d/source/zap/ReaderArena.d

// Copyright (c) 2013-2014 Sandstorm Development Group, Inc. and contributors
// Licensed under the MIT License:
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

module zap.ReaderArena;

import std.array : Appender;

import java.nio.ByteBuffer;

import zap.Arena;
import zap.DecodeException;
import zap.SegmentReader;

final class ReaderArena : Arena
{
public: //Variables.
	long limit; //Current limit.
	Appender!(SegmentReader[]) segments;

public: //Methods.
	this(ByteBuffer[] segmentSlices, long traversalLimitInWords)
	{
		this.limit = traversalLimitInWords;
		foreach(ii; 0..segmentSlices.length)
			this.segments ~= SegmentReader(segmentSlices[ii], this);
	}
	
	SegmentReader* tryGetSegment(int id)
	{
		return &segments.data[id];
	}
	
	void checkReadLimit(int numBytes)
	{
		if(numBytes > limit)
			throw new DecodeException("Read limit exceeded.");
		limit -= numBytes;
	}
}