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+/* Fixed.java -- Utility methods for fixed point arithmetics
+ Copyright (C) 2006 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package gnu.java.math;
+
+/**
+ * Utility methods for fixed point arithmetics.
+ */
+public final class Fixed
+{
+
+ /**
+ * Private constructor to avoid instantiation.
+ */
+ private Fixed()
+ {
+ // Forbidden constructor.
+ }
+
+ /**
+ * Divides two fixed point values with <code>n</code> digits.
+ *
+ * @param n the number of digits
+ * @param a the first operand as fixed point value
+ * @param b the second operand as fixed point value
+ *
+ * @return <code>a / b</code> as fixed point value
+ */
+ public static int div(int n, int a, int b)
+ {
+ return (int) ((((long) a) << n) / b);
+ }
+
+ /**
+ * Multiplies two fixed point values with <code>n</code> digits.
+ *
+ * @param n the number of digits
+ * @param a the first operand as fixed point value
+ * @param b the second operand as fixed point value
+ *
+ * @return <code>a * b</code> as fixed point value
+ */
+ public static int mul(int n, int a, int b)
+ {
+ return (int) ((((long) a) * b) >> n);
+ }
+
+ /**
+ * Returns the ceiling value of a fixed point value <code>a</code> with
+ * the <code>n</code> digits.
+ *
+ * @param n the number of digits
+ * @param a the fixed point value
+ *
+ * @return <code>ceil(a)</code> as fixed point value
+ */
+ public static int ceil(int n, int a)
+ {
+ return (a + (1 << n - 1)) & -(1 << n);
+ }
+
+ /**
+ * Returns the floor value of a fixed point value <code>a</code> with
+ * <code>n</code> digits.
+ *
+ * @param n the number of digits
+ * @param a the fixed point value
+ *
+ * @return <code>floor(a)</code> as fixed point value
+ */
+ public static int floor(int n, int a)
+ {
+ return a & -(1 << n);
+ }
+
+ /**
+ * Truncates the number so that only the digits after the point are left.
+ *
+ * @param n the number of digits
+ * @param a the fixed point value
+ *
+ * @return the truncated value
+ */
+ public static int trunc(int n, int a)
+ {
+ return a & (0xFFFFFFFF >>> 32 - n);
+ }
+
+ /**
+ * Returns the round value of a fixed point value <code>a</code> with
+ * the <code>n</code> digits.
+ *
+ * @param n the number of digits
+ * @param a the fixed point value
+ *
+ * @return <code>round(a)</code> as fixed point value
+ */
+ public static int round(int n, int a)
+ {
+ return (a + (1 << (n - 1))) & -(1 << n);
+ }
+
+ /**
+ * Returns the fixed point value <code>a</code> with <code>n</code> digits
+ * as float.
+ *
+ * @param n the number of digits
+ * @param a the fixed point value
+ *
+ * @return the float value of <code>a</code>
+ */
+ public static float floatValue(int n, int a)
+ {
+ return ((float) a) / (1 << n);
+ }
+
+ /**
+ * Returns the fixed point value <code>a</code> with <code>n</code> digits
+ * as double.
+ *
+ * @param n the number of digits
+ * @param a the fixed point value
+ *
+ * @return the double value of <code>a</code>
+ */
+ public static double doubleValue(int n, int a)
+ {
+ return ((double) a) / (1 << n);
+ }
+
+ /**
+ * Returns the fixed point value that corresponds to the specified float
+ * value <code>a</code> with <code>n</code> digits.
+ *
+ * @param n the number of digits
+ * @param a the float value
+ *
+ * @return the fixed point value
+ */
+ public static int fixedValue(int n, float a)
+ {
+ return (int) (a * (1 << n));
+ }
+
+ /**
+ * Returns the fixed point value that corresponds to the specified double
+ * value <code>a</code> with <code>n</code> digits.
+ *
+ * @param n the number of digits
+ * @param a the double value
+ *
+ * @return the fixed point value
+ */
+ public static int fixedValue(int n, double a)
+ {
+ return (int) (a * (1 << n));
+ }
+
+ /**
+ * Returns the integer value of the specified fixed point value
+ * <code>a</code>. This simply cuts of the digits (== floor(a)).
+ *
+ * @param n the number of digits
+ * @param a the fixed point value
+ *
+ * @return the integer value
+ */
+ public static int intValue(int n, int a)
+ {
+ return a >> n;
+ }
+
+ /**
+ * Returns a fixed point decimal as rounded integer value.
+ *
+ * @param n the number of digits
+ * @param a the fixed point number
+ *
+ * @return the fixed point decimal as rounded integer value
+ */
+ public static int roundIntValue(int n, int a)
+ {
+ return (a + (1 << (n - 1))) >> n;
+ }
+}