flatbuffers/net/FlatBuffers/Table.cs

110 lines
3.7 KiB
C#

/*
* Copyright 2014 Google Inc. All rights reserved.
*
* 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.Text;
namespace FlatBuffers
{
/// <summary>
/// All tables in the generated code derive from this class, and add their own accessors.
/// </summary>
public abstract class Table
{
protected int bb_pos;
protected ByteBuffer bb;
public ByteBuffer ByteBuffer { get { return bb; } }
// Look up a field in the vtable, return an offset into the object, or 0 if the field is not
// present.
protected int __offset(int vtableOffset)
{
int vtable = bb_pos - bb.GetInt(bb_pos);
return vtableOffset < bb.GetShort(vtable) ? (int)bb.GetShort(vtable + vtableOffset) : 0;
}
// Retrieve the relative offset stored at "offset"
protected int __indirect(int offset)
{
return offset + bb.GetInt(offset);
}
// Create a .NET String from UTF-8 data stored inside the flatbuffer.
protected string __string(int offset)
{
offset += bb.GetInt(offset);
var len = bb.GetInt(offset);
var startPos = offset + sizeof(int);
return Encoding.UTF8.GetString(bb.Data, startPos , len);
}
// Get the length of a vector whose offset is stored at "offset" in this object.
protected int __vector_len(int offset)
{
offset += bb_pos;
offset += bb.GetInt(offset);
return bb.GetInt(offset);
}
// Get the start of data of a vector whose offset is stored at "offset" in this object.
protected int __vector(int offset)
{
offset += bb_pos;
return offset + bb.GetInt(offset) + sizeof(int); // data starts after the length
}
// Get the data of a vector whoses offset is stored at "offset" in this object as an
// ArraySegment&lt;byte&gt;. If the vector is not present in the ByteBuffer,
// then a null value will be returned.
protected ArraySegment<byte>? __vector_as_arraysegment(int offset) {
var o = this.__offset(offset);
if (0 == o)
{
return null;
}
var pos = this.__vector(o);
var len = this.__vector_len(o);
return new ArraySegment<byte>(this.bb.Data, pos, len);
}
// Initialize any Table-derived type to point to the union at the given offset.
protected TTable __union<TTable>(TTable t, int offset) where TTable : Table
{
offset += bb_pos;
t.bb_pos = offset + bb.GetInt(offset);
t.bb = bb;
return t;
}
protected static bool __has_identifier(ByteBuffer bb, string ident)
{
if (ident.Length != FlatBufferConstants.FileIdentifierLength)
throw new ArgumentException("FlatBuffers: file identifier must be length " + FlatBufferConstants.FileIdentifierLength, "ident");
for (var i = 0; i < FlatBufferConstants.FileIdentifierLength; i++)
{
if (ident[i] != (char)bb.Get(bb.Position + sizeof(int) + i)) return false;
}
return true;
}
}
}