/*
  * 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 "targa.h"

 
 typedef struct TargaContext {
     AVFrame picture;
 
     int width, height;
     int bpp;
     int color_type;
     int compression_type;
 } TargaContext;
 

 #define CHECK_BUFFER_SIZE(buf, buf_end, needed, where) \

     if(needed > buf_end - buf){ \

         av_log(avctx, AV_LOG_ERROR, "Problem: unexpected end of data while reading " where "\n"); \
         return -1; \
     } \
 
 static int targa_decode_rle(AVCodecContext *avctx, TargaContext *s, const uint8_t *src, int src_size, uint8_t *dst, int w, int h, int stride, int bpp)

 {
     int i, x, y;
     int depth = (bpp + 1) >> 3;
     int type, count;
     int diff;

     const uint8_t *src_end = src + src_size;

 
     diff = stride - w * depth;
     x = y = 0;
     while(y < h){

         CHECK_BUFFER_SIZE(src, src_end, 1, "image type");

         type = *src++;
         count = (type & 0x7F) + 1;
         type &= 0x80;
         if((x + count > w) && (x + count + 1 > (h - y) * w)){
             av_log(avctx, AV_LOG_ERROR, "Packet went out of bounds: position (%i,%i) size %i\n", x, y, count);

             return -1;
         }
         if(type){
             CHECK_BUFFER_SIZE(src, src_end, depth, "image data");
         }else{
             CHECK_BUFFER_SIZE(src, src_end, count * depth, "image data");

         }
         for(i = 0; i < count; i++){
             switch(depth){
             case 1:
                 *dst = *src;
                 break;
             case 2:

                 *((uint16_t*)dst) = AV_RL16(src);

                 break;
             case 3:
                 dst[0] = src[0];
                 dst[1] = src[1];
                 dst[2] = src[2];
                 break;

             case 4:

                 *((uint32_t*)dst) = AV_RL32(src);

                 break;

             }
             dst += depth;
             if(!type)
                 src += depth;
 
             x++;
             if(x == w){
                 x = 0;
                 y++;
                 dst += diff;
             }
         }
         if(type)
             src += depth;
     }

     return src_size;

 }
 
 static int decode_frame(AVCodecContext *avctx,
                         void *data, int *data_size,

                         AVPacket *avpkt)

 {

     const uint8_t *buf = avpkt->data;

     const uint8_t *buf_end = avpkt->data + avpkt->size;

     TargaContext * const s = avctx->priv_data;
     AVFrame *picture = data;
     AVFrame * const p= (AVFrame*)&s->picture;
     uint8_t *dst;
     int stride;

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

     int first_clr, colors, csize;
 
     /* parse image header */

     CHECK_BUFFER_SIZE(buf, buf_end, 18, "header");

     idlen = *buf++;

     buf++; /* pal */

     compr = *buf++;

     first_clr = AV_RL16(buf); buf += 2;
     colors = AV_RL16(buf); buf += 2;

     csize = *buf++;

     buf += 2; /* x */

     y = AV_RL16(buf); buf += 2;
     w = AV_RL16(buf); buf += 2;
     h = AV_RL16(buf); buf += 2;

     bpp = *buf++;
     flags = *buf++;
     //skip identifier if any

     CHECK_BUFFER_SIZE(buf, buf_end, idlen, "identifiers");

     buf += idlen;
     s->bpp = bpp;
     s->width = w;
     s->height = h;
     switch(s->bpp){
     case 8:
         avctx->pix_fmt = ((compr & (~TGA_RLE)) == TGA_BW) ? PIX_FMT_GRAY8 : PIX_FMT_PAL8;
         break;
     case 15:
         avctx->pix_fmt = PIX_FMT_RGB555;
         break;
     case 16:
         avctx->pix_fmt = PIX_FMT_RGB555;
         break;
     case 24:
         avctx->pix_fmt = PIX_FMT_BGR24;
         break;

     case 32:

         avctx->pix_fmt = PIX_FMT_RGB32;

         break;

     default:

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

         return -1;
     }
 
     if(s->picture.data[0])
         avctx->release_buffer(avctx, &s->picture);
 

     if(av_image_check_size(w, h, 0, avctx))

         return -1;
     if(w != avctx->width || h != avctx->height)
         avcodec_set_dimensions(avctx, w, h);
     if(avctx->get_buffer(avctx, p) < 0){
         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return -1;
     }
     if(flags & 0x20){
         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];
     }
 
     if(avctx->pix_fmt == PIX_FMT_PAL8 && avctx->palctrl){
         memcpy(p->data[1], avctx->palctrl->palette, AVPALETTE_SIZE);
         if(avctx->palctrl->palette_changed){
             p->palette_has_changed = 1;
             avctx->palctrl->palette_changed = 0;
         }
     }
     if(colors){

         size_t pal_size;

         if((colors + first_clr) > 256){
             av_log(avctx, AV_LOG_ERROR, "Incorrect palette: %i colors with offset %i\n", colors, first_clr);
             return -1;
         }
         if(csize != 24){
             av_log(avctx, AV_LOG_ERROR, "Palette entry size %i bits is not supported\n", csize);
             return -1;
         }

         pal_size = colors * ((csize + 1) >> 3);
         CHECK_BUFFER_SIZE(buf, buf_end, pal_size, "color table");

         if(avctx->pix_fmt != PIX_FMT_PAL8)//should not occur but skip palette anyway

             buf += pal_size;

         else{
             int r, g, b, t;
             int32_t *pal = ((int32_t*)p->data[1]) + first_clr;
             for(t = 0; t < colors; t++){
                 b = *buf++;

                 g = *buf++;
                 r = *buf++;
                 *pal++ = (0xff<<24) | (r << 16) | (g << 8) | b;

             }
             p->palette_has_changed = 1;
         }
     }
     if((compr & (~TGA_RLE)) == TGA_NODATA)
         memset(p->data[0], 0, p->linesize[0] * s->height);
     else{

         if(compr & TGA_RLE){
             int res = targa_decode_rle(avctx, s, buf, buf_end - buf, dst, avctx->width, avctx->height, stride, bpp);
             if (res < 0)
                 return -1;
             buf += res;
         }else{
             size_t img_size = s->width * ((s->bpp + 1) >> 3);
             CHECK_BUFFER_SIZE(buf, buf_end, img_size, "image data");

             for(y = 0; y < s->height; y++){

 #if HAVE_BIGENDIAN

                 int x;

                 if((s->bpp + 1) >> 3 == 2){
                     uint16_t *dst16 = (uint16_t*)dst;
                     for(x = 0; x < s->width; x++)

                         dst16[x] = AV_RL16(buf + x * 2);

                 }else if((s->bpp + 1) >> 3 == 4){
                     uint32_t *dst32 = (uint32_t*)dst;
                     for(x = 0; x < s->width; x++)

                         dst32[x] = AV_RL32(buf + x * 4);

                 }else
 #endif

                     memcpy(dst, buf, img_size);

 
                 dst += stride;

                 buf += img_size;

             }
         }
     }
 
     *picture= *(AVFrame*)&s->picture;
     *data_size = sizeof(AVPicture);
 

     return avpkt->size;

 }
 

 static av_cold int targa_init(AVCodecContext *avctx){

     TargaContext *s = avctx->priv_data;
 
     avcodec_get_frame_defaults((AVFrame*)&s->picture);
     avctx->coded_frame= (AVFrame*)&s->picture;
 
     return 0;
 }
 

 static av_cold int targa_end(AVCodecContext *avctx){

     TargaContext *s = avctx->priv_data;
 
     if(s->picture.data[0])
         avctx->release_buffer(avctx, &s->picture);
 
     return 0;
 }
 

 AVCodec ff_targa_decoder = {

     "targa",

     AVMEDIA_TYPE_VIDEO,

     CODEC_ID_TARGA,
     sizeof(TargaContext),
     targa_init,
     NULL,
     targa_end,
     decode_frame,

     CODEC_CAP_DR1,

     NULL,

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

 };