1/*
2 * SGI image decoder
3 * Todd Kirby <doubleshot@pacbell.net>
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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 "avcodec.h"
24#include "bytestream.h"
25#include "sgi.h"
26
27typedef struct SgiState {
28    AVFrame picture;
29    unsigned int width;
30    unsigned int height;
31    unsigned int depth;
32    unsigned int bytes_per_channel;
33    int linesize;
34    GetByteContext g;
35} SgiState;
36
37/**
38 * Expand an RLE row into a channel.
39 * @param s the current image state
40 * @param out_buf Points to one line after the output buffer.
41 * @param out_end end of line in output buffer
42 * @param pixelstride pixel stride of input buffer
43 * @return size of output in bytes, -1 if buffer overflows
44 */
45static int expand_rle_row(SgiState *s, uint8_t *out_buf,
46                          uint8_t *out_end, int pixelstride)
47{
48    unsigned char pixel, count;
49    unsigned char *orig = out_buf;
50
51    while (1) {
52        if (bytestream2_get_bytes_left(&s->g) < 1)
53            return AVERROR_INVALIDDATA;
54        pixel = bytestream2_get_byteu(&s->g);
55        if (!(count = (pixel & 0x7f))) {
56            return (out_buf - orig) / pixelstride;
57        }
58
59        /* Check for buffer overflow. */
60        if(out_buf + pixelstride * count >= out_end) return -1;
61
62        if (pixel & 0x80) {
63            while (count--) {
64                *out_buf = bytestream2_get_byte(&s->g);
65                out_buf += pixelstride;
66            }
67        } else {
68            pixel = bytestream2_get_byte(&s->g);
69
70            while (count--) {
71                *out_buf = pixel;
72                out_buf += pixelstride;
73            }
74        }
75    }
76}
77
78/**
79 * Read a run length encoded SGI image.
80 * @param out_buf output buffer
81 * @param s the current image state
82 * @return 0 if no error, else return error number.
83 */
84static int read_rle_sgi(uint8_t *out_buf, SgiState *s)
85{
86    uint8_t *dest_row;
87    unsigned int len = s->height * s->depth * 4;
88    GetByteContext g_table = s->g;
89    unsigned int y, z;
90    unsigned int start_offset;
91
92    /* size of  RLE offset and length tables */
93    if (len * 2  > bytestream2_get_bytes_left(&s->g)) {
94        return AVERROR_INVALIDDATA;
95    }
96
97    for (z = 0; z < s->depth; z++) {
98        dest_row = out_buf;
99        for (y = 0; y < s->height; y++) {
100            dest_row -= s->linesize;
101            start_offset = bytestream2_get_be32(&g_table);
102            bytestream2_seek(&s->g, start_offset, SEEK_SET);
103            if (expand_rle_row(s, dest_row + z, dest_row + FFABS(s->linesize),
104                               s->depth) != s->width) {
105                return AVERROR_INVALIDDATA;
106            }
107        }
108    }
109    return 0;
110}
111
112/**
113 * Read an uncompressed SGI image.
114 * @param out_buf output buffer
115 * @param out_end end ofoutput buffer
116 * @param s the current image state
117 * @return 0 if read success, otherwise return -1.
118 */
119static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end,
120                                 SgiState *s)
121{
122    int x, y, z;
123    unsigned int offset = s->height * s->width * s->bytes_per_channel;
124    GetByteContext gp[4];
125
126    /* Test buffer size. */
127    if (offset * s->depth > bytestream2_get_bytes_left(&s->g))
128        return AVERROR_INVALIDDATA;
129
130    /* Create a reader for each plane */
131    for (z = 0; z < s->depth; z++) {
132        gp[z] = s->g;
133        bytestream2_skip(&gp[z], z * offset);
134    }
135
136    for (y = s->height - 1; y >= 0; y--) {
137        out_end = out_buf + (y * s->linesize);
138        if (s->bytes_per_channel == 1) {
139            for (x = s->width; x > 0; x--)
140                for (z = 0; z < s->depth; z++)
141                    *out_end++ = bytestream2_get_byteu(&gp[z]);
142        } else {
143            uint16_t *out16 = (uint16_t *)out_end;
144            for (x = s->width; x > 0; x--)
145                for (z = 0; z < s->depth; z++)
146                    *out16++ = bytestream2_get_ne16u(&gp[z]);
147        }
148    }
149    return 0;
150}
151
152static int decode_frame(AVCodecContext *avctx,
153                        void *data, int *data_size,
154                        AVPacket *avpkt)
155{
156    SgiState *s = avctx->priv_data;
157    AVFrame *picture = data;
158    AVFrame *p = &s->picture;
159    unsigned int dimension, rle;
160    int ret = 0;
161    uint8_t *out_buf, *out_end;
162
163    bytestream2_init(&s->g, avpkt->data, avpkt->size);
164    if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) {
165        av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size);
166        return AVERROR_INVALIDDATA;
167    }
168
169    /* Test for SGI magic. */
170    if (bytestream2_get_be16(&s->g) != SGI_MAGIC) {
171        av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
172        return AVERROR_INVALIDDATA;
173    }
174
175    rle                  = bytestream2_get_byte(&s->g);
176    s->bytes_per_channel = bytestream2_get_byte(&s->g);
177    dimension            = bytestream2_get_be16(&s->g);
178    s->width             = bytestream2_get_be16(&s->g);
179    s->height            = bytestream2_get_be16(&s->g);
180    s->depth             = bytestream2_get_be16(&s->g);
181
182    if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) {
183        av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
184        return -1;
185    }
186
187    /* Check for supported image dimensions. */
188    if (dimension != 2 && dimension != 3) {
189        av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
190        return -1;
191    }
192
193    if (s->depth == SGI_GRAYSCALE) {
194        avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_GRAY16BE : PIX_FMT_GRAY8;
195    } else if (s->depth == SGI_RGB) {
196        avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_RGB48BE : PIX_FMT_RGB24;
197    } else if (s->depth == SGI_RGBA && s->bytes_per_channel == 1) {
198        avctx->pix_fmt = PIX_FMT_RGBA;
199    } else {
200        av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
201        return -1;
202    }
203
204    if (av_image_check_size(s->width, s->height, 0, avctx))
205        return -1;
206    avcodec_set_dimensions(avctx, s->width, s->height);
207
208    if (p->data[0])
209        avctx->release_buffer(avctx, p);
210
211    p->reference = 0;
212    if (avctx->get_buffer(avctx, p) < 0) {
213        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
214        return -1;
215    }
216
217    p->pict_type = AV_PICTURE_TYPE_I;
218    p->key_frame = 1;
219    out_buf = p->data[0];
220
221    out_end = out_buf + p->linesize[0] * s->height;
222
223    s->linesize = p->linesize[0];
224
225    /* Skip header. */
226    bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET);
227    if (rle) {
228        ret = read_rle_sgi(out_end, s);
229    } else {
230        ret = read_uncompressed_sgi(out_buf, out_end, s);
231    }
232
233    if (ret == 0) {
234        *picture   = s->picture;
235        *data_size = sizeof(AVPicture);
236        return avpkt->size;
237    } else {
238        return ret;
239    }
240}
241
242static av_cold int sgi_init(AVCodecContext *avctx){
243    SgiState *s = avctx->priv_data;
244
245    avcodec_get_frame_defaults(&s->picture);
246    avctx->coded_frame = &s->picture;
247
248    return 0;
249}
250
251static av_cold int sgi_end(AVCodecContext *avctx)
252{
253    SgiState * const s = avctx->priv_data;
254
255    if (s->picture.data[0])
256        avctx->release_buffer(avctx, &s->picture);
257
258    return 0;
259}
260
261AVCodec ff_sgi_decoder = {
262    .name           = "sgi",
263    .type           = AVMEDIA_TYPE_VIDEO,
264    .id             = CODEC_ID_SGI,
265    .priv_data_size = sizeof(SgiState),
266    .init           = sgi_init,
267    .close          = sgi_end,
268    .decode         = decode_frame,
269    .long_name = NULL_IF_CONFIG_SMALL("SGI image"),
270};
271
272