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Diffstat (limited to 'libjava/java/util/BitSet.java')
| -rw-r--r-- | libjava/java/util/BitSet.java | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/libjava/java/util/BitSet.java b/libjava/java/util/BitSet.java new file mode 100644 index 0000000..e588695 --- /dev/null +++ b/libjava/java/util/BitSet.java @@ -0,0 +1,183 @@ +// BitSet - A vector of bits. + +/* Copyright (C) 1998, 1999 Cygnus Solutions + + This file is part of libgcj. + +This software is copyrighted work licensed under the terms of the +Libgcj License. Please consult the file "LIBGCJ_LICENSE" for +details. */ + +package java.util; +import java.io.Serializable; + +/** + * @author Tom Tromey <tromey@cygnus.com> + * @date October 23, 1998. + */ + +/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3 + * hashCode algorithm taken from JDK 1.2 docs. + */ + +public final class BitSet implements Cloneable, Serializable +{ + public void and (BitSet bs) + { + if (bs == null) + throw new NullPointerException (); + int max = Math.min(bits.length, bs.bits.length); + int i; + for (i = 0; i < max; ++i) + bits[i] &= bs.bits[i]; + for ( ; i < bits.length; ++i) + bits[i] = 0; + } + + public BitSet () + { + this (64); + } + + public BitSet (int nbits) + { + if (nbits < 0) + throw new NegativeArraySizeException (); + int length = nbits / 64; + if (nbits % 64 != 0) + ++length; + bits = new long[length]; + } + + public void clear (int pos) + { + if (pos < 0) + throw new IndexOutOfBoundsException (); + int bit = pos % 64; + int offset = pos / 64; + ensure (offset); + bits[offset] &= ~ (1 << bit); + } + + public Object clone () + { + BitSet bs = new BitSet (bits.length * 64); + System.arraycopy(bits, 0, bs.bits, 0, bits.length); + return bs; + } + + public boolean equals (Object obj) + { + if (! (obj instanceof BitSet)) + return false; + BitSet bs = (BitSet) obj; + int max = Math.min(bits.length, bs.bits.length); + int i; + for (i = 0; i < max; ++i) + if (bits[i] != bs.bits[i]) + return false; + // If one is larger, check to make sure all extra bits are 0. + for (int j = i; j < bits.length; ++j) + if (bits[j] != 0) + return false; + for (int j = i; j < bs.bits.length; ++j) + if (bs.bits[j] != 0) + return false; + return true; + } + + public boolean get (int pos) + { + if (pos < 0) + throw new IndexOutOfBoundsException (); + + int bit = pos % 64; + int offset = pos / 64; + + if (offset >= bits.length) + return false; + + return (bits[offset] & (1 << bit)) == 0 ? false : true; + } + + public int hashCode () + { + long h = 1234; + for (int i = bits.length - 1; i >= 0; --i) + h ^= bits[i] * (i + 1); + return (int) ((h >> 32) ^ h); + } + + public void or (BitSet bs) + { + if (bs == null) + throw new NullPointerException (); + ensure (bs.bits.length - 1); + int i; + for (i = 0; i < bs.bits.length; ++i) + bits[i] |= bs.bits[i]; + } + + public void set (int pos) + { + if (pos < 0) + throw new IndexOutOfBoundsException (); + int bit = pos % 64; + int offset = pos / 64; + ensure (offset); + bits[offset] |= 1 << bit; + } + + public int size () + { + return bits.length * 64; + } + + public String toString () + { + StringBuffer result = new StringBuffer ("{"); + boolean first = true; + for (int i = 0; i < bits.length; ++i) + { + int bit = 1; + long word = bits[i]; + for (int j = 0; j < 64; ++j) + { + if ((word & bit) != 0) + { + if (! first) + result.append(", "); + result.append(64 * i + j); + first = false; + } + bit <<= 1; + } + } + + return result.append("}").toString(); + } + + public void xor (BitSet bs) + { + if (bs == null) + throw new NullPointerException (); + ensure (bs.bits.length - 1); + int i; + for (i = 0; i < bs.bits.length; ++i) + bits[i] ^= bs.bits[i]; + } + + // Make sure the vector is big enough. + private final void ensure (int lastElt) + { + if (lastElt + 1 > bits.length) + { + long[] nd = new long[lastElt + 1]; + System.arraycopy(bits, 0, nd, 0, bits.length); + bits = nd; + } + } + + // The actual bits. + private long[] bits; +} |