RESTRICT dst = fDst.writable_addr16(x, y);
        const uint16_t* SK_RESTRICT src = fSource.addr16(x - fLeft, y - fTop);
        size_t dstRB = fDst.rowBytes();
        size_t srcRB = fSource.rowBytes();

        while (--height >= 0) {
            memcpy(dst, src, width << 1);
            dst = (uint16_t*)((char*)dst + dstRB);
            src = (const uint16_t*)((const char*)src + srcRB);
        }
    }
};

#define D16_S16_Blend_Pixel(dst, sc, scale)     \
    do {                                        \
        uint16_t dc = *dst;                     \
        *dst = SkBlendRGB16(sc, dc, scale);     \
    } while (0)

#define SkSPRITE_CLASSNAME                  Sprite_D16_S16_Blend
#define SkSPRITE_ARGS                       , uint8_t alpha
#define SkSPRITE_FIELDS                     uint8_t  fSrcAlpha;
#define SkSPRITE_INIT                       fSrcAlpha = alpha;
#define SkSPRITE_DST_TYPE                   uint16_t
#define SkSPRITE_SRC_TYPE                   uint16_t
#define SkSPRITE_DST_GETADDR                writable_addr16
#define SkSPRITE_SRC_GETADDR                addr16
#define SkSPRITE_PREAMBLE(srcBM, x, y)      int scale = SkAlpha255To256(fSrcAlpha);
#define SkSPRITE_BLIT_PIXEL(dst, src)       D16_S16_Blend_Pixel(dst, src, scale)
#define SkSPRITE_NEXT_ROW
#define SkSPRITE_POSTAMBLE(srcBM)
#include "SkSpriteBlitterTemplate.h"

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

#define D16_S4444_Opaque(dst, sc)           \
    do {                                    \
        uint16_t dc = *dst;                 \
        *dst = SkSrcOver4444To16(sc, dc);   \
    } while (0)

#define SkSPRITE_CLASSNAME                  Sprite_D16_S4444_Opaque
#define SkSPRITE_ARGS
#define SkSPRITE_FIELDS
#define SkSPRITE_INIT
#define SkSPRITE_DST_TYPE                   uint16_t
#define SkSPRITE_SRC_TYPE                   SkPMColor16
#define SkSPRITE_DST_GETADDR                writable_addr16
#define SkSPRITE_SRC_GETADDR                addr16
#define SkSPRITE_PREAMBLE(srcBM, x, y)
#define SkSPRITE_BLIT_PIXEL(dst, src)       D16_S4444_Opaque(dst, src)
#define SkSPRITE_NEXT_ROW
#define SkSPRITE_POSTAMBLE(srcBM)
#include "SkSpriteBlitterTemplate.h"

#define D16_S4444_Blend(dst, sc, scale16)           \
    do {                                            \
        uint16_t dc = *dst;                         \
        *dst = SkBlend4444To16(sc, dc, scale16);    \
    } while (0)


#define SkSPRITE_CLASSNAME                  Sprite_D16_S4444_Blend
#define SkSPRITE_ARGS                       , uint8_t alpha
#define SkSPRITE_FIELDS                     uint8_t  fSrcAlpha;
#define SkSPRITE_INIT                       fSrcAlpha = alpha;
#define SkSPRITE_DST_TYPE                   uint16_t
#define SkSPRITE_SRC_TYPE                   uint16_t
#define SkSPRITE_DST_GETADDR                writable_addr16
#define SkSPRITE_SRC_GETADDR                addr16
#define SkSPRITE_PREAMBLE(srcBM, x, y)      int scale = SkAlpha15To16(fSrcAlpha);
#define SkSPRITE_BLIT_PIXEL(dst, src)       D16_S4444_Blend(dst, src, scale)
#define SkSPRITE_NEXT_ROW
#define SkSPRITE_POSTAMBLE(srcBM)
#include "SkSpriteBlitterTemplate.h"

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

#define SkSPRITE_CLASSNAME                  Sprite_D16_SIndex8A_Opaque
#define SkSPRITE_ARGS
#define SkSPRITE_FIELDS
#define SkSPRITE_INIT
#define SkSPRITE_DST_TYPE                   uint16_t
#define SkSPRITE_SRC_TYPE                   uint8_t
#define SkSPRITE_DST_GETADDR                writable_addr16
#define SkSPRITE_SRC_GETADDR                addr8
#define SkSPRITE_PREAMBLE(srcBM, x, y)      const SkPMColor* ctable = srcBM.ctable()->readColors()
#define SkSPRITE_BLIT_PIXEL(dst, src)       D16_S32A_Opaque_Pixel(dst, ctable[src])
#define SkSPRITE_NEXT_ROW
#define SkSPRITE_POSTAMBLE(srcBM)
#include "SkSpriteBlitterTemplate.h"

#define SkSPRITE_CLASSNAME                  Sprite_D16_SIndex8A_Blend
#define SkSPRITE_ARGS                       , uint8_t alpha
#define SkSPRITE_FIELDS                     uint8_t fSrcAlpha;
#define SkSPRITE_INIT                       fSrcAlpha = alpha;
#define SkSPRITE_DST_TYPE                   uint16_t
#define SkSPRITE_SRC_TYPE                   uint8_t
#define SkSPRITE_DST_GETADDR                writable_addr16
#define SkSPRITE_SRC_GETADDR                addr8
#define SkSPRITE_PREAMBLE(srcBM, x, y)      const SkPMColor* ctable = srcBM.ctable()->readColors(); unsigned src_scale = SkAlpha255To256(fSrcAlpha);
#define SkSPRITE_BLIT_PIXEL(dst, src)       D16_S32A_Blend_Pixel(dst, ctable[src], src_scale)
#define SkSPRITE_NEXT_ROW
#define SkSPRITE_POSTAMBLE(srcBM)
#include "SkSpriteBlitterTemplate.h"

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

static intptr_t asint(const void* ptr) {
    return reinterpret_cast<const char*>(ptr) - (const char*)0;
}

static void blitrow_d16_si8(uint16_t* SK_RESTRICT dst,
                            const uint8_t* SK_RESTRICT src, int count,
                            const uint16_t* SK_RESTRICT ctable) {
    if (count <= 8) {
        do {
            *dst++ = ctable[*src++];
        } while (--count);
        return;
    }

    // eat src until we're on a 4byte boundary
    while (asint(src) & 3) {
        *dst++ = ctable[*src++];
        count -= 1;
    }

    int qcount = count >> 2;
    SkASSERT(qcount > 0);
    const uint32_t* qsrc = reinterpret_cast<const uint32_t*>(src);
    if (asint(dst) & 2) {
        do {
            uint32_t s4 = *qsrc++;
#ifdef SK_CPU_LENDIAN
            *dst++ = ctable[s4 & 0xFF];
            *dst++ = ctable[(s4 >> 8) & 0xFF];
            *dst++ = ctable[(s4 >> 16) & 0xFF];
            *dst++ = ctable[s4 >> 24];
#else   // BENDIAN
            *dst++ = ctable[s4 >> 24];
            *dst++ = ctable[(s4 >> 16) & 0xFF];
            *dst++ = ctable[(s4 >> 8) & 0xFF];
            *dst++ = ctable[s4 & 0xFF];
#endif
        } while (--qcount);
    } else {    // dst is on a 4byte boundary
        uint32_t* ddst = reinterpret_cast<uint32_t*>(dst);
        do {
            uint32_t s4 = *qsrc++;
#ifdef SK_CPU_LENDIAN
            *ddst++ = (ctable[(s4 >> 8) & 0xFF] << 16) | ctable[s4 & 0xFF];
            *ddst++ = (ctable[s4 >> 24] << 16) | ctable[(s4 >> 16) & 0xFF];
#else   // BENDIAN
            *ddst++ = (ctable[s4 >> 24] << 16) | ctable[(s4 >> 16) & 0xFF];
            *ddst++ = (ctable[(s4 >> 8) & 0xFF] << 16) | ctable[s4 & 0xFF];
#endif
        } while (--qcount);
        dst = reinterpret_cast<uint16_t*>(ddst);
    }
    src = reinterpret_cast<const uint8_t*>(qsrc);
    count &= 3;
    // catch any remaining (will be < 4)
    while (--count >= 0) {
        *dst++ = ctable[*src++];
    }
}

#define SkSPRITE_ROW_PROC(d, s, n, x, y)    blitrow_d16_si8(d, s, n, ctable)

#define SkSPRITE_CLASSNAME                  Sprite_D16_SIndex8_Opaque
#define SkSPRITE_ARGS
#define SkSPRITE_FIELDS
#define SkSPRITE_INIT
#define SkSPRITE_DST_TYPE                   uint16_t
#define SkSPRITE_SRC_TYPE                   uint8_t
#define SkSPRITE_DST_GETADDR                writable_addr16
#define SkSPRITE_SRC_GETADDR                addr8
#define SkSPRITE_PREAMBLE(srcBM, x, y)      const uint16_t* ctable = srcBM.ctable()->read16BitCache()
#define SkSPRITE_BLIT_PIXEL(dst, src)       *dst = ctable[src]
#define SkSPRITE_NEXT_ROW
#define SkSPRITE_POSTAMBLE(srcBM)
#include "SkSpriteBlitterTemplate.h"

#define SkSPRITE_CLASSNAME                  Sprite_D16_SIndex8_Blend
#define SkSPRITE_ARGS                       , uint8_t alpha
#define SkSPRITE_FIELDS                     uint8_t fSrcAlpha;
#define SkSPRITE_INIT                       fSrcAlpha = alpha;
#define SkSPRITE_DST_TYPE                   uint16_t
#define SkSPRITE_SRC_TYPE                   uint8_t
#define SkSPRITE_DST_GETADDR                writable_addr16
#define SkSPRITE_SRC_GETADDR                addr8
#define SkSPRITE_PREAMBLE(srcBM, x, y)      const uint16_t* ctable = srcBM.ctable()->read16BitCache(); unsigned src_scale = SkAlpha255To256(fSrcAlpha);
#define SkSPRITE_BLIT_PIXEL(dst, src)       D16_S16_Blend_Pixel(dst, ctable[src], src_scale)
#define SkSPRITE_NEXT_ROW
#define SkSPRITE_POSTAMBLE(srcBM)
#include "SkSpriteBlitterTemplate.h"

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

class Sprite_D16_S32_BlitRowProc : public SkSpriteBlitter {
public:
    Sprite_D16_S32_BlitRowProc(const SkPixmap& source) : SkSpriteBlitter(source) {}

    void setup(const SkPixmap& dst, int left, int top, const SkPaint& paint) override {
        this->INHERITED::setup(dst, left, top, paint);

        unsigned flags = 0;

        if (paint.getAlpha() < 0xFF) {
            flags |= SkBlitRow::kGlobalAlpha_Flag;
        }
        if (!fSource.isOpaque()) {
            flags |= SkBlitRow::kSrcPixelAlpha_Flag;
        }
        if (paint.isDither()) {
            flags |= SkBlitRow::kDither_Flag;
        }
        fProc = SkBlitRow::Factory16(flags);
    }

    void blitRect(int x, int y, int width, int height) override {
        uint16_t* SK_RESTRICT dst = fDst.writable_addr16(x, y);
        const SkPMColor* SK_RESTRICT src = fSource.addr32(x - fLeft, y - fTop);
        size_t dstRB = fDst.rowBytes();
        size_t srcRB = fSource.rowBytes();
        SkBlitRow::Proc16 proc = fProc;
        U8CPU alpha = fPaint->getAlpha();

        while (--height >= 0) {
            proc(dst, src, width, alpha, x, y);
            y += 1;
            dst = (uint16_t* SK_RESTRICT)((char*)dst + dstRB);
            src = (const SkPMColor* SK_RESTRICT)((const char*)src + srcRB);
        }
    }

private:
    SkBlitRow::Proc16 fProc;

    typedef SkSpriteBlitter INHERITED;
};

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

SkSpriteBlitter* SkSpriteBlitter::ChooseD16(const SkPixmap& source, const SkPaint& paint,
                                            SkArenaAlloc* allocator) {

    SkASSERT(allocator != nullptr);

    if (paint.getMaskFilter() != nullptr) { // may add cases for this
        return nullptr;
    }
    if (!paint.isSrcOver()) { // may add cases for this
        return nullptr;
    }
    if (paint.getColorFilter() != nullptr) { // may add cases for this
        return nullptr;
    }

    const SkAlphaType at = source.alphaType();

    SkSpriteBlitter* blitter = nullptr;
    unsigned alpha = paint.getAlpha();

    switch (source.colorType()) {
        case kN32_SkColorType: {
            if (kPremul_SkAlphaType != at && kOpaque_SkAlphaType != at) {
                break;
            }
            blitter = allocator->make<Sprite_D16_S32_BlitRowProc>(source);
            break;
        }
        case kARGB_4444_SkColorType:
            if (kPremul_SkAlphaType != at && kOpaque_SkAlphaType != at) {
                break;
            }
            if (255 == alpha) {
                blitter = allocator->make<Sprite_D16_S4444_Opaque>(source);
            } else {
                blitter = allocator->make<Sprite_D16_S4444_Blend>(source, alpha >> 4);
            }
            break;
        case kRGB_565_SkColorType:
            if (255 == alpha) {
                blitter = allocator->make<Sprite_D16_S16_Opaque>(source);
            } else {
                blitter = allocator->make<Sprite_D16_S16_Blend>(source, alpha);
            }
            break;
        case kIndex_8_SkColorType:
            if (kPremul_SkAlphaType != at && kOpaque_SkAlphaType != at) {
                break;
            }
            if (paint.isDither()) {
                // we don't support dither yet in these special cases
                break;
            }
            if (source.isOpaque()) {
                if (255 == alpha) {
                    blitter = allocator->make<Sprite_D16_SIndex8_Opaque>(source);
                } else {
                    blitter = allocator->make<Sprite_D16_SIndex8_Blend>(source, alpha);
                }
            } else {
                if (255 == alpha) {
                    blitter = allocator->make<Sprite_D16_SIndex8A_Opaque>(source);
                } else {
                    blitter = allocator->make<Sprite_D16_SIndex8A_Blend>(source, alpha);
                }
            }
            break;
        default:
            break;
    }
    return blitter;
}