binary_i_memory_block.cpp

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/** @file
 *  @author Bram de Greve (bramz@users.sourceforge.net)
 *  @author Tom De Muer (tomdemuer@users.sourceforge.net)
 *
 *  *** BEGIN LICENSE INFORMATION ***
 *  
 *  The contents of this file are subject to the Common Public Attribution License 
 *  Version 1.0 (the "License"); you may not use this file except in compliance with 
 *  the License. You may obtain a copy of the License at 
 *  http://lass.sourceforge.net/cpal-license. The License is based on the 
 *  Mozilla Public License Version 1.1 but Sections 14 and 15 have been added to cover 
 *  use of software over a computer network and provide for limited attribution for 
 *  the Original Developer. In addition, Exhibit A has been modified to be consistent 
 *  with Exhibit B.
 *  
 *  Software distributed under the License is distributed on an "AS IS" basis, WITHOUT 
 *  WARRANTY OF ANY KIND, either express or implied. See the License for the specific 
 *  language governing rights and limitations under the License.
 *  
 *  The Original Code is LASS - Library of Assembled Shared Sources.
 *  
 *  The Initial Developer of the Original Code is Bram de Greve and Tom De Muer.
 *  The Original Developer is the Initial Developer.
 *  
 *  All portions of the code written by the Initial Developer are:
 *  Copyright (C) 2004-2007 the Initial Developer.
 *  All Rights Reserved.
 *  
 *  Contributor(s):
 *
 *  Alternatively, the contents of this file may be used under the terms of the 
 *  GNU General Public License Version 2 or later (the GPL), in which case the 
 *  provisions of GPL are applicable instead of those above.  If you wish to allow use
 *  of your version of this file only under the terms of the GPL and not to allow 
 *  others to use your version of this file under the CPAL, indicate your decision by 
 *  deleting the provisions above and replace them with the notice and other 
 *  provisions required by the GPL License. If you do not delete the provisions above,
 *  a recipient may use your version of this file under either the CPAL or the GPL.
 *  
 *  *** END LICENSE INFORMATION ***
 */

#include "io_common.h"
#include "binary_i_memory_block.h"

namespace lass
{

namespace io
{

/** Construct an "empty" closed stream..
 */
BinaryIMemoryBlock::BinaryIMemoryBlock():
    BinaryIStream(),
    begin_(0),
    size_(0),
    position_(0)
{
}



/** Construct stream by pointer to memory block and length of block
 */
BinaryIMemoryBlock::BinaryIMemoryBlock( const void* iBegin, long iSize ):
    BinaryIStream(),
    begin_(static_cast<const TByte*>(iBegin)),
    size_(iSize),
    position_(0)
{
    LASS_ASSERT(size_ >= 0);
}



/** Construct stream by pointer to memory block and to one byte past end of block.
 */
BinaryIMemoryBlock::BinaryIMemoryBlock( const void* iBegin, const void* iEnd ):
    BinaryIStream(),
    begin_(static_cast<const TByte*>(iBegin)),
    size_(static_cast<long>(static_cast<const TByte*>(iEnd) - static_cast<const TByte*>(iBegin))),
    position_(0)
{
    LASS_ASSERT(size_ >= 0);
}



// --- private -------------------------------------------------------------------------------------

void BinaryIMemoryBlock::doRead(void* oOutput, size_t iNumberOfBytes)
{
    if (!begin_)
    {
        setstate(std::ios_base::failbit);
        return;
    }
    if (!good())
    {
        return;
    }

    LASS_ASSERT(static_cast<long>(iNumberOfBytes) >= 0);
    const long next = position_ + static_cast<long>(iNumberOfBytes);
    if (next > size_ || next < position_)
    {
        setstate(std::ios_base::eofbit | std::ios_base::failbit);
    }
    else
    {
        memcpy(oOutput, &begin_[position_], iNumberOfBytes);
        position_ = next;
    }
}



long BinaryIMemoryBlock::doTellg() const
{
    return position_;
}



void BinaryIMemoryBlock::doSeekg(long iOffset, std::ios_base::seekdir iDirection)
{
    switch (iDirection)
    {
    case std::ios_base::beg: 
        position_ = iOffset;
        break;
    case std::ios_base::cur:
        position_ += iOffset;
        break;
    case std::ios_base::end:
        position_ = size_ + iOffset;
        break;
    default:
        LASS_ASSERT(false);
    };
}

}

}