int.c

关于JPEG2000压缩标准的模板程序的内容,是我们导师给的,据说是国外的版本.

/*
 * 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.
 */

/// <summary>
/// Get the minimum of two integers.
/// </summary>
int int_min(int a, int b) {
    return a<b?a:b;
}

/// <summary>
/// Get the maximum of two integers.
/// </summary>
int int_max(int a, int b) {
    return a>b?a:b;
}

/// <summary>
/// Clamp an integer inside an interval.
/// </summary>
int int_clamp(int a, int min, int max) {
    if (a<min) return min;
    if (a>max) return max;
    return a;
}

/// <summary>
/// Get absolute value of integer.
/// </summary>
int int_abs(int a) {
    return a<0?-a:a;
}

/// <summary>
/// Divide an integer and round upwards.
/// </summary>
int int_ceildiv(int a, int b) {
    return (a+b-1)/b;
}

/// <summary>
/// Divide an integer by a power of 2 and round upwards.
/// </summary>
int int_ceildivpow2(int a, int b) {
    return (a+(1<<b)-1)>>b;
}

/// <summary>
/// Divide an integer by a power of 2 and round downwards.
/// </summary>
int int_floordivpow2(int a, int b) {
    return a>>b;
}

/// <summary>
/// Get logarithm of an integer and round downwards.
/// </summary>
int int_floorlog2(int a) {
    int l;
    for (l=0; a>1; l++) {
        a>>=1;
    }
    return l;
}