/*

 * PC Paintbrush PCX (.pcx) image decoder

 * Copyright (c) 2007, 2008 Ivo van Poorten

 *

 * This decoder does not support CGA palettes. I am unable to find samples

 * and Netpbm cannot generate them.

 *

 * 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 "avcodec.h"

#include "bytestream.h"

#include "codec_internal.h"

#include "decode.h"

#include "get_bits.h"

#define PCX_HEADER_SIZE 128

static int pcx_rle_decode(GetByteContext *gb,

                           uint8_t *dst,

                           unsigned int bytes_per_scanline,

                           int compressed)

{

    unsigned int i = 0;

    unsigned char run, value;

    if (bytestream2_get_bytes_left(gb) < 1)

        return AVERROR_INVALIDDATA;

    if (compressed) {

        while (i < bytes_per_scanline && bytestream2_get_bytes_left(gb)>0) {

            run   = 1;

            value = bytestream2_get_byte(gb);

            if (value >= 0xc0 && bytestream2_get_bytes_left(gb)>0) {

                run   = value & 0x3f;

                value = bytestream2_get_byte(gb);

            }

            while (i < bytes_per_scanline && run--)

                dst[i++] = value;

        }

    } else {

        bytestream2_get_buffer(gb, dst, bytes_per_scanline);

    }

    return 0;

}

static void pcx_palette(GetByteContext *gb, uint32_t *dst, int pallen)

{

    int i;

    pallen = FFMIN(pallen, bytestream2_get_bytes_left(gb) / 3);

    for (i = 0; i < pallen; i++)

        *dst++ = 0xFF000000 | bytestream2_get_be24u(gb);

    if (pallen < 256)

        memset(dst, 0, (256 - pallen) * sizeof(*dst));

}

static int pcx_decode_frame(AVCodecContext *avctx, AVFrame *p,

                            int *got_frame, AVPacket *avpkt)

{

    GetByteContext gb;

    int compressed, xmin, ymin, xmax, ymax;

    int ret;

    unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, y, x,

                 bytes_per_scanline;

    uint8_t *ptr, *scanline;

    ptrdiff_t stride;

    if (avpkt->size < PCX_HEADER_SIZE) {

        av_log(avctx, AV_LOG_ERROR, "Packet too small\n");

        return AVERROR_INVALIDDATA;

    }

    bytestream2_init(&gb, avpkt->data, avpkt->size);

    if (bytestream2_get_byteu(&gb) != 0x0a || bytestream2_get_byteu(&gb) > 5) {

        av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");

        return AVERROR_INVALIDDATA;

    }

    compressed                     = bytestream2_get_byteu(&gb);

    bits_per_pixel                 = bytestream2_get_byteu(&gb);

    xmin                           = bytestream2_get_le16u(&gb);

    ymin                           = bytestream2_get_le16u(&gb);

    xmax                           = bytestream2_get_le16u(&gb);

    ymax                           = bytestream2_get_le16u(&gb);

    avctx->sample_aspect_ratio.num = bytestream2_get_le16u(&gb);

    avctx->sample_aspect_ratio.den = bytestream2_get_le16u(&gb);

    if (xmax < xmin || ymax < ymin) {

        av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");

        return AVERROR_INVALIDDATA;

    }

    w = xmax - xmin + 1;

    h = ymax - ymin + 1;

    bytestream2_skipu(&gb, 49);

    nplanes            = bytestream2_get_byteu(&gb);

    bytes_per_line     = bytestream2_get_le16u(&gb);

    bytes_per_scanline = nplanes * bytes_per_line;

    if (bytes_per_scanline < (w * bits_per_pixel * nplanes + 7) / 8 ||

        (!compressed && bytes_per_scanline > bytestream2_get_bytes_left(&gb) / h)) {

        av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");

        return AVERROR_INVALIDDATA;

    }

    switch ((nplanes << 8) + bits_per_pixel) {

    case 0x0308:

        avctx->pix_fmt = AV_PIX_FMT_RGB24;

        break;

    case 0x0108:

    case 0x0104:

    case 0x0102:

    case 0x0101:

    case 0x0401:

    case 0x0301:

    case 0x0201:

        avctx->pix_fmt = AV_PIX_FMT_PAL8;

        break;

    default:

        av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");

        return AVERROR_INVALIDDATA;

    }

    bytestream2_skipu(&gb, 60);

    if ((ret = ff_set_dimensions(avctx, w, h)) < 0)

        return ret;

    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)

        return ret;

    p->pict_type = AV_PICTURE_TYPE_I;

    ptr    = p->data[0];

    stride = p->linesize[0];

    scanline = av_malloc(bytes_per_scanline + AV_INPUT_BUFFER_PADDING_SIZE);

    if (!scanline)

        return AVERROR(ENOMEM);

    if (nplanes == 3 && bits_per_pixel == 8) {

        for (y = 0; y < h; y++) {

            ret = pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);

            if (ret < 0)

                goto end;

            for (x = 0; x < w; x++) {

                ptr[3 * x]     = scanline[x];

                ptr[3 * x + 1] = scanline[x + bytes_per_line];

                ptr[3 * x + 2] = scanline[x + (bytes_per_line << 1)];

            }

            ptr += stride;

        }

    } else if (nplanes == 1 && bits_per_pixel == 8) {

        int palstart = avpkt->size - 769;

        if (avpkt->size < 769) {

            av_log(avctx, AV_LOG_ERROR, "File is too short\n");

            ret = avctx->err_recognition & AV_EF_EXPLODE ?

                  AVERROR_INVALIDDATA : avpkt->size;

            goto end;

        }

        for (y = 0; y < h; y++, ptr += stride) {

            ret = pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);

            if (ret < 0)

                goto end;

            memcpy(ptr, scanline, w);

        }

        if (bytestream2_tell(&gb) != palstart) {

            av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");

            bytestream2_seek(&gb, palstart, SEEK_SET);

        }

        if (bytestream2_get_byte(&gb) != 12) {

            av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");

            ret = avctx->err_recognition & AV_EF_EXPLODE ?

                  AVERROR_INVALIDDATA : avpkt->size;

            goto end;

        }

    } else if (nplanes == 1) {   /* all packed formats, max. 16 colors */

        GetBitContext s;

        for (y = 0; y < h; y++) {

            init_get_bits8(&s, scanline, bytes_per_scanline);

            ret = pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);

            if (ret < 0)

                goto end;

            for (x = 0; x < w; x++)

                ptr[x] = get_bits(&s, bits_per_pixel);

            ptr += stride;

        }

    } else {    /* planar, 4, 8 or 16 colors */

        int i;

        for (y = 0; y < h; y++) {

            ret = pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);

            if (ret < 0)

                goto end;

            for (x = 0; x < w; x++) {

                int m = 0x80 >> (x & 7), v = 0;

                for (i = nplanes - 1; i >= 0; i--) {

                    v <<= 1;

                    v  += !!(scanline[i * bytes_per_line + (x >> 3)] & m);

                }

                ptr[x] = v;

            }

            ptr += stride;

        }

    }

    ret = bytestream2_tell(&gb);

    if (nplanes == 1 && bits_per_pixel == 8) {

        pcx_palette(&gb, (uint32_t *)p->data[1], 256);

        ret += 256 * 3;

    } else if (bits_per_pixel * nplanes == 1) {

        AV_WN32A(p->data[1]  , 0xFF000000);

        AV_WN32A(p->data[1]+4, 0xFFFFFFFF);

    } else if (bits_per_pixel < 8) {

        bytestream2_seek(&gb, 16, SEEK_SET);

        pcx_palette(&gb, (uint32_t *)p->data[1], 16);

    }

    *got_frame = 1;

end:

    av_free(scanline);

    return ret;

}

const FFCodec ff_pcx_decoder = {

    .p.name       = "pcx",

    CODEC_LONG_NAME("PC Paintbrush PCX image"),

    .p.type       = AVMEDIA_TYPE_VIDEO,

    .p.id         = AV_CODEC_ID_PCX,

    FF_CODEC_DECODE_CB(pcx_decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1,

};