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author | Jon Skeet <skeet@pobox.com> | 2008-10-22 13:30:34 +0100 |
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committer | Jon Skeet <skeet@pobox.com> | 2008-10-22 13:30:34 +0100 |
commit | 6803686bc06c4d96afd9bd2637f7b37a58596699 (patch) | |
tree | 4b21c563f4cd4e399fbc0b253bc2f15e822eae88 /src/ProtocolBuffers/WireFormat.cs | |
parent | f0589506c96600dcd01319b9d1929d87505f3daa (diff) | |
download | protobuf-6803686bc06c4d96afd9bd2637f7b37a58596699.tar.gz protobuf-6803686bc06c4d96afd9bd2637f7b37a58596699.tar.bz2 protobuf-6803686bc06c4d96afd9bd2637f7b37a58596699.zip |
First cut at new layout
Diffstat (limited to 'src/ProtocolBuffers/WireFormat.cs')
-rw-r--r-- | src/ProtocolBuffers/WireFormat.cs | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/src/ProtocolBuffers/WireFormat.cs b/src/ProtocolBuffers/WireFormat.cs new file mode 100644 index 00000000..0ea93322 --- /dev/null +++ b/src/ProtocolBuffers/WireFormat.cs @@ -0,0 +1,122 @@ +// 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. +using System; +using System.Reflection; +using Google.ProtocolBuffers.Descriptors; +using System.Collections.Generic; +using Google.ProtocolBuffers.Collections; +namespace Google.ProtocolBuffers { + + /// <summary> + /// This class is used internally by the Protocol Buffer Library and generated + /// message implementations. It is public only for the sake of those generated + /// messages. Others should not use this class directly. + /// <para> + /// This class contains constants and helper functions useful for dealing with + /// the Protocol Buffer wire format. + /// </para> + /// </summary> + public static class WireFormat { + public enum WireType : uint { + Varint = 0, + Fixed64 = 1, + LengthDelimited = 2, + StartGroup = 3, + EndGroup = 4, + Fixed32 = 5 + } + + internal static class MessageSetField { + internal const int Item = 1; + internal const int TypeID = 2; + internal const int Message = 3; + } + + internal static class MessageSetTag { + internal static readonly uint ItemStart = MakeTag(MessageSetField.Item, WireType.StartGroup); + internal static readonly uint ItemEnd = MakeTag(MessageSetField.Item, WireType.EndGroup); + internal static readonly uint TypeID = MakeTag(MessageSetField.TypeID, WireType.Varint); + internal static readonly uint Message = MakeTag(MessageSetField.Message, WireType.LengthDelimited); + } + + private const int TagTypeBits = 3; + private const uint TagTypeMask = (1 << TagTypeBits) - 1; + + /// <summary> + /// Given a tag value, determines the wire type (lower 3 bits). + /// </summary> + public static WireType GetTagWireType(uint tag) { + return (WireType) (tag & TagTypeMask); + } + + /// <summary> + /// Given a tag value, determines the field number (the upper 29 bits). + /// </summary> + public static int GetTagFieldNumber(uint tag) { + return (int) tag >> TagTypeBits; + } + + /// <summary> + /// Makes a tag value given a field number and wire type. + /// TODO(jonskeet): Should we just have a Tag structure? + /// </summary> + public static uint MakeTag(int fieldNumber, WireType wireType) { + return (uint) (fieldNumber << TagTypeBits) | (uint) wireType; + } + + /// <summary> + /// Converts a field type to its wire type. Done with a switch for the sake + /// of speed - this is significantly faster than a dictionary lookup. + /// </summary> + public static WireType GetWireType(FieldType fieldType) { + switch (fieldType) { + case FieldType.Double: + return WireType.Fixed64; + case FieldType.Float: + return WireType.Fixed32; + case FieldType.Int64: + case FieldType.UInt64: + case FieldType.Int32: + return WireType.Varint; + case FieldType.Fixed64: + return WireType.Fixed64; + case FieldType.Fixed32: + return WireType.Fixed32; + case FieldType.Bool: + return WireType.Varint; + case FieldType.String: + return WireType.LengthDelimited; + case FieldType.Group: + return WireType.StartGroup; + case FieldType.Message: + case FieldType.Bytes: + return WireType.LengthDelimited; + case FieldType.UInt32: + return WireType.Varint; + case FieldType.SFixed32: + return WireType.Fixed32; + case FieldType.SFixed64: + return WireType.Fixed64; + case FieldType.SInt32: + case FieldType.SInt64: + case FieldType.Enum: + return WireType.Varint; + default: + throw new ArgumentOutOfRangeException("No such field type"); + } + } + } +} |