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FFmpeg/libavcodec/fmvc.c
Andreas Rheinhardt 4243da4ff4 avcodec/codec_internal: Use union for FFCodec decode/encode callbacks 
This is possible, because every given FFCodec has to implement
exactly one of these. Doing so decreases sizeof(FFCodec) and
therefore decreases the size of the binary.
Notice that in case of position-independent code the decrease
is in .data.rel.ro, so that this translates to decreased
memory consumption.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-04-05 20:02:37 +02:00

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/*
* FM Screen Capture Codec decoder
*
* Copyright (c) 2017 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "avcodec.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "internal.h"
#define BLOCK_HEIGHT 112u
#define BLOCK_WIDTH 84u
typedef struct InterBlock {
int w, h;
int size;
int xor;
} InterBlock;
typedef struct FMVCContext {
GetByteContext gb;
PutByteContext pb;
uint8_t *buffer;
size_t buffer_size;
uint8_t *pbuffer;
size_t pbuffer_size;
ptrdiff_t stride;
int bpp;
int yb, xb;
InterBlock *blocks;
unsigned nb_blocks;
} FMVCContext;
static int decode_type2(GetByteContext *gb, PutByteContext *pb)
{
unsigned repeat = 0, first = 1, opcode = 0;
int i, len, pos;
while (bytestream2_get_bytes_left(gb) > 0) {
GetByteContext gbc;
while (bytestream2_get_bytes_left(gb) > 0) {
if (first) {
first = 0;
if (bytestream2_peek_byte(gb) > 17) {
len = bytestream2_get_byte(gb) - 17;
if (len < 4) {
do {
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
--len;
} while (len);
opcode = bytestream2_peek_byte(gb);
continue;
} else {
do {
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
--len;
} while (len);
opcode = bytestream2_peek_byte(gb);
if (opcode < 0x10) {
bytestream2_skip(gb, 1);
pos = - (opcode >> 2) - 4 * bytestream2_get_byte(gb) - 2049;
bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
len = opcode & 3;
if (!len) {
repeat = 1;
} else {
do {
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
--len;
} while (len);
opcode = bytestream2_peek_byte(gb);
}
continue;
}
}
repeat = 0;
}
repeat = 1;
}
if (repeat) {
repeat = 0;
opcode = bytestream2_peek_byte(gb);
if (opcode < 0x10) {
bytestream2_skip(gb, 1);
if (!opcode) {
if (!bytestream2_peek_byte(gb)) {
do {
bytestream2_skip(gb, 1);
opcode += 255;
} while (!bytestream2_peek_byte(gb) && bytestream2_get_bytes_left(gb) > 0);
}
opcode += bytestream2_get_byte(gb) + 15;
}
bytestream2_put_le32(pb, bytestream2_get_le32(gb));
for (i = opcode - 1; i > 0; --i)
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
opcode = bytestream2_peek_byte(gb);
if (opcode < 0x10) {
bytestream2_skip(gb, 1);
pos = - (opcode >> 2) - 4 * bytestream2_get_byte(gb) - 2049;
bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
len = opcode & 3;
if (!len) {
repeat = 1;
} else {
do {
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
--len;
} while (len);
opcode = bytestream2_peek_byte(gb);
}
continue;
}
}
}
if (opcode >= 0x40) {
bytestream2_skip(gb, 1);
pos = - ((opcode >> 2) & 7) - 1 - 8 * bytestream2_get_byte(gb);
len = (opcode >> 5) - 1;
bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
do {
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
--len;
} while (len);
len = opcode & 3;
if (!len) {
repeat = 1;
} else {
do {
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
--len;
} while (len);
opcode = bytestream2_peek_byte(gb);
}
continue;
} else if (opcode < 0x20) {
break;
}
len = opcode & 0x1F;
bytestream2_skip(gb, 1);
if (!len) {
if (!bytestream2_peek_byte(gb)) {
do {
bytestream2_skip(gb, 1);
len += 255;
} while (!bytestream2_peek_byte(gb) && bytestream2_get_bytes_left(gb) > 0);
}
len += bytestream2_get_byte(gb) + 31;
}
i = bytestream2_get_le16(gb);
pos = - (i >> 2) - 1;
bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
if (len < 6 || bytestream2_tell_p(pb) - bytestream2_tell(&gbc) < 4) {
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
do {
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
--len;
} while (len);
} else {
bytestream2_put_le32(pb, bytestream2_get_le32(&gbc));
for (len = len - 2; len; --len)
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
}
len = i & 3;
if (!len) {
repeat = 1;
} else {
do {
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
--len;
} while (len);
opcode = bytestream2_peek_byte(gb);
}
}
bytestream2_skip(gb, 1);
if (opcode < 0x10) {
pos = -(opcode >> 2) - 1 - 4 * bytestream2_get_byte(gb);
bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
len = opcode & 3;
if (!len) {
repeat = 1;
} else {
do {
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
--len;
} while (len);
opcode = bytestream2_peek_byte(gb);
}
continue;
}
len = opcode & 7;
if (!len) {
if (!bytestream2_peek_byte(gb)) {
do {
bytestream2_skip(gb, 1);
len += 255;
} while (!bytestream2_peek_byte(gb) && bytestream2_get_bytes_left(gb) > 0);
}
len += bytestream2_get_byte(gb) + 7;
}
i = bytestream2_get_le16(gb);
pos = bytestream2_tell_p(pb) - 2048 * (opcode & 8);
pos = pos - (i >> 2);
if (pos == bytestream2_tell_p(pb))
break;
pos = pos - 0x4000;
bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
bytestream2_seek(&gbc, pos, SEEK_SET);
if (len < 6 || bytestream2_tell_p(pb) - bytestream2_tell(&gbc) < 4) {
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
do {
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
--len;
} while (len);
} else {
bytestream2_put_le32(pb, bytestream2_get_le32(&gbc));
for (len = len - 2; len; --len)
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
}
len = i & 3;
if (!len) {
repeat = 1;
} else {
do {
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
--len;
} while (len);
opcode = bytestream2_peek_byte(gb);
}
}
return 0;
}
static int decode_type1(GetByteContext *gb, PutByteContext *pb)
{
unsigned opcode = 0, len;
int high = 0;
int i, pos;
while (bytestream2_get_bytes_left(gb) > 0) {
GetByteContext gbc;
while (bytestream2_get_bytes_left(gb) > 0) {
while (bytestream2_get_bytes_left(gb) > 0) {
opcode = bytestream2_get_byte(gb);
high = opcode >= 0x20;
if (high)
break;
if (opcode)
break;
opcode = bytestream2_get_byte(gb);
if (opcode < 0xF8) {
opcode += 32;
break;
}
i = opcode - 0xF8;
if (i) {
len = 256;
do {
len *= 2;
--i;
} while (i);
} else {
len = 280;
}
do {
bytestream2_put_le32(pb, bytestream2_get_le32(gb));
bytestream2_put_le32(pb, bytestream2_get_le32(gb));
len -= 8;
} while (len && bytestream2_get_bytes_left(gb) > 0);
}
if (!high) {
do {
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
--opcode;
} while (opcode && bytestream2_get_bytes_left(gb) > 0);
while (bytestream2_get_bytes_left(gb) > 0) {
GetByteContext gbc;
opcode = bytestream2_get_byte(gb);
if (opcode >= 0x20)
break;
bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
pos = -(opcode | 32 * bytestream2_get_byte(gb)) - 1;
bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
}
}
high = 0;
if (opcode < 0x40)
break;
bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
pos = (-((opcode & 0x1F) | 32 * bytestream2_get_byte(gb)) - 1);
bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
len = (opcode >> 5) - 1;
do {
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
--len;
} while (len && bytestream2_get_bytes_left(&gbc) > 0);
}
len = opcode & 0x1F;
if (!len) {
if (!bytestream2_peek_byte(gb)) {
do {
bytestream2_skip(gb, 1);
len += 255;
} while (!bytestream2_peek_byte(gb) && bytestream2_get_bytes_left(gb) > 0);
}
len += bytestream2_get_byte(gb) + 31;
}
pos = -bytestream2_get_byte(gb);
bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos - (bytestream2_get_byte(gb) << 8), SEEK_SET);
if (bytestream2_tell_p(pb) == bytestream2_tell(&gbc))
break;
if (len < 5 || bytestream2_tell_p(pb) - bytestream2_tell(&gbc) < 4) {
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
} else {
bytestream2_put_le32(pb, bytestream2_get_le32(&gbc));
len--;
}
do {
bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
len--;
} while (len && bytestream2_get_bytes_left(&gbc) > 0);
}
return 0;
}
static int decode_frame(AVCodecContext *avctx, AVFrame *frame,
int *got_frame, AVPacket *avpkt)
{
FMVCContext *s = avctx->priv_data;
GetByteContext *gb = &s->gb;
PutByteContext *pb = &s->pb;
int ret, y, x;
if (avpkt->size < 8)
return AVERROR_INVALIDDATA;
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
bytestream2_init(gb, avpkt->data, avpkt->size);
bytestream2_skip(gb, 2);
frame->key_frame = !!bytestream2_get_le16(gb);
frame->pict_type = frame->key_frame ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
if (frame->key_frame) {
const uint8_t *src;
unsigned type, size;
uint8_t *dst;
type = bytestream2_get_le16(gb);
size = bytestream2_get_le16(gb);
if (size > bytestream2_get_bytes_left(gb))
return AVERROR_INVALIDDATA;
bytestream2_init_writer(pb, s->buffer, s->buffer_size);
if (type == 1) {
decode_type1(gb, pb);
} else if (type == 2){
decode_type2(gb, pb);
} else {
avpriv_report_missing_feature(avctx, "Compression type %d", type);
return AVERROR_PATCHWELCOME;
}
src = s->buffer;
dst = frame->data[0] + (avctx->height - 1) * frame->linesize[0];
for (y = 0; y < avctx->height; y++) {
memcpy(dst, src, avctx->width * s->bpp);
dst -= frame->linesize[0];
src += s->stride * 4;
if (bytestream2_tell_p(pb) < y*s->stride * 4)
break;
}
} else {
unsigned block, nb_blocks;
int type, k, l;
uint8_t *ssrc, *ddst;
const uint32_t *src;
uint32_t *dst;
for (block = 0; block < s->nb_blocks; block++)
s->blocks[block].xor = 0;
nb_blocks = bytestream2_get_le16(gb);
if (nb_blocks > s->nb_blocks)
return AVERROR_INVALIDDATA;
bytestream2_init_writer(pb, s->pbuffer, s->pbuffer_size);
type = bytestream2_get_le16(gb);
for (block = 0; block < nb_blocks; block++) {
unsigned size, offset;
int start = 0;
offset = bytestream2_get_le16(gb);
if (offset >= s->nb_blocks)
return AVERROR_INVALIDDATA;
size = bytestream2_get_le16(gb);
if (size > bytestream2_get_bytes_left(gb))
return AVERROR_INVALIDDATA;
start = bytestream2_tell_p(pb);
if (type == 1) {
decode_type1(gb, pb);
} else if (type == 2){
decode_type2(gb, pb);
} else {
avpriv_report_missing_feature(avctx, "Compression type %d", type);
return AVERROR_PATCHWELCOME;
}
if (s->blocks[offset].size * 4 != bytestream2_tell_p(pb) - start)
return AVERROR_INVALIDDATA;
s->blocks[offset].xor = 1;
}
src = (const uint32_t *)s->pbuffer;
dst = (uint32_t *)s->buffer;
for (block = 0, y = 0; y < s->yb; y++) {
int block_h = s->blocks[block].h;
uint32_t *rect = dst;
for (x = 0; x < s->xb; x++) {
int block_w = s->blocks[block].w;
uint32_t *row = dst;
block_h = s->blocks[block].h;
if (s->blocks[block].xor) {
for (k = 0; k < block_h; k++) {
uint32_t *column = dst;
for (l = 0; l < block_w; l++)
*dst++ ^= *src++;
dst = &column[s->stride];
}
}
dst = &row[block_w];
++block;
}
dst = &rect[block_h * s->stride];
}
ssrc = s->buffer;
ddst = frame->data[0] + (avctx->height - 1) * frame->linesize[0];
for (y = 0; y < avctx->height; y++) {
memcpy(ddst, ssrc, avctx->width * s->bpp);
ddst -= frame->linesize[0];
ssrc += s->stride * 4;
}
}
*got_frame = 1;
return avpkt->size;
}
static av_cold int decode_init(AVCodecContext *avctx)
{
FMVCContext *s = avctx->priv_data;
int i, j, m, block = 0, h = BLOCK_HEIGHT, w = BLOCK_WIDTH;
switch (avctx->bits_per_coded_sample) {
case 16:
avctx->pix_fmt = AV_PIX_FMT_RGB555LE;
break;
case 24:
avctx->pix_fmt = AV_PIX_FMT_BGR24;
break;
case 32:
avctx->pix_fmt = AV_PIX_FMT_BGRA;
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unsupported bitdepth %i\n",
avctx->bits_per_coded_sample);
return AVERROR_INVALIDDATA;
}
s->stride = (avctx->width * avctx->bits_per_coded_sample + 31) / 32;
s->xb = s->stride / BLOCK_WIDTH;
m = s->stride % BLOCK_WIDTH;
if (m) {
if (m < 37) {
w = m + BLOCK_WIDTH;
} else {
w = m;
s->xb++;
}
}
s->yb = avctx->height / BLOCK_HEIGHT;
m = avctx->height % BLOCK_HEIGHT;
if (m) {
if (m < 49) {
h = m + BLOCK_HEIGHT;
} else {
h = m;
s->yb++;
}
}
s->nb_blocks = s->xb * s->yb;
if (!s->nb_blocks)
return AVERROR_INVALIDDATA;
s->blocks = av_calloc(s->nb_blocks, sizeof(*s->blocks));
if (!s->blocks)
return AVERROR(ENOMEM);
for (i = 0; i < s->yb; i++) {
for (j = 0; j < s->xb; j++) {
if (i != (s->yb - 1) || j != (s->xb - 1)) {
if (i == s->yb - 1) {
s->blocks[block].w = BLOCK_WIDTH;
s->blocks[block].h = h;
s->blocks[block].size = BLOCK_WIDTH * h;
} else if (j == s->xb - 1) {
s->blocks[block].w = w;
s->blocks[block].h = BLOCK_HEIGHT;
s->blocks[block].size = BLOCK_HEIGHT * w;
} else {
s->blocks[block].w = BLOCK_WIDTH;
s->blocks[block].h = BLOCK_HEIGHT;
s->blocks[block].size = BLOCK_WIDTH * BLOCK_HEIGHT;
}
} else {
s->blocks[block].w = w;
s->blocks[block].h = h;
s->blocks[block].size = w * h;
}
block++;
}
}
s->bpp = avctx->bits_per_coded_sample >> 3;
s->buffer_size = avctx->width * avctx->height * 4;
s->pbuffer_size = avctx->width * avctx->height * 4;
s->buffer = av_mallocz(s->buffer_size);
s->pbuffer = av_mallocz(s->pbuffer_size);
if (!s->buffer || !s->pbuffer)
return AVERROR(ENOMEM);
return 0;
}
static av_cold int decode_close(AVCodecContext *avctx)
{
FMVCContext *s = avctx->priv_data;
av_freep(&s->buffer);
av_freep(&s->pbuffer);
av_freep(&s->blocks);
return 0;
}
const FFCodec ff_fmvc_decoder = {
.p.name = "fmvc",
.p.long_name = NULL_IF_CONFIG_SMALL("FM Screen Capture Codec"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_FMVC,
.priv_data_size = sizeof(FMVCContext),
.init = decode_init,
.close = decode_close,
FF_CODEC_DECODE_CB(decode_frame),
.p.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
FF_CODEC_CAP_INIT_CLEANUP,
};
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