/* * 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 (pixelstride * (count - 1) >= len) { 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 * s->bytes_per_channel; 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 = CODEC_CAP_DR1, };