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 "libavutil/imgutils.h"
23#include "libavutil/avassert.h"
24#include "avcodec.h"
25#include "bytestream.h"
26#include "internal.h"
27#include "sgi.h"
28
29typedef struct SgiState {
30    AVCodecContext *avctx;
31    unsigned int width;
32    unsigned int height;
33    unsigned int depth;
34    unsigned int bytes_per_channel;
35    int linesize;
36    GetByteContext g;
37} SgiState;
38
39/**
40 * Expand an RLE row into a channel.
41 * @param s the current image state
42 * @param out_buf Points to one line after the output buffer.
43 * @param len length of out_buf in bytes
44 * @param pixelstride pixel stride of input buffer
45 * @return size of output in bytes, else return error code.
46 */
47static int expand_rle_row8(SgiState *s, uint8_t *out_buf,
48                           int len, int pixelstride)
49{
50    unsigned char pixel, count;
51    unsigned char *orig = out_buf;
52    uint8_t *out_end = out_buf + len;
53
54    while (out_buf < out_end) {
55        if (bytestream2_get_bytes_left(&s->g) < 1)
56            return AVERROR_INVALIDDATA;
57        pixel = bytestream2_get_byteu(&s->g);
58        if (!(count = (pixel & 0x7f))) {
59            break;
60        }
61
62        /* Check for buffer overflow. */
63        if (out_end - out_buf <= pixelstride * (count - 1)) {
64            av_log(s->avctx, AV_LOG_ERROR, "Invalid pixel count.\n");
65            return AVERROR_INVALIDDATA;
66        }
67
68        if (pixel & 0x80) {
69            while (count--) {
70                *out_buf = bytestream2_get_byte(&s->g);
71                out_buf += pixelstride;
72            }
73        } else {
74            pixel = bytestream2_get_byte(&s->g);
75
76            while (count--) {
77                *out_buf = pixel;
78                out_buf += pixelstride;
79            }
80        }
81    }
82    return (out_buf - orig) / pixelstride;
83}
84
85static int expand_rle_row16(SgiState *s, uint16_t *out_buf,
86                            int len, int pixelstride)
87{
88    unsigned short pixel;
89    unsigned char count;
90    unsigned short *orig = out_buf;
91    uint16_t *out_end = out_buf + len;
92
93    while (out_buf < out_end) {
94        if (bytestream2_get_bytes_left(&s->g) < 2)
95            return AVERROR_INVALIDDATA;
96        pixel = bytestream2_get_be16u(&s->g);
97        if (!(count = (pixel & 0x7f)))
98            break;
99
100        /* Check for buffer overflow. */
101        if (pixelstride * (count - 1) >= len) {
102            av_log(s->avctx, AV_LOG_ERROR, "Invalid pixel count.\n");
103            return AVERROR_INVALIDDATA;
104        }
105
106        if (pixel & 0x80) {
107            while (count--) {
108                pixel = bytestream2_get_ne16(&s->g);
109                AV_WN16A(out_buf, pixel);
110                out_buf += pixelstride;
111            }
112        } else {
113            pixel = bytestream2_get_ne16(&s->g);
114
115            while (count--) {
116                AV_WN16A(out_buf, pixel);
117                out_buf += pixelstride;
118            }
119        }
120    }
121    return (out_buf - orig) / pixelstride;
122}
123
124
125/**
126 * Read a run length encoded SGI image.
127 * @param out_buf output buffer
128 * @param s the current image state
129 * @return 0 if no error, else return error code.
130 */
131static int read_rle_sgi(uint8_t *out_buf, SgiState *s)
132{
133    uint8_t *dest_row;
134    unsigned int len = s->height * s->depth * 4;
135    GetByteContext g_table = s->g;
136    unsigned int y, z;
137    unsigned int start_offset;
138    int linesize, ret;
139
140    /* size of  RLE offset and length tables */
141    if (len * 2 > bytestream2_get_bytes_left(&s->g)) {
142        return AVERROR_INVALIDDATA;
143    }
144
145    for (z = 0; z < s->depth; z++) {
146        dest_row = out_buf;
147        for (y = 0; y < s->height; y++) {
148            linesize = s->width * s->depth * s->bytes_per_channel;
149            dest_row -= s->linesize;
150            start_offset = bytestream2_get_be32(&g_table);
151            bytestream2_seek(&s->g, start_offset, SEEK_SET);
152            if (s->bytes_per_channel == 1)
153                ret = expand_rle_row8(s, dest_row + z, linesize, s->depth);
154            else
155                ret = expand_rle_row16(s, (uint16_t *)dest_row + z, linesize, s->depth);
156            if (ret != s->width)
157                return AVERROR_INVALIDDATA;
158        }
159    }
160    return 0;
161}
162
163/**
164 * Read an uncompressed SGI image.
165 * @param out_buf output buffer
166 * @param s the current image state
167 * @return 0 if read success, else return error code.
168 */
169static int read_uncompressed_sgi(unsigned char *out_buf, SgiState *s)
170{
171    int x, y, z;
172    unsigned int offset = s->height * s->width * s->bytes_per_channel;
173    GetByteContext gp[4];
174    uint8_t *out_end;
175
176    /* Test buffer size. */
177    if (offset * s->depth > bytestream2_get_bytes_left(&s->g))
178        return AVERROR_INVALIDDATA;
179
180    /* Create a reader for each plane */
181    for (z = 0; z < s->depth; z++) {
182        gp[z] = s->g;
183        bytestream2_skip(&gp[z], z * offset);
184    }
185
186    for (y = s->height - 1; y >= 0; y--) {
187        out_end = out_buf + (y * s->linesize);
188        if (s->bytes_per_channel == 1) {
189            for (x = s->width; x > 0; x--)
190                for (z = 0; z < s->depth; z++)
191                    *out_end++ = bytestream2_get_byteu(&gp[z]);
192        } else {
193            uint16_t *out16 = (uint16_t *)out_end;
194            for (x = s->width; x > 0; x--)
195                for (z = 0; z < s->depth; z++)
196                    *out16++ = bytestream2_get_ne16u(&gp[z]);
197        }
198    }
199    return 0;
200}
201
202static int decode_frame(AVCodecContext *avctx,
203                        void *data, int *got_frame,
204                        AVPacket *avpkt)
205{
206    SgiState *s = avctx->priv_data;
207    AVFrame *p = data;
208    unsigned int dimension, rle;
209    int ret = 0;
210    uint8_t *out_buf, *out_end;
211
212    bytestream2_init(&s->g, avpkt->data, avpkt->size);
213    if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) {
214        av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size);
215        return AVERROR_INVALIDDATA;
216    }
217
218    /* Test for SGI magic. */
219    if (bytestream2_get_be16u(&s->g) != SGI_MAGIC) {
220        av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
221        return AVERROR_INVALIDDATA;
222    }
223
224    rle                  = bytestream2_get_byteu(&s->g);
225    s->bytes_per_channel = bytestream2_get_byteu(&s->g);
226    dimension            = bytestream2_get_be16u(&s->g);
227    s->width             = bytestream2_get_be16u(&s->g);
228    s->height            = bytestream2_get_be16u(&s->g);
229    s->depth             = bytestream2_get_be16u(&s->g);
230
231    if (s->bytes_per_channel != 1 && s->bytes_per_channel != 2) {
232        av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
233        return AVERROR_INVALIDDATA;
234    }
235
236    /* Check for supported image dimensions. */
237    if (dimension != 2 && dimension != 3) {
238        av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
239        return AVERROR_INVALIDDATA;
240    }
241
242    if (s->depth == SGI_GRAYSCALE) {
243        avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
244    } else if (s->depth == SGI_RGB) {
245        avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGB48BE : AV_PIX_FMT_RGB24;
246    } else if (s->depth == SGI_RGBA) {
247        avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGBA64BE : AV_PIX_FMT_RGBA;
248    } else {
249        av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
250        return AVERROR_INVALIDDATA;
251    }
252
253    ret = ff_set_dimensions(avctx, s->width, s->height);
254    if (ret < 0)
255        return ret;
256
257    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
258        return ret;
259
260    p->pict_type = AV_PICTURE_TYPE_I;
261    p->key_frame = 1;
262    out_buf = p->data[0];
263
264    out_end = out_buf + p->linesize[0] * s->height;
265
266    s->linesize = p->linesize[0];
267
268    /* Skip header. */
269    bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET);
270    if (rle) {
271        ret = read_rle_sgi(out_end, s);
272    } else {
273        ret = read_uncompressed_sgi(out_buf, s);
274    }
275    if (ret)
276        return ret;
277
278    *got_frame = 1;
279    return avpkt->size;
280}
281
282static av_cold int sgi_decode_init(AVCodecContext *avctx)
283{
284    SgiState *s = avctx->priv_data;
285
286    s->avctx = avctx;
287
288    return 0;
289}
290
291AVCodec ff_sgi_decoder = {
292    .name           = "sgi",
293    .long_name      = NULL_IF_CONFIG_SMALL("SGI image"),
294    .type           = AVMEDIA_TYPE_VIDEO,
295    .id             = AV_CODEC_ID_SGI,
296    .priv_data_size = sizeof(SgiState),
297    .decode         = decode_frame,
298    .init           = sgi_decode_init,
299    .capabilities   = CODEC_CAP_DR1,
300};
301