| /* 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#parseByte(String, int) |
| * @see Short#parseShort(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("string length is null"); |
| int ch = str.charAt(index); |
| if (ch == '-') |
| { |
| if (len == 1) |
| throw new NumberFormatException("pure '-'"); |
| 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("non terminated number: " + str); |
| |
| 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("number overflow (pos=" + index + ") : " + str); |
| |
| ch = Character.digit(str.charAt(index++), radix); |
| val = val * radix + ch; |
| if (ch < 0 || (val < 0 && (! isNeg || val != MIN_VALUE))) |
| throw new NumberFormatException("invalid character at position " + index + " in " + str); |
| } |
| return isNeg ? -val : val; |
| } |
| } |