/*
  * PNM image format

  * Copyright (c) 2002, 2003 Fabrice Bellard

  *

  * 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/imgutils.h"

 #include "avcodec.h"

 #include "pnm.h"

 static inline int pnm_space(int c)
 {

     return c == ' ' || c == '\n' || c == '\r' || c == '\t';

 }
 

 static void pnm_get(PNMContext *sc, char *str, int buf_size)

 {

     char *s;
     int c;
 
     /* skip spaces and comments */

     for (;;) {

         c = *sc->bytestream++;
         if (c == '#')  {

             do {

                 c = *sc->bytestream++;
             } while (c != '\n' && sc->bytestream < sc->bytestream_end);
         } else if (!pnm_space(c)) {
             break;
         }

     }

     s = str;
     while (sc->bytestream < sc->bytestream_end && !pnm_space(c)) {
         if ((s - str)  < buf_size - 1)
             *s++ = c;
         c = *sc->bytestream++;
     }
     *s = '\0';
 }

 int ff_pnm_decode_header(AVCodecContext *avctx, PNMContext * const s)
 {

     char buf1[32], tuple_type[32];
     int h, w, depth, maxval;
 
     pnm_get(s, buf1, sizeof(buf1));

     s->type= buf1[1]-'0';
     if(buf1[0] != 'P')
         return -1;
 
     if (s->type==1 || s->type==4) {

         avctx->pix_fmt = PIX_FMT_MONOWHITE;

     } else if (s->type==2 || s->type==5) {

         if (avctx->codec_id == CODEC_ID_PGMYUV)
             avctx->pix_fmt = PIX_FMT_YUV420P;
         else
             avctx->pix_fmt = PIX_FMT_GRAY8;

     } else if (s->type==3 || s->type==6) {

         avctx->pix_fmt = PIX_FMT_RGB24;

     } else if (s->type==7) {

         w      = -1;
         h      = -1;

         maxval = -1;

         depth  = -1;

         tuple_type[0] = '\0';

         for (;;) {

             pnm_get(s, buf1, sizeof(buf1));
             if (!strcmp(buf1, "WIDTH")) {
                 pnm_get(s, buf1, sizeof(buf1));
                 w = strtol(buf1, NULL, 10);
             } else if (!strcmp(buf1, "HEIGHT")) {
                 pnm_get(s, buf1, sizeof(buf1));
                 h = strtol(buf1, NULL, 10);
             } else if (!strcmp(buf1, "DEPTH")) {
                 pnm_get(s, buf1, sizeof(buf1));
                 depth = strtol(buf1, NULL, 10);
             } else if (!strcmp(buf1, "MAXVAL")) {
                 pnm_get(s, buf1, sizeof(buf1));
                 maxval = strtol(buf1, NULL, 10);

             } else if (!strcmp(buf1, "TUPLTYPE") ||

                        /* libavcodec used to write invalid files */

                        !strcmp(buf1, "TUPLETYPE")) {

                 pnm_get(s, tuple_type, sizeof(tuple_type));
             } else if (!strcmp(buf1, "ENDHDR")) {
                 break;
             } else {

                 return -1;

             }
         }

         /* check that all tags are present */

         if (w <= 0 || h <= 0 || maxval <= 0 || depth <= 0 || tuple_type[0] == '\0' || av_image_check_size(w, h, 0, avctx))

             return -1;

         avctx->width  = w;

         avctx->height = h;

         s->maxval     = maxval;

         if (depth == 1) {

             if (maxval == 1) {

                 avctx->pix_fmt = PIX_FMT_MONOBLACK;

             } else if (maxval == 255) {

                 avctx->pix_fmt = PIX_FMT_GRAY8;

             } else {

                 avctx->pix_fmt = PIX_FMT_GRAY16BE;
             }

         } else if (depth == 2) {
             if (maxval == 255)
                 avctx->pix_fmt = PIX_FMT_GRAY8A;

         } else if (depth == 3) {

             if (maxval < 256) {

             avctx->pix_fmt = PIX_FMT_RGB24;

             } else {

                 avctx->pix_fmt = PIX_FMT_RGB48BE;

             }

         } else if (depth == 4) {

             if (maxval < 256) {

                 avctx->pix_fmt = PIX_FMT_RGBA;

             } else {

                 avctx->pix_fmt = PIX_FMT_RGBA64BE;

             }

         } else {
             return -1;

         }

         return 0;
     } else {

         return -1;
     }

     pnm_get(s, buf1, sizeof(buf1));
     avctx->width = atoi(buf1);
     if (avctx->width <= 0)
         return -1;
     pnm_get(s, buf1, sizeof(buf1));
     avctx->height = atoi(buf1);

     if(avctx->height <= 0 || av_image_check_size(avctx->width, avctx->height, 0, avctx))

         return -1;

     if (avctx->pix_fmt != PIX_FMT_MONOWHITE && avctx->pix_fmt != PIX_FMT_MONOBLACK) {

         pnm_get(s, buf1, sizeof(buf1));
         s->maxval = atoi(buf1);

         if (s->maxval <= 0) {
             av_log(avctx, AV_LOG_ERROR, "Invalid maxval: %d\n", s->maxval);

             s->maxval = 255;

         }

         if (s->maxval >= 256) {
             if (avctx->pix_fmt == PIX_FMT_GRAY8) {

                 avctx->pix_fmt = PIX_FMT_GRAY16BE;
                 if (s->maxval != 65535)
                     avctx->pix_fmt = PIX_FMT_GRAY16;

             } else if (avctx->pix_fmt == PIX_FMT_RGB24) {

                 if (s->maxval > 255)
                     avctx->pix_fmt = PIX_FMT_RGB48BE;

             } else {

                 av_log(avctx, AV_LOG_ERROR, "Unsupported pixel format\n");

                 avctx->pix_fmt = PIX_FMT_NONE;
                 return -1;
             }

         }

     }else
         s->maxval=1;

     /* more check if YUV420 */
     if (avctx->pix_fmt == PIX_FMT_YUV420P) {
         if ((avctx->width & 1) != 0)
             return -1;
         h = (avctx->height * 2);
         if ((h % 3) != 0)
             return -1;
         h /= 3;
         avctx->height = h;

     }

     return 0;

 }

 
 av_cold int ff_pnm_end(AVCodecContext *avctx)
 {
     PNMContext *s = avctx->priv_data;
 
     if (s->picture.data[0])
         avctx->release_buffer(avctx, &s->picture);
 
     return 0;
 }
 
 av_cold int ff_pnm_init(AVCodecContext *avctx)
 {
     PNMContext *s = avctx->priv_data;
 

     avcodec_get_frame_defaults(&s->picture);
     avctx->coded_frame = &s->picture;

 
     return 0;
 }