/*
 * Copyright 2019 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "src/gpu/GrSwizzle.h"

#include "src/core/SkRasterPipeline.h"

void GrSwizzle::apply(SkRasterPipeline* pipeline) const {
    SkASSERT(pipeline);
#if defined(COBALT)
    // GrSwizzle cannot be a constant expression in C++11 because its
    // constructor depends on CToI(), which cannot be a constant expression in
    // C++11 either because it includes switch case statements and multiple
    // return statements. So in situations where are still using C++11, we
    // cannot use GrSwizzle objects in switch case statements because the case
    // needs to be a constant value.
    if (fKey == GrSwizzle("bgra").asKey()) {
        pipeline->append(SkRasterPipeline::swap_rb);
    } else if (fKey == GrSwizzle("aaa1").asKey()) {
        pipeline->append(SkRasterPipeline::alpha_to_gray);
    } else if (fKey == GrSwizzle("rgb1").asKey()) {
        pipeline->append(SkRasterPipeline::force_opaque);
    } else {
        GR_STATIC_ASSERT(sizeof(uintptr_t) >= 4 * sizeof(char));
        // Rather than allocate the 4 control bytes on the heap somewhere, just jam them right
        // into a uintptr_t context.
        uintptr_t ctx;
        memcpy(&ctx, fSwiz, 4 * sizeof(char));
        pipeline->append(SkRasterPipeline::swizzle, ctx);
    }
    return;
#else
    switch (fKey) {
        case GrSwizzle("rgba").asKey():
            return;
        case GrSwizzle("bgra").asKey():
            pipeline->append(SkRasterPipeline::swap_rb);
            return;
        case GrSwizzle("aaa1").asKey():
            pipeline->append(SkRasterPipeline::alpha_to_gray);
            return;
        case GrSwizzle("rgb1").asKey():
            pipeline->append(SkRasterPipeline::force_opaque);
            return;
        default: {
            GR_STATIC_ASSERT(sizeof(uintptr_t) >= 4 * sizeof(char));
            // Rather than allocate the 4 control bytes on the heap somewhere, just jam them right
            // into a uintptr_t context.
            uintptr_t ctx;
            memcpy(&ctx, fSwiz, 4 * sizeof(char));
            pipeline->append(SkRasterPipeline::swizzle, ctx);
            return;
        }
    }
#endif
}