--- /dev/null
+/*
+ * Copyright (c) 2019 PANTHEON.tech, s.r.o. and others. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.cluster.datastore.node.utils.stream;
+
+/**
+ * Path Argument types used in Magnesium encoding. These are encoded as a single byte, three bits of which are reserved
+ * for PathArgument type itself:
+ * <pre>
+ * 7 6 5 4 3 2 1 0
+ * +-+-+-+-+-+-+-+-+
+ * | | Type|
+ * +-+-+-+-+-+-+-+-+
+ * </pre>
+ * There are five type defined:
+ * <ul>
+ * <li>{@link #AUGMENTATION_IDENTIFIER}, which additionally holds the number of QName elements encoded:
+ * <pre>
+ * 7 6 5 4 3 2 1 0
+ * +-+-+-+-+-+-+-+-+
+ * | Count |0 0 0|
+ * +-+-+-+-+-+-+-+-+
+ * </pre>
+ * Where count is coded as an unsigned integer, with {@link #AID_COUNT_1B} and {@link #AID_COUNT_2B} and
+ * {@link #AID_COUNT_4B} indicating extended coding with up to 4 additional bytes. This byte is followed by
+ * {@code count} {@link MagnesiumValue} QNames.
+ * <pre>
+ * 7 6 5 4 3 2 1 0
+ * +-+-+-+-+-+-+-+-+
+ * |0 0 0| Q |0 0 1|
+ * +-+-+-+-+-+-+-+-+
+ * </pre>
+ * Where QName coding is achieved via {@link #QNAME_DEF}, {@link #QNAME_REF_1B}, {@link #QNAME_REF_2B} and
+ * {@link #QNAME_REF_4B}.
+ * </li>
+ * <li>{@link #NODE_IDENTIFIER_WITH_PREDICATES}, which encodes a QName same way NodeIdentifier does:
+ * <pre>
+ * 7 6 5 4 3 2 1 0
+ * +-+-+-+-+-+-+-+-+
+ * | Size| Q |0 1 0|
+ * +-+-+-+-+-+-+-+-+
+ * </pre>
+ * but additionally encodes number of predicates contained using {@link #SIZE_0} through {@link #SIZE_4}. If that
+ * number cannot be expressed, {@link #SIZE_1B}, {@value #SIZE_2B} and {@link #SIZE_4B} indicate number and format
+ * of additional bytes that hold number of predicates.
+ *
+ * <p>
+ * This is then followed by the specified number of QName/Object key/value pairs based on {@link MagnesiumValue}
+ * encoding.
+ * </li>
+ * <li>{@link #NODE_WITH_VALUE}, which encodes a QName same way NodeIdentifier does:
+ * <pre>
+ * 7 6 5 4 3 2 1 0
+ * +-+-+-+-+-+-+-+-+
+ * |0 0 0| Q |0 1 1|
+ * +-+-+-+-+-+-+-+-+
+ * </pre>
+ * but is additionally followed by a single encoded value, as per {@link MagnesiumValue}.
+ * </li>
+ * <li>{@link #MOUNTPOINT_IDENTIFIER}, which encodes a QName same way NodeIdentifier does:
+ * <pre>
+ * 7 6 5 4 3 2 1 0
+ * +-+-+-+-+-+-+-+-+
+ * |0 0 0| Q |1 0 0|
+ * +-+-+-+-+-+-+-+-+
+ * </pre>
+ * </li>
+ * </ul>
+ */
+final class MagnesiumPathArgument {
+ // 3 bits reserved for type...
+ static final byte AUGMENTATION_IDENTIFIER = 0x00;
+ static final byte NODE_IDENTIFIER = 0x01;
+ static final byte NODE_IDENTIFIER_WITH_PREDICATES = 0x02;
+ static final byte NODE_WITH_VALUE = 0x03;
+ static final byte MOUNTPOINT_IDENTIFIER = 0x04;
+
+ // ... leaving three values currently unused
+ // 0x05 reserved
+ // 0x06 reserved
+ // 0x07 reserved
+
+ static final byte TYPE_MASK = 0x07;
+
+ // In case of AUGMENTATION_IDENTIFIER, top 5 bits are used to encode the number of path arguments, except last three
+ // values. This means that up to AugmentationIdentifiers with up to 28 components have this length encoded inline,
+ // otherwise we encode them in following 1 (unsigned), 2 (unsigned) or 4 (signed) bytes
+ static final byte AID_COUNT_1B = (byte) 0xE8;
+ static final byte AID_COUNT_2B = (byte) 0xF0;
+ static final byte AID_COUNT_4B = (byte) 0xF8;
+ static final byte AID_COUNT_MASK = AID_COUNT_4B;
+ static final byte AID_COUNT_SHIFT = 3;
+
+ // For normal path path arguments we can either define a QName reference or follow a 1-4 byte reference.
+ static final byte QNAME_DEF = 0x00;
+ static final byte QNAME_REF_1B = 0x08; // Unsigned
+ static final byte QNAME_REF_2B = 0x10; // Unsigned
+ static final byte QNAME_REF_4B = 0x18; // Signed
+ static final byte QNAME_MASK = QNAME_REF_4B;
+
+ // For NodeIdentifierWithPredicates we also carry the number of subsequent path arguments. The case of 0-4 arguments
+ // is indicated directly, otherwise there is 1-4 bytes carrying the reference.
+ static final byte SIZE_0 = 0x00;
+ static final byte SIZE_1 = 0x20;
+ static final byte SIZE_2 = 0x40;
+ static final byte SIZE_3 = 0x60;
+ static final byte SIZE_4 = (byte) 0x80;
+ static final byte SIZE_1B = (byte) 0xA0;
+ static final byte SIZE_2B = (byte) 0xC0;
+ static final byte SIZE_4B = (byte) 0xE0;
+ static final byte SIZE_MASK = SIZE_4B;
+ static final byte SIZE_SHIFT = 5;
+
+ private MagnesiumPathArgument() {
+
+ }
+}
Code Review / controller.git / blobdiff