440 lines
14 KiB
C
440 lines
14 KiB
C
/*
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* Copyright (c) 1999-2000, Image Power, Inc. and the University of
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* British Columbia.
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* Copyright (c) 2001-2003 Michael David Adams.
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* All rights reserved.
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*/
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/* __START_OF_JASPER_LICENSE__
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*
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* JasPer License Version 2.0
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*
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* Copyright (c) 2001-2006 Michael David Adams
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* Copyright (c) 1999-2000 Image Power, Inc.
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* Copyright (c) 1999-2000 The University of British Columbia
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*
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* All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person (the
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* "User") obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without restriction,
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* including without limitation the rights to use, copy, modify, merge,
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* publish, distribute, and/or sell copies of the Software, and to permit
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* persons to whom the Software is furnished to do so, subject to the
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* following conditions:
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*
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* 1. The above copyright notices and this permission notice (which
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* includes the disclaimer below) shall be included in all copies or
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* substantial portions of the Software.
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*
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* 2. The name of a copyright holder shall not be used to endorse or
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* promote products derived from the Software without specific prior
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* written permission.
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*
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* THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS
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* LICENSE. NO USE OF THE SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER
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* THIS DISCLAIMER. THE SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
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* "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
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* BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
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* PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN NO
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* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
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* INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
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* FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
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* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
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* WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. NO ASSURANCES ARE
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* PROVIDED BY THE COPYRIGHT HOLDERS THAT THE SOFTWARE DOES NOT INFRINGE
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* THE PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OF ANY OTHER ENTITY.
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* EACH COPYRIGHT HOLDER DISCLAIMS ANY LIABILITY TO THE USER FOR CLAIMS
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* BROUGHT BY ANY OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL
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* PROPERTY RIGHTS OR OTHERWISE. AS A CONDITION TO EXERCISING THE RIGHTS
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* GRANTED HEREUNDER, EACH USER HEREBY ASSUMES SOLE RESPONSIBILITY TO SECURE
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* ANY OTHER INTELLECTUAL PROPERTY RIGHTS NEEDED, IF ANY. THE SOFTWARE
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* IS NOT FAULT-TOLERANT AND IS NOT INTENDED FOR USE IN MISSION-CRITICAL
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* SYSTEMS, SUCH AS THOSE USED IN THE OPERATION OF NUCLEAR FACILITIES,
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* AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL
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* SYSTEMS, DIRECT LIFE SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH
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* THE FAILURE OF THE SOFTWARE OR SYSTEM COULD LEAD DIRECTLY TO DEATH,
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* PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH
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* RISK ACTIVITIES"). THE COPYRIGHT HOLDERS SPECIFICALLY DISCLAIM ANY
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* EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR HIGH RISK ACTIVITIES.
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*
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* __END_OF_JASPER_LICENSE__
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*/
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/*
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* Bit Stream Class
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*
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* $Id: jpc_bs.c,v 1.2 2008-05-26 09:40:52 vp153 Exp $
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*/
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/******************************************************************************\
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* Includes.
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\******************************************************************************/
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#include <assert.h>
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#include <stdlib.h>
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#include <stdarg.h>
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#include "jasper/jas_malloc.h"
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#include "jasper/jas_math.h"
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#include "jasper/jas_debug.h"
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#include "jpc_bs.h"
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/******************************************************************************\
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* Local function prototypes.
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\******************************************************************************/
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static jpc_bitstream_t *jpc_bitstream_alloc(void);
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/******************************************************************************\
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* Code for opening and closing bit streams.
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\******************************************************************************/
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/* Open a bit stream from a stream. */
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jpc_bitstream_t *jpc_bitstream_sopen(jas_stream_t *stream, char *mode)
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{
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jpc_bitstream_t *bitstream;
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/* Ensure that the open mode is valid. */
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#if 1
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/* This causes a string literal too long error (with c99 pedantic mode). */
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assert(!strcmp(mode, "r") || !strcmp(mode, "w") || !strcmp(mode, "r+")
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|| !strcmp(mode, "w+"));
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#endif
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if (!(bitstream = jpc_bitstream_alloc())) {
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return 0;
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}
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/* By default, do not close the underlying (character) stream, upon
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the close of the bit stream. */
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bitstream->flags_ = JPC_BITSTREAM_NOCLOSE;
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bitstream->stream_ = stream;
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bitstream->openmode_ = (mode[0] == 'w') ? JPC_BITSTREAM_WRITE :
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JPC_BITSTREAM_READ;
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/* Mark the data buffer as empty. */
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bitstream->cnt_ = (bitstream->openmode_ == JPC_BITSTREAM_READ) ? 0 : 8;
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bitstream->buf_ = 0;
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return bitstream;
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}
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/* Close a bit stream. */
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int jpc_bitstream_close(jpc_bitstream_t *bitstream)
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{
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int ret = 0;
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/* Align to the next byte boundary while considering the effects of
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bit stuffing. */
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if (jpc_bitstream_align(bitstream)) {
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ret = -1;
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}
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/* If necessary, close the underlying (character) stream. */
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if (!(bitstream->flags_ & JPC_BITSTREAM_NOCLOSE) && bitstream->stream_) {
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if (jas_stream_close(bitstream->stream_)) {
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ret = -1;
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}
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bitstream->stream_ = 0;
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}
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jas_free(bitstream);
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return ret;
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}
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/* Allocate a new bit stream. */
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static jpc_bitstream_t *jpc_bitstream_alloc()
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{
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jpc_bitstream_t *bitstream;
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/* Allocate memory for the new bit stream object. */
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if (!(bitstream = jas_malloc(sizeof(jpc_bitstream_t)))) {
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return 0;
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}
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/* Initialize all of the data members. */
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bitstream->stream_ = 0;
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bitstream->cnt_ = 0;
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bitstream->flags_ = 0;
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bitstream->openmode_ = 0;
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return bitstream;
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}
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/******************************************************************************\
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* Code for reading/writing from/to bit streams.
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\******************************************************************************/
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/* Get a bit from a bit stream. */
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int jpc_bitstream_getbit_func(jpc_bitstream_t *bitstream)
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{
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int ret;
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JAS_DBGLOG(1000, ("jpc_bitstream_getbit_func(%p)\n", bitstream));
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ret = jpc_bitstream_getbit_macro(bitstream);
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JAS_DBGLOG(1000, ("jpc_bitstream_getbit_func -> %d\n", ret));
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return ret;
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}
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/* Put a bit to a bit stream. */
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int jpc_bitstream_putbit_func(jpc_bitstream_t *bitstream, int b)
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{
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int ret;
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JAS_DBGLOG(1000, ("jpc_bitstream_putbit_func(%p, %d)\n", bitstream, b));
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ret = jpc_bitstream_putbit_macro(bitstream, b);
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JAS_DBGLOG(1000, ("jpc_bitstream_putbit_func() -> %d\n", ret));
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return ret;
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}
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/* Get one or more bits from a bit stream. */
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long jpc_bitstream_getbits(jpc_bitstream_t *bitstream, int n)
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{
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long v;
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int u;
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/* We can reliably get at most 31 bits since ISO/IEC 9899 only
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guarantees that a long can represent values up to 2^31-1. */
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assert(n >= 0 && n < 32);
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/* Get the number of bits requested from the specified bit stream. */
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v = 0;
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while (--n >= 0) {
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if ((u = jpc_bitstream_getbit(bitstream)) < 0) {
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return -1;
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}
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v = (v << 1) | u;
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}
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return v;
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}
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/* Put one or more bits to a bit stream. */
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int jpc_bitstream_putbits(jpc_bitstream_t *bitstream, int n, long v)
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{
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int m;
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/* We can reliably put at most 31 bits since ISO/IEC 9899 only
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guarantees that a long can represent values up to 2^31-1. */
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assert(n >= 0 && n < 32);
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/* Ensure that only the bits to be output are nonzero. */
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assert(!(v & (~JAS_ONES(n))));
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/* Put the desired number of bits to the specified bit stream. */
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m = n - 1;
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while (--n >= 0) {
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if (jpc_bitstream_putbit(bitstream, (v >> m) & 1) == EOF) {
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return EOF;
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}
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v <<= 1;
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}
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return 0;
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}
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/******************************************************************************\
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* Code for buffer filling and flushing.
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\******************************************************************************/
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/* Fill the buffer for a bit stream. */
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int jpc_bitstream_fillbuf(jpc_bitstream_t *bitstream)
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{
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int c;
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/* Note: The count has already been decremented by the caller. */
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assert(bitstream->openmode_ & JPC_BITSTREAM_READ);
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assert(bitstream->cnt_ <= 0);
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if (bitstream->flags_ & JPC_BITSTREAM_ERR) {
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bitstream->cnt_ = 0;
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return -1;
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}
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if (bitstream->flags_ & JPC_BITSTREAM_EOF) {
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bitstream->buf_ = 0x7f;
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bitstream->cnt_ = 7;
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return 1;
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}
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bitstream->buf_ = (bitstream->buf_ << 8) & 0xffff;
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if ((c = jas_stream_getc((bitstream)->stream_)) == EOF) {
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bitstream->flags_ |= JPC_BITSTREAM_EOF;
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return 1;
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}
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bitstream->cnt_ = (bitstream->buf_ == 0xff00) ? 6 : 7;
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bitstream->buf_ |= c & ((1 << (bitstream->cnt_ + 1)) - 1);
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return (bitstream->buf_ >> bitstream->cnt_) & 1;
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}
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/******************************************************************************\
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* Code related to flushing.
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\******************************************************************************/
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/* Does the bit stream need to be aligned to a byte boundary (considering
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the effects of bit stuffing)? */
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int jpc_bitstream_needalign(jpc_bitstream_t *bitstream)
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{
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if (bitstream->openmode_ & JPC_BITSTREAM_READ) {
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/* The bit stream is open for reading. */
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/* If there are any bits buffered for reading, or the
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previous byte forced a stuffed bit, alignment is
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required. */
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if ((bitstream->cnt_ < 8 && bitstream->cnt_ > 0) ||
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((bitstream->buf_ >> 8) & 0xff) == 0xff) {
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return 1;
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}
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} else if (bitstream->openmode_ & JPC_BITSTREAM_WRITE) {
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/* The bit stream is open for writing. */
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/* If there are any bits buffered for writing, or the
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previous byte forced a stuffed bit, alignment is
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required. */
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if ((bitstream->cnt_ < 8 && bitstream->cnt_ >= 0) ||
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((bitstream->buf_ >> 8) & 0xff) == 0xff) {
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return 1;
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}
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} else {
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/* This should not happen. Famous last words, eh? :-) */
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assert(0);
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return -1;
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}
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return 0;
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}
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/* How many additional bytes would be output if we align the bit stream? */
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int jpc_bitstream_pending(jpc_bitstream_t *bitstream)
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{
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if (bitstream->openmode_ & JPC_BITSTREAM_WRITE) {
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/* The bit stream is being used for writing. */
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#if 1
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/* XXX - Is this really correct? Check someday... */
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if (bitstream->cnt_ < 8) {
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return 1;
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}
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#else
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if (bitstream->cnt_ < 8) {
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if (((bitstream->buf_ >> 8) & 0xff) == 0xff) {
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return 2;
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}
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return 1;
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}
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#endif
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return 0;
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} else {
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/* This operation should not be invoked on a bit stream that
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is being used for reading. */
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return -1;
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}
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}
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/* Align the bit stream to a byte boundary. */
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int jpc_bitstream_align(jpc_bitstream_t *bitstream)
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{
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int ret;
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if (bitstream->openmode_ & JPC_BITSTREAM_READ) {
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ret = jpc_bitstream_inalign(bitstream, 0, 0);
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} else if (bitstream->openmode_ & JPC_BITSTREAM_WRITE) {
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ret = jpc_bitstream_outalign(bitstream, 0);
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} else {
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abort();
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}
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return ret;
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}
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/* Align a bit stream in the input case. */
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int jpc_bitstream_inalign(jpc_bitstream_t *bitstream, int fillmask,
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int filldata)
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{
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int n;
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int v;
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int u;
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int numfill;
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int m;
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numfill = 7;
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m = 0;
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v = 0;
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if (bitstream->cnt_ > 0) {
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n = bitstream->cnt_;
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} else if (!bitstream->cnt_) {
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n = ((bitstream->buf_ & 0xff) == 0xff) ? 7 : 0;
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} else {
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n = 0;
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}
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if (n > 0) {
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if ((u = jpc_bitstream_getbits(bitstream, n)) < 0) {
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return -1;
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}
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m += n;
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v = (v << n) | u;
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}
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if ((bitstream->buf_ & 0xff) == 0xff) {
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if ((u = jpc_bitstream_getbits(bitstream, 7)) < 0) {
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return -1;
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}
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v = (v << 7) | u;
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m += 7;
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}
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if (m > numfill) {
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v >>= m - numfill;
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} else {
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filldata >>= numfill - m;
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fillmask >>= numfill - m;
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}
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if (((~(v ^ filldata)) & fillmask) != fillmask) {
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/* The actual fill pattern does not match the expected one. */
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return 1;
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}
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return 0;
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}
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/* Align a bit stream in the output case. */
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int jpc_bitstream_outalign(jpc_bitstream_t *bitstream, int filldata)
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{
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int n;
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int v;
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/* Ensure that this bit stream is open for writing. */
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assert(bitstream->openmode_ & JPC_BITSTREAM_WRITE);
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/* Ensure that the first bit of fill data is zero. */
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/* Note: The first bit of fill data must be zero. If this were not
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the case, the fill data itself could cause further bit stuffing to
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be required (which would cause numerous complications). */
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assert(!(filldata & (~0x3f)));
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if (!bitstream->cnt_) {
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if ((bitstream->buf_ & 0xff) == 0xff) {
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n = 7;
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v = filldata;
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} else {
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n = 0;
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v = 0;
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}
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} else if (bitstream->cnt_ > 0 && bitstream->cnt_ < 8) {
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n = bitstream->cnt_;
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v = filldata >> (7 - n);
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} else {
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n = 0;
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v = 0;
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return 0;
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}
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/* Write the appropriate fill data to the bit stream. */
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if (n > 0) {
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if (jpc_bitstream_putbits(bitstream, n, v)) {
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return -1;
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}
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}
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if (bitstream->cnt_ < 8) {
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assert(bitstream->cnt_ >= 0 && bitstream->cnt_ < 8);
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assert((bitstream->buf_ & 0xff) != 0xff);
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/* Force the pending byte of output to be written to the
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underlying (character) stream. */
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if (jas_stream_putc(bitstream->stream_, bitstream->buf_ & 0xff) == EOF) {
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return -1;
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}
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bitstream->cnt_ = 8;
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bitstream->buf_ = (bitstream->buf_ << 8) & 0xffff;
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}
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return 0;
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}
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