/*

 * Alias PIX image encoder

 * Copyright (C) 2014 Vittorio Giovara <vittorio.giovara@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/intreadwrite.h"

#include "avcodec.h"

#include "bytestream.h"

#include "codec_internal.h"

#include "encode.h"

#define ALIAS_HEADER_SIZE 10

static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,

                        const AVFrame *frame, int *got_packet)

{

    int width, height, bits_pixel, length, ret;

    uint8_t *buf;

    width  = avctx->width;

    height = avctx->height;

    if (width > 65535 || height > 65535 ||

        width * height >= INT_MAX / 4 - ALIAS_HEADER_SIZE) {

        av_log(avctx, AV_LOG_ERROR, "Invalid image size %dx%d.\n", width, height);

        return AVERROR_INVALIDDATA;

    }

    switch (avctx->pix_fmt) {

    case AV_PIX_FMT_GRAY8:

        bits_pixel = 8;

        break;

    case AV_PIX_FMT_BGR24:

        bits_pixel = 24;

        break;

    default:

        return AVERROR(EINVAL);

    }

    length = ALIAS_HEADER_SIZE + 4 * width * height; // max possible

    if ((ret = ff_alloc_packet(avctx, pkt, length)) < 0)

        return ret;

    buf = pkt->data;

    /* Encode header. */

    bytestream_put_be16(&buf, width);

    bytestream_put_be16(&buf, height);

    bytestream_put_be32(&buf, 0); /* X, Y offset */

    bytestream_put_be16(&buf, bits_pixel);

    for (int j = 0, bytes_pixel = bits_pixel >> 3; j < height; j++) {

        const uint8_t *in_buf = frame->data[0] + frame->linesize[0] * j;

        const uint8_t *const line_end = in_buf + bytes_pixel * width;

        while (in_buf < line_end) {

            int count = 0;

            int pixel;

            if (avctx->pix_fmt == AV_PIX_FMT_GRAY8) {

                pixel = *in_buf;

                while (count < 255 && in_buf < line_end && pixel == *in_buf) {

                    count++;

                    in_buf++;

                }

                bytestream_put_byte(&buf, count);

                bytestream_put_byte(&buf, pixel);

            } else { /* AV_PIX_FMT_BGR24 */

                pixel = AV_RB24(in_buf);

                while (count < 255 && in_buf < line_end &&

                       pixel == AV_RB24(in_buf)) {

                    count++;

                    in_buf += 3;

                }

                bytestream_put_byte(&buf, count);

                bytestream_put_be24(&buf, pixel);

            }

        }

    }

    /* Total length */

    av_shrink_packet(pkt, buf - pkt->data);

    *got_packet = 1;

    return 0;

}

const FFCodec ff_alias_pix_encoder = {

    .p.name    = "alias_pix",

    CODEC_LONG_NAME("Alias/Wavefront PIX image"),

    .p.type    = AVMEDIA_TYPE_VIDEO,

    .p.id      = AV_CODEC_ID_ALIAS_PIX,

    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,

    FF_CODEC_ENCODE_CB(encode_frame),

    CODEC_PIXFMTS(AV_PIX_FMT_BGR24, AV_PIX_FMT_GRAY8),

};