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Diffstat (limited to 'libjava/classpath/java/lang/Integer.java')
| -rw-r--r-- | libjava/classpath/java/lang/Integer.java | 772 |
1 files changed, 772 insertions, 0 deletions
diff --git a/libjava/classpath/java/lang/Integer.java b/libjava/classpath/java/lang/Integer.java new file mode 100644 index 00000000000..07be4e30728 --- /dev/null +++ b/libjava/classpath/java/lang/Integer.java @@ -0,0 +1,772 @@ +/* Integer.java -- object wrapper for int + Copyright (C) 1998, 1999, 2001, 2002, 2004, 2005 + 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 java.lang; + +/** + * Instances of class <code>Integer</code> represent primitive + * <code>int</code> values. + * + * Additionally, this class provides various helper functions and variables + * related to ints. + * + * @author Paul Fisher + * @author John Keiser + * @author Warren Levy + * @author Eric Blake (ebb9@email.byu.edu) + * @author Tom Tromey (tromey@redhat.com) + * @since 1.0 + * @status largely updated to 1.5 + */ +public final class Integer extends Number implements Comparable +{ + /** + * Compatible with JDK 1.0.2+. + */ + private static final long serialVersionUID = 1360826667806852920L; + + /** + * The minimum value an <code>int</code> can represent is -2147483648 (or + * -2<sup>31</sup>). + */ + public static final int MIN_VALUE = 0x80000000; + + /** + * The maximum value an <code>int</code> can represent is 2147483647 (or + * 2<sup>31</sup> - 1). + */ + public static final int MAX_VALUE = 0x7fffffff; + + /** + * The primitive type <code>int</code> is represented by this + * <code>Class</code> object. + * @since 1.1 + */ + public static final Class TYPE = VMClassLoader.getPrimitiveClass('I'); + + /** + * The number of bits needed to represent an <code>int</code>. + * @since 1.5 + */ + public static final int SIZE = 32; + + // This caches some Integer values, and is used by boxing + // conversions via valueOf(). We must cache at least -128..127; + // these constants control how much we actually cache. + private static final int MIN_CACHE = -128; + private static final int MAX_CACHE = 127; + private static Integer[] intCache = new Integer[MAX_CACHE - MIN_CACHE + 1]; + + /** + * The immutable value of this Integer. + * + * @serial the wrapped int + */ + private final int value; + + /** + * Create an <code>Integer</code> object representing the value of the + * <code>int</code> argument. + * + * @param value the value to use + */ + public Integer(int value) + { + this.value = value; + } + + /** + * Create an <code>Integer</code> object representing the value of the + * argument after conversion to an <code>int</code>. + * + * @param s the string to convert + * @throws NumberFormatException if the String does not contain an int + * @see #valueOf(String) + */ + public Integer(String s) + { + value = parseInt(s, 10, false); + } + + /** + * Converts the <code>int</code> to a <code>String</code> using + * the specified radix (base). If the radix exceeds + * <code>Character.MIN_RADIX</code> or <code>Character.MAX_RADIX</code>, 10 + * is used instead. If the result is negative, the leading character is + * '-' ('\\u002D'). The remaining characters come from + * <code>Character.forDigit(digit, radix)</code> ('0'-'9','a'-'z'). + * + * @param num the <code>int</code> to convert to <code>String</code> + * @param radix the radix (base) to use in the conversion + * @return the <code>String</code> representation of the argument + */ + public static String toString(int num, int radix) + { + if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX) + radix = 10; + + // For negative numbers, print out the absolute value w/ a leading '-'. + // Use an array large enough for a binary number. + char[] buffer = new char[33]; + int i = 33; + boolean isNeg = false; + if (num < 0) + { + isNeg = true; + num = -num; + + // When the value is MIN_VALUE, it overflows when made positive + if (num < 0) + { + buffer[--i] = digits[(int) (-(num + radix) % radix)]; + num = -(num / radix); + } + } + + do + { + buffer[--i] = digits[num % radix]; + num /= radix; + } + while (num > 0); + + if (isNeg) + buffer[--i] = '-'; + + // Package constructor avoids an array copy. + return new String(buffer, i, 33 - i, true); + } + + /** + * Converts the <code>int</code> to a <code>String</code> assuming it is + * unsigned in base 16. + * + * @param i the <code>int</code> to convert to <code>String</code> + * @return the <code>String</code> representation of the argument + */ + public static String toHexString(int i) + { + return toUnsignedString(i, 4); + } + + /** + * Converts the <code>int</code> to a <code>String</code> assuming it is + * unsigned in base 8. + * + * @param i the <code>int</code> to convert to <code>String</code> + * @return the <code>String</code> representation of the argument + */ + public static String toOctalString(int i) + { + return toUnsignedString(i, 3); + } + + /** + * Converts the <code>int</code> to a <code>String</code> assuming it is + * unsigned in base 2. + * + * @param i the <code>int</code> to convert to <code>String</code> + * @return the <code>String</code> representation of the argument + */ + public static String toBinaryString(int i) + { + return toUnsignedString(i, 1); + } + + /** + * Converts the <code>int</code> to a <code>String</code> and assumes + * a radix of 10. + * + * @param i the <code>int</code> to convert to <code>String</code> + * @return the <code>String</code> representation of the argument + * @see #toString(int, int) + */ + public static String toString(int i) + { + // This is tricky: in libgcj, String.valueOf(int) is a fast native + // implementation. In Classpath it just calls back to + // Integer.toString(int, int). + return String.valueOf(i); + } + + /** + * Converts the specified <code>String</code> into an <code>int</code> + * using the specified radix (base). The string must not be <code>null</code> + * or empty. It may begin with an optional '-', which will negate the answer, + * provided that there are also valid digits. Each digit is parsed as if by + * <code>Character.digit(d, radix)</code>, and must be in the range + * <code>0</code> to <code>radix - 1</code>. Finally, the result must be + * within <code>MIN_VALUE</code> to <code>MAX_VALUE</code>, inclusive. + * Unlike Double.parseDouble, you may not have a leading '+'. + * + * @param str the <code>String</code> to convert + * @param radix the radix (base) to use in the conversion + * @return the <code>String</code> argument converted to <code>int</code> + * @throws NumberFormatException if <code>s</code> cannot be parsed as an + * <code>int</code> + */ + public static int parseInt(String str, int radix) + { + return parseInt(str, radix, false); + } + + /** + * Converts the specified <code>String</code> into an <code>int</code>. + * This function assumes a radix of 10. + * + * @param s the <code>String</code> to convert + * @return the <code>int</code> value of <code>s</code> + * @throws NumberFormatException if <code>s</code> cannot be parsed as an + * <code>int</code> + * @see #parseInt(String, int) + */ + public static int parseInt(String s) + { + return parseInt(s, 10, false); + } + + /** + * Creates a new <code>Integer</code> object using the <code>String</code> + * and specified radix (base). + * + * @param s the <code>String</code> to convert + * @param radix the radix (base) to convert with + * @return the new <code>Integer</code> + * @throws NumberFormatException if <code>s</code> cannot be parsed as an + * <code>int</code> + * @see #parseInt(String, int) + */ + public static Integer valueOf(String s, int radix) + { + return new Integer(parseInt(s, radix, false)); + } + + /** + * Creates a new <code>Integer</code> object using the <code>String</code>, + * assuming a radix of 10. + * + * @param s the <code>String</code> to convert + * @return the new <code>Integer</code> + * @throws NumberFormatException if <code>s</code> cannot be parsed as an + * <code>int</code> + * @see #Integer(String) + * @see #parseInt(String) + */ + public static Integer valueOf(String s) + { + return new Integer(parseInt(s, 10, false)); + } + + /** + * Returns an <code>Integer</code> object wrapping the value. + * In contrast to the <code>Integer</code> constructor, this method + * will cache some values. It is used by boxing conversion. + * + * @param val the value to wrap + * @return the <code>Integer</code> + */ + public static Integer valueOf(int val) + { + if (val < MIN_CACHE || val > MAX_CACHE) + return new Integer(val); + synchronized (intCache) + { + if (intCache[val - MIN_CACHE] == null) + intCache[val - MIN_CACHE] = new Integer(val); + return intCache[val - MIN_CACHE]; + } + } + + /** + * Return the value of this <code>Integer</code> as a <code>byte</code>. + * + * @return the byte value + */ + public byte byteValue() + { + return (byte) value; + } + + /** + * Return the value of this <code>Integer</code> as a <code>short</code>. + * + * @return the short value + */ + public short shortValue() + { + return (short) value; + } + + /** + * Return the value of this <code>Integer</code>. + * @return the int value + */ + public int intValue() + { + return value; + } + + /** + * Return the value of this <code>Integer</code> as a <code>long</code>. + * + * @return the long value + */ + public long longValue() + { + return value; + } + + /** + * Return the value of this <code>Integer</code> as a <code>float</code>. + * + * @return the float value + */ + public float floatValue() + { + return value; + } + + /** + * Return the value of this <code>Integer</code> as a <code>double</code>. + * + * @return the double value + */ + public double doubleValue() + { + return value; + } + + /** + * Converts the <code>Integer</code> value to a <code>String</code> and + * assumes a radix of 10. + * + * @return the <code>String</code> representation + */ + public String toString() + { + return String.valueOf(value); + } + + /** + * Return a hashcode representing this Object. <code>Integer</code>'s hash + * code is simply its value. + * + * @return this Object's hash code + */ + public int hashCode() + { + return value; + } + + /** + * Returns <code>true</code> if <code>obj</code> is an instance of + * <code>Integer</code> and represents the same int value. + * + * @param obj the object to compare + * @return whether these Objects are semantically equal + */ + public boolean equals(Object obj) + { + return obj instanceof Integer && value == ((Integer) obj).value; + } + + /** + * Get the specified system property as an <code>Integer</code>. The + * <code>decode()</code> method will be used to interpret the value of + * the property. + * + * @param nm the name of the system property + * @return the system property as an <code>Integer</code>, or null if the + * property is not found or cannot be decoded + * @throws SecurityException if accessing the system property is forbidden + * @see System#getProperty(String) + * @see #decode(String) + */ + public static Integer getInteger(String nm) + { + return getInteger(nm, null); + } + + /** + * Get the specified system property as an <code>Integer</code>, or use a + * default <code>int</code> value if the property is not found or is not + * decodable. The <code>decode()</code> method will be used to interpret + * the value of the property. + * + * @param nm the name of the system property + * @param val the default value + * @return the value of the system property, or the default + * @throws SecurityException if accessing the system property is forbidden + * @see System#getProperty(String) + * @see #decode(String) + */ + public static Integer getInteger(String nm, int val) + { + Integer result = getInteger(nm, null); + return result == null ? new Integer(val) : result; + } + + /** + * Get the specified system property as an <code>Integer</code>, or use a + * default <code>Integer</code> value if the property is not found or is + * not decodable. The <code>decode()</code> method will be used to + * interpret the value of the property. + * + * @param nm the name of the system property + * @param def the default value + * @return the value of the system property, or the default + * @throws SecurityException if accessing the system property is forbidden + * @see System#getProperty(String) + * @see #decode(String) + */ + public static Integer getInteger(String nm, Integer def) + { + if (nm == null || "".equals(nm)) + return def; + nm = System.getProperty(nm); + if (nm == null) + return def; + try + { + return decode(nm); + } + catch (NumberFormatException e) + { + return def; + } + } + + /** + * Convert the specified <code>String</code> into an <code>Integer</code>. + * The <code>String</code> may represent decimal, hexadecimal, or + * octal numbers. + * + * <p>The extended BNF grammar is as follows:<br> + * <pre> + * <em>DecodableString</em>: + * ( [ <code>-</code> ] <em>DecimalNumber</em> ) + * | ( [ <code>-</code> ] ( <code>0x</code> | <code>0X</code> + * | <code>#</code> ) <em>HexDigit</em> { <em>HexDigit</em> } ) + * | ( [ <code>-</code> ] <code>0</code> { <em>OctalDigit</em> } ) + * <em>DecimalNumber</em>: + * <em>DecimalDigit except '0'</em> { <em>DecimalDigit</em> } + * <em>DecimalDigit</em>: + * <em>Character.digit(d, 10) has value 0 to 9</em> + * <em>OctalDigit</em>: + * <em>Character.digit(d, 8) has value 0 to 7</em> + * <em>DecimalDigit</em>: + * <em>Character.digit(d, 16) has value 0 to 15</em> + * </pre> + * Finally, the value must be in the range <code>MIN_VALUE</code> to + * <code>MAX_VALUE</code>, or an exception is thrown. + * + * @param str the <code>String</code> to interpret + * @return the value of the String as an <code>Integer</code> + * @throws NumberFormatException if <code>s</code> cannot be parsed as a + * <code>int</code> + * @throws NullPointerException if <code>s</code> is null + * @since 1.2 + */ + public static Integer decode(String str) + { + return new Integer(parseInt(str, 10, true)); + } + + /** + * Compare two Integers numerically by comparing their <code>int</code> + * values. The result is positive if the first is greater, negative if the + * second is greater, and 0 if the two are equal. + * + * @param i the Integer to compare + * @return the comparison + * @since 1.2 + */ + public int compareTo(Integer i) + { + if (value == i.value) + return 0; + // Returns just -1 or 1 on inequality; doing math might overflow. + return value > i.value ? 1 : -1; + } + + /** + * Behaves like <code>compareTo(Integer)</code> unless the Object + * is not an <code>Integer</code>. + * + * @param o the object to compare + * @return the comparison + * @throws ClassCastException if the argument is not an <code>Integer</code> + * @see #compareTo(Integer) + * @see Comparable + * @since 1.2 + */ + public int compareTo(Object o) + { + return compareTo((Integer) o); + } + + /** + * Return the number of bits set in x. + * @param x value to examine + * @since 1.5 + */ + public static int bitCount(int x) + { + // Successively collapse alternating bit groups into a sum. + x = ((x >> 1) & 0x55555555) + (x & 0x55555555); + x = ((x >> 2) & 0x33333333) + (x & 0x33333333); + x = ((x >> 4) & 0x0f0f0f0f) + (x & 0x0f0f0f0f); + x = ((x >> 8) & 0x00ff00ff) + (x & 0x00ff00ff); + return ((x >> 16) & 0x0000ffff) + (x & 0x0000ffff); + } + + /** + * Rotate x to the left by distance bits. + * @param x the value to rotate + * @param distance the number of bits by which to rotate + * @since 1.5 + */ + public static int rotateLeft(int x, int distance) + { + // This trick works because the shift operators implicitly mask + // the shift count. + return (x << distance) | (x >>> - distance); + } + + /** + * Rotate x to the right by distance bits. + * @param x the value to rotate + * @param distance the number of bits by which to rotate + * @since 1.5 + */ + public static int rotateRight(int x, int distance) + { + // This trick works because the shift operators implicitly mask + // the shift count. + return (x << - distance) | (x >>> distance); + } + + /** + * Find the highest set bit in value, and return a new value + * with only that bit set. + * @param value the value to examine + * @since 1.5 + */ + public static int highestOneBit(int value) + { + value |= value >>> 1; + value |= value >>> 2; + value |= value >>> 4; + value |= value >>> 8; + value |= value >>> 16; + return value ^ (value >>> 1); + } + + /** + * Return the number of leading zeros in value. + * @param value the value to examine + * @since 1.5 + */ + public static int numberOfLeadingZeros(int value) + { + value |= value >>> 1; + value |= value >>> 2; + value |= value >>> 4; + value |= value >>> 8; + value |= value >>> 16; + return bitCount(~value); + } + + /** + * Find the lowest set bit in value, and return a new value + * with only that bit set. + * @param value the value to examine + * @since 1.5 + */ + public static int lowestOneBit(int value) + { + // Classic assembly trick. + return value & - value; + } + + /** + * Find the number of trailing zeros in value. + * @param value the value to examine + * @since 1.5 + */ + public static int numberOfTrailingZeros(int value) + { + return bitCount((value & -value) - 1); + } + + /** + * Return 1 if x is positive, -1 if it is negative, and 0 if it is + * zero. + * @param x the value to examine + * @since 1.5 + */ + public static int signum(int x) + { + return x < 0 ? -1 : (x > 0 ? 1 : 0); + } + + /** + * Reverse the bytes in val. + * @since 1.5 + */ + public static int reverseBytes(int val) + { + return ( ((val >> 24) & 0xff) + | ((val >> 8) & 0xff00) + | ((val << 8) & 0xff0000) + | ((val << 24) & 0xff000000)); + } + + /** + * Reverse the bits in val. + * @since 1.5 + */ + public static int reverse(int val) + { + // Successively swap alternating bit groups. + val = ((val >> 1) & 0x55555555) + ((val << 1) & ~0x55555555); + val = ((val >> 2) & 0x33333333) + ((val << 2) & ~0x33333333); + val = ((val >> 4) & 0x0f0f0f0f) + ((val << 4) & ~0x0f0f0f0f); + val = ((val >> 8) & 0x00ff00ff) + ((val << 8) & ~0x00ff00ff); + return ((val >> 16) & 0x0000ffff) + ((val << 16) & ~0x0000ffff); + } + + /** + * Helper for converting unsigned numbers to String. + * + * @param num the number + * @param exp log2(digit) (ie. 1, 3, or 4 for binary, oct, hex) + */ + // Package visible for use by Long. + static String toUnsignedString(int num, int exp) + { + // Use an array large enough for a binary number. + int mask = (1 << exp) - 1; + char[] buffer = new char[32]; + int i = 32; + do + { + buffer[--i] = digits[num & mask]; + num >>>= exp; + } + while (num != 0); + + // Package constructor avoids an array copy. + return new String(buffer, i, 32 - i, true); + } + + /** + * Helper for parsing ints, used by Integer, Short, and Byte. + * + * @param str the string to parse + * @param radix the radix to use, must be 10 if decode is true + * @param decode if called from decode + * @return the parsed int value + * @throws NumberFormatException if there is an error + * @throws NullPointerException if decode is true and str if null + * @see #parseInt(String, int) + * @see #decode(String) + * @see Byte#parseInt(String, int) + * @see Short#parseInt(String, int) + */ + static int parseInt(String str, int radix, boolean decode) + { + if (! decode && str == null) + throw new NumberFormatException(); + int index = 0; + int len = str.length(); + boolean isNeg = false; + if (len == 0) + throw new NumberFormatException(); + int ch = str.charAt(index); + if (ch == '-') + { + if (len == 1) + throw new NumberFormatException(); + isNeg = true; + ch = str.charAt(++index); + } + if (decode) + { + if (ch == '0') + { + if (++index == len) + return 0; + if ((str.charAt(index) & ~('x' ^ 'X')) == 'X') + { + radix = 16; + index++; + } + else + radix = 8; + } + else if (ch == '#') + { + radix = 16; + index++; + } + } + if (index == len) + throw new NumberFormatException(); + + int max = MAX_VALUE / radix; + // We can't directly write `max = (MAX_VALUE + 1) / radix'. + // So instead we fake it. + if (isNeg && MAX_VALUE % radix == radix - 1) + ++max; + + int val = 0; + while (index < len) + { + if (val < 0 || val > max) + throw new NumberFormatException(); + + ch = Character.digit(str.charAt(index++), radix); + val = val * radix + ch; + if (ch < 0 || (val < 0 && (! isNeg || val != MIN_VALUE))) + throw new NumberFormatException(); + } + return isNeg ? -val : val; + } +} |