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Diffstat (limited to 'java/src/main/java/com/google/protobuf/WireFormat.java')
| -rw-r--r-- | java/src/main/java/com/google/protobuf/WireFormat.java | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/java/src/main/java/com/google/protobuf/WireFormat.java b/java/src/main/java/com/google/protobuf/WireFormat.java new file mode 100644 index 00000000..31bfd402 --- /dev/null +++ b/java/src/main/java/com/google/protobuf/WireFormat.java @@ -0,0 +1,99 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2008 Google Inc. +// http://code.google.com/p/protobuf/ +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package com.google.protobuf; + +/** + * This class is used internally by the Protocol Buffer library and generated + * message implementations. It is public only because those generated messages + * do not reside in the {@code protocol2} package. Others should not use this + * class directly. + * + * This class contains constants and helper functions useful for dealing with + * the Protocol Buffer wire format. + * + * @author kenton@google.com Kenton Varda + */ +public final class WireFormat { + // Do not allow instantiation. + private WireFormat() {} + + static final int WIRETYPE_VARINT = 0; + static final int WIRETYPE_FIXED64 = 1; + static final int WIRETYPE_LENGTH_DELIMITED = 2; + static final int WIRETYPE_START_GROUP = 3; + static final int WIRETYPE_END_GROUP = 4; + static final int WIRETYPE_FIXED32 = 5; + + static final int TAG_TYPE_BITS = 3; + static final int TAG_TYPE_MASK = (1 << TAG_TYPE_BITS) - 1; + + /** Given a tag value, determines the wire type (the lower 3 bits). */ + static int getTagWireType(int tag) { + return tag & TAG_TYPE_MASK; + } + + /** Given a tag value, determines the field number (the upper 29 bits). */ + public static int getTagFieldNumber(int tag) { + return tag >>> TAG_TYPE_BITS; + } + + /** Makes a tag value given a field number and wire type. */ + static int makeTag(int fieldNumber, int wireType) { + return (fieldNumber << TAG_TYPE_BITS) | wireType; + } + + static int getWireFormatForFieldType(Descriptors.FieldDescriptor.Type type) { + switch (type) { + case DOUBLE : return WIRETYPE_FIXED64; + case FLOAT : return WIRETYPE_FIXED32; + case INT64 : return WIRETYPE_VARINT; + case UINT64 : return WIRETYPE_VARINT; + case INT32 : return WIRETYPE_VARINT; + case FIXED64 : return WIRETYPE_FIXED64; + case FIXED32 : return WIRETYPE_FIXED32; + case BOOL : return WIRETYPE_VARINT; + case STRING : return WIRETYPE_LENGTH_DELIMITED; + case GROUP : return WIRETYPE_START_GROUP; + case MESSAGE : return WIRETYPE_LENGTH_DELIMITED; + case BYTES : return WIRETYPE_LENGTH_DELIMITED; + case UINT32 : return WIRETYPE_VARINT; + case ENUM : return WIRETYPE_VARINT; + case SFIXED32: return WIRETYPE_FIXED32; + case SFIXED64: return WIRETYPE_FIXED64; + case SINT32 : return WIRETYPE_VARINT; + case SINT64 : return WIRETYPE_VARINT; + } + + throw new RuntimeException( + "There is no way to get here, but the compiler thinks otherwise."); + } + + // Field numbers for feilds in MessageSet wire format. + static final int MESSAGE_SET_ITEM = 1; + static final int MESSAGE_SET_TYPE_ID = 2; + static final int MESSAGE_SET_MESSAGE = 3; + + // Tag numbers. + static final int MESSAGE_SET_ITEM_TAG = + makeTag(MESSAGE_SET_ITEM, WIRETYPE_START_GROUP); + static final int MESSAGE_SET_ITEM_END_TAG = + makeTag(MESSAGE_SET_ITEM, WIRETYPE_END_GROUP); + static final int MESSAGE_SET_TYPE_ID_TAG = + makeTag(MESSAGE_SET_TYPE_ID, WIRETYPE_VARINT); + static final int MESSAGE_SET_MESSAGE_TAG = + makeTag(MESSAGE_SET_MESSAGE, WIRETYPE_LENGTH_DELIMITED); +} |