summaryrefslogtreecommitdiff
path: root/libavcodec/sgidec.c
blob: a4b31288f29133565d28f31b8a1acfdd4b2ec4c3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
/*
 * SGI image decoder
 * Todd Kirby <doubleshot@pacbell.net>
 *
 * This file is part of Libav.
 *
 * Libav 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.
 *
 * Libav 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 Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "libavutil/imgutils.h"
#include "avcodec.h"
#include "bytestream.h"
#include "internal.h"
#include "sgi.h"

typedef struct SgiState {
    unsigned int width;
    unsigned int height;
    unsigned int depth;
    unsigned int bytes_per_channel;
    int linesize;
    GetByteContext g;
} SgiState;

/**
 * Expand an RLE row into a channel.
 * @param s the current image state
 * @param out_buf Points to one line after the output buffer.
 * @param out_end end of line in output buffer
 * @param pixelstride pixel stride of input buffer
 * @return size of output in bytes, -1 if buffer overflows
 */
static int expand_rle_row(SgiState *s, uint8_t *out_buf,
                          uint8_t *out_end, int pixelstride)
{
    unsigned char pixel, count;
    unsigned char *orig = out_buf;

    while (1) {
        if (bytestream2_get_bytes_left(&s->g) < 1)
            return AVERROR_INVALIDDATA;
        pixel = bytestream2_get_byteu(&s->g);
        if (!(count = (pixel & 0x7f))) {
            return (out_buf - orig) / pixelstride;
        }

        /* Check for buffer overflow. */
        if(out_buf + pixelstride * count >= out_end) return -1;

        if (pixel & 0x80) {
            while (count--) {
                *out_buf = bytestream2_get_byte(&s->g);
                out_buf += pixelstride;
            }
        } else {
            pixel = bytestream2_get_byte(&s->g);

            while (count--) {
                *out_buf = pixel;
                out_buf += pixelstride;
            }
        }
    }
}

/**
 * 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 number.
 */
static int read_rle_sgi(uint8_t *out_buf, SgiState *s)
{
    uint8_t *dest_row;
    unsigned int len = s->height * s->depth * 4;
    GetByteContext g_table = s->g;
    unsigned int y, z;
    unsigned int start_offset;

    /* size of  RLE offset and length tables */
    if (len * 2  > bytestream2_get_bytes_left(&s->g)) {
        return AVERROR_INVALIDDATA;
    }

    for (z = 0; z < s->depth; z++) {
        dest_row = out_buf;
        for (y = 0; y < s->height; y++) {
            dest_row -= s->linesize;
            start_offset = bytestream2_get_be32(&g_table);
            bytestream2_seek(&s->g, start_offset, SEEK_SET);
            if (expand_rle_row(s, dest_row + z, dest_row + FFABS(s->linesize),
                               s->depth) != s->width) {
                return AVERROR_INVALIDDATA;
            }
        }
    }
    return 0;
}

/**
 * Read an uncompressed SGI image.
 * @param out_buf output buffer
 * @param out_end end ofoutput buffer
 * @param s the current image state
 * @return 0 if read success, otherwise return -1.
 */
static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end,
                                 SgiState *s)
{
    int x, y, z;
    unsigned int offset = s->height * s->width * s->bytes_per_channel;
    GetByteContext gp[4];

    /* Test buffer size. */
    if (offset * s->depth > bytestream2_get_bytes_left(&s->g))
        return AVERROR_INVALIDDATA;

    /* Create a reader for each plane */
    for (z = 0; z < s->depth; z++) {
        gp[z] = s->g;
        bytestream2_skip(&gp[z], z * offset);
    }

    for (y = s->height - 1; y >= 0; y--) {
        out_end = out_buf + (y * s->linesize);
        if (s->bytes_per_channel == 1) {
            for (x = s->width; x > 0; x--)
                for (z = 0; z < s->depth; z++)
                    *out_end++ = bytestream2_get_byteu(&gp[z]);
        } else {
            uint16_t *out16 = (uint16_t *)out_end;
            for (x = s->width; x > 0; x--)
                for (z = 0; z < s->depth; z++)
                    *out16++ = bytestream2_get_ne16u(&gp[z]);
        }
    }
    return 0;
}

static int decode_frame(AVCodecContext *avctx,
                        void *data, int *got_frame,
                        AVPacket *avpkt)
{
    SgiState *s = avctx->priv_data;
    AVFrame *p = data;
    unsigned int dimension, rle;
    int ret = 0;
    uint8_t *out_buf, *out_end;

    bytestream2_init(&s->g, avpkt->data, avpkt->size);
    if (bytestream2_get_bytes_left(&s->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_be16(&s->g) != SGI_MAGIC) {
        av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
        return AVERROR_INVALIDDATA;
    }

    rle                  = bytestream2_get_byte(&s->g);
    s->bytes_per_channel = bytestream2_get_byte(&s->g);
    dimension            = bytestream2_get_be16(&s->g);
    s->width             = bytestream2_get_be16(&s->g);
    s->height            = bytestream2_get_be16(&s->g);
    s->depth             = bytestream2_get_be16(&s->g);

    if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) {
        av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
        return -1;
    }

    /* Check for supported image dimensions. */
    if (dimension != 2 && dimension != 3) {
        av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
        return -1;
    }

    if (s->depth == SGI_GRAYSCALE) {
        avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
    } else if (s->depth == SGI_RGB) {
        avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGB48BE : AV_PIX_FMT_RGB24;
    } else if (s->depth == SGI_RGBA && s->bytes_per_channel == 1) {
        avctx->pix_fmt = AV_PIX_FMT_RGBA;
    } else {
        av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
        return -1;
    }

    if (av_image_check_size(s->width, s->height, 0, avctx))
        return -1;
    avcodec_set_dimensions(avctx, s->width, s->height);

    if (ff_get_buffer(avctx, p, 0) < 0) {
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
        return -1;
    }

    p->pict_type = AV_PICTURE_TYPE_I;
    p->key_frame = 1;
    out_buf = p->data[0];

    out_end = out_buf + p->linesize[0] * s->height;

    s->linesize = p->linesize[0];

    /* Skip header. */
    bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET);
    if (rle) {
        ret = read_rle_sgi(out_end, s);
    } else {
        ret = read_uncompressed_sgi(out_buf, out_end, s);
    }

    if (ret == 0) {
        *got_frame = 1;
        return avpkt->size;
    } else {
        return ret;
    }
}

AVCodec ff_sgi_decoder = {
    .name           = "sgi",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_SGI,
    .priv_data_size = sizeof(SgiState),
    .decode         = decode_frame,
    .long_name      = NULL_IF_CONFIG_SMALL("SGI image"),
    .capabilities   = CODEC_CAP_DR1,
};