You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
121 lines
2.7 KiB
121 lines
2.7 KiB
/*
|
|
|
|
Copyright (C) 2000 Stefan Westerfeld
|
|
stefan@space.twc.de
|
|
|
|
This library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Library General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2 of the License, or (at your option) any later version.
|
|
|
|
This library 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
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public License
|
|
along with this library; see the file COPYING.LIB. If not, write to
|
|
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
|
|
Boston, MA 02110-1301, USA.
|
|
|
|
*/
|
|
|
|
#include "huffmanlookup.h"
|
|
#include <assert.h>
|
|
|
|
|
|
|
|
|
|
struct HuffmanLookup::decodeData HuffmanLookup::qdecode[32][256];
|
|
/* for initialization */
|
|
static HuffmanLookup l;
|
|
|
|
HuffmanLookup::HuffmanLookup()
|
|
{
|
|
int table,p,x,y;
|
|
|
|
for(table = 0; table < 32; table++)
|
|
{
|
|
// 8 bits pattern
|
|
for(p = 0; p < 256; p++)
|
|
{
|
|
bits = 24;
|
|
pattern = (p << 16);
|
|
|
|
huffmandecoder_1(&Mpegtoraw::ht[table], &x,&y);
|
|
|
|
int used = 24 - bits;
|
|
qdecode[table][p].skip = (used <= 8)?used:0;
|
|
qdecode[table][p].x = x;
|
|
qdecode[table][p].y = y;
|
|
}
|
|
}
|
|
}
|
|
|
|
int HuffmanLookup::wgetbit()
|
|
{
|
|
return (pattern >> --bits) & 1;
|
|
}
|
|
|
|
int HuffmanLookup::wgetbits (int b)
|
|
{
|
|
bits -= b;
|
|
return (pattern >> bits) & ((1 << b) - 1);
|
|
}
|
|
|
|
void HuffmanLookup::huffmandecoder_1(const HUFFMANCODETABLE *h, int *x, int *y)
|
|
{
|
|
typedef unsigned int HUFFBITS;
|
|
|
|
HUFFBITS level=(1<<(sizeof(HUFFBITS)*8-1));
|
|
int point=0;
|
|
/* Lookup in Huffman table. */
|
|
for(;;)
|
|
{
|
|
if(h->val[point][0]==0)
|
|
{ /*end of tree*/
|
|
int xx,yy;
|
|
|
|
xx=h->val[point][1]>>4;
|
|
yy=h->val[point][1]&0xf;
|
|
|
|
if(h->linbits)
|
|
{
|
|
if((h->xlen)==(unsigned)xx)xx+=wgetbits(h->linbits);
|
|
if(xx)if(wgetbit())xx=-xx;
|
|
if((h->ylen)==(unsigned)yy)yy+=wgetbits(h->linbits);
|
|
if(yy)if(wgetbit())yy=-yy;
|
|
}
|
|
else
|
|
{
|
|
if(xx)if(wgetbit())xx=-xx;
|
|
if(yy)if(wgetbit())yy=-yy;
|
|
}
|
|
*x=xx;*y=yy;
|
|
break;
|
|
}
|
|
|
|
point+=h->val[point][wgetbit()];
|
|
|
|
level>>=1;
|
|
if(!(level || ((unsigned)point<Mpegtoraw::ht->treelen)))
|
|
{
|
|
register int xx,yy;
|
|
|
|
xx=(h->xlen<<1);// set x and y to a medium value as a simple concealment
|
|
yy=(h->ylen<<1);
|
|
|
|
// h->xlen and h->ylen can't be 1 under tablename 32
|
|
// if(xx)
|
|
if(wgetbit())xx=-xx;
|
|
// if(yy)
|
|
if(wgetbit())yy=-yy;
|
|
|
|
*x=xx;*y=yy;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
|