libavcodec/sgidec.c - third_party/ffmpeg - Git at Google

 /*
  * 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 "avcodec.h"
 #include "bytestream.h"
 #include "codec_internal.h"
 #include "decode.h"
 #include "sgi.h"

 /**
  * Expand an RLE row into a channel.
  * @param logctx a logcontext
  * @param out_buf Points to one line after the output buffer.
  * @param g   GetByteContext used to read input from
  * @param width length of out_buf in nb of elements
  * @return nb of elements written, else return error code.
  */
 static int expand_rle_row8(void *logctx, uint8_t *out_buf,
                            GetByteContext *g, unsigned width)
 {
     unsigned char pixel, count;
     unsigned char *orig = out_buf;
     uint8_t *out_end = out_buf + width;

     while (out_buf < out_end) {
         if (bytestream2_get_bytes_left(g) < 1)
             return AVERROR_INVALIDDATA;
         pixel = bytestream2_get_byteu(g);
         if (!(count = (pixel & 0x7f))) {
             break;
         }

         /* Check for buffer overflow. */
         if (out_end - out_buf < count) {
             av_log(logctx, AV_LOG_ERROR, "Invalid pixel count.\n");
             return AVERROR_INVALIDDATA;
         }

         if (pixel & 0x80) {
             while (count--)
                 *out_buf++ = bytestream2_get_byte(g);
         } else {
             pixel = bytestream2_get_byte(g);

             while (count--)
                 *out_buf++ = pixel;
         }
     }
     return out_buf - orig;
 }

 static int expand_rle_row16(void *logctx, uint16_t *out_buf,
                             GetByteContext *g, unsigned width)
 {
     unsigned short pixel;
     unsigned char count;
     unsigned short *orig = out_buf;
     uint16_t *out_end = out_buf + width;

     while (out_buf < out_end) {
         if (bytestream2_get_bytes_left(g) < 2)
             return AVERROR_INVALIDDATA;
         pixel = bytestream2_get_be16u(g);
         if (!(count = (pixel & 0x7f)))
             break;

         /* Check for buffer overflow. */
         if (out_end - out_buf < count) {
             av_log(logctx, AV_LOG_ERROR, "Invalid pixel count.\n");
             return AVERROR_INVALIDDATA;
         }

         if (pixel & 0x80) {
             while (count--) {
                 pixel = bytestream2_get_ne16(g);
                 AV_WN16A(out_buf, pixel);
                 out_buf++;
             }
         } else {
             pixel = bytestream2_get_ne16(g);

             while (count--) {
                 AV_WN16A(out_buf, pixel);
                 out_buf++;
             }
         }
     }
     return out_buf - orig;
 }


 /**
  * 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(void *logctx, uint8_t *out[4], ptrdiff_t stride[4],
                         GetByteContext *g, unsigned width, int height,
                         unsigned nb_components, unsigned bytes_per_channel)
 {
     unsigned int len = height * nb_components * 4;
     GetByteContext g_table = *g;
     unsigned int start_offset;
     int ret;

     /* size of  RLE offset and length tables */
     if (len * 2 > bytestream2_get_bytes_left(g)) {
         return AVERROR_INVALIDDATA;
     }

     for (unsigned z = 0; z < nb_components; z++) {
         uint8_t *dest_row = out[z] + (height - 1) * stride[z];
         while (1) {
             start_offset = bytestream2_get_be32(&g_table);
             bytestream2_seek(g, start_offset, SEEK_SET);
             if (bytes_per_channel == 1)
                 ret = expand_rle_row8(logctx, dest_row, g, width);
             else
                 ret = expand_rle_row16(logctx, (uint16_t *)dest_row, g, width);
             if (ret != width)
                 return AVERROR_INVALIDDATA;
             if (dest_row == out[z])
                 break;
             dest_row -= stride[z];
         }
     }
     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(uint8_t *const out[4], const ptrdiff_t stride[4],
                                  GetByteContext *g, unsigned width, int height,
                                  unsigned nb_components, unsigned bytes_per_channel)
 {
     unsigned rowsize = width * bytes_per_channel;

     /* Test buffer size. */
     if (rowsize * (int64_t)height * nb_components > bytestream2_get_bytes_left(g))
         return AVERROR_INVALIDDATA;

     for (unsigned z = 0; z < nb_components; z++) {
         uint8_t *cur_row = out[z] + (height - 1) * stride[z];
         while (1) {
             bytestream2_get_bufferu(g, cur_row, rowsize);
             if (cur_row == out[z])
                 break;
             cur_row -= stride[z];
         }
     }
     return 0;
 }

 static int decode_frame(AVCodecContext *avctx, AVFrame *p,
                         int *got_frame, AVPacket *avpkt)
 {
     GetByteContext g;
     unsigned int bytes_per_channel, nb_components, dimension, rle, width;
     uint8_t *out[4];
     ptrdiff_t linesize[4];
     int height;
     int ret = 0;

     bytestream2_init(&g, avpkt->data, avpkt->size);
     if (bytestream2_get_bytes_left(&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(&g) != SGI_MAGIC) {
         av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
         return AVERROR_INVALIDDATA;
     }

     rle                  = bytestream2_get_byteu(&g);
     bytes_per_channel    = bytestream2_get_byteu(&g);
     dimension            = bytestream2_get_be16u(&g);
     width                = bytestream2_get_be16u(&g);
     height               = bytestream2_get_be16u(&g);
     nb_components        = bytestream2_get_be16u(&g);

     if (bytes_per_channel != 1 && 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 (nb_components == SGI_GRAYSCALE) {
         avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
     } else if (nb_components == SGI_RGB) {
         avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GBRP16BE : AV_PIX_FMT_GBRP;
     } else if (nb_components == SGI_RGBA) {
         avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GBRAP16BE : AV_PIX_FMT_GBRAP;
     } else {
         av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
         return AVERROR_INVALIDDATA;
     }

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

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

     switch (nb_components) {
 #define MAP(in_idx, out_idx) \
     out[(in_idx)]      = p->data[(out_idx)]; \
     linesize[(in_idx)] = p->linesize[(out_idx)]
     case SGI_GRAYSCALE:
         MAP(0, 0);
         break;
     case SGI_RGBA:
         MAP(3, 3);
         /* fallthrough */
     case SGI_RGB:
         MAP(0, 2);
         MAP(1, 0);
         MAP(2, 1);
         break;
     }
     p->pict_type = AV_PICTURE_TYPE_I;
     p->flags |= AV_FRAME_FLAG_KEY;

     /* Skip header. */
     bytestream2_seek(&g, SGI_HEADER_SIZE, SEEK_SET);
     if (rle) {
         ret = read_rle_sgi(avctx, out, linesize, &g,
                            width, height, nb_components, bytes_per_channel);
     } else {
         ret = read_uncompressed_sgi(out, linesize, &g,
                                     width, height, nb_components, bytes_per_channel);
     }
     if (ret)
         return ret;

     *got_frame = 1;
     return avpkt->size;
 }

 const FFCodec ff_sgi_decoder = {
     .p.name         = "sgi",
     CODEC_LONG_NAME("SGI image"),
     .p.type         = AVMEDIA_TYPE_VIDEO,
     .p.id           = AV_CODEC_ID_SGI,
     FF_CODEC_DECODE_CB(decode_frame),
     .p.capabilities = AV_CODEC_CAP_DR1,
 };
	/*
	* 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 "avcodec.h"
	#include "bytestream.h"
	#include "codec_internal.h"
	#include "decode.h"
	#include "sgi.h"

	/**
	* Expand an RLE row into a channel.
	* @param logctx a logcontext
	* @param out_buf Points to one line after the output buffer.
	* @param g GetByteContext used to read input from
	* @param width length of out_buf in nb of elements
	* @return nb of elements written, else return error code.
	*/
	static int expand_rle_row8(void logctx, uint8_t out_buf,
	GetByteContext *g, unsigned width)
	{
	unsigned char pixel, count;
	unsigned char *orig = out_buf;
	uint8_t *out_end = out_buf + width;

	while (out_buf < out_end) {
	if (bytestream2_get_bytes_left(g) < 1)
	return AVERROR_INVALIDDATA;
	pixel = bytestream2_get_byteu(g);
	if (!(count = (pixel & 0x7f))) {
	break;
	}

	/* Check for buffer overflow. */
	if (out_end - out_buf < count) {
	av_log(logctx, AV_LOG_ERROR, "Invalid pixel count.\n");
	return AVERROR_INVALIDDATA;
	}

	if (pixel & 0x80) {
	while (count--)
	*out_buf++ = bytestream2_get_byte(g);
	} else {
	pixel = bytestream2_get_byte(g);

	while (count--)
	*out_buf++ = pixel;
	}
	}
	return out_buf - orig;
	}

	static int expand_rle_row16(void logctx, uint16_t out_buf,
	GetByteContext *g, unsigned width)
	{
	unsigned short pixel;
	unsigned char count;
	unsigned short *orig = out_buf;
	uint16_t *out_end = out_buf + width;

	while (out_buf < out_end) {
	if (bytestream2_get_bytes_left(g) < 2)
	return AVERROR_INVALIDDATA;
	pixel = bytestream2_get_be16u(g);
	if (!(count = (pixel & 0x7f)))
	break;

	/* Check for buffer overflow. */
	if (out_end - out_buf < count) {
	av_log(logctx, AV_LOG_ERROR, "Invalid pixel count.\n");
	return AVERROR_INVALIDDATA;
	}

	if (pixel & 0x80) {
	while (count--) {
	pixel = bytestream2_get_ne16(g);
	AV_WN16A(out_buf, pixel);
	out_buf++;
	}
	} else {
	pixel = bytestream2_get_ne16(g);

	while (count--) {
	AV_WN16A(out_buf, pixel);
	out_buf++;
	}
	}
	}
	return out_buf - orig;
	}


	/**
	* 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(void logctx, uint8_t out[4], ptrdiff_t stride[4],
	GetByteContext *g, unsigned width, int height,
	unsigned nb_components, unsigned bytes_per_channel)
	{
	unsigned int len = height * nb_components * 4;
	GetByteContext g_table = *g;
	unsigned int start_offset;
	int ret;

	/* size of RLE offset and length tables */
	if (len * 2 > bytestream2_get_bytes_left(g)) {
	return AVERROR_INVALIDDATA;
	}

	for (unsigned z = 0; z < nb_components; z++) {
	uint8_t dest_row = out[z] + (height - 1) stride[z];
	while (1) {
	start_offset = bytestream2_get_be32(&g_table);
	bytestream2_seek(g, start_offset, SEEK_SET);
	if (bytes_per_channel == 1)
	ret = expand_rle_row8(logctx, dest_row, g, width);
	else
	ret = expand_rle_row16(logctx, (uint16_t *)dest_row, g, width);
	if (ret != width)
	return AVERROR_INVALIDDATA;
	if (dest_row == out[z])
	break;
	dest_row -= stride[z];
	}
	}
	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(uint8_t *const out[4], const ptrdiff_t stride[4],
	GetByteContext *g, unsigned width, int height,
	unsigned nb_components, unsigned bytes_per_channel)
	{
	unsigned rowsize = width * bytes_per_channel;

	/* Test buffer size. */
	if (rowsize * (int64_t)height * nb_components > bytestream2_get_bytes_left(g))
	return AVERROR_INVALIDDATA;

	for (unsigned z = 0; z < nb_components; z++) {
	uint8_t cur_row = out[z] + (height - 1) stride[z];
	while (1) {
	bytestream2_get_bufferu(g, cur_row, rowsize);
	if (cur_row == out[z])
	break;
	cur_row -= stride[z];
	}
	}
	return 0;
	}

	static int decode_frame(AVCodecContext avctx, AVFrame p,
	int got_frame, AVPacket avpkt)
	{
	GetByteContext g;
	unsigned int bytes_per_channel, nb_components, dimension, rle, width;
	uint8_t *out[4];
	ptrdiff_t linesize[4];
	int height;
	int ret = 0;

	bytestream2_init(&g, avpkt->data, avpkt->size);
	if (bytestream2_get_bytes_left(&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(&g) != SGI_MAGIC) {
	av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
	return AVERROR_INVALIDDATA;
	}

	rle = bytestream2_get_byteu(&g);
	bytes_per_channel = bytestream2_get_byteu(&g);
	dimension = bytestream2_get_be16u(&g);
	width = bytestream2_get_be16u(&g);
	height = bytestream2_get_be16u(&g);
	nb_components = bytestream2_get_be16u(&g);

	if (bytes_per_channel != 1 && 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 (nb_components == SGI_GRAYSCALE) {
	avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
	} else if (nb_components == SGI_RGB) {
	avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GBRP16BE : AV_PIX_FMT_GBRP;
	} else if (nb_components == SGI_RGBA) {
	avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GBRAP16BE : AV_PIX_FMT_GBRAP;
	} else {
	av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
	return AVERROR_INVALIDDATA;
	}

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

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

	switch (nb_components) {
	#define MAP(in_idx, out_idx) \
	out[(in_idx)] = p->data[(out_idx)]; \
	linesize[(in_idx)] = p->linesize[(out_idx)]
	case SGI_GRAYSCALE:
	MAP(0, 0);
	break;
	case SGI_RGBA:
	MAP(3, 3);
	/* fallthrough */
	case SGI_RGB:
	MAP(0, 2);
	MAP(1, 0);
	MAP(2, 1);
	break;
	}
	p->pict_type = AV_PICTURE_TYPE_I;
	p->flags \|= AV_FRAME_FLAG_KEY;

	/* Skip header. */
	bytestream2_seek(&g, SGI_HEADER_SIZE, SEEK_SET);
	if (rle) {
	ret = read_rle_sgi(avctx, out, linesize, &g,
	width, height, nb_components, bytes_per_channel);
	} else {
	ret = read_uncompressed_sgi(out, linesize, &g,
	width, height, nb_components, bytes_per_channel);
	}
	if (ret)
	return ret;

	*got_frame = 1;
	return avpkt->size;
	}

	const FFCodec ff_sgi_decoder = {
	.p.name = "sgi",
	CODEC_LONG_NAME("SGI image"),
	.p.type = AVMEDIA_TYPE_VIDEO,
	.p.id = AV_CODEC_ID_SGI,
	FF_CODEC_DECODE_CB(decode_frame),
	.p.capabilities = AV_CODEC_CAP_DR1,
	};