diff options
Diffstat (limited to 'pki/base/util/src/netscape/security/util/BitArray.java')
-rw-r--r-- | pki/base/util/src/netscape/security/util/BitArray.java | 273 |
1 files changed, 136 insertions, 137 deletions
diff --git a/pki/base/util/src/netscape/security/util/BitArray.java b/pki/base/util/src/netscape/security/util/BitArray.java index 43af482d5..ab77c226e 100644 --- a/pki/base/util/src/netscape/security/util/BitArray.java +++ b/pki/base/util/src/netscape/security/util/BitArray.java @@ -21,7 +21,7 @@ import java.io.ByteArrayOutputStream; /** * A packed array of booleans. - * + * * @author Joshua Bloch * @author Douglas Hoover * @version 1.2 97/12/10 @@ -35,224 +35,223 @@ public class BitArray { private static final int BITS_PER_UNIT = 8; private static int subscript(int idx) { - return idx / BITS_PER_UNIT; + return idx / BITS_PER_UNIT; } private static int position(int idx) { // bits big-endian in each unit - return 1 << (BITS_PER_UNIT - 1 - (idx % BITS_PER_UNIT)); + return 1 << (BITS_PER_UNIT - 1 - (idx % BITS_PER_UNIT)); } /** * Creates a BitArray of the specified size, initialized to zeros. */ public BitArray(int length) throws IllegalArgumentException { - if (length < 0) { - throw new IllegalArgumentException("Negative length for BitArray"); - } + if (length < 0) { + throw new IllegalArgumentException("Negative length for BitArray"); + } - this.length = length; + this.length = length; - repn = new byte[(length + BITS_PER_UNIT - 1)/BITS_PER_UNIT]; + repn = new byte[(length + BITS_PER_UNIT - 1) / BITS_PER_UNIT]; } - /** * Creates a BitArray of the specified size, initialized from the - * specified byte array. The most significant bit of a[0] gets - * index zero in the BitArray. The array a must be large enough - * to specify a value for every bit in the BitArray. In other words, + * specified byte array. The most significant bit of a[0] gets + * index zero in the BitArray. The array a must be large enough + * to specify a value for every bit in the BitArray. In other words, * 8*a.length >= length. */ public BitArray(int length, byte[] a) throws IllegalArgumentException { - - if (length < 0) { - throw new IllegalArgumentException("Negative length for BitArray"); - } - if (a.length * BITS_PER_UNIT < length) { - throw new IllegalArgumentException("Byte array too short to represent " + - "bit array of given length"); - } - - this.length = length; - - int repLength = ((length + BITS_PER_UNIT - 1)/BITS_PER_UNIT); - int unusedBits = repLength*BITS_PER_UNIT - length; - byte bitMask = (byte) (0xFF << unusedBits); - - /* - normalize the representation: - 1. discard extra bytes - 2. zero out extra bits in the last byte - */ - repn = new byte[repLength]; - System.arraycopy(a, 0, repn, 0, repLength); - if (repn.length > 0) - repn[repn.length -1] = (byte) (repn[repn.length -1] & bitMask); + + if (length < 0) { + throw new IllegalArgumentException("Negative length for BitArray"); + } + if (a.length * BITS_PER_UNIT < length) { + throw new IllegalArgumentException("Byte array too short to represent " + + "bit array of given length"); + } + + this.length = length; + + int repLength = ((length + BITS_PER_UNIT - 1) / BITS_PER_UNIT); + int unusedBits = repLength * BITS_PER_UNIT - length; + byte bitMask = (byte) (0xFF << unusedBits); + + /* + normalize the representation: + 1. discard extra bytes + 2. zero out extra bits in the last byte + */ + repn = new byte[repLength]; + System.arraycopy(a, 0, repn, 0, repLength); + if (repn.length > 0) + repn[repn.length - 1] = (byte) (repn[repn.length - 1] & bitMask); } /** - * Create a BitArray whose bits are those of the given array - * of Booleans. + * Create a BitArray whose bits are those of the given array + * of Booleans. */ public BitArray(boolean[] bits) { - length = bits.length; - repn = new byte[(length + 7)/8]; + length = bits.length; + repn = new byte[(length + 7) / 8]; - for (int i=0; i < length; i++) { - set(i, bits[i]); - } + for (int i = 0; i < length; i++) { + set(i, bits[i]); + } } - - + /** - * Copy constructor (for cloning). + * Copy constructor (for cloning). */ private BitArray(BitArray ba) { - length = ba.length; - repn = (byte[]) ba.repn.clone(); + length = ba.length; + repn = (byte[]) ba.repn.clone(); } /** - * Returns the indexed bit in this BitArray. + * Returns the indexed bit in this BitArray. */ public boolean get(int index) throws ArrayIndexOutOfBoundsException { - if (index < 0 || index >= length) { - throw new ArrayIndexOutOfBoundsException(Integer.toString(index)); - } - - return (repn[subscript(index)] & position(index)) != 0; + if (index < 0 || index >= length) { + throw new ArrayIndexOutOfBoundsException(Integer.toString(index)); + } + + return (repn[subscript(index)] & position(index)) != 0; } /** - * Sets the indexed bit in this BitArray. + * Sets the indexed bit in this BitArray. */ public void set(int index, boolean value) - throws ArrayIndexOutOfBoundsException { - if (index < 0 || index >= length) { - throw new ArrayIndexOutOfBoundsException(Integer.toString(index)); - } - int idx = subscript(index); - int bit = position(index); - - if (value) { - repn[idx] |= bit; - } else { - repn[idx] &= ~bit; - } + throws ArrayIndexOutOfBoundsException { + if (index < 0 || index >= length) { + throw new ArrayIndexOutOfBoundsException(Integer.toString(index)); + } + int idx = subscript(index); + int bit = position(index); + + if (value) { + repn[idx] |= bit; + } else { + repn[idx] &= ~bit; + } } /** * Returns the length of this BitArray. */ public int length() { - return length; + return length; } /** * Returns a Byte array containing the contents of this BitArray. * The bit stored at index zero in this BitArray will be copied - * into the most significant bit of the zeroth element of the - * returned byte array. The last byte of the returned byte array + * into the most significant bit of the zeroth element of the + * returned byte array. The last byte of the returned byte array * will be contain zeros in any bits that do not have corresponding - * bits in the BitArray. (This matters only if the BitArray's size + * bits in the BitArray. (This matters only if the BitArray's size * is not a multiple of 8.) - */ + */ public byte[] toByteArray() { - return (byte[]) repn.clone(); + return (byte[]) repn.clone(); } public boolean equals(Object obj) { - if (obj == this) return true; - if (obj == null || !(obj instanceof BitArray)) return false; - - BitArray ba = (BitArray) obj; - - if (ba.length != length) return false; - - for (int i = 0; i < repn.length; i += 1) { - if (repn[i] != ba.repn[i]) return false; - } - return true; + if (obj == this) + return true; + if (obj == null || !(obj instanceof BitArray)) + return false; + + BitArray ba = (BitArray) obj; + + if (ba.length != length) + return false; + + for (int i = 0; i < repn.length; i += 1) { + if (repn[i] != ba.repn[i]) + return false; + } + return true; } /** * Return a boolean array with the same bit values a this BitArray. */ public boolean[] toBooleanArray() { - boolean[] bits = new boolean[length]; + boolean[] bits = new boolean[length]; - for (int i=0; i < length; i++) { - bits[i] = get(i); - } - return bits; + for (int i = 0; i < length; i++) { + bits[i] = get(i); + } + return bits; } /** * Returns a hash code value for this bit array. - * - * @return a hash code value for this bit array. + * + * @return a hash code value for this bit array. */ public int hashCode() { - int hashCode = 0; + int hashCode = 0; - for (int i = 0; i < repn.length; i++) - hashCode = 31*hashCode + repn[i]; + for (int i = 0; i < repn.length; i++) + hashCode = 31 * hashCode + repn[i]; - return hashCode ^ length; + return hashCode ^ length; } - public Object clone() { - return new BitArray(this); + return new BitArray(this); } - private static final byte[][] NYBBLE = { - { (byte)'0',(byte)'0',(byte)'0',(byte)'0'}, - { (byte)'0',(byte)'0',(byte)'0',(byte)'1'}, - { (byte)'0',(byte)'0',(byte)'1',(byte)'0'}, - { (byte)'0',(byte)'0',(byte)'1',(byte)'1'}, - { (byte)'0',(byte)'1',(byte)'0',(byte)'0'}, - { (byte)'0',(byte)'1',(byte)'0',(byte)'1'}, - { (byte)'0',(byte)'1',(byte)'1',(byte)'0'}, - { (byte)'0',(byte)'1',(byte)'1',(byte)'1'}, - { (byte)'1',(byte)'0',(byte)'0',(byte)'0'}, - { (byte)'1',(byte)'0',(byte)'0',(byte)'1'}, - { (byte)'1',(byte)'0',(byte)'1',(byte)'0'}, - { (byte)'1',(byte)'0',(byte)'1',(byte)'1'}, - { (byte)'1',(byte)'1',(byte)'0',(byte)'0'}, - { (byte)'1',(byte)'1',(byte)'0',(byte)'1'}, - { (byte)'1',(byte)'1',(byte)'1',(byte)'0'}, - { (byte)'1',(byte)'1',(byte)'1',(byte)'1'} + { (byte) '0', (byte) '0', (byte) '0', (byte) '0' }, + { (byte) '0', (byte) '0', (byte) '0', (byte) '1' }, + { (byte) '0', (byte) '0', (byte) '1', (byte) '0' }, + { (byte) '0', (byte) '0', (byte) '1', (byte) '1' }, + { (byte) '0', (byte) '1', (byte) '0', (byte) '0' }, + { (byte) '0', (byte) '1', (byte) '0', (byte) '1' }, + { (byte) '0', (byte) '1', (byte) '1', (byte) '0' }, + { (byte) '0', (byte) '1', (byte) '1', (byte) '1' }, + { (byte) '1', (byte) '0', (byte) '0', (byte) '0' }, + { (byte) '1', (byte) '0', (byte) '0', (byte) '1' }, + { (byte) '1', (byte) '0', (byte) '1', (byte) '0' }, + { (byte) '1', (byte) '0', (byte) '1', (byte) '1' }, + { (byte) '1', (byte) '1', (byte) '0', (byte) '0' }, + { (byte) '1', (byte) '1', (byte) '0', (byte) '1' }, + { (byte) '1', (byte) '1', (byte) '1', (byte) '0' }, + { (byte) '1', (byte) '1', (byte) '1', (byte) '1' } }; private static final int BYTES_PER_LINE = 8; /** - * Returns a string representation of this BitArray. + * Returns a string representation of this BitArray. */ public String toString() { - ByteArrayOutputStream out = new ByteArrayOutputStream(); - - for (int i = 0; i < repn.length - 1; i++) { - out.write(NYBBLE[(repn[i] >> 4) & 0x0F], 0, 4); - out.write(NYBBLE[repn[i] & 0x0F], 0, 4); - - if (i % BYTES_PER_LINE == BYTES_PER_LINE - 1) { - out.write('\n'); - } else { - out.write(' '); - } - } - - // in last byte of repn, use only the valid bits - for (int i = BITS_PER_UNIT * (repn.length - 1); i < length; i++) { - out.write(get(i) ? '1' : '0'); - } - - return new String(out.toByteArray()); - + ByteArrayOutputStream out = new ByteArrayOutputStream(); + + for (int i = 0; i < repn.length - 1; i++) { + out.write(NYBBLE[(repn[i] >> 4) & 0x0F], 0, 4); + out.write(NYBBLE[repn[i] & 0x0F], 0, 4); + + if (i % BYTES_PER_LINE == BYTES_PER_LINE - 1) { + out.write('\n'); + } else { + out.write(' '); + } + } + + // in last byte of repn, use only the valid bits + for (int i = BITS_PER_UNIT * (repn.length - 1); i < length; i++) { + out.write(get(i) ? '1' : '0'); + } + + return new String(out.toByteArray()); + } - -} +} |