| /* |
| * Copyright (c) 2001-2002, David Janssens |
| * Copyright (c) 2003, Yannick Verschueren |
| * Copyright (c) 2003, Communications and remote sensing Laboratory, Universite catholique de Louvain, Belgium |
| * |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS' |
| * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| * POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "bio.h" |
| #include <stdio.h> |
| #include <setjmp.h> |
| |
| static unsigned char *bio_start; /* pointer to the start of the buffer */ |
| static unsigned char *bio_end; /* pointer to the end of the buffer */ |
| static unsigned char *bio_bp; /* pointer to the present position in the buffer */ |
| static unsigned int bio_buf; /* temporary place where each byte is read or written */ |
| static int bio_ct; /* coder : number of bits free to write // decoder : number of bits read */ |
| |
| extern jmp_buf j2k_error; |
| |
| /* |
| * Number of bytes written. |
| */ |
| int bio_numbytes() |
| { |
| return bio_bp - bio_start; |
| } |
| |
| /* |
| * Init encoder. |
| * |
| * bp : Output buffer |
| * len : Output buffer length |
| */ |
| void bio_init_enc(unsigned char *bp, int len) |
| { |
| bio_start = bp; |
| bio_end = bp + len; |
| bio_bp = bp; |
| bio_buf = 0; |
| bio_ct = 8; |
| } |
| |
| /* |
| * Init decoder. |
| * |
| * bp : Input buffer |
| * len : Input buffer length |
| */ |
| void bio_init_dec(unsigned char *bp, int len) |
| { |
| bio_start = bp; |
| bio_end = bp + len; |
| bio_bp = bp; |
| bio_buf = 0; |
| bio_ct = 0; |
| } |
| |
| /* |
| * Write byte. --> function modified to eliminate longjmp !!! |
| * |
| */ |
| int bio_byteout() |
| { |
| bio_buf = (bio_buf << 8) & 0xffff; |
| bio_ct = bio_buf == 0xff00 ? 7 : 8; |
| if (bio_bp >= bio_end) |
| return 1; |
| *bio_bp++ = bio_buf >> 8; |
| return 0; |
| } |
| |
| /* |
| * Read byte. --> function modified to eliminate longjmp !! |
| * |
| */ |
| int bio_bytein() |
| { |
| bio_buf = (bio_buf << 8) & 0xffff; |
| bio_ct = bio_buf == 0xff00 ? 7 : 8; |
| if (bio_bp >= bio_end) |
| return 1; |
| bio_buf |= *bio_bp++; |
| return 0; |
| } |
| |
| /* |
| * Write bit. |
| * |
| * b : Bit to write (0 or 1) |
| */ |
| void bio_putbit(int b) |
| { |
| if (bio_ct == 0) { |
| bio_byteout(); |
| } |
| bio_ct--; |
| bio_buf |= b << bio_ct; |
| } |
| |
| /* |
| * Read bit. |
| * |
| */ |
| int bio_getbit() |
| { |
| if (bio_ct == 0) { |
| bio_bytein(); |
| } |
| bio_ct--; |
| return (bio_buf >> bio_ct) & 1; |
| } |
| |
| /* |
| * Write bits. |
| * |
| * v : Value of bits |
| * n : Number of bits to write |
| */ |
| void bio_write(int v, int n) |
| { |
| int i; |
| for (i = n - 1; i >= 0; i--) { |
| bio_putbit((v >> i) & 1); |
| } |
| } |
| |
| /* |
| * Read bits. |
| * |
| * n : Number of bits to read |
| */ |
| int bio_read(int n) |
| { |
| int i, v; |
| v = 0; |
| for (i = n - 1; i >= 0; i--) { |
| v += bio_getbit() << i; |
| } |
| return v; |
| } |
| |
| /* |
| * Flush bits. Modified to eliminate longjmp !! |
| * |
| */ |
| int bio_flush() |
| { |
| bio_ct = 0; |
| if (bio_byteout()) |
| return 1; |
| if (bio_ct == 7) { |
| bio_ct = 0; |
| |
| if (bio_byteout()) |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* |
| * Passes the ending bits (coming from flushing) |
| */ |
| int bio_inalign() |
| { |
| bio_ct = 0; |
| if ((bio_buf & 0xff) == 0xff) { |
| if (bio_bytein()) |
| return 1; |
| bio_ct = 0; |
| } |
| return 0; |
| } |