/**

  * vim: set ts=4 :

  * =============================================================================

  * SourceMod

  * Copyright (C) 2004-2008 AlliedModders LLC.  All rights reserved.

  * =============================================================================

  *

  * This program is free software; you can redistribute it and/or modify it under

  * the terms of the GNU General Public License, version 3.0, as published by the

  * Free Software Foundation.

  * 

  * This program 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

  * this program.  If not, see <http://www.gnu.org/licenses/>.

  *

  * As a special exception, AlliedModders LLC gives you permission to link the

  * code of this program (as well as its derivative works) to "Half-Life 2," the

  * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software

  * by the Valve Corporation.  You must obey the GNU General Public License in

  * all respects for all other code used.  Additionally, AlliedModders LLC grants

  * this exception to all derivative works.  AlliedModders LLC defines further

  * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),

  * or <http://www.sourcemod.net/license.php>.

  *

  * Version: $Id$

  */

 #include <stdlib.h>

 #include <string.h>

 #include "CDataPack.h"

 #define DATAPACK_INITIAL_SIZE		512

 CDataPack::CDataPack()

 {

 	m_pBase = (char *)malloc(DATAPACK_INITIAL_SIZE);

 	m_capacity = DATAPACK_INITIAL_SIZE;

 	Initialize();

 }

 CDataPack::~CDataPack()

 {

 	free(m_pBase);

 }

 void CDataPack::Initialize()

 {

 	m_curptr = m_pBase;

 	m_size = 0;

 }

 void CDataPack::CheckSize(size_t typesize)

 {

 	if (m_curptr - m_pBase + typesize <= m_capacity)

 	{

 		return;

 	}

 	size_t pos = m_curptr - m_pBase;

 	do

 	{

 		m_capacity *= 2;

 		m_pBase = (char *)realloc(m_pBase, m_capacity);

 		m_curptr = m_pBase + pos;

 	} while (m_curptr - m_pBase + typesize > m_capacity);

 }

 void CDataPack::ResetSize()

 {

 	m_size = 0;

 }

 size_t CDataPack::CreateMemory(size_t size, void **addr)

 {

 	CheckSize(sizeof(size_t) + size);

 	size_t pos = m_curptr - m_pBase;

 	*(size_t *)m_curptr = size;

 	m_curptr += sizeof(size_t);

 	if (addr)

 	{

 		*addr = m_curptr;

 	}

 	m_curptr += size;

 	m_size += sizeof(size_t) + size;

 	return pos;

 }

 void CDataPack::PackCell(cell_t cell)

 {

 	CheckSize(sizeof(size_t) + sizeof(cell_t));

 	*(size_t *)m_curptr = sizeof(cell_t);

 	m_curptr += sizeof(size_t);

 	*(cell_t *)m_curptr = cell;

 	m_curptr += sizeof(cell_t);

 	m_size += sizeof(size_t) + sizeof(cell_t);

 }

 void CDataPack::PackFloat(float val)

 {

 	CheckSize(sizeof(size_t) + sizeof(float));

 	*(size_t *)m_curptr = sizeof(float);

 	m_curptr += sizeof(size_t);

 	*(float *)m_curptr = val;

 	m_curptr += sizeof(float);

 	m_size += sizeof(size_t) + sizeof(float);

 }

 void CDataPack::PackString(const char *string)

 {

 	size_t len = strlen(string);

 	size_t maxsize = sizeof(size_t) + len + 1;

 	CheckSize(maxsize);

 	// Pack the string length first for buffer overrun checking.

 	*(size_t *)m_curptr = len;

 	m_curptr += sizeof(size_t);

 	// Now pack the string.

 	memcpy(m_curptr, string, len);

 	m_curptr[len] = '\0';

 	m_curptr += len + 1;

 	m_size += maxsize;

 }

 void CDataPack::Reset() const

 {

 	m_curptr = m_pBase;

 }

 size_t CDataPack::GetPosition() const

 {

 	return static_cast<size_t>(m_curptr - m_pBase);

 }

 bool CDataPack::SetPosition(size_t pos) const

 {

 	if (pos > m_size-1)

 	{

 		return false;

 	}

 	m_curptr = m_pBase + pos;

 	return true;

 }

 cell_t CDataPack::ReadCell() const

 {

 	if (!IsReadable(sizeof(size_t) + sizeof(cell_t)))

 	{

 		return 0;

 	}

 	if (*reinterpret_cast<size_t *>(m_curptr) != sizeof(cell_t))

 	{

 		return 0;

 	}

 	m_curptr += sizeof(size_t);

 	cell_t val = *reinterpret_cast<cell_t *>(m_curptr);

 	m_curptr += sizeof(cell_t);

 	return val;

 }

 float CDataPack::ReadFloat() const

 {

 	if (!IsReadable(sizeof(size_t) + sizeof(float)))

 	{

 		return 0;

 	}

 	if (*reinterpret_cast<size_t *>(m_curptr) != sizeof(float))

 	{

 		return 0;

 	}

 	m_curptr += sizeof(size_t);

 	float val = *reinterpret_cast<float *>(m_curptr);

 	m_curptr += sizeof(float);

 	return val;

 }

 bool CDataPack::IsReadable(size_t bytes) const

 {

 	return (bytes + (m_curptr - m_pBase) > m_size) ? false : true;

 }

 const char *CDataPack::ReadString(size_t *len) const

 {

 	if (!IsReadable(sizeof(size_t)))

 	{

 		return NULL;

 	}

 	size_t real_len = *(size_t *)m_curptr;

 	m_curptr += sizeof(size_t);

 	char *str = (char *)m_curptr;

 	if ((strlen(str) != real_len) || !(IsReadable(real_len+1)))

 	{

 		return NULL;

 	}

 	if (len)

 	{

 		*len = real_len;

 	}

 	m_curptr += real_len + 1;

 	return str;

 }

 void *CDataPack::GetMemory() const

 {

 	return m_curptr;

 }

 void *CDataPack::ReadMemory(size_t *size) const

 {

 	if (!IsReadable(sizeof(size_t)))

 	{

 		return NULL;

 	}

 	size_t bytecount = *(size_t *)m_curptr;

 	m_curptr += sizeof(size_t);

 	if (!IsReadable(bytecount))

 	{

 		return NULL;

 	}

 	void *ptr = m_curptr;

 	if (size)

 	{

 		*size = bytecount;

 	}

 	m_curptr += bytecount;

 	return ptr;

 }