/*
  * PC Paintbrush PCX (.pcx) image encoder
  * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
  *
  * 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
  */
 
 /**

  * @file

  * PCX image encoder

  * @author Daniel Verkamp

  * @see http://www.qzx.com/pc-gpe/pcx.txt

  */
 
 #include "avcodec.h"
 #include "bytestream.h"
 
 typedef struct PCXContext {
     AVFrame picture;
 } PCXContext;
 

 static const uint32_t monoblack_pal[16] = { 0x000000, 0xFFFFFF };

 
 static av_cold int pcx_encode_init(AVCodecContext *avctx)
 {
     PCXContext *s = avctx->priv_data;
 
     avcodec_get_frame_defaults(&s->picture);
     avctx->coded_frame = &s->picture;
 
     return 0;
 }
 
 /**
  * PCX run-length encoder
  * @param dst output buffer
  * @param dst_size size of output buffer
  * @param src input buffer
  * @param src_plane_size size of one plane of input buffer in bytes
  * @param nplanes number of planes in input buffer
  * @return number of bytes written to dst or -1 on error
  * @bug will not work for nplanes != 1 && bpp != 8
  */
 static int pcx_rle_encode(      uint8_t *dst, int dst_size,
                           const uint8_t *src, int src_plane_size, int nplanes)
 {
     int p;
     const uint8_t *dst_start = dst;
 
     // check worst-case upper bound on dst_size
     if (dst_size < 2LL * src_plane_size * nplanes || src_plane_size <= 0)
         return -1;
 
     for (p = 0; p < nplanes; p++) {
         int count = 1;
         const uint8_t *src_plane = src + p;
         const uint8_t *src_plane_end = src_plane + src_plane_size * nplanes;
         uint8_t prev = *src_plane;
         src_plane += nplanes;
 
         for (; ; src_plane += nplanes) {
             if (src_plane < src_plane_end && *src_plane == prev && count < 0x3F) {
                 // current byte is same as prev
                 ++count;
             } else {
                 // output prev * count
                 if (count != 1 || prev >= 0xC0)
                     *dst++ = 0xC0 | count;
                 *dst++ = prev;
 
                 if (src_plane == src_plane_end)
                     break;
 
                 // start new run
                 count = 1;
                 prev = *src_plane;
             }
         }
     }
 
     return dst - dst_start;
 }
 
 static int pcx_encode_frame(AVCodecContext *avctx,
                             unsigned char *buf, int buf_size, void *data)
 {
     PCXContext *s = avctx->priv_data;
     AVFrame *const pict = &s->picture;
     const uint8_t *buf_start = buf;
     const uint8_t *buf_end   = buf + buf_size;
 
     int bpp, nplanes, i, y, line_bytes, written;
     const uint32_t *pal = NULL;
     const uint8_t *src;
 
     *pict = *(AVFrame *)data;

     pict->pict_type = AV_PICTURE_TYPE_I;

     pict->key_frame = 1;
 
     if (avctx->width > 65535 || avctx->height > 65535) {
         av_log(avctx, AV_LOG_ERROR, "image dimensions do not fit in 16 bits\n");
         return -1;
     }
 
     switch (avctx->pix_fmt) {
     case PIX_FMT_RGB24:
         bpp = 8;
         nplanes = 3;
         break;
     case PIX_FMT_RGB8:
     case PIX_FMT_BGR8:
     case PIX_FMT_RGB4_BYTE:
     case PIX_FMT_BGR4_BYTE:
     case PIX_FMT_GRAY8:
     case PIX_FMT_PAL8:
         bpp = 8;
         nplanes = 1;
         pal = (uint32_t *)pict->data[1];
         break;
     case PIX_FMT_MONOBLACK:
         bpp = 1;
         nplanes = 1;
         pal = monoblack_pal;
         break;
     default:
         av_log(avctx, AV_LOG_ERROR, "unsupported pixfmt\n");
         return -1;
     }
 
     line_bytes = (avctx->width * bpp + 7) >> 3;
     line_bytes = (line_bytes + 1) & ~1;
 
     bytestream_put_byte(&buf, 10);                  // manufacturer
     bytestream_put_byte(&buf, 5);                   // version
     bytestream_put_byte(&buf, 1);                   // encoding
     bytestream_put_byte(&buf, bpp);                 // bits per pixel per plane
     bytestream_put_le16(&buf, 0);                   // x min
     bytestream_put_le16(&buf, 0);                   // y min
     bytestream_put_le16(&buf, avctx->width - 1);    // x max
     bytestream_put_le16(&buf, avctx->height - 1);   // y max
     bytestream_put_le16(&buf, 0);                   // horizontal DPI
     bytestream_put_le16(&buf, 0);                   // vertical DPI
     for (i = 0; i < 16; i++)
         bytestream_put_be24(&buf, pal ? pal[i] : 0);// palette (<= 16 color only)
     bytestream_put_byte(&buf, 0);                   // reserved
     bytestream_put_byte(&buf, nplanes);             // number of planes
     bytestream_put_le16(&buf, line_bytes);          // scanline plane size in bytes
 
     while (buf - buf_start < 128)
         *buf++= 0;
 
     src = pict->data[0];
 
     for (y = 0; y < avctx->height; y++) {
         if ((written = pcx_rle_encode(buf, buf_end - buf,
                                       src, line_bytes, nplanes)) < 0) {
             av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
             return -1;
         }
         buf += written;
         src += pict->linesize[0];
     }
 
     if (nplanes == 1 && bpp == 8) {
         if (buf_end - buf < 257) {
             av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
             return -1;
         }
         bytestream_put_byte(&buf, 12);
         for (i = 0; i < 256; i++) {
             bytestream_put_be24(&buf, pal[i]);
         }
     }
 
     return buf - buf_start;
 }
 

 AVCodec ff_pcx_encoder = {

     .name           = "pcx",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = CODEC_ID_PCX,
     .priv_data_size = sizeof(PCXContext),
     .init           = pcx_encode_init,
     .encode         = pcx_encode_frame,

     .pix_fmts = (const enum PixelFormat[]){

         PIX_FMT_RGB24,
         PIX_FMT_RGB8, PIX_FMT_BGR8, PIX_FMT_RGB4_BYTE, PIX_FMT_BGR4_BYTE, PIX_FMT_GRAY8, PIX_FMT_PAL8,
         PIX_FMT_MONOBLACK,
         PIX_FMT_NONE},
     .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
 };