3 * Todd Kirby <doubleshot@pacbell.net>
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 #include "bytestream.h"
26 typedef struct SgiState {
35 * Expand an RLE row into a channel.
36 * @param in_buf input buffer
37 * @param in_end end of input buffer
38 * @param out_buf Points to one line after the output buffer.
39 * @param out_end end of line in output buffer
40 * @param pixelstride pixel stride of input buffer
41 * @return size of output in bytes, -1 if buffer overflows
43 static int expand_rle_row(const uint8_t *in_buf, const uint8_t* in_end,
44 unsigned char *out_buf, uint8_t* out_end, int pixelstride)
46 unsigned char pixel, count;
47 unsigned char *orig = out_buf;
50 if(in_buf + 1 > in_end) return -1;
51 pixel = bytestream_get_byte(&in_buf);
52 if (!(count = (pixel & 0x7f))) {
53 return (out_buf - orig) / pixelstride;
56 /* Check for buffer overflow. */
57 if(out_buf + pixelstride * count >= out_end) return -1;
61 *out_buf = bytestream_get_byte(&in_buf);
62 out_buf += pixelstride;
65 pixel = bytestream_get_byte(&in_buf);
69 out_buf += pixelstride;
76 * Read a run length encoded SGI image.
77 * @param out_buf output buffer
78 * @param in_buf input buffer
79 * @param in_end end of input buffer
80 * @param s the current image state
81 * @return 0 if no error, else return error number.
83 static int read_rle_sgi(unsigned char* out_buf, const uint8_t *in_buf,
84 const uint8_t *in_end, SgiState* s)
87 unsigned int len = s->height * s->depth * 4;
88 const uint8_t *start_table = in_buf;
90 unsigned int start_offset;
92 /* size of RLE offset and length tables */
93 if(len * 2 > in_end - in_buf) {
94 return AVERROR_INVALIDDATA;
97 in_buf -= SGI_HEADER_SIZE;
98 for (z = 0; z < s->depth; z++) {
100 for (y = 0; y < s->height; y++) {
101 dest_row -= s->linesize;
102 start_offset = bytestream_get_be32(&start_table);
103 if(start_offset > in_end - in_buf) {
104 return AVERROR_INVALIDDATA;
106 if (expand_rle_row(in_buf + start_offset, in_end, dest_row + z,
107 dest_row + FFABS(s->linesize), s->depth) != s->width)
108 return AVERROR_INVALIDDATA;
115 * Read an uncompressed SGI image.
116 * @param out_buf output buffer
117 * @param out_end end ofoutput buffer
118 * @param in_buf input buffer
119 * @param in_end end of input buffer
120 * @param s the current image state
121 * @return 0 if read success, otherwise return -1.
123 static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end,
124 const uint8_t *in_buf, const uint8_t *in_end, SgiState* s)
128 unsigned int offset = s->height * s->width;
130 /* Test buffer size. */
131 if (offset * s->depth > in_end - in_buf) {
135 for (y = s->height - 1; y >= 0; y--) {
136 out_end = out_buf + (y * s->linesize);
137 for (x = s->width; x > 0; x--) {
139 for(z = 0; z < s->depth; z ++) {
140 bytestream_put_byte(&out_end, *ptr);
148 static int decode_frame(AVCodecContext *avctx,
149 void *data, int *data_size,
152 const uint8_t *in_buf = avpkt->data;
153 int buf_size = avpkt->size;
154 SgiState *s = avctx->priv_data;
155 AVFrame *picture = data;
156 AVFrame *p = &s->picture;
157 const uint8_t *in_end = in_buf + buf_size;
158 unsigned int dimension, bytes_per_channel, rle;
160 uint8_t *out_buf, *out_end;
162 if (buf_size < SGI_HEADER_SIZE){
163 av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", buf_size);
167 /* Test for SGI magic. */
168 if (bytestream_get_be16(&in_buf) != SGI_MAGIC) {
169 av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
173 rle = bytestream_get_byte(&in_buf);
174 bytes_per_channel = bytestream_get_byte(&in_buf);
175 dimension = bytestream_get_be16(&in_buf);
176 s->width = bytestream_get_be16(&in_buf);
177 s->height = bytestream_get_be16(&in_buf);
178 s->depth = bytestream_get_be16(&in_buf);
180 if (bytes_per_channel != 1) {
181 av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
185 /* Check for supported image dimensions. */
186 if (dimension != 2 && dimension != 3) {
187 av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
191 if (s->depth == SGI_GRAYSCALE) {
192 avctx->pix_fmt = PIX_FMT_GRAY8;
193 } else if (s->depth == SGI_RGB) {
194 avctx->pix_fmt = PIX_FMT_RGB24;
195 } else if (s->depth == SGI_RGBA) {
196 avctx->pix_fmt = PIX_FMT_RGBA;
198 av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
202 if (avcodec_check_dimensions(avctx, s->width, s->height))
204 avcodec_set_dimensions(avctx, s->width, s->height);
207 avctx->release_buffer(avctx, p);
210 if (avctx->get_buffer(avctx, p) < 0) {
211 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
215 p->pict_type = FF_I_TYPE;
217 out_buf = p->data[0];
219 out_end = out_buf + p->linesize[0] * s->height;
221 s->linesize = p->linesize[0];
224 in_buf += SGI_HEADER_SIZE - 12;
226 ret = read_rle_sgi(out_end, in_buf, in_end, s);
228 ret = read_uncompressed_sgi(out_buf, out_end, in_buf, in_end, s);
232 *picture = s->picture;
233 *data_size = sizeof(AVPicture);
240 static av_cold int sgi_init(AVCodecContext *avctx){
241 SgiState *s = avctx->priv_data;
243 avcodec_get_frame_defaults(&s->picture);
244 avctx->coded_frame = &s->picture;
249 static av_cold int sgi_end(AVCodecContext *avctx)
251 SgiState * const s = avctx->priv_data;
253 if (s->picture.data[0])
254 avctx->release_buffer(avctx, &s->picture);
259 AVCodec sgi_decoder = {
268 .long_name = NULL_IF_CONFIG_SMALL("SGI image"),