| /* |
| * Copyright (c) 2001-2002, David Janssens |
| * 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 "cio.h" |
| #include <setjmp.h> |
| |
| static unsigned char *cio_start; /* pointer to the start of the stream */ |
| static unsigned char *cio_end; /* pointer to the end of the stream */ |
| static unsigned char *cio_bp; /* pointer to the present position */ |
| |
| extern jmp_buf j2k_error; |
| |
| /* |
| * Number of bytes written. |
| */ |
| int cio_numbytes() |
| { |
| return cio_bp - cio_start; |
| } |
| |
| /* |
| * Get position in byte stream. |
| */ |
| int cio_tell() |
| { |
| return cio_bp - cio_start; |
| } |
| |
| /* |
| * Set position in byte stream. |
| * |
| * pos : position, in number of bytes, from the beginning of the stream |
| */ |
| void cio_seek(int pos) |
| { |
| cio_bp = cio_start + pos; |
| } |
| |
| /* |
| * Number of bytes left before the end of the stream. |
| */ |
| int cio_numbytesleft() |
| { |
| return cio_end - cio_bp; |
| } |
| |
| /* |
| * Get pointer to the current position in the stream. |
| */ |
| unsigned char *cio_getbp() |
| { |
| return cio_bp; |
| } |
| |
| /* |
| * Initialize byte IO |
| * |
| * bp : destination/source stream |
| * len : length of the stream |
| */ |
| void cio_init(unsigned char *bp, int len) |
| { |
| cio_start = bp; |
| cio_end = bp + len; |
| cio_bp = bp; |
| } |
| |
| /* |
| * Write a byte. |
| */ |
| void cio_byteout(unsigned char v) |
| { |
| if (cio_bp >= cio_end) |
| longjmp(j2k_error, 1); |
| *cio_bp++ = v; |
| |
| } |
| |
| /* |
| * Read a byte. |
| */ |
| unsigned char cio_bytein() |
| { |
| if (cio_bp >= cio_end) |
| longjmp(j2k_error, 1); |
| return *cio_bp++; |
| } |
| |
| /* |
| * Write some bytes. |
| * |
| * v : value to write |
| * n : number of bytes to write |
| */ |
| void cio_write(unsigned int v, int n) |
| { |
| int i; |
| for (i = n - 1; i >= 0; i--) { |
| cio_byteout((unsigned char) ((v >> (i << 3)) & 0xff)); |
| } |
| } |
| |
| /* |
| * Read some bytes. |
| * |
| * n : number of bytes to read |
| * |
| * return : value of the n bytes read |
| */ |
| unsigned int cio_read(int n) |
| { |
| int i; |
| unsigned int v; |
| v = 0; |
| for (i = n - 1; i >= 0; i--) { |
| v += cio_bytein() << (i << 3); |
| } |
| return v; |
| } |
| |
| /* |
| * Skip some bytes. |
| * |
| * n : number of bytes to skip |
| */ |
| void cio_skip(int n) |
| { |
| cio_bp += n; |
| } |