/*
  * 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 "libavutil/avassert.h"

 #include "avcodec.h"
 #include "bytestream.h"

 #include "internal.h"

 #include "sgi.h"
 
 typedef struct SgiState {

     AVCodecContext *avctx;

     unsigned int width;
     unsigned int height;
     unsigned int depth;

     unsigned int bytes_per_channel;

     int linesize;

     GetByteContext g;

 } SgiState;
 
 /**
  * Expand an RLE row into a channel.

  * @param s the current image state

  * @param out_buf Points to one line after the output buffer.

  * @param len length of out_buf in bytes

  * @param pixelstride pixel stride of input buffer

  * @return size of output in bytes, else return error code.

  */

 static int expand_rle_row8(SgiState *s, uint8_t *out_buf,
                            int len, int pixelstride)

 {
     unsigned char pixel, count;
     unsigned char *orig = out_buf;

     uint8_t *out_end = out_buf + len;

     while (out_buf < out_end) {

         if (bytestream2_get_bytes_left(&s->g) < 1)
             return AVERROR_INVALIDDATA;
         pixel = bytestream2_get_byteu(&s->g);

         if (!(count = (pixel & 0x7f))) {

             break;

         }
 
         /* Check for buffer overflow. */

         if (out_end - out_buf <= pixelstride * (count - 1)) {

             av_log(s->avctx, AV_LOG_ERROR, "Invalid pixel count.\n");

             return AVERROR_INVALIDDATA;

         }

 
         if (pixel & 0x80) {
             while (count--) {

                 *out_buf = bytestream2_get_byte(&s->g);

                 out_buf += pixelstride;
             }
         } else {

             pixel = bytestream2_get_byte(&s->g);

 
             while (count--) {
                 *out_buf = pixel;
                 out_buf += pixelstride;
             }
         }
     }

     return (out_buf - orig) / pixelstride;

 }
 

 static int expand_rle_row16(SgiState *s, uint16_t *out_buf,
                             int len, int pixelstride)
 {
     unsigned short pixel;
     unsigned char count;
     unsigned short *orig = out_buf;
     uint16_t *out_end = out_buf + len;
 
     while (out_buf < out_end) {
         if (bytestream2_get_bytes_left(&s->g) < 2)
             return AVERROR_INVALIDDATA;
         pixel = bytestream2_get_be16u(&s->g);
         if (!(count = (pixel & 0x7f)))
             break;
 
         /* Check for buffer overflow. */

         if (out_end - out_buf <= pixelstride * (count - 1)) {

             av_log(s->avctx, AV_LOG_ERROR, "Invalid pixel count.\n");
             return AVERROR_INVALIDDATA;
         }
 
         if (pixel & 0x80) {
             while (count--) {
                 pixel = bytestream2_get_ne16(&s->g);
                 AV_WN16A(out_buf, pixel);
                 out_buf += pixelstride;
             }
         } else {
             pixel = bytestream2_get_ne16(&s->g);
 
             while (count--) {
                 AV_WN16A(out_buf, pixel);
                 out_buf += pixelstride;
             }
         }
     }
     return (out_buf - orig) / pixelstride;
 }
 
 

 /**
  * Read a run length encoded SGI image.
  * @param out_buf output buffer
  * @param s the current image state

  * @return 0 if no error, else return error code.

  */

 static int read_rle_sgi(uint8_t *out_buf, SgiState *s)

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

     GetByteContext g_table = s->g;

     unsigned int y, z;
     unsigned int start_offset;

     int linesize, ret;

 
     /* size of  RLE offset and length tables */

     if (len * 2 > bytestream2_get_bytes_left(&s->g)) {

         return AVERROR_INVALIDDATA;
     }
 
     for (z = 0; z < s->depth; z++) {
         dest_row = out_buf;
         for (y = 0; y < s->height; y++) {

             linesize = s->width * s->depth;

             dest_row -= s->linesize;

             start_offset = bytestream2_get_be32(&g_table);
             bytestream2_seek(&s->g, start_offset, SEEK_SET);

             if (s->bytes_per_channel == 1)
                 ret = expand_rle_row8(s, dest_row + z, linesize, s->depth);
             else
                 ret = expand_rle_row16(s, (uint16_t *)dest_row + z, linesize, s->depth);
             if (ret != s->width)

                 return AVERROR_INVALIDDATA;
         }
     }
     return 0;
 }
 
 /**
  * Read an uncompressed SGI image.
  * @param out_buf output buffer
  * @param s the current image state

  * @return 0 if read success, else return error code.

  */

 static int read_uncompressed_sgi(unsigned char *out_buf, SgiState *s)

 {
     int x, y, z;

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

     GetByteContext gp[4];

     uint8_t *out_end;

 
     /* Test buffer size. */

     if (offset * s->depth > bytestream2_get_bytes_left(&s->g))
         return AVERROR_INVALIDDATA;
 
     /* Create a reader for each plane */
     for (z = 0; z < s->depth; z++) {
         gp[z] = s->g;
         bytestream2_skip(&gp[z], z * offset);

     }
 
     for (y = s->height - 1; y >= 0; y--) {
         out_end = out_buf + (y * s->linesize);

         if (s->bytes_per_channel == 1) {

             for (x = s->width; x > 0; x--)
                 for (z = 0; z < s->depth; z++)
                     *out_end++ = bytestream2_get_byteu(&gp[z]);

         } else {
             uint16_t *out16 = (uint16_t *)out_end;
             for (x = s->width; x > 0; x--)
                 for (z = 0; z < s->depth; z++)
                     *out16++ = bytestream2_get_ne16u(&gp[z]);

         }
     }
     return 0;
 }
 
 static int decode_frame(AVCodecContext *avctx,

                         void *data, int *got_frame,

                         AVPacket *avpkt)

 {
     SgiState *s = avctx->priv_data;

     AVFrame *p = data;

     unsigned int dimension, rle;

     int ret = 0;
     uint8_t *out_buf, *out_end;
 

     bytestream2_init(&s->g, avpkt->data, avpkt->size);
     if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) {
         av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size);
         return AVERROR_INVALIDDATA;

     }
 
     /* Test for SGI magic. */

     if (bytestream2_get_be16u(&s->g) != SGI_MAGIC) {

         av_log(avctx, AV_LOG_ERROR, "bad magic number\n");

         return AVERROR_INVALIDDATA;

     }
 

     rle                  = bytestream2_get_byteu(&s->g);
     s->bytes_per_channel = bytestream2_get_byteu(&s->g);
     dimension            = bytestream2_get_be16u(&s->g);
     s->width             = bytestream2_get_be16u(&s->g);
     s->height            = bytestream2_get_be16u(&s->g);
     s->depth             = bytestream2_get_be16u(&s->g);

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

         av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");

         return AVERROR_INVALIDDATA;

     }
 
     /* Check for supported image dimensions. */
     if (dimension != 2 && dimension != 3) {
         av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");

         return AVERROR_INVALIDDATA;

     }
 
     if (s->depth == SGI_GRAYSCALE) {

         avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;

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

         avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGB48BE : AV_PIX_FMT_RGB24;

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

         avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGBA64BE : AV_PIX_FMT_RGBA;

     } else {
         av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");

         return AVERROR_INVALIDDATA;

     }
 

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

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

     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. */

     bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET);

     if (rle) {

         ret = read_rle_sgi(out_end, s);

     } else {

         ret = read_uncompressed_sgi(out_buf, s);

     }

     if (ret)

         return ret;

 
     *got_frame = 1;
     return avpkt->size;

 }
 

 static av_cold int sgi_decode_init(AVCodecContext *avctx)
 {
     SgiState *s = avctx->priv_data;
 
     s->avctx = avctx;
 
     return 0;
 }
 

 AVCodec ff_sgi_decoder = {

     .name           = "sgi",

     .long_name      = NULL_IF_CONFIG_SMALL("SGI image"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_SGI,

     .priv_data_size = sizeof(SgiState),
     .decode         = decode_frame,

     .init           = sgi_decode_init,

     .capabilities   = AV_CODEC_CAP_DR1,

 };