/src/FreeImage/Source/LibOpenJPEG/bio.c

  1/*
  2 * Copyright (c) 2002-2007, Communications and Remote Sensing Laboratory, Universite catholique de Louvain (UCL), Belgium
  3 * Copyright (c) 2002-2007, Professor Benoit Macq
  4 * Copyright (c) 2001-2003, David Janssens
  5 * Copyright (c) 2002-2003, Yannick Verschueren
  6 * Copyright (c) 2003-2007, Francois-Olivier Devaux and Antonin Descampe
  7 * Copyright (c) 2005, Herve Drolon, FreeImage Team
  8 * All rights reserved.
  9 *
 10 * Redistribution and use in source and binary forms, with or without
 11 * modification, are permitted provided that the following conditions
 12 * are met:
 13 * 1. Redistributions of source code must retain the above copyright
 14 *    notice, this list of conditions and the following disclaimer.
 15 * 2. Redistributions in binary form must reproduce the above copyright
 16 *    notice, this list of conditions and the following disclaimer in the
 17 *    documentation and/or other materials provided with the distribution.
 18 *
 19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
 20 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 23 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 29 * POSSIBILITY OF SUCH DAMAGE.
 30 */
 31
 32#include "opj_includes.h"
 33
 34/** @defgroup BIO BIO - Individual bit input-output stream */
 35/*@{*/
 36
 37/** @name Local static functions */
 38/*@{*/
 39
 40/**
 41Write a bit
 42@param bio BIO handle
 43@param b Bit to write (0 or 1)
 44*/
 45static void bio_putbit(opj_bio_t *bio, int b);
 46/**
 47Read a bit
 48@param bio BIO handle
 49@return Returns the read bit
 50*/
 51static int bio_getbit(opj_bio_t *bio);
 52/**
 53Write a byte
 54@param bio BIO handle
 55@return Returns 0 if successful, returns 1 otherwise
 56*/
 57static int bio_byteout(opj_bio_t *bio);
 58/**
 59Read a byte
 60@param bio BIO handle
 61@return Returns 0 if successful, returns 1 otherwise
 62*/
 63static int bio_bytein(opj_bio_t *bio);
 64
 65/*@}*/
 66
 67/*@}*/
 68
 69/* 
 70==========================================================
 71   local functions
 72==========================================================
 73*/
 74
 75static int bio_byteout(opj_bio_t *bio) {
 76	bio->buf = (bio->buf << 8) & 0xffff;
 77	bio->ct = bio->buf == 0xff00 ? 7 : 8;
 78	if (bio->bp >= bio->end) {
 79		return 1;
 80	}
 81	*bio->bp++ = bio->buf >> 8;
 82	return 0;
 83}
 84
 85static int bio_bytein(opj_bio_t *bio) {
 86	bio->buf = (bio->buf << 8) & 0xffff;
 87	bio->ct = bio->buf == 0xff00 ? 7 : 8;
 88	if (bio->bp >= bio->end) {
 89		return 1;
 90	}
 91	bio->buf |= *bio->bp++;
 92	return 0;
 93}
 94
 95static void bio_putbit(opj_bio_t *bio, int b) {
 96	if (bio->ct == 0) {
 97		bio_byteout(bio);
 98	}
 99	bio->ct--;
100	bio->buf |= b << bio->ct;
101}
102
103static int bio_getbit(opj_bio_t *bio) {
104	if (bio->ct == 0) {
105		bio_bytein(bio);
106	}
107	bio->ct--;
108	return (bio->buf >> bio->ct) & 1;
109}
110
111/* 
112==========================================================
113   Bit Input/Output interface
114==========================================================
115*/
116
117opj_bio_t* bio_create(void) {
118	opj_bio_t *bio = (opj_bio_t*)opj_malloc(sizeof(opj_bio_t));
119	return bio;
120}
121
122void bio_destroy(opj_bio_t *bio) {
123	if(bio) {
124		opj_free(bio);
125	}
126}
127
128int bio_numbytes(opj_bio_t *bio) {
129	return (bio->bp - bio->start);
130}
131
132void bio_init_enc(opj_bio_t *bio, unsigned char *bp, int len) {
133	bio->start = bp;
134	bio->end = bp + len;
135	bio->bp = bp;
136	bio->buf = 0;
137	bio->ct = 8;
138}
139
140void bio_init_dec(opj_bio_t *bio, unsigned char *bp, int len) {
141	bio->start = bp;
142	bio->end = bp + len;
143	bio->bp = bp;
144	bio->buf = 0;
145	bio->ct = 0;
146}
147
148void bio_write(opj_bio_t *bio, int v, int n) {
149	int i;
150	for (i = n - 1; i >= 0; i--) {
151		bio_putbit(bio, (v >> i) & 1);
152	}
153}
154
155int bio_read(opj_bio_t *bio, int n) {
156	int i, v;
157	v = 0;
158	for (i = n - 1; i >= 0; i--) {
159		v += bio_getbit(bio) << i;
160	}
161	return v;
162}
163
164int bio_flush(opj_bio_t *bio) {
165	bio->ct = 0;
166	if (bio_byteout(bio)) {
167		return 1;
168	}
169	if (bio->ct == 7) {
170		bio->ct = 0;
171		if (bio_byteout(bio)) {
172			return 1;
173		}
174	}
175	return 0;
176}
177
178int bio_inalign(opj_bio_t *bio) {
179	bio->ct = 0;
180	if ((bio->buf & 0xff) == 0xff) {
181		if (bio_bytein(bio)) {
182			return 1;
183		}
184		bio->ct = 0;
185	}
186	return 0;
187}