GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/cdgraphics.c Lines: 98 176 55.7 %
Date: 2019-11-18 18:00:01 Branches: 37 89 41.6 %

Line Branch Exec Source
1
/*
2
 * CD Graphics Video Decoder
3
 * Copyright (c) 2009 Michael Tison
4
 *
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 * This file is part of FFmpeg.
6
 *
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 * FFmpeg is free software; you can redistribute it and/or
8
 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
21
22
#include "avcodec.h"
23
#include "bytestream.h"
24
#include "internal.h"
25
26
/**
27
 * @file
28
 * @brief CD Graphics Video Decoder
29
 * @author Michael Tison
30
 * @see http://wiki.multimedia.cx/index.php?title=CD_Graphics
31
 * @see http://www.ccs.neu.edu/home/bchafy/cdb/info/cdg
32
 */
33
34
/// default screen sizes
35
#define CDG_FULL_WIDTH           300
36
#define CDG_FULL_HEIGHT          216
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#define CDG_DISPLAY_WIDTH        294
38
#define CDG_DISPLAY_HEIGHT       204
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#define CDG_BORDER_WIDTH           6
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#define CDG_BORDER_HEIGHT         12
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42
/// masks
43
#define CDG_COMMAND             0x09
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#define CDG_MASK                0x3F
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46
/// instruction codes
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#define CDG_INST_MEMORY_PRESET     1
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#define CDG_INST_BORDER_PRESET     2
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#define CDG_INST_TILE_BLOCK        6
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#define CDG_INST_SCROLL_PRESET    20
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#define CDG_INST_SCROLL_COPY      24
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#define CDG_INST_TRANSPARENT_COL  28
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#define CDG_INST_LOAD_PAL_LO      30
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#define CDG_INST_LOAD_PAL_HIGH    31
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#define CDG_INST_TILE_BLOCK_XOR   38
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57
/// data sizes
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#define CDG_PACKET_SIZE           24
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#define CDG_DATA_SIZE             16
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#define CDG_TILE_HEIGHT           12
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#define CDG_TILE_WIDTH             6
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#define CDG_MINIMUM_PKT_SIZE       6
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#define CDG_MINIMUM_SCROLL_SIZE    3
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#define CDG_HEADER_SIZE            8
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#define CDG_PALETTE_SIZE          16
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67
typedef struct CDGraphicsContext {
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    AVFrame *frame;
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    int hscroll;
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    int vscroll;
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    int transparency;
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    int cleared;
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} CDGraphicsContext;
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2
static av_cold int cdg_decode_init(AVCodecContext *avctx)
76
{
77
2
    CDGraphicsContext *cc = avctx->priv_data;
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79
2
    cc->frame = av_frame_alloc();
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2
    if (!cc->frame)
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        return AVERROR(ENOMEM);
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2
    cc->transparency = -1;
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84
2
    avctx->pix_fmt = AV_PIX_FMT_PAL8;
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2
    return ff_set_dimensions(avctx, CDG_FULL_WIDTH, CDG_FULL_HEIGHT);
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}
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88
6
static void cdg_border_preset(CDGraphicsContext *cc, uint8_t *data)
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{
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    int y;
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6
    int lsize    = cc->frame->linesize[0];
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6
    uint8_t *buf = cc->frame->data[0];
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6
    int color    = data[0] & 0x0F;
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95
6
    if (!(data[1] & 0x0F)) {
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        /// fill the top and bottom borders
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6
        memset(buf, color, CDG_BORDER_HEIGHT * lsize);
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6
        memset(buf + (CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT) * lsize,
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6
               color, CDG_BORDER_HEIGHT * lsize);
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101
        /// fill the side borders
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1158
        for (y = CDG_BORDER_HEIGHT; y < CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT; y++) {
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1152
            memset(buf + y * lsize, color, CDG_BORDER_WIDTH);
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1152
            memset(buf + CDG_FULL_WIDTH - CDG_BORDER_WIDTH + y * lsize,
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                   color, CDG_BORDER_WIDTH);
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        }
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    }
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6
}
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10
static void cdg_load_palette(CDGraphicsContext *cc, uint8_t *data, int low)
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{
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    uint8_t r, g, b;
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    uint16_t color;
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    int i;
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10
    int array_offset  = low ? 0 : 8;
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10
    uint32_t *palette = (uint32_t *) cc->frame->data[1];
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118
90
    for (i = 0; i < 8; i++) {
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80
        color = (data[2 * i] << 6) + (data[2 * i + 1] & 0x3F);
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80
        r = ((color >> 8) & 0x000F) * 17;
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80
        g = ((color >> 4) & 0x000F) * 17;
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80
        b = ((color     ) & 0x000F) * 17;
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80
        palette[i + array_offset] = 0xFFU << 24 | r << 16 | g << 8 | b;
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80
        if (cc->transparency >= 0)
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16
            palette[cc->transparency] &= 0xFFFFFF;
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    }
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10
    cc->frame->palette_has_changed = 1;
128
10
}
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130
180
static int cdg_tile_block(CDGraphicsContext *cc, uint8_t *data, int b)
131
{
132
    unsigned ci, ri;
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    int color;
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    int x, y;
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    int ai;
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180
    int stride   = cc->frame->linesize[0];
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180
    uint8_t *buf = cc->frame->data[0];
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139
180
    ri = (data[2] & 0x1F) * CDG_TILE_HEIGHT + cc->vscroll;
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180
    ci = (data[3] & 0x3F) * CDG_TILE_WIDTH  + cc->hscroll;
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180
    if (ri > (CDG_FULL_HEIGHT - CDG_TILE_HEIGHT))
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        return AVERROR(EINVAL);
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180
    if (ci > (CDG_FULL_WIDTH - CDG_TILE_WIDTH))
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        return AVERROR(EINVAL);
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147
2340
    for (y = 0; y < CDG_TILE_HEIGHT; y++) {
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15120
        for (x = 0; x < CDG_TILE_WIDTH; x++) {
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12960
            if (!((data[4 + y] >> (5 - x)) & 0x01))
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10153
                color = data[0] & 0x0F;
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            else
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2807
                color = data[1] & 0x0F;
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154
12960
            ai = ci + x + (stride * (ri + y));
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12960
            if (b)
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12960
                color ^= buf[ai];
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12960
            buf[ai] = color;
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        }
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    }
160
161
180
    return 0;
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}
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#define UP    2
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#define DOWN  1
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#define LEFT  2
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#define RIGHT 1
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static void cdg_copy_rect_buf(int out_tl_x, int out_tl_y, uint8_t *out,
170
                              int in_tl_x, int in_tl_y, uint8_t *in,
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                              int w, int h, int stride)
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{
173
    int y;
174
175
    in  += in_tl_x  + in_tl_y  * stride;
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    out += out_tl_x + out_tl_y * stride;
177
    for (y = 0; y < h; y++)
178
        memcpy(out + y * stride, in + y * stride, w);
179
}
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181
static void cdg_fill_rect_preset(int tl_x, int tl_y, uint8_t *out,
182
                                 int color, int w, int h, int stride)
183
{
184
    int y;
185
186
    for (y = tl_y; y < tl_y + h; y++)
187
        memset(out + tl_x + y * stride, color, w);
188
}
189
190
static void cdg_fill_wrapper(int out_tl_x, int out_tl_y, uint8_t *out,
191
                             int in_tl_x, int in_tl_y, uint8_t *in,
192
                             int color, int w, int h, int stride, int roll)
193
{
194
    if (roll) {
195
        cdg_copy_rect_buf(out_tl_x, out_tl_y, out, in_tl_x, in_tl_y,
196
                          in, w, h, stride);
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    } else {
198
        cdg_fill_rect_preset(out_tl_x, out_tl_y, out, color, w, h, stride);
199
    }
200
}
201
202
static void cdg_scroll(CDGraphicsContext *cc, uint8_t *data,
203
                       AVFrame *new_frame, int roll_over)
204
{
205
    int color;
206
    int hscmd, h_off, hinc, vscmd, v_off, vinc;
207
    int y;
208
    int stride   = cc->frame->linesize[0];
209
    uint8_t *in  = cc->frame->data[0];
210
    uint8_t *out = new_frame->data[0];
211
212
    color =  data[0] & 0x0F;
213
    hscmd = (data[1] & 0x30) >> 4;
214
    vscmd = (data[2] & 0x30) >> 4;
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216
    h_off =  FFMIN(data[1] & 0x07, CDG_BORDER_WIDTH  - 1);
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    v_off =  FFMIN(data[2] & 0x0F, CDG_BORDER_HEIGHT - 1);
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219
    /// find the difference and save the offset for cdg_tile_block usage
220
    hinc = h_off - cc->hscroll;
221
    vinc = v_off - cc->vscroll;
222
    cc->hscroll = h_off;
223
    cc->vscroll = v_off;
224
225
    if (vscmd == UP)
226
        vinc -= 12;
227
    if (vscmd == DOWN)
228
        vinc += 12;
229
    if (hscmd == LEFT)
230
        hinc -= 6;
231
    if (hscmd == RIGHT)
232
        hinc += 6;
233
234
    if (!hinc && !vinc)
235
        return;
236
237
    memcpy(new_frame->data[1], cc->frame->data[1], CDG_PALETTE_SIZE * 4);
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239
    for (y = FFMAX(0, vinc); y < FFMIN(CDG_FULL_HEIGHT + vinc, CDG_FULL_HEIGHT); y++)
240
        memcpy(out + FFMAX(0, hinc) + stride * y,
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               in + FFMAX(0, hinc) - hinc + (y - vinc) * stride,
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               FFMIN(stride + hinc, stride));
243
244
    if (vinc > 0)
245
        cdg_fill_wrapper(0, 0, out,
246
                         0, CDG_FULL_HEIGHT - vinc, in, color,
247
                         stride, vinc, stride, roll_over);
248
    else if (vinc < 0)
249
        cdg_fill_wrapper(0, CDG_FULL_HEIGHT + vinc, out,
250
                         0, 0, in, color,
251
                         stride, -1 * vinc, stride, roll_over);
252
253
    if (hinc > 0)
254
        cdg_fill_wrapper(0, 0, out,
255
                         CDG_FULL_WIDTH - hinc, 0, in, color,
256
                         hinc, CDG_FULL_HEIGHT, stride, roll_over);
257
    else if (hinc < 0)
258
        cdg_fill_wrapper(CDG_FULL_WIDTH + hinc, 0, out,
259
                         0, 0, in, color,
260
                         -1 * hinc, CDG_FULL_HEIGHT, stride, roll_over);
261
262
}
263
264
213
static int cdg_decode_frame(AVCodecContext *avctx,
265
                            void *data, int *got_frame, AVPacket *avpkt)
266
{
267
    GetByteContext gb;
268
213
    int buf_size       = avpkt->size;
269
    int ret;
270
    uint8_t command, inst;
271
213
    uint8_t cdg_data[CDG_DATA_SIZE] = {0};
272
213
    AVFrame *frame = data;
273
213
    CDGraphicsContext *cc = avctx->priv_data;
274
275
213
    if (buf_size < CDG_MINIMUM_PKT_SIZE) {
276
        av_log(avctx, AV_LOG_ERROR, "buffer too small for decoder\n");
277
        return AVERROR(EINVAL);
278
    }
279
213
    if (buf_size > CDG_HEADER_SIZE + CDG_DATA_SIZE) {
280
        av_log(avctx, AV_LOG_ERROR, "buffer too big for decoder\n");
281
        return AVERROR(EINVAL);
282
    }
283
284
213
    bytestream2_init(&gb, avpkt->data, avpkt->size);
285
286
213
    if ((ret = ff_reget_buffer(avctx, cc->frame, 0)) < 0)
287
        return ret;
288
213
    if (!cc->cleared) {
289
1
        memset(cc->frame->data[0], 0, cc->frame->linesize[0] * avctx->height);
290
1
        memset(cc->frame->data[1], 0, AVPALETTE_SIZE);
291
1
        cc->cleared = 1;
292
    }
293
294
213
    command = bytestream2_get_byte(&gb);
295
213
    inst    = bytestream2_get_byte(&gb);
296
213
    inst    &= CDG_MASK;
297
213
    bytestream2_skip(&gb, 2);
298
213
    bytestream2_get_buffer(&gb, cdg_data, sizeof(cdg_data));
299
300
213
    if ((command & CDG_MASK) == CDG_COMMAND) {
301

213
        switch (inst) {
302
16
        case CDG_INST_MEMORY_PRESET:
303
16
            if (!(cdg_data[1] & 0x0F))
304
1
                memset(cc->frame->data[0], cdg_data[0] & 0x0F,
305
1
                       cc->frame->linesize[0] * CDG_FULL_HEIGHT);
306
16
            break;
307
10
        case CDG_INST_LOAD_PAL_LO:
308
        case CDG_INST_LOAD_PAL_HIGH:
309
10
            if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
310
                av_log(avctx, AV_LOG_ERROR, "buffer too small for loading palette\n");
311
                return AVERROR(EINVAL);
312
            }
313
314
10
            cdg_load_palette(cc, cdg_data, inst == CDG_INST_LOAD_PAL_LO);
315
10
            break;
316
6
        case CDG_INST_BORDER_PRESET:
317
6
            cdg_border_preset(cc, cdg_data);
318
6
            break;
319
180
        case CDG_INST_TILE_BLOCK_XOR:
320
        case CDG_INST_TILE_BLOCK:
321
180
            if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
322
                av_log(avctx, AV_LOG_ERROR, "buffer too small for drawing tile\n");
323
                return AVERROR(EINVAL);
324
            }
325
326
180
            ret = cdg_tile_block(cc, cdg_data, inst == CDG_INST_TILE_BLOCK_XOR);
327
180
            if (ret) {
328
                av_log(avctx, AV_LOG_ERROR, "tile is out of range\n");
329
                return ret;
330
            }
331
180
            break;
332
        case CDG_INST_SCROLL_PRESET:
333
        case CDG_INST_SCROLL_COPY:
334
            if (buf_size - CDG_HEADER_SIZE < CDG_MINIMUM_SCROLL_SIZE) {
335
                av_log(avctx, AV_LOG_ERROR, "buffer too small for scrolling\n");
336
                return AVERROR(EINVAL);
337
            }
338
339
            if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
340
                return ret;
341
342
            cdg_scroll(cc, cdg_data, frame, inst == CDG_INST_SCROLL_COPY);
343
            av_frame_unref(cc->frame);
344
            ret = av_frame_ref(cc->frame, frame);
345
            if (ret < 0)
346
                return ret;
347
            break;
348
1
        case CDG_INST_TRANSPARENT_COL:
349
1
            cc->transparency = cdg_data[0] & 0xF;
350
1
            break;
351
        default:
352
            break;
353
        }
354
355
213
        if (!frame->data[0]) {
356
213
            ret = av_frame_ref(frame, cc->frame);
357
213
            if (ret < 0)
358
                return ret;
359
        }
360
213
        *got_frame = 1;
361
    } else {
362
        *got_frame = 0;
363
    }
364
365
213
    return avpkt->size;
366
}
367
368
2
static av_cold int cdg_decode_end(AVCodecContext *avctx)
369
{
370
2
    CDGraphicsContext *cc = avctx->priv_data;
371
372
2
    av_frame_free(&cc->frame);
373
374
2
    return 0;
375
}
376
377
AVCodec ff_cdgraphics_decoder = {
378
    .name           = "cdgraphics",
379
    .long_name      = NULL_IF_CONFIG_SMALL("CD Graphics video"),
380
    .type           = AVMEDIA_TYPE_VIDEO,
381
    .id             = AV_CODEC_ID_CDGRAPHICS,
382
    .priv_data_size = sizeof(CDGraphicsContext),
383
    .init           = cdg_decode_init,
384
    .close          = cdg_decode_end,
385
    .decode         = cdg_decode_frame,
386
    .capabilities   = AV_CODEC_CAP_DR1,
387
};