/*

 * Targa (.tga) image decoder

 * Copyright (c) 2006 Konstantin Shishkov

 *

 * 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 "avcodec.h"

#include "bytestream.h"

#include "codec_internal.h"

#include "decode.h"

#include "targa.h"

typedef struct TargaContext {

    GetByteContext gb;

} TargaContext;

static uint8_t *advance_line(uint8_t *start, uint8_t *line,

                             int stride, int *y, int h, int interleave)

{

    *y += interleave;

    if (*y < h) {

        return line + interleave * stride;

    } else {

        *y = (*y + 1) & (interleave - 1);

        if (*y && *y < h) {

            return start + *y * stride;

        } else {

            return NULL;

        }

    }

}

static int targa_decode_rle(AVCodecContext *avctx, TargaContext *s,

                            uint8_t *start, int w, int h, int stride,

                            int bpp, int interleave)

{

    int x, y;

    int depth = (bpp + 1) >> 3;

    int type, count;

    uint8_t *line = start;

    uint8_t *dst  = line;

    x = y = count = 0;

    while (dst) {

        if (bytestream2_get_bytes_left(&s->gb) <= 0) {

            av_log(avctx, AV_LOG_ERROR,

                   "Ran ouf of data before end-of-image\n");

            return AVERROR_INVALIDDATA;

        }

        type  = bytestream2_get_byteu(&s->gb);

        count = (type & 0x7F) + 1;

        type &= 0x80;

        if (!type) {

            do {

                int n  = FFMIN(count, w - x);

                bytestream2_get_buffer(&s->gb, dst, n * depth);

                count -= n;

                dst   += n * depth;

                x     += n;

                if (x == w) {

                    x    = 0;

                    dst = line = advance_line(start, line, stride, &y, h, interleave);

                }

            } while (dst && count > 0);

        } else {

            uint8_t tmp[4];

            bytestream2_get_buffer(&s->gb, tmp, depth);

            do {

                int n  = FFMIN(count, w - x);

                count -= n;

                x     += n;

                do {

                    memcpy(dst, tmp, depth);

                    dst += depth;

                } while (--n);

                if (x == w) {

                    x    = 0;

                    dst = line = advance_line(start, line, stride, &y, h, interleave);

                }

            } while (dst && count > 0);

        }

    }

    if (count) {

        av_log(avctx, AV_LOG_ERROR, "Packet went out of bounds\n");

        return AVERROR_INVALIDDATA;

    }

    return 0;

}

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

                        int *got_frame, AVPacket *avpkt)

{

    TargaContext * const s = avctx->priv_data;

    uint8_t *dst;

    int stride;

    int idlen, pal, compr, y, w, h, bpp, flags, ret;

    int first_clr, colors, csize;

    int interleave;

    size_t img_size;

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

    /* parse image header */

    idlen     = bytestream2_get_byte(&s->gb);

    pal       = bytestream2_get_byte(&s->gb);

    compr     = bytestream2_get_byte(&s->gb);

    first_clr = bytestream2_get_le16(&s->gb);

    colors    = bytestream2_get_le16(&s->gb);

    csize     = bytestream2_get_byte(&s->gb);

    bytestream2_skip(&s->gb, 4); /* 2: x, 2: y */

    w         = bytestream2_get_le16(&s->gb);

    h         = bytestream2_get_le16(&s->gb);

    bpp       = bytestream2_get_byte(&s->gb);

    flags     = bytestream2_get_byte(&s->gb);

    if (!pal && (first_clr || colors || csize)) {

        av_log(avctx, AV_LOG_WARNING, "File without colormap has colormap information set.\n");

        // specification says we should ignore those value in this case

        first_clr = colors = csize = 0;

    }

    if (bytestream2_get_bytes_left(&s->gb) < idlen + 2*colors) {

        av_log(avctx, AV_LOG_ERROR,

                "Not enough data to read header\n");

        return AVERROR_INVALIDDATA;

    }

    // skip identifier if any

    bytestream2_skip(&s->gb, idlen);

    switch (bpp) {

    case 8:

        avctx->pix_fmt = ((compr & (~TGA_RLE)) == TGA_BW) ? AV_PIX_FMT_GRAY8 : AV_PIX_FMT_PAL8;

        break;

    case 15:

    case 16:

        avctx->pix_fmt = AV_PIX_FMT_RGB555LE;

        break;

    case 24:

        avctx->pix_fmt = AV_PIX_FMT_BGR24;

        break;

    case 32:

        avctx->pix_fmt = AV_PIX_FMT_BGRA;

        break;

    default:

        av_log(avctx, AV_LOG_ERROR, "Bit depth %i is not supported\n", bpp);

        return AVERROR_INVALIDDATA;

    }

    if (colors && (colors + first_clr) > 256) {

        av_log(avctx, AV_LOG_ERROR, "Incorrect palette: %i colors with offset %i\n", colors, first_clr);

        return AVERROR_INVALIDDATA;

    }

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

        return ret;

    if ((compr & (~TGA_RLE)) == TGA_NODATA) {

        return avpkt->size;

    }

    if (!(compr & TGA_RLE)) {

        img_size = w * ((bpp + 1) >> 3);

        if (bytestream2_get_bytes_left(&s->gb) < img_size * h) {

            av_log(avctx, AV_LOG_ERROR,

                    "Not enough data available for image\n");

            return AVERROR_INVALIDDATA;

        }

    }

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

        return ret;

    p->pict_type = AV_PICTURE_TYPE_I;

    if (flags & TGA_TOPTOBOTTOM) {

        dst = p->data[0];

        stride = p->linesize[0];

    } else { //image is upside-down

        dst = p->data[0] + p->linesize[0] * (h - 1);

        stride = -p->linesize[0];

    }

    interleave = flags & TGA_INTERLEAVE2 ? 2 :

                 flags & TGA_INTERLEAVE4 ? 4 : 1;

    if (colors) {

        int pal_size, pal_sample_size;

        switch (csize) {

        case 32: pal_sample_size = 4; break;

        case 24: pal_sample_size = 3; break;

        case 16:

        case 15: pal_sample_size = 2; break;

        default:

            av_log(avctx, AV_LOG_ERROR, "Palette entry size %i bits is not supported\n", csize);

            return AVERROR_INVALIDDATA;

        }

        pal_size = colors * pal_sample_size;

        if (avctx->pix_fmt != AV_PIX_FMT_PAL8) //should not occur but skip palette anyway

            bytestream2_skip(&s->gb, pal_size);

        else {

            int t;

            uint32_t *pal = ((uint32_t *)p->data[1]) + first_clr;

            if (bytestream2_get_bytes_left(&s->gb) < pal_size) {

                av_log(avctx, AV_LOG_ERROR,

                       "Not enough data to read palette\n");

                return AVERROR_INVALIDDATA;

            }

            switch (pal_sample_size) {

            case 4:

                for (t = 0; t < colors; t++)

                    *pal++ = bytestream2_get_le32u(&s->gb);

                break;

            case 3:

                /* RGB24 */

                for (t = 0; t < colors; t++)

                    *pal++ = (0xffU<<24) | bytestream2_get_le24u(&s->gb);

                break;

            case 2:

                /* RGB555 */

                for (t = 0; t < colors; t++) {

                    uint32_t v = bytestream2_get_le16u(&s->gb);

                    v = ((v & 0x7C00) <<  9) |

                        ((v & 0x03E0) <<  6) |

                        ((v & 0x001F) <<  3);

                    /* left bit replication */

                    v |= (v & 0xE0E0E0U) >> 5;

                    *pal++ = (0xffU<<24) | v;

                }

                break;

            }

        }

    }

    if (compr & TGA_RLE) {

        int res = targa_decode_rle(avctx, s, dst, w, h, stride, bpp, interleave);

        if (res < 0)

            return res;

    } else {

        uint8_t *line;

        if (bytestream2_get_bytes_left(&s->gb) < img_size * h) {

            av_log(avctx, AV_LOG_ERROR,

                    "Not enough data available for image\n");

            return AVERROR_INVALIDDATA;

        }

        line = dst;

        y = 0;

        do {

            bytestream2_get_buffer(&s->gb, line, img_size);

            line = advance_line(dst, line, stride, &y, h, interleave);

        } while (line);

    }

    if (flags & TGA_RIGHTTOLEFT) { // right-to-left, needs horizontal flip

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

            void *line = &p->data[0][y * p->linesize[0]];

            for (int x = 0; x < w >> 1; x++) {

                switch (bpp) {

                case 32:

                    FFSWAP(uint32_t, ((uint32_t *)line)[x], ((uint32_t *)line)[w - x - 1]);

                    break;

                case 24:

                    FFSWAP(uint8_t, ((uint8_t *)line)[3 * x    ], ((uint8_t *)line)[3 * w - 3 * x - 3]);

                    FFSWAP(uint8_t, ((uint8_t *)line)[3 * x + 1], ((uint8_t *)line)[3 * w - 3 * x - 2]);

                    FFSWAP(uint8_t, ((uint8_t *)line)[3 * x + 2], ((uint8_t *)line)[3 * w - 3 * x - 1]);

                    break;

                case 16:

                    FFSWAP(uint16_t, ((uint16_t *)line)[x], ((uint16_t *)line)[w - x - 1]);

                    break;

                case 8:

                    FFSWAP(uint8_t, ((uint8_t *)line)[x], ((uint8_t *)line)[w - x - 1]);

                }

            }

        }

    }

    *got_frame = 1;

    return avpkt->size;

}

const FFCodec ff_targa_decoder = {

    .p.name         = "targa",

    CODEC_LONG_NAME("Truevision Targa image"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_TARGA,

    .p.capabilities = AV_CODEC_CAP_DR1,

    .priv_data_size = sizeof(TargaContext),

    FF_CODEC_DECODE_CB(decode_frame),

};