/* * SGI image decoder * Todd Kirby <doubleshot@pacbell.net> * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; 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 = { .name = "sgi", .type = AVMEDIA_TYPE_VIDEO, .id = CODEC_ID_SGI, .priv_data_size = sizeof(SgiState), .init = sgi_init, .close = sgi_end, .decode = decode_frame, .long_name = NULL_IF_CONFIG_SMALL("SGI image"), };