1 // Copyright (c) 2013-2014 Sandstorm Development Group, Inc. and contributors
2 // Licensed under the MIT License:
3 //
4 // Permission is hereby granted, free of charge, to any person obtaining a copy
5 // of this software and associated documentation files (the "Software"), to deal
6 // in the Software without restriction, including without limitation the rights
7 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 // copies of the Software, and to permit persons to whom the Software is
9 // furnished to do so, subject to the following conditions:
10 //
11 // The above copyright notice and this permission notice shall be included in
12 // all copies or substantial portions of the Software.
13 //
14 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20 // THE SOFTWARE.
21 
22 module capnproto.SegmentBuilder;
23 
24 import java.nio.ByteBuffer;
25 
26 import capnproto.Arena;
27 import capnproto.BuilderArena;
28 import capnproto.Constants;
29 import capnproto.SegmentReader;
30 
31 struct SegmentBuilder
32 {
33 public: //Variables.
34 	static int FAILED_ALLOCATION = -1;
35 	
36 	size_t pos = 0; //In words.
37 	int id = 0;
38 
39 public: //Methods.
40 	this(ByteBuffer buf, Arena arena)
41 	{
42 		reader = SegmentReader(buf, arena);
43 	}
44 	
45 	///Returns how many words have already been allocated.
46 	size_t currentSize() const
47 	{
48 		return this.pos;
49 	}
50 	
51 	///Allocate `amount` words.
52 	size_t allocate(size_t amount)
53 	{
54 		assert(amount >= 0, "Tried to allocate a negative number of words.");
55 		if(amount > this.capacity() - this.pos)
56 			return FAILED_ALLOCATION; //No space left.
57 		scope(exit) this.pos += amount;
58 		return this.pos;
59 	}
60 	
61 	BuilderArena getArena()
62 	{
63 		return cast(BuilderArena)reader.arena;
64 	}
65 	
66 	bool isWritable() const
67 	{
68 		//TODO: Support external non-writable segments.
69 		return true;
70 	}
71 	
72 	void put(int index, long value)
73 	{
74 		buffer.put!long(index * Constants.BYTES_PER_WORD, value);
75 	}
76 	
77 	SegmentReader* asReader()
78 	{
79 		return &reader;
80 	}
81 	
82 	alias reader this;
83 
84 package: //Variables.
85 	SegmentReader reader;
86 
87 private: //Methods.
88 	///The total number of words the buffer can hold.
89 	size_t capacity()
90 	{
91 		this.buffer.rewind();
92 		return this.buffer.remaining() / 8;
93 	}
94 }