/* * SGI image decoder * Todd Kirby * * 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, };