/*
  * 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 "libavutil/intreadwrite.h"

 #include "libavutil/imgutils.h"

 #include "avcodec.h"

 #include "bytestream.h"

 #include "internal.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,

                         void *data, int *got_frame,

                         AVPacket *avpkt)

 {
     TargaContext * const s = avctx->priv_data;

     AVFrame * const p = data;

     uint8_t *dst;
     int stride;

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

     int first_clr, colors, csize;

     int interleave;

     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);

 
     if (bytestream2_get_bytes_left(&s->gb) <= idlen) {
         av_log(avctx, AV_LOG_ERROR,
                 "Not enough data to read header\n");
         return AVERROR_INVALIDDATA;
     }
 

     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;
     }

     // 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 ((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;

             }
             p->palette_has_changed = 1;
         }
     }

     if ((compr & (~TGA_RLE)) == TGA_NODATA) {
         memset(p->data[0], 0, p->linesize[0] * h);
     } else {

         if (compr & TGA_RLE) {

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

             if (res < 0)

                 return res;
         } else {
             size_t img_size = w * ((bpp + 1) >> 3);

             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

         int x;

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

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

             for (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;

 }
 

 AVCodec ff_targa_decoder = {

     .name           = "targa",

     .long_name      = NULL_IF_CONFIG_SMALL("Truevision Targa image"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_TARGA,

     .priv_data_size = sizeof(TargaContext),
     .decode         = decode_frame,
     .capabilities   = CODEC_CAP_DR1,

 };