/*
  * PC Paintbrush PCX (.pcx) image decoder
  * Copyright (c) 2007, 2008 Ivo van Poorten
  *
  * This decoder does not support CGA palettes. I am unable to find samples
  * and Netpbm cannot generate them.
  *
  * 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 "get_bits.h"

 
 typedef struct PCXContext {
     AVFrame picture;
 } PCXContext;
 

 static av_cold int pcx_init(AVCodecContext *avctx) {

     PCXContext *s = avctx->priv_data;
 
     avcodec_get_frame_defaults(&s->picture);
     avctx->coded_frame= &s->picture;
 
     return 0;
 }
 
 /**
  * @return advanced src pointer
  */

 static const uint8_t *pcx_rle_decode(const uint8_t *src, uint8_t *dst,

                             unsigned int bytes_per_scanline, int compressed) {

     unsigned int i = 0;
     unsigned char run, value;
 

     if (compressed) {
         while (i<bytes_per_scanline) {
             run = 1;

             value = *src++;

             if (value >= 0xc0) {
                 run = value & 0x3f;
                 value = *src++;
             }
             while (i<bytes_per_scanline && run--)
                 dst[i++] = value;

         }

     } else {
         memcpy(dst, src, bytes_per_scanline);
         src += bytes_per_scanline;

     }
 
     return src;
 }
 

 static void pcx_palette(const uint8_t **src, uint32_t *dst, unsigned int pallen) {

     unsigned int i;
 
     for (i=0; i<pallen; i++)
         *dst++ = bytestream_get_be24(src);

     if (pallen < 256)

         memset(dst, 0, (256 - pallen) * sizeof(*dst));

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

                             AVPacket *avpkt) {
     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;

     PCXContext * const s = avctx->priv_data;
     AVFrame *picture = data;

     AVFrame * const p = &s->picture;

     int compressed, xmin, ymin, xmax, ymax;

     unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
                  bytes_per_scanline;

     uint8_t *ptr;
     uint8_t const *bufstart = buf;

     if (buf[0] != 0x0a || buf[1] > 5) {

         av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");
         return -1;
     }
 

     compressed = buf[2];

     xmin = AV_RL16(buf+ 4);
     ymin = AV_RL16(buf+ 6);
     xmax = AV_RL16(buf+ 8);
     ymax = AV_RL16(buf+10);
 
     if (xmax < xmin || ymax < ymin) {
         av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");
         return -1;
     }
 
     w = xmax - xmin + 1;
     h = ymax - ymin + 1;
 
     bits_per_pixel     = buf[3];
     bytes_per_line     = AV_RL16(buf+66);
     nplanes            = buf[65];
     bytes_per_scanline = nplanes * bytes_per_line;
 
     if (bytes_per_scanline < w * bits_per_pixel * nplanes / 8) {
         av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
         return -1;
     }
 
     switch ((nplanes<<8) + bits_per_pixel) {
         case 0x0308:
             avctx->pix_fmt = PIX_FMT_RGB24;
             break;
         case 0x0108:
         case 0x0104:
         case 0x0102:
         case 0x0101:
         case 0x0401:
         case 0x0301:
         case 0x0201:
             avctx->pix_fmt = PIX_FMT_PAL8;
             break;
         default:
             av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");
             return -1;
     }
 
     buf += 128;
 
     if (p->data[0])
         avctx->release_buffer(avctx, p);
 
     if (avcodec_check_dimensions(avctx, w, h))
         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;
     }
 
     p->pict_type = FF_I_TYPE;
 
     ptr    = p->data[0];
     stride = p->linesize[0];
 
     if (nplanes == 3 && bits_per_pixel == 8) {
         uint8_t scanline[bytes_per_scanline];
 
         for (y=0; y<h; y++) {

             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);

 
             for (x=0; x<w; x++) {
                 ptr[3*x  ] = scanline[x                    ];
                 ptr[3*x+1] = scanline[x+ bytes_per_line    ];
                 ptr[3*x+2] = scanline[x+(bytes_per_line<<1)];
             }
 
             ptr += stride;
         }
 
     } else if (nplanes == 1 && bits_per_pixel == 8) {
         uint8_t scanline[bytes_per_scanline];

         const uint8_t *palstart = bufstart + buf_size - 769;

 
         for (y=0; y<h; y++, ptr+=stride) {

             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);

             memcpy(ptr, scanline, w);
         }
 
         if (buf != palstart) {
             av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");
             buf = palstart;
         }
         if (*buf++ != 12) {
             av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");
             return -1;
         }
 
     } else if (nplanes == 1) {   /* all packed formats, max. 16 colors */
         uint8_t scanline[bytes_per_scanline];
         GetBitContext s;
 
         for (y=0; y<h; y++) {
             init_get_bits(&s, scanline, bytes_per_scanline<<3);
 

             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);

 
             for (x=0; x<w; x++)
                 ptr[x] = get_bits(&s, bits_per_pixel);
             ptr += stride;
         }
 
     } else {    /* planar, 4, 8 or 16 colors */
         uint8_t scanline[bytes_per_scanline];
         int i;
 
         for (y=0; y<h; y++) {

             buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);

 
             for (x=0; x<w; x++) {
                 int m = 0x80 >> (x&7), v = 0;
                 for (i=nplanes - 1; i>=0; i--) {
                     v <<= 1;
                     v  += !!(scanline[i*bytes_per_line + (x>>3)] & m);
                 }
                 ptr[x] = v;
             }
             ptr += stride;
         }
     }
 
     if (nplanes == 1 && bits_per_pixel == 8) {
         pcx_palette(&buf, (uint32_t *) p->data[1], 256);
     } else if (bits_per_pixel < 8) {

         const uint8_t *palette = bufstart+16;

         pcx_palette(&palette, (uint32_t *) p->data[1], 16);
     }
 
     *picture = s->picture;
     *data_size = sizeof(AVFrame);
 
     return buf - bufstart;
 }
 

 static av_cold int pcx_end(AVCodecContext *avctx) {

     PCXContext *s = avctx->priv_data;
 
     if(s->picture.data[0])
         avctx->release_buffer(avctx, &s->picture);
 
     return 0;
 }
 
 AVCodec pcx_decoder = {
     "pcx",

     AVMEDIA_TYPE_VIDEO,

     CODEC_ID_PCX,
     sizeof(PCXContext),
     pcx_init,
     NULL,
     pcx_end,
     pcx_decode_frame,

     CODEC_CAP_DR1,

     NULL,

     .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),

 };