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Diffstat (limited to 'lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangObject.java')
| -rw-r--r-- | lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangObject.java | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangObject.java b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangObject.java new file mode 100644 index 0000000000..81220c5685 --- /dev/null +++ b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangObject.java @@ -0,0 +1,190 @@ +/* + * %CopyrightBegin% + * + * Copyright Ericsson AB 2000-2009. All Rights Reserved. + * + * The contents of this file are subject to the Erlang Public License, + * Version 1.1, (the "License"); you may not use this file except in + * compliance with the License. You should have received a copy of the + * Erlang Public License along with this software. If not, it can be + * retrieved online at http://www.erlang.org/. + * + * Software distributed under the License is distributed on an "AS IS" + * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See + * the License for the specific language governing rights and limitations + * under the License. + * + * %CopyrightEnd% + */ +package com.ericsson.otp.erlang; + +import java.io.Serializable; + +/** + * Base class of the Erlang data type classes. This class is used to represent + * an arbitrary Erlang term. + */ +public abstract class OtpErlangObject implements Serializable, Cloneable { + protected int hashCodeValue = 0; + + // don't change this! + static final long serialVersionUID = -8435938572339430044L; + + /** + * @return the printable representation of the object. This is usually + * similar to the representation used by Erlang for the same type of + * object. + */ + @Override + public abstract String toString(); + + /** + * Convert the object according to the rules of the Erlang external format. + * This is mainly used for sending Erlang terms in messages, however it can + * also be used for storing terms to disk. + * + * @param buf + * an output stream to which the encoded term should be + * written. + */ + public abstract void encode(OtpOutputStream buf); + + /** + * Read binary data in the Erlang external format, and produce a + * corresponding Erlang data type object. This method is normally used when + * Erlang terms are received in messages, however it can also be used for + * reading terms from disk. + * + * @param buf + * an input stream containing one or more encoded Erlang + * terms. + * + * @return an object representing one of the Erlang data types. + * + * @exception OtpErlangDecodeException + * if the stream does not contain a valid representation + * of an Erlang term. + */ + public static OtpErlangObject decode(final OtpInputStream buf) + throws OtpErlangDecodeException { + return buf.read_any(); + } + + /** + * Determine if two Erlang objects are equal. In general, Erlang objects are + * equal if the components they consist of are equal. + * + * @param o + * the object to compare to. + * + * @return true if the objects are identical. + */ + @Override + public abstract boolean equals(Object o); + + @Override + public int hashCode() { + if (hashCodeValue == 0) { + hashCodeValue = doHashCode(); + } + return hashCodeValue; + } + + protected int doHashCode() { + return super.hashCode(); + } + + @Override + public Object clone() { + try { + return super.clone(); + } catch (final CloneNotSupportedException e) { + /* cannot happen */ + throw new InternalError(e.toString()); + } + } + + protected final static class Hash { + int abc[] = {0, 0, 0}; + + /* Hash function suggested by Bob Jenkins. + * The same as in the Erlang VM (beam); utils.c. + */ + + private final static int HASH_CONST[] = { + 0, // not used + 0x9e3779b9, // the golden ratio; an arbitrary value + 0x3c6ef372, // (hashHConst[1] * 2) % (1<<32) + 0xdaa66d2b, // 1 3 + 0x78dde6e4, // 1 4 + 0x1715609d, // 1 5 + 0xb54cda56, // 1 6 + 0x5384540f, // 1 7 + 0xf1bbcdc8, // 1 8 + 0x8ff34781, // 1 9 + 0x2e2ac13a, // 1 10 + 0xcc623af3, // 1 11 + 0x6a99b4ac, // 1 12 + 0x08d12e65, // 1 13 + 0xa708a81e, // 1 14 + 0x454021d7, // 1 15 + }; + + protected Hash(int i) { + abc[0] = abc[1] = HASH_CONST[i]; + abc[2] = 0; + } + + //protected Hash() { + // Hash(1); + //} + + private void mix() { + abc[0] -= abc[1]; abc[0] -= abc[2]; abc[0] ^= (abc[2]>>>13); + abc[1] -= abc[2]; abc[1] -= abc[0]; abc[1] ^= (abc[0]<<8); + abc[2] -= abc[0]; abc[2] -= abc[1]; abc[2] ^= (abc[1]>>>13); + abc[0] -= abc[1]; abc[0] -= abc[2]; abc[0] ^= (abc[2]>>>12); + abc[1] -= abc[2]; abc[1] -= abc[0]; abc[1] ^= (abc[0]<<16); + abc[2] -= abc[0]; abc[2] -= abc[1]; abc[2] ^= (abc[1]>>>5); + abc[0] -= abc[1]; abc[0] -= abc[2]; abc[0] ^= (abc[2]>>>3); + abc[1] -= abc[2]; abc[1] -= abc[0]; abc[1] ^= (abc[0]<<10); + abc[2] -= abc[0]; abc[2] -= abc[1]; abc[2] ^= (abc[1]>>>15); + } + + protected void combine(int a) { + abc[0] += a; + mix(); + } + + protected void combine(long a) { + combine((int)(a >>> 32), (int) a); + } + + protected void combine(int a, int b) { + abc[0] += a; + abc[1] += b; + mix(); + } + + protected void combine(byte b[]) { + int j, k; + for (j = 0, k = 0; + j + 4 < b.length; + j += 4, k += 1, k %= 3) { + abc[k] += ((int)b[j+0] & 0xFF) + ((int)b[j+1]<<8 & 0xFF00) + + ((int)b[j+2]<<16 & 0xFF0000) + ((int)b[j+3]<<24); + mix(); + } + for (int n = 0, m = 0xFF; + j < b.length; + j++, n += 8, m <<= 8) { + abc[k] += (int)b[j]<<n & m; + } + mix(); + } + + protected int valueOf() { + return abc[2]; + } + } +} |