/*
  * SGI image decoder
  * Todd Kirby <doubleshot@pacbell.net>
  *
  * 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 "bytestream.h"
 #include "sgi.h"
 
 typedef struct SgiState {
     AVFrame picture;
     unsigned int width;
     unsigned int height;
     unsigned int depth;

     unsigned int bytes_per_channel;

     int linesize;
 } SgiState;
 
 /**
  * Expand an RLE row into a channel.
  * @param in_buf input buffer
  * @param in_end end of input buffer
  * @param out_buf Points to one line after the output buffer.
  * @param out_end end of line in output buffer
  * @param pixelstride pixel stride of input buffer
  * @return size of output in bytes, -1 if buffer overflows
  */

 static int expand_rle_row(const uint8_t *in_buf, const uint8_t* in_end,

             unsigned char *out_buf, uint8_t* out_end, int pixelstride)
 {
     unsigned char pixel, count;
     unsigned char *orig = out_buf;
 
     while (1) {
         if(in_buf + 1 > in_end) return -1;
         pixel = bytestream_get_byte(&in_buf);
         if (!(count = (pixel & 0x7f))) {
             return (out_buf - orig) / pixelstride;
         }
 
         /* Check for buffer overflow. */
         if(out_buf + pixelstride * count >= out_end) return -1;
 
         if (pixel & 0x80) {
             while (count--) {
                 *out_buf = bytestream_get_byte(&in_buf);
                 out_buf += pixelstride;
             }
         } else {
             pixel = bytestream_get_byte(&in_buf);
 
             while (count--) {
                 *out_buf = pixel;
                 out_buf += pixelstride;
             }
         }
     }
 }
 
 /**
  * Read a run length encoded SGI image.
  * @param out_buf output buffer
  * @param in_buf input buffer
  * @param in_end end of input buffer
  * @param s the current image state
  * @return 0 if no error, else return error number.
  */

 static int read_rle_sgi(unsigned char* out_buf, const uint8_t *in_buf,
                         const uint8_t *in_end, SgiState* s)

 {
     uint8_t *dest_row;
     unsigned int len = s->height * s->depth * 4;

     const uint8_t *start_table = in_buf;

     unsigned int y, z;
     unsigned int start_offset;
 
     /* size of  RLE offset and length tables */
     if(len * 2  > in_end - in_buf) {
         return AVERROR_INVALIDDATA;
     }
 
     in_buf -= SGI_HEADER_SIZE;
     for (z = 0; z < s->depth; z++) {
         dest_row = out_buf;
         for (y = 0; y < s->height; y++) {
             dest_row -= s->linesize;
             start_offset = bytestream_get_be32(&start_table);
             if(start_offset > in_end - in_buf) {
                 return AVERROR_INVALIDDATA;
             }
             if (expand_rle_row(in_buf + start_offset, in_end, dest_row + z,
                 dest_row + FFABS(s->linesize), s->depth) != s->width)
                 return AVERROR_INVALIDDATA;
         }
     }
     return 0;
 }
 
 /**
  * Read an uncompressed SGI image.
  * @param out_buf output buffer
  * @param out_end end ofoutput buffer
  * @param in_buf input buffer
  * @param in_end end of input buffer
  * @param s the current image state
  * @return 0 if read success, otherwise return -1.
  */
 static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end,

                 const uint8_t *in_buf, const uint8_t *in_end, SgiState* s)

 {
     int x, y, z;

     const uint8_t *ptr;

     unsigned int offset = s->height * s->width * s->bytes_per_channel;

 
     /* Test buffer size. */
     if (offset * s->depth > in_end - in_buf) {
        return -1;
     }
 
     for (y = s->height - 1; y >= 0; y--) {
         out_end = out_buf + (y * s->linesize);
         for (x = s->width; x > 0; x--) {

             ptr = in_buf += s->bytes_per_channel;

             for(z = 0; z < s->depth; z ++) {

                 memcpy(out_end, ptr, s->bytes_per_channel);
                 out_end += s->bytes_per_channel;

                 ptr += offset;
             }
         }
     }
     return 0;
 }
 
 static int decode_frame(AVCodecContext *avctx,
                         void *data, int *data_size,

                         AVPacket *avpkt)

 {

     const uint8_t *in_buf = avpkt->data;
     int buf_size = avpkt->size;

     SgiState *s = avctx->priv_data;
     AVFrame *picture = data;
     AVFrame *p = &s->picture;

     const uint8_t *in_end = in_buf + buf_size;

     unsigned int dimension, rle;

     int ret = 0;
     uint8_t *out_buf, *out_end;
 
     if (buf_size < SGI_HEADER_SIZE){
         av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", buf_size);
         return -1;
     }
 
     /* Test for SGI magic. */
     if (bytestream_get_be16(&in_buf) != SGI_MAGIC) {
         av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
         return -1;
     }
 
     rle = bytestream_get_byte(&in_buf);

     s->bytes_per_channel = bytestream_get_byte(&in_buf);

     dimension = bytestream_get_be16(&in_buf);
     s->width  = bytestream_get_be16(&in_buf);
     s->height = bytestream_get_be16(&in_buf);
     s->depth  = bytestream_get_be16(&in_buf);
 

     if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) {

         av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
         return -1;
     }
 
     /* Check for supported image dimensions. */
     if (dimension != 2 && dimension != 3) {
         av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
         return -1;
     }
 
     if (s->depth == SGI_GRAYSCALE) {

         avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_GRAY16BE : PIX_FMT_GRAY8;

     } else if (s->depth == SGI_RGB) {

         avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_RGB48BE : PIX_FMT_RGB24;
     } else if (s->depth == SGI_RGBA && s->bytes_per_channel == 1) {

         avctx->pix_fmt = PIX_FMT_RGBA;
     } else {
         av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
         return -1;
     }
 

     if (av_image_check_size(s->width, s->height, 0, avctx))

         return -1;
     avcodec_set_dimensions(avctx, s->width, s->height);
 
     if (p->data[0])
         avctx->release_buffer(avctx, p);
 
     p->reference = 0;
     if (avctx->get_buffer(avctx, p) < 0) {
         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
         return -1;
     }
 

     p->pict_type = AV_PICTURE_TYPE_I;

     p->key_frame = 1;
     out_buf = p->data[0];
 
     out_end = out_buf + p->linesize[0] * s->height;
 
     s->linesize = p->linesize[0];
 
     /* Skip header. */
     in_buf += SGI_HEADER_SIZE - 12;
     if (rle) {
         ret = read_rle_sgi(out_end, in_buf, in_end, s);
     } else {
         ret = read_uncompressed_sgi(out_buf, out_end, in_buf, in_end, s);
     }
 
     if (ret == 0) {
         *picture   = s->picture;
         *data_size = sizeof(AVPicture);
         return buf_size;
     } else {
         return -1;
     }
 }
 

 static av_cold int sgi_init(AVCodecContext *avctx){

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

 static av_cold int sgi_end(AVCodecContext *avctx)

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

 AVCodec ff_sgi_decoder = {

     "sgi",

     AVMEDIA_TYPE_VIDEO,

     CODEC_ID_SGI,
     sizeof(SgiState),
     sgi_init,
     NULL,
     sgi_end,
     decode_frame,

     .long_name = NULL_IF_CONFIG_SMALL("SGI image"),

 };