forked from KolibriOS/kolibrios
140 lines
2.6 KiB
C
140 lines
2.6 KiB
C
|
/*
|
||
|
|
jbig2dec
|
||
|
|
|
||
|
|
Copyright (C) 2001 Artifex Software, Inc.
|
||
|
|
|
||
|
|
This software is provided AS-IS with no warranty,
|
||
|
|
either express or implied.
|
||
|
|
|
||
|
|
This software is distributed under license and may not
|
||
|
|
be copied, modified or distributed except as expressly
|
||
|
|
authorized under the terms of the license contained in
|
||
|
|
the file LICENSE in this distribution.
|
||
|
|
|
||
|
|
For further licensing information refer to http://artifex.com/ or
|
||
|
|
contact Artifex Software, Inc., 7 Mt. Lassen Drive - Suite A-134,
|
||
|
|
San Rafael, CA 94903, U.S.A., +1(415)492-9861.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* Annex A */
|
||
|
|
|
||
|
|
#ifdef HAVE_CONFIG_H
|
||
|
|
#include "config.h"
|
||
|
|
#endif
|
||
|
|
#include "os_types.h"
|
||
|
|
|
||
|
|
#include <stddef.h>
|
||
|
|
#include <string.h> /* memset() */
|
||
|
|
|
||
|
|
#include "jbig2.h"
|
||
|
|
#include "jbig2_priv.h"
|
||
|
|
#include "jbig2_arith.h"
|
||
|
|
#include "jbig2_arith_int.h"
|
||
|
|
|
||
|
|
struct _Jbig2ArithIntCtx {
|
||
|
|
Jbig2ArithCx IAx[512];
|
||
|
|
};
|
||
|
|
|
||
|
|
Jbig2ArithIntCtx *
|
||
|
|
jbig2_arith_int_ctx_new(Jbig2Ctx *ctx)
|
||
|
|
{
|
||
|
|
Jbig2ArithIntCtx *result = jbig2_new(ctx, Jbig2ArithIntCtx, 1);
|
||
|
|
|
||
|
|
memset(result->IAx, 0, sizeof(result->IAx));
|
||
|
|
|
||
|
|
return result;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* A.2 */
|
||
|
|
/* Return value: -1 on error, 0 on normal value, 1 on OOB return. */
|
||
|
|
int
|
||
|
|
jbig2_arith_int_decode(Jbig2ArithIntCtx *ctx, Jbig2ArithState *as,
|
||
|
|
int32_t *p_result)
|
||
|
|
{
|
||
|
|
Jbig2ArithCx *IAx = ctx->IAx;
|
||
|
|
int PREV = 1;
|
||
|
|
int S, V;
|
||
|
|
int bit;
|
||
|
|
int n_tail, offset;
|
||
|
|
int i;
|
||
|
|
|
||
|
|
S = jbig2_arith_decode(as, &IAx[PREV]);
|
||
|
|
PREV = (PREV << 1) | S;
|
||
|
|
|
||
|
|
bit = jbig2_arith_decode(as, &IAx[PREV]);
|
||
|
|
PREV = (PREV << 1) | bit;
|
||
|
|
if (bit)
|
||
|
|
{
|
||
|
|
bit = jbig2_arith_decode(as, &IAx[PREV]);
|
||
|
|
PREV = (PREV << 1) | bit;
|
||
|
|
|
||
|
|
if (bit)
|
||
|
|
{
|
||
|
|
bit = jbig2_arith_decode(as, &IAx[PREV]);
|
||
|
|
PREV = (PREV << 1) | bit;
|
||
|
|
|
||
|
|
if (bit)
|
||
|
|
{
|
||
|
|
bit = jbig2_arith_decode(as, &IAx[PREV]);
|
||
|
|
PREV = (PREV << 1) | bit;
|
||
|
|
|
||
|
|
if (bit)
|
||
|
|
{
|
||
|
|
bit = jbig2_arith_decode(as, &IAx[PREV]);
|
||
|
|
PREV = (PREV << 1) | bit;
|
||
|
|
|
||
|
|
if (bit)
|
||
|
|
{
|
||
|
|
n_tail = 32;
|
||
|
|
offset = 4436;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
n_tail = 12;
|
||
|
|
offset = 340;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
n_tail = 8;
|
||
|
|
offset = 84;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
n_tail = 6;
|
||
|
|
offset = 20;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
n_tail = 4;
|
||
|
|
offset = 4;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
n_tail = 2;
|
||
|
|
offset = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
V = 0;
|
||
|
|
for (i = 0; i < n_tail; i++)
|
||
|
|
{
|
||
|
|
bit = jbig2_arith_decode(as, &IAx[PREV]);
|
||
|
|
PREV = ((PREV << 1) & 511) | (PREV & 256) | bit;
|
||
|
|
V = (V << 1) | bit;
|
||
|
|
}
|
||
|
|
|
||
|
|
V += offset;
|
||
|
|
V = S ? -V : V;
|
||
|
|
*p_result = V;
|
||
|
|
return S && V == 0 ? 1 : 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
void
|
||
|
|
jbig2_arith_int_ctx_free(Jbig2Ctx *ctx, Jbig2ArithIntCtx *iax)
|
||
|
|
{
|
||
|
|
jbig2_free(ctx->allocator, iax);
|
||
|
|
}
|