/*
  * XBM image format
  *
  * Copyright (c) 2012 Paul B Mahol
  *
  * 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/avstring.h"
 

 #include "avcodec.h"
 #include "internal.h"

 #include "mathops.h"

 
 static int convert(uint8_t x)
 {
     if (x >= 'a')
         x -= 87;
     else if (x >= 'A')
         x -= 55;
     else
         x -= '0';
     return x;
 }
 

 static int parse_str_int(const uint8_t *p, int len, const uint8_t *key)
 {
     const uint8_t *end = p + len;
 
     for(; p<end - strlen(key); p++) {
         if (!memcmp(p, key, strlen(key)))
             break;
     }
     p += strlen(key);
     if (p >= end)
         return INT_MIN;
 
     for(; p<end; p++) {

         char *eptr;

         int64_t ret = strtol(p, &eptr, 10);

         if ((const uint8_t *)eptr != p)

             return ret;
     }
     return INT_MIN;
 }
 

 static int xbm_decode_frame(AVCodecContext *avctx, void *data,

                             int *got_frame, AVPacket *avpkt)

 {

     AVFrame *p = data;

     int ret, linesize, i, j;

     int width  = 0;
     int height = 0;

     const uint8_t *end, *ptr = avpkt->data;

     const uint8_t *next;

     uint8_t *dst;
 

     avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;

     end = avpkt->data + avpkt->size;
 

     width  = parse_str_int(avpkt->data, avpkt->size, "_width");
     height = parse_str_int(avpkt->data, avpkt->size, "_height");

     if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
         return ret;
 

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

         return ret;
 

     // goto start of image data

     next = memchr(ptr, '{', avpkt->size);
     if (!next)
         next = memchr(ptr, '(', avpkt->size);
     if (!next)

         return AVERROR_INVALIDDATA;
     ptr = next + 1;

     linesize = (avctx->width + 7) / 8;
     for (i = 0; i < avctx->height; i++) {
         dst = p->data[0] + i * p->linesize[0];
         for (j = 0; j < linesize; j++) {
             uint8_t val;
 

             while (ptr < end && *ptr != 'x' && *ptr != '$')
                 ptr++;
 
             ptr ++;

             if (ptr < end && av_isxdigit(*ptr)) {

                 val = convert(*ptr++);

                 if (av_isxdigit(*ptr))

                     val = (val << 4) + convert(*ptr++);

                 *dst++ = ff_reverse[val];

                 if (av_isxdigit(*ptr) && j+1 < linesize) {
                     j++;
                     val = convert(*ptr++);
                     if (av_isxdigit(*ptr))
                         val = (val << 4) + convert(*ptr++);
                     *dst++ = ff_reverse[val];
                 }

             } else {

                 av_log(avctx, AV_LOG_ERROR,
                        "Unexpected data at %.8s.\n", ptr);

                 return AVERROR_INVALIDDATA;
             }
         }
     }
 
     p->key_frame = 1;
     p->pict_type = AV_PICTURE_TYPE_I;
 

     *got_frame       = 1;

 
     return avpkt->size;
 }
 
 AVCodec ff_xbm_decoder = {
     .name         = "xbm",

     .long_name    = NULL_IF_CONFIG_SMALL("XBM (X BitMap) image"),

     .type         = AVMEDIA_TYPE_VIDEO,

     .id           = AV_CODEC_ID_XBM,

     .decode       = xbm_decode_frame,

     .capabilities = AV_CODEC_CAP_DR1,

 };