1/*
2 * SGI image decoder
3 * Todd Kirby <doubleshot@pacbell.net>
4 *
5 * This file is part of FFmpeg.
6 *
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.
11 *
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.
16 *
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
20 */
21
22#include "avcodec.h"
23#include "bytestream.h"
24#include "sgi.h"
25
26typedef struct SgiState {
27    AVFrame picture;
28    unsigned int width;
29    unsigned int height;
30    unsigned int depth;
31    int linesize;
32} SgiState;
33
34/**
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
42 */
43static 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)
45{
46    unsigned char pixel, count;
47    unsigned char *orig = out_buf;
48
49    while (1) {
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;
54        }
55
56        /* Check for buffer overflow. */
57        if(out_buf + pixelstride * count >= out_end) return -1;
58
59        if (pixel & 0x80) {
60            while (count--) {
61                *out_buf = bytestream_get_byte(&in_buf);
62                out_buf += pixelstride;
63            }
64        } else {
65            pixel = bytestream_get_byte(&in_buf);
66
67            while (count--) {
68                *out_buf = pixel;
69                out_buf += pixelstride;
70            }
71        }
72    }
73}
74
75/**
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.
82 */
83static int read_rle_sgi(unsigned char* out_buf, const uint8_t *in_buf,
84                        const uint8_t *in_end, SgiState* s)
85{
86    uint8_t *dest_row;
87    unsigned int len = s->height * s->depth * 4;
88    const uint8_t *start_table = in_buf;
89    unsigned int y, z;
90    unsigned int start_offset;
91
92    /* size of  RLE offset and length tables */
93    if(len * 2  > in_end - in_buf) {
94        return AVERROR_INVALIDDATA;
95    }
96
97    in_buf -= SGI_HEADER_SIZE;
98    for (z = 0; z < s->depth; z++) {
99        dest_row = out_buf;
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;
105            }
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;
109        }
110    }
111    return 0;
112}
113
114/**
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.
122 */
123static 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)
125{
126    int x, y, z;
127    const uint8_t *ptr;
128    unsigned int offset = s->height * s->width;
129
130    /* Test buffer size. */
131    if (offset * s->depth > in_end - in_buf) {
132       return -1;
133    }
134
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--) {
138            ptr = in_buf++;
139            for(z = 0; z < s->depth; z ++) {
140                bytestream_put_byte(&out_end, *ptr);
141                ptr += offset;
142            }
143        }
144    }
145    return 0;
146}
147
148static int decode_frame(AVCodecContext *avctx,
149                        void *data, int *data_size,
150                        const uint8_t *in_buf, int buf_size)
151{
152    SgiState *s = avctx->priv_data;
153    AVFrame *picture = data;
154    AVFrame *p = &s->picture;
155    const uint8_t *in_end = in_buf + buf_size;
156    unsigned int dimension, bytes_per_channel, rle;
157    int ret = 0;
158    uint8_t *out_buf, *out_end;
159
160    if (buf_size < SGI_HEADER_SIZE){
161        av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", buf_size);
162        return -1;
163    }
164
165    /* Test for SGI magic. */
166    if (bytestream_get_be16(&in_buf) != SGI_MAGIC) {
167        av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
168        return -1;
169    }
170
171    rle = bytestream_get_byte(&in_buf);
172    bytes_per_channel = bytestream_get_byte(&in_buf);
173    dimension = bytestream_get_be16(&in_buf);
174    s->width  = bytestream_get_be16(&in_buf);
175    s->height = bytestream_get_be16(&in_buf);
176    s->depth  = bytestream_get_be16(&in_buf);
177
178    if (bytes_per_channel != 1) {
179        av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
180        return -1;
181    }
182
183    /* Check for supported image dimensions. */
184    if (dimension != 2 && dimension != 3) {
185        av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
186        return -1;
187    }
188
189    if (s->depth == SGI_GRAYSCALE) {
190        avctx->pix_fmt = PIX_FMT_GRAY8;
191    } else if (s->depth == SGI_RGB) {
192        avctx->pix_fmt = PIX_FMT_RGB24;
193    } else if (s->depth == SGI_RGBA) {
194        avctx->pix_fmt = PIX_FMT_RGBA;
195    } else {
196        av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
197        return -1;
198    }
199
200    if (avcodec_check_dimensions(avctx, s->width, s->height))
201        return -1;
202    avcodec_set_dimensions(avctx, s->width, s->height);
203
204    if (p->data[0])
205        avctx->release_buffer(avctx, p);
206
207    p->reference = 0;
208    if (avctx->get_buffer(avctx, p) < 0) {
209        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
210        return -1;
211    }
212
213    p->pict_type = FF_I_TYPE;
214    p->key_frame = 1;
215    out_buf = p->data[0];
216
217    out_end = out_buf + p->linesize[0] * s->height;
218
219    s->linesize = p->linesize[0];
220
221    /* Skip header. */
222    in_buf += SGI_HEADER_SIZE - 12;
223    if (rle) {
224        ret = read_rle_sgi(out_end, in_buf, in_end, s);
225    } else {
226        ret = read_uncompressed_sgi(out_buf, out_end, in_buf, in_end, s);
227    }
228
229    if (ret == 0) {
230        *picture   = s->picture;
231        *data_size = sizeof(AVPicture);
232        return buf_size;
233    } else {
234        return -1;
235    }
236}
237
238static av_cold int sgi_init(AVCodecContext *avctx){
239    SgiState *s = avctx->priv_data;
240
241    avcodec_get_frame_defaults(&s->picture);
242    avctx->coded_frame = &s->picture;
243
244    return 0;
245}
246
247static av_cold int sgi_end(AVCodecContext *avctx)
248{
249    SgiState * const s = avctx->priv_data;
250
251    if (s->picture.data[0])
252        avctx->release_buffer(avctx, &s->picture);
253
254    return 0;
255}
256
257AVCodec sgi_decoder = {
258    "sgi",
259    CODEC_TYPE_VIDEO,
260    CODEC_ID_SGI,
261    sizeof(SgiState),
262    sgi_init,
263    NULL,
264    sgi_end,
265    decode_frame,
266    .long_name = NULL_IF_CONFIG_SMALL("SGI image"),
267};
268
269