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FFmpeg/libavcodec/sga.c
Andreas Rheinhardt 20f9727018 avcodec/codec_internal: Add FFCodec, hide internal part of AVCodec 
Up until now, codec.h contains both public and private parts
of AVCodec. This exposes the internals of AVCodec to users
and leads them into the temptation of actually using them
and forces us to forward-declare structures and types that
users can't use at all.

This commit changes this by adding a new structure FFCodec to
codec_internal.h that extends AVCodec, i.e. contains the public
AVCodec as first member; the private fields of AVCodec are moved
to this structure, leaving codec.h clean.

Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-03-21 01:33:09 +01:00

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/*
* Copyright (c) 2021 Paul B Mahol
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/common.h"
#include "avcodec.h"
#include "get_bits.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "internal.h"
#define PALDATA_FOLLOWS_TILEDATA 4
#define HAVE_COMPRESSED_TILEMAP 32
#define HAVE_TILEMAP 128
typedef struct SGAVideoContext {
GetByteContext gb;
int metadata_size;
int tiledata_size;
int tiledata_offset;
int tilemapdata_size;
int tilemapdata_offset;
int paldata_size;
int paldata_offset;
int palmapdata_offset;
int palmapdata_size;
int flags;
int nb_pal;
int nb_tiles;
int tiles_w, tiles_h;
int shift;
int plus;
int swap;
uint32_t pal[256];
uint8_t *tileindex_data;
unsigned tileindex_size;
uint8_t *palmapindex_data;
unsigned palmapindex_size;
uint8_t uncompressed[65536];
} SGAVideoContext;
static av_cold int sga_decode_init(AVCodecContext *avctx)
{
avctx->pix_fmt = AV_PIX_FMT_PAL8;
return 0;
}
static int decode_palette(GetByteContext *gb, uint32_t *pal)
{
GetBitContext gbit;
if (bytestream2_get_bytes_left(gb) < 18)
return AVERROR_INVALIDDATA;
memset(pal, 0, 16 * sizeof(*pal));
init_get_bits8(&gbit, gb->buffer, 18);
for (int RGBIndex = 0; RGBIndex < 3; RGBIndex++) {
for (int index = 0; index < 16; index++) {
unsigned color = get_bits1(&gbit) << RGBIndex;
pal[15 - index] |= color << (5 + 16);
}
}
for (int RGBIndex = 0; RGBIndex < 3; RGBIndex++) {
for (int index = 0; index < 16; index++) {
unsigned color = get_bits1(&gbit) << RGBIndex;
pal[15 - index] |= color << (5 + 8);
}
}
for (int RGBIndex = 0; RGBIndex < 3; RGBIndex++) {
for (int index = 0; index < 16; index++) {
unsigned color = get_bits1(&gbit) << RGBIndex;
pal[15 - index] |= color << (5 + 0);
}
}
for (int index = 0; index < 16; index++)
pal[index] = (0xFFU << 24) | pal[index] | (pal[index] >> 3);
bytestream2_skip(gb, 18);
return 0;
}
static int decode_index_palmap(SGAVideoContext *s, AVFrame *frame)
{
const uint8_t *tt = s->tileindex_data;
for (int y = 0; y < s->tiles_h; y++) {
for (int x = 0; x < s->tiles_w; x++) {
int pal_idx = s->palmapindex_data[y * s->tiles_w + x] * 16;
uint8_t *dst = frame->data[0] + y * 8 * frame->linesize[0] + x * 8;
for (int yy = 0; yy < 8; yy++) {
for (int xx = 0; xx < 8; xx++)
dst[xx] = pal_idx + tt[xx];
tt += 8;
dst += frame->linesize[0];
}
}
}
return 0;
}
static int decode_index_tilemap(SGAVideoContext *s, AVFrame *frame)
{
GetByteContext *gb = &s->gb;
GetBitContext pm;
bytestream2_seek(gb, s->tilemapdata_offset, SEEK_SET);
if (bytestream2_get_bytes_left(gb) < s->tilemapdata_size)
return AVERROR_INVALIDDATA;
init_get_bits8(&pm, gb->buffer, s->tilemapdata_size);
for (int y = 0; y < s->tiles_h; y++) {
for (int x = 0; x < s->tiles_w; x++) {
uint8_t tile[64];
int tilemap = get_bits(&pm, 16);
int flip_x = (tilemap >> 11) & 1;
int flip_y = (tilemap >> 12) & 1;
int tindex = av_clip((tilemap & 511) - 1, 0, s->nb_tiles - 1);
const uint8_t *tt = s->tileindex_data + tindex * 64;
int pal_idx = ((tilemap >> 13) & 3) * 16;
uint8_t *dst = frame->data[0] + y * 8 * frame->linesize[0] + x * 8;
if (!flip_x && !flip_y) {
memcpy(tile, tt, 64);
} else if (flip_x && flip_y) {
for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++)
tile[i * 8 + j] = tt[(7 - i) * 8 + 7 - j];
}
} else if (flip_x) {
for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++)
tile[i * 8 + j] = tt[i * 8 + 7 - j];
}
} else {
for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++)
tile[i * 8 + j] = tt[(7 - i) * 8 + j];
}
}
for (int yy = 0; yy < 8; yy++) {
for (int xx = 0; xx < 8; xx++)
dst[xx] = pal_idx + tile[xx + yy * 8];
dst += frame->linesize[0];
}
}
}
return 0;
}
static int decode_index(SGAVideoContext *s, AVFrame *frame)
{
const uint8_t *src = s->tileindex_data;
uint8_t *dst = frame->data[0];
for (int y = 0; y < frame->height; y += 8) {
for (int x = 0; x < frame->width; x += 8) {
for (int yy = 0; yy < 8; yy++) {
for (int xx = 0; xx < 8; xx++)
dst[x + xx + yy * frame->linesize[0]] = src[xx];
src += 8;
}
}
dst += 8 * frame->linesize[0];
}
return 0;
}
static int lzss_decompress(AVCodecContext *avctx,
GetByteContext *gb, uint8_t *dst,
int dst_size, int shift, int plus)
{
int oi = 0;
while (bytestream2_get_bytes_left(gb) > 0 && oi < dst_size) {
uint16_t displace, header = bytestream2_get_be16(gb);
int count, offset;
for (int i = 0; i < 16; i++) {
switch (header >> 15) {
case 0:
if (oi + 2 < dst_size) {
dst[oi++] = bytestream2_get_byte(gb);
dst[oi++] = bytestream2_get_byte(gb);
}
break;
case 1:
displace = bytestream2_get_be16(gb);
count = displace >> shift;
offset = displace & ((1 << shift) - 1);
if (displace == 0) {
while (bytestream2_get_bytes_left(gb) > 0 &&
oi < dst_size)
dst[oi++] = bytestream2_get_byte(gb);
return oi;
}
count += plus;
if (offset <= 0)
offset = 1;
if (oi < offset || oi + count * 2 > dst_size)
return AVERROR_INVALIDDATA;
for (int j = 0; j < count * 2; j++) {
dst[oi] = dst[oi - offset];
oi++;
}
break;
}
header <<= 1;
}
}
return AVERROR_INVALIDDATA;
}
static int decode_palmapdata(AVCodecContext *avctx)
{
SGAVideoContext *s = avctx->priv_data;
const int bits = (s->nb_pal + 1) / 2;
GetByteContext *gb = &s->gb;
GetBitContext pm;
bytestream2_seek(gb, s->palmapdata_offset, SEEK_SET);
if (bytestream2_get_bytes_left(gb) < s->palmapdata_size)
return AVERROR_INVALIDDATA;
init_get_bits8(&pm, gb->buffer, s->palmapdata_size);
for (int y = 0; y < s->tiles_h; y++) {
uint8_t *dst = s->palmapindex_data + y * s->tiles_w;
for (int x = 0; x < s->tiles_w; x++)
dst[x] = get_bits(&pm, bits);
dst += s->tiles_w;
}
return 0;
}
static int decode_tiledata(AVCodecContext *avctx)
{
SGAVideoContext *s = avctx->priv_data;
GetByteContext *gb = &s->gb;
GetBitContext tm;
bytestream2_seek(gb, s->tiledata_offset, SEEK_SET);
if (bytestream2_get_bytes_left(gb) < s->tiledata_size)
return AVERROR_INVALIDDATA;
init_get_bits8(&tm, gb->buffer, s->tiledata_size);
for (int n = 0; n < s->nb_tiles; n++) {
uint8_t *dst = s->tileindex_data + n * 64;
for (int yy = 0; yy < 8; yy++) {
for (int xx = 0; xx < 8; xx++)
dst[xx] = get_bits(&tm, 4);
dst += 8;
}
}
for (int i = 0; i < s->nb_tiles && s->swap; i++) {
uint8_t *dst = s->tileindex_data + i * 64;
for (int j = 8; j < 64; j += 16) {
for (int k = 0; k < 8; k += 2)
FFSWAP(uint8_t, dst[j + k], dst[j+k+1]);
}
}
return 0;
}
static int sga_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame, AVPacket *avpkt)
{
SGAVideoContext *s = avctx->priv_data;
GetByteContext *gb = &s->gb;
AVFrame *frame = data;
int ret, type;
if (avpkt->size <= 14)
return AVERROR_INVALIDDATA;
s->flags = avpkt->data[8];
s->nb_pal = avpkt->data[9];
s->tiles_w = avpkt->data[10];
s->tiles_h = avpkt->data[11];
if (s->nb_pal > 4)
return AVERROR_INVALIDDATA;
if ((ret = ff_set_dimensions(avctx,
s->tiles_w * 8,
s->tiles_h * 8)) < 0)
return ret;
av_fast_padded_malloc(&s->tileindex_data, &s->tileindex_size,
avctx->width * avctx->height);
if (!s->tileindex_data)
return AVERROR(ENOMEM);
av_fast_padded_malloc(&s->palmapindex_data, &s->palmapindex_size,
s->tiles_w * s->tiles_h);
if (!s->palmapindex_data)
return AVERROR(ENOMEM);
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
bytestream2_init(gb, avpkt->data, avpkt->size);
type = bytestream2_get_byte(gb);
s->metadata_size = 12 + ((!!(s->flags & HAVE_TILEMAP)) * 2);
s->nb_tiles = s->flags & HAVE_TILEMAP ? AV_RB16(avpkt->data + 12) : s->tiles_w * s->tiles_h;
if (s->nb_tiles > s->tiles_w * s->tiles_h)
return AVERROR_INVALIDDATA;
av_log(avctx, AV_LOG_DEBUG, "type: %X flags: %X nb_tiles: %d\n", type, s->flags, s->nb_tiles);
switch (type) {
case 0xE7:
case 0xCB:
case 0xCD:
s->swap = 1;
s->shift = 12;
s->plus = 1;
break;
case 0xC9:
s->swap = 1;
s->shift = 13;
s->plus = 1;
break;
case 0xC8:
s->swap = 1;
s->shift = 13;
s->plus = 0;
break;
case 0xC7:
s->swap = 0;
s->shift = 13;
s->plus = 1;
break;
case 0xC6:
s->swap = 0;
s->shift = 13;
s->plus = 0;
break;
}
if (type == 0xE7) {
int offset = s->metadata_size, left;
int sizes[3];
bytestream2_seek(gb, s->metadata_size, SEEK_SET);
for (int i = 0; i < 3; i++)
sizes[i] = bytestream2_get_be16(gb);
for (int i = 0; i < 3; i++) {
int size = sizes[i];
int raw = size >> 15;
size &= (1 << 15) - 1;
if (raw) {
if (bytestream2_get_bytes_left(gb) < size)
return AVERROR_INVALIDDATA;
if (sizeof(s->uncompressed) - offset < size)
return AVERROR_INVALIDDATA;
memcpy(s->uncompressed + offset, gb->buffer, size);
bytestream2_skip(gb, size);
} else {
GetByteContext gb2;
if (bytestream2_get_bytes_left(gb) < size)
return AVERROR_INVALIDDATA;
bytestream2_init(&gb2, gb->buffer, size);
ret = lzss_decompress(avctx, &gb2, s->uncompressed + offset,
sizeof(s->uncompressed) - offset, s->shift, s->plus);
if (ret < 0)
return ret;
bytestream2_skip(gb, size);
size = ret;
}
offset += size;
}
left = bytestream2_get_bytes_left(gb);
if (sizeof(s->uncompressed) - offset < left)
return AVERROR_INVALIDDATA;
bytestream2_get_buffer(gb, s->uncompressed + offset, left);
offset += left;
bytestream2_init(gb, s->uncompressed, offset);
}
switch (type) {
case 0xCD:
case 0xCB:
case 0xC9:
case 0xC8:
case 0xC7:
case 0xC6:
bytestream2_seek(gb, s->metadata_size, SEEK_SET);
ret = lzss_decompress(avctx, gb, s->uncompressed + s->metadata_size,
sizeof(s->uncompressed) - s->metadata_size, s->shift, s->plus);
if (ret < 0)
return ret;
bytestream2_init(gb, s->uncompressed, ret + s->metadata_size);
case 0xE7:
case 0xC1:
s->tiledata_size = s->nb_tiles * 32;
s->paldata_size = s->nb_pal * 18;
s->tiledata_offset = s->flags & PALDATA_FOLLOWS_TILEDATA ? s->metadata_size : s->metadata_size + s->paldata_size;
s->paldata_offset = s->flags & PALDATA_FOLLOWS_TILEDATA ? s->metadata_size + s->tiledata_size : s->metadata_size;
s->palmapdata_offset = (s->flags & HAVE_TILEMAP) ? -1 : s->paldata_offset + s->paldata_size;
s->palmapdata_size = (s->flags & HAVE_TILEMAP) || s->nb_pal < 2 ? 0 : (s->tiles_w * s->tiles_h * ((s->nb_pal + 1) / 2) + 7) / 8;
s->tilemapdata_size = (s->flags & HAVE_TILEMAP) ? s->tiles_w * s->tiles_h * 2 : 0;
s->tilemapdata_offset = (s->flags & HAVE_TILEMAP) ? s->paldata_offset + s->paldata_size: -1;
bytestream2_seek(gb, s->paldata_offset, SEEK_SET);
for (int n = 0; n < s->nb_pal; n++) {
ret = decode_palette(gb, s->pal + 16 * n);
if (ret < 0)
return ret;
}
if (s->tiledata_size > 0) {
ret = decode_tiledata(avctx);
if (ret < 0)
return ret;
}
if (s->palmapdata_size > 0) {
ret = decode_palmapdata(avctx);
if (ret < 0)
return ret;
}
if (s->palmapdata_size > 0 && s->tiledata_size > 0) {
ret = decode_index_palmap(s, frame);
if (ret < 0)
return ret;
} else if (s->tilemapdata_size > 0 && s->tiledata_size > 0) {
ret = decode_index_tilemap(s, frame);
if (ret < 0)
return ret;
} else if (s->tiledata_size > 0) {
ret = decode_index(s, frame);
if (ret < 0)
return ret;
}
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unknown type: %X\n", type);
return AVERROR_INVALIDDATA;
}
memcpy(frame->data[1], s->pal, AVPALETTE_SIZE);
frame->palette_has_changed = 1;
frame->pict_type = AV_PICTURE_TYPE_I;
frame->key_frame = 1;
*got_frame = 1;
return avpkt->size;
}
static av_cold int sga_decode_end(AVCodecContext *avctx)
{
SGAVideoContext *s = avctx->priv_data;
av_freep(&s->tileindex_data);
s->tileindex_size = 0;
av_freep(&s->palmapindex_data);
s->palmapindex_size = 0;
return 0;
}
const FFCodec ff_sga_decoder = {
.p.name = "sga",
.p.long_name = NULL_IF_CONFIG_SMALL("Digital Pictures SGA Video"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_SGA_VIDEO,
.priv_data_size = sizeof(SGAVideoContext),
.init = sga_decode_init,
.decode = sga_decode_frame,
.close = sga_decode_end,
.p.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};
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