1/*
2 * Tiertex Limited SEQ Video Decoder
3 * Copyright (c) 2006 Gregory Montoir (cyx@users.sourceforge.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/**
23 * @file
24 * Tiertex Limited SEQ video decoder
25 */
26
27#include "avcodec.h"
28#define BITSTREAM_READER_LE
29#include "get_bits.h"
30#include "internal.h"
31
32
33typedef struct SeqVideoContext {
34    AVCodecContext *avctx;
35    AVFrame *frame;
36} SeqVideoContext;
37
38
39static const unsigned char *seq_unpack_rle_block(const unsigned char *src,
40                                                 const unsigned char *src_end,
41                                                 unsigned char *dst, int dst_size)
42{
43    int i, len, sz;
44    GetBitContext gb;
45    int code_table[64];
46
47    /* get the rle codes */
48    init_get_bits(&gb, src, (src_end - src) * 8);
49    for (i = 0, sz = 0; i < 64 && sz < dst_size; i++) {
50        if (get_bits_left(&gb) < 4)
51            return NULL;
52        code_table[i] = get_sbits(&gb, 4);
53        sz += FFABS(code_table[i]);
54    }
55    src += (get_bits_count(&gb) + 7) / 8;
56
57    /* do the rle unpacking */
58    for (i = 0; i < 64 && dst_size > 0; i++) {
59        len = code_table[i];
60        if (len < 0) {
61            len = -len;
62            if (src_end - src < 1)
63                return NULL;
64            memset(dst, *src++, FFMIN(len, dst_size));
65        } else {
66            if (src_end - src < len)
67                return NULL;
68            memcpy(dst, src, FFMIN(len, dst_size));
69            src += len;
70        }
71        dst += len;
72        dst_size -= len;
73    }
74    return src;
75}
76
77static const unsigned char *seq_decode_op1(SeqVideoContext *seq,
78                                           const unsigned char *src,
79                                           const unsigned char *src_end,
80                                           unsigned char *dst)
81{
82    const unsigned char *color_table;
83    int b, i, len, bits;
84    GetBitContext gb;
85    unsigned char block[8 * 8];
86
87    if (src_end - src < 1)
88        return NULL;
89    len = *src++;
90    if (len & 0x80) {
91        switch (len & 3) {
92        case 1:
93            src = seq_unpack_rle_block(src, src_end, block, sizeof(block));
94            for (b = 0; b < 8; b++) {
95                memcpy(dst, &block[b * 8], 8);
96                dst += seq->frame->linesize[0];
97            }
98            break;
99        case 2:
100            src = seq_unpack_rle_block(src, src_end, block, sizeof(block));
101            for (i = 0; i < 8; i++) {
102                for (b = 0; b < 8; b++)
103                    dst[b * seq->frame->linesize[0]] = block[i * 8 + b];
104                ++dst;
105            }
106            break;
107        }
108    } else {
109        if (len <= 0)
110            return NULL;
111        bits = ff_log2_tab[len - 1] + 1;
112        if (src_end - src < len + 8 * bits)
113            return NULL;
114        color_table = src;
115        src += len;
116        init_get_bits(&gb, src, bits * 8 * 8); src += bits * 8;
117        for (b = 0; b < 8; b++) {
118            for (i = 0; i < 8; i++)
119                dst[i] = color_table[get_bits(&gb, bits)];
120            dst += seq->frame->linesize[0];
121        }
122    }
123
124    return src;
125}
126
127static const unsigned char *seq_decode_op2(SeqVideoContext *seq,
128                                           const unsigned char *src,
129                                           const unsigned char *src_end,
130                                           unsigned char *dst)
131{
132    int i;
133
134    if (src_end - src < 8 * 8)
135        return NULL;
136
137    for (i = 0; i < 8; i++) {
138        memcpy(dst, src, 8);
139        src += 8;
140        dst += seq->frame->linesize[0];
141    }
142
143    return src;
144}
145
146static const unsigned char *seq_decode_op3(SeqVideoContext *seq,
147                                           const unsigned char *src,
148                                           const unsigned char *src_end,
149                                           unsigned char *dst)
150{
151    int pos, offset;
152
153    do {
154        if (src_end - src < 2)
155            return NULL;
156        pos = *src++;
157        offset = ((pos >> 3) & 7) * seq->frame->linesize[0] + (pos & 7);
158        dst[offset] = *src++;
159    } while (!(pos & 0x80));
160
161    return src;
162}
163
164static int seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int data_size)
165{
166    const unsigned char *data_end = data + data_size;
167    GetBitContext gb;
168    int flags, i, j, x, y, op;
169    unsigned char c[3];
170    unsigned char *dst;
171    uint32_t *palette;
172
173    flags = *data++;
174
175    if (flags & 1) {
176        palette = (uint32_t *)seq->frame->data[1];
177        if (data_end - data < 256 * 3)
178            return AVERROR_INVALIDDATA;
179        for (i = 0; i < 256; i++) {
180            for (j = 0; j < 3; j++, data++)
181                c[j] = (*data << 2) | (*data >> 4);
182            palette[i] = 0xFFU << 24 | AV_RB24(c);
183        }
184        seq->frame->palette_has_changed = 1;
185    }
186
187    if (flags & 2) {
188        if (data_end - data < 128)
189            return AVERROR_INVALIDDATA;
190        init_get_bits(&gb, data, 128 * 8); data += 128;
191        for (y = 0; y < 128; y += 8)
192            for (x = 0; x < 256; x += 8) {
193                dst = &seq->frame->data[0][y * seq->frame->linesize[0] + x];
194                op = get_bits(&gb, 2);
195                switch (op) {
196                case 1:
197                    data = seq_decode_op1(seq, data, data_end, dst);
198                    break;
199                case 2:
200                    data = seq_decode_op2(seq, data, data_end, dst);
201                    break;
202                case 3:
203                    data = seq_decode_op3(seq, data, data_end, dst);
204                    break;
205                }
206                if (!data)
207                    return AVERROR_INVALIDDATA;
208            }
209    }
210    return 0;
211}
212
213static av_cold int seqvideo_decode_init(AVCodecContext *avctx)
214{
215    SeqVideoContext *seq = avctx->priv_data;
216
217    seq->avctx = avctx;
218    avctx->pix_fmt = AV_PIX_FMT_PAL8;
219
220    seq->frame = av_frame_alloc();
221    if (!seq->frame)
222        return AVERROR(ENOMEM);
223
224    return 0;
225}
226
227static int seqvideo_decode_frame(AVCodecContext *avctx,
228                                 void *data, int *got_frame,
229                                 AVPacket *avpkt)
230{
231    const uint8_t *buf = avpkt->data;
232    int buf_size = avpkt->size;
233    int ret;
234
235    SeqVideoContext *seq = avctx->priv_data;
236
237    if ((ret = ff_reget_buffer(avctx, seq->frame)) < 0)
238        return ret;
239
240    if (seqvideo_decode(seq, buf, buf_size))
241        return AVERROR_INVALIDDATA;
242
243    if ((ret = av_frame_ref(data, seq->frame)) < 0)
244        return ret;
245    *got_frame       = 1;
246
247    return buf_size;
248}
249
250static av_cold int seqvideo_decode_end(AVCodecContext *avctx)
251{
252    SeqVideoContext *seq = avctx->priv_data;
253
254    av_frame_free(&seq->frame);
255
256    return 0;
257}
258
259AVCodec ff_tiertexseqvideo_decoder = {
260    .name           = "tiertexseqvideo",
261    .long_name      = NULL_IF_CONFIG_SMALL("Tiertex Limited SEQ video"),
262    .type           = AVMEDIA_TYPE_VIDEO,
263    .id             = AV_CODEC_ID_TIERTEXSEQVIDEO,
264    .priv_data_size = sizeof(SeqVideoContext),
265    .init           = seqvideo_decode_init,
266    .close          = seqvideo_decode_end,
267    .decode         = seqvideo_decode_frame,
268    .capabilities   = CODEC_CAP_DR1,
269};
270