/*

 * Copyright (C) 2015 Pedro Arthur <bygrandao@gmail.com>

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "libavutil/mem.h"

#include "swscale_internal.h"

typedef struct GammaContext

{

    uint16_t *table;

} GammaContext;

// gamma_convert expects 16 bit rgb format

// it writes directly in src slice thus it must be modifiable (done through cascade context)

static int gamma_convert(SwsInternal *c, SwsFilterDescriptor *desc, int sliceY, int sliceH)

{

    GammaContext *instance = desc->instance;

    uint16_t *table = instance->table;

    int srcW = desc->src->width;

    int i;

    for (i = 0; i < sliceH; ++i) {

        uint8_t ** src = desc->src->plane[0].line;

        int src_pos = sliceY+i - desc->src->plane[0].sliceY;

        uint16_t *src1 = (uint16_t*)*(src+src_pos);

        int j;

        for (j = 0; j < srcW; ++j) {

            uint16_t r = AV_RL16(src1 + j*4 + 0);

            uint16_t g = AV_RL16(src1 + j*4 + 1);

            uint16_t b = AV_RL16(src1 + j*4 + 2);

            AV_WL16(src1 + j*4 + 0, table[r]);

            AV_WL16(src1 + j*4 + 1, table[g]);

            AV_WL16(src1 + j*4 + 2, table[b]);

        }

    }

    return sliceH;

}

int ff_init_gamma_convert(SwsFilterDescriptor *desc, SwsSlice * src, uint16_t *table)

{

    GammaContext *li = av_malloc(sizeof(GammaContext));

    if (!li)

        return AVERROR(ENOMEM);

    li->table = table;

    desc->instance = li;

    desc->src = src;

    desc->dst = NULL;

    desc->process = &gamma_convert;

    return 0;

}