//-----------------------------------------------------------------------------
//
//	Stream.h
//
//	Cross-platform circular buffer with signalling
//
//	Copyright (c) 2010 Mal Lansell <mal@lansell.org>
//	All rights reserved.
//
//	SOFTWARE NOTICE AND LICENSE
//
//	This file is part of OpenZWave.
//
//	OpenZWave is free software: you can redistribute it and/or modify
//	it under the terms of the GNU Lesser General Public License as published
//	by the Free Software Foundation, either version 3 of the License,
//	or (at your option) any later version.
//
//	OpenZWave 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 Lesser General Public License for more details.
//
//	You should have received a copy of the GNU Lesser General Public License
//	along with OpenZWave.  If not, see <http://www.gnu.org/licenses/>.
//
//-----------------------------------------------------------------------------
#include "platform/Stream.h"
#include "platform/Mutex.h"
#include "platform/Log.h"

#include <string.h>

#include <cstdio>

namespace OpenZWave
{
	namespace Internal
	{
		namespace Platform
		{

//-----------------------------------------------------------------------------
//	<Stream::Stream>
//	Constructor
//-----------------------------------------------------------------------------
			Stream::Stream(uint32 _bufferSize) :
					m_bufferSize(_bufferSize), m_signalSize(1), m_dataSize(0), m_head(0), m_tail(0), m_mutex(new Mutex())
			{
				m_buffer = new uint8[m_bufferSize];
				memset(m_buffer, 0x00, m_bufferSize);
			}

//-----------------------------------------------------------------------------
//	<Stream::~Stream>
//	Destructor
//-----------------------------------------------------------------------------
			Stream::~Stream()
			{
				m_mutex->Release();
				delete[] m_buffer;
			}

//-----------------------------------------------------------------------------
//	<Stream::SetSignalThreshold>
//	Set the amount of data that must be in the buffer for to to be signalled
//-----------------------------------------------------------------------------
			void Stream::SetSignalThreshold(uint32 _size)
			{
				m_signalSize = _size;
				if (IsSignalled())
				{
					// We have more data than we are waiting for, so notify the watchers
					Notify();
				}
			}

//-----------------------------------------------------------------------------
//	<Stream::Get>
//	Remove data from the buffer
//-----------------------------------------------------------------------------
			bool Stream::Get(uint8* _buffer, uint32 _size)
			{
				if (m_dataSize < _size)
				{
					// There is not enough data in the buffer to fulfill the request
					Log::Write(LogLevel_Error, "ERROR: Not enough data in stream buffer");
					return false;
				}

				m_mutex->Lock();
				if ((m_tail + _size) > m_bufferSize)
				{
					// We will have to wrap around
					uint32 block1 = m_bufferSize - m_tail;
					uint32 block2 = _size - block1;

					memcpy(_buffer, &m_buffer[m_tail], block1);
					memcpy(&_buffer[block1], m_buffer, block2);
					m_tail = block2;
				}
				else
				{
					// Requested data is in a contiguous block
					memcpy(_buffer, &m_buffer[m_tail], _size);
					m_tail += _size;
				}

				LogData(_buffer, _size, "      Read (buffer->application): ");

				m_dataSize -= _size;
				m_mutex->Unlock();
				return true;
			}

//-----------------------------------------------------------------------------
//	<Stream::Put>
//	Add data to the buffer
//-----------------------------------------------------------------------------
			bool Stream::Put(uint8* _buffer, uint32 _size)
			{
				if ((m_bufferSize - m_dataSize) < _size)
				{
					// There is not enough space left in the buffer for the data
					Log::Write(LogLevel_Error, "ERROR: Not enough space in stream buffer");
					return false;
				}

				m_mutex->Lock();
				if ((m_head + _size) > m_bufferSize)
				{
					// We will have to wrap around
					uint32 block1 = m_bufferSize - m_head;
					uint32 block2 = _size - block1;

					memcpy(&m_buffer[m_head], _buffer, block1);
					memcpy(m_buffer, &_buffer[block1], block2);
					uint8 * logpos = m_buffer + m_head;
					m_head = block2;
					LogData(logpos, block1, "      Read (controller->buffer):  ");
					LogData(m_buffer, block2, "      Read (controller->buffer):  ");
				}
				else
				{
					// There is enough space before we reach the end of the buffer
					memcpy(&m_buffer[m_head], _buffer, _size);
					m_head += _size;
					LogData(m_buffer + m_head - _size, _size, "      Read (controller->buffer):  ");
				}

				m_dataSize += _size;

				if (IsSignalled())
				{
					// We now have more data than we are waiting for, so notify the watchers
					Notify();
				}

				m_mutex->Unlock();
				return true;
			}

//-----------------------------------------------------------------------------
//	<Stream::Purge>
//	Empty the data buffer
//-----------------------------------------------------------------------------
			void Stream::Purge()
			{
				m_tail = 0;
				m_head = 0;
				m_dataSize = 0;
			}

//-----------------------------------------------------------------------------
//	<Stream::IsSignalled>
//	Test whether there is enough data to be signalled
//-----------------------------------------------------------------------------
			bool Stream::IsSignalled()
			{
				return (m_dataSize >= m_signalSize);
			}

//-----------------------------------------------------------------------------
//	<Stream::LogData>
//	Format the stream buffer data for log output
//-----------------------------------------------------------------------------
			void Stream::LogData(uint8* _buffer, uint32 _length, const string &_function)
			{
				if (!_length)
					return;

				string str = "";
				for (uint32 i = 0; i < _length; ++i)
				{
					if (i)
					{
						str += ", ";
					}

					char byteStr[8];
					snprintf(byteStr, sizeof(byteStr), "0x%.2x", _buffer[i]);
					str += byteStr;
				}
				Log::Write(LogLevel_StreamDetail, "%s%s", _function.c_str(), str.c_str());
			}
		} // namespace Platform
	} // namespace Internal
} // namespace OpenZWave