openspades/Sources/Core/DynamicMemoryStream.cpp

/*
 Copyright (c) 2013 yvt

 This file is part of OpenSpades.

 OpenSpades is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 OpenSpades is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with OpenSpades.  If not, see <http://www.gnu.org/licenses/>.

 */

#include <cstdlib>
#include <cstring>

#include "../Core/Debug.h"
#include "../Core/Exception.h"
#include "DynamicMemoryStream.h"

namespace spades {
#define MaxSize ((uint64_t)((size_t)(-1)))
	DynamicMemoryStream::DynamicMemoryStream() : position(0) { SPADES_MARK_FUNCTION(); }
	DynamicMemoryStream::~DynamicMemoryStream() { SPADES_MARK_FUNCTION(); }

	int DynamicMemoryStream::ReadByte() {
		SPADES_MARK_FUNCTION();
		if (position >= (uint64_t)memory.size()) {
			return -1;
		} else {
			return memory[(size_t)(position++)];
		}
	}

	size_t DynamicMemoryStream::Read(void *buf, size_t bytes) {
		SPADES_MARK_FUNCTION();

		if (position >= (uint64_t)memory.size()) {
			return 0;
		}

		uint64_t maxBytes = memory.size() - (size_t)position;
		if ((uint64_t)bytes > maxBytes)
			bytes = (size_t)maxBytes;

		memcpy(buf, memory.data() + (size_t)position, bytes);
		position += bytes;
		return bytes;
	}

	std::string DynamicMemoryStream::Read(size_t bytes) {
		SPADES_MARK_FUNCTION();

		if (position >= (uint64_t)memory.size()) {
			return std::string();
		}

		uint64_t maxBytes = memory.size() - (size_t)position;
		if ((uint64_t)bytes > maxBytes)
			bytes = (size_t)maxBytes;

		std::string ret((const char *)(memory.data() + (size_t)position), bytes);
		position += bytes;
		return ret;
	}

	void DynamicMemoryStream::WriteByte(int b) {
		SPADES_MARK_FUNCTION();

		if ((uint64_t)position + 1 > MaxSize) {
			SPRaise("Memory block size exceeded");
		}

		size_t minSize = (size_t)position + 1;
		if (minSize > memory.size())
			memory.resize(minSize);

		memory[(size_t)position] = b;
		position++;
	}

	void DynamicMemoryStream::Write(const void *data, size_t bytes) {

		if ((uint64_t)position + (uint64_t)bytes > MaxSize ||
		    (uint64_t)position + (uint64_t)bytes < position) {
			SPRaise("Memory block size exceeded");
		}

		size_t minSize = (size_t)position + bytes;
		if (minSize > memory.size())
			memory.resize(minSize);

		memcpy(memory.data() + (size_t)position, data, bytes);
		position += bytes;
	}

	uint64_t DynamicMemoryStream::GetPosition() { return position; }

	void DynamicMemoryStream::SetPosition(uint64_t pos) { position = pos; }

	uint64_t DynamicMemoryStream::GetLength() { return (uint64_t)memory.size(); }

	void DynamicMemoryStream::SetLength(uint64_t l) {
		if (l > MaxSize) {
			SPRaise("Memory block size exceeded");
		}
		memory.resize((size_t)l);
	}
}