394 lines
10 KiB
C++
394 lines
10 KiB
C++
/****************************************************************************
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Copyright (c) 2006, Radon Labs GmbH
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Copyright (c) 2011-2013,WebJet Business Division,CYOU
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http://www.genesis-3d.com.cn
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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****************************************************************************/
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#include "stdneb.h"
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#include "io/memorystream.h"
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#include "math/scalar.h"
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namespace IO
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{
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__ImplementClass(IO::MemoryStream, 'MSTR', IO::Stream);
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//------------------------------------------------------------------------------
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/**
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*/
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MemoryStream::MemoryStream() :
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capacity(0),
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size(0),
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position(0),
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buffer(0)
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{
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// empty
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}
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//------------------------------------------------------------------------------
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/**
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*/
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MemoryStream::~MemoryStream()
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{
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// close the stream if still open
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if (this->IsOpen())
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{
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this->Close();
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}
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// release memory buffer if allocated
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if (0 != this->buffer)
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{
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Memory::Free(Memory::StreamDataHeap, this->buffer);
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this->buffer = 0;
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}
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}
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//------------------------------------------------------------------------------
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/**
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*/
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bool
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MemoryStream::CanRead() const
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{
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return true;
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}
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//------------------------------------------------------------------------------
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/**
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*/
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bool
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MemoryStream::CanWrite() const
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{
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return true;
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}
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//------------------------------------------------------------------------------
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/**
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*/
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bool
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MemoryStream::CanSeek() const
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{
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return true;
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}
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//------------------------------------------------------------------------------
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/**
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*/
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bool
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MemoryStream::CanBeMapped() const
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{
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return true;
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}
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//------------------------------------------------------------------------------
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/**
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*/
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void
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MemoryStream::SetSize(Size s)
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{
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if (s > this->capacity)
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{
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this->Realloc(s);
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}
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this->size = s;
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}
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//------------------------------------------------------------------------------
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/**
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*/
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Stream::Size
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MemoryStream::GetSize() const
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{
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return this->size;
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}
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//------------------------------------------------------------------------------
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/**
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*/
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Stream::Position
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MemoryStream::GetPosition() const
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{
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return this->position;
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}
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//------------------------------------------------------------------------------
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/**
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Open the stream for reading or writing. The stream may already contain
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data if it has been opened/closed before.
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*/
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bool
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MemoryStream::Open()
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{
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n_assert(!this->IsOpen());
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// nothing to do here, allocation happens in the first Write() call
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// if necessary, all we do is reset the read/write position to the
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// beginning of the stream
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if (Stream::Open())
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{
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if (WriteAccess == this->accessMode)
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{
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this->position = 0;
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this->size = 0;
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}
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else if (AppendAccess == this->accessMode)
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{
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this->position = this->size;
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}
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else
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{
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this->position = 0;
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}
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return true;
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}
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return false;
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}
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//------------------------------------------------------------------------------
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/**
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Close the stream. The contents of the stream will remain intact until
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destruction of the object, so that the same data may be accessed
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or modified during a later session.
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*/
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void
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MemoryStream::Close()
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{
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n_assert(this->IsOpen());
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if (this->IsMapped())
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{
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this->Unmap();
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}
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Stream::Close();
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}
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//------------------------------------------------------------------------------
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/**
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*/
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void
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MemoryStream::Write(const void* ptr, Size numBytes)
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{
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n_assert(this->IsOpen());
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n_assert(!this->IsMapped());
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n_assert((WriteAccess == this->accessMode) || (AppendAccess == this->accessMode) || (ReadWriteAccess == this->accessMode))
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n_assert((this->position >= 0) && (this->position <= this->size));
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// if not enough room, allocate more memory
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if (!this->HasRoom(numBytes))
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{
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this->MakeRoom(numBytes);
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}
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// write data to stream
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n_assert((this->position + numBytes) <= this->capacity);
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Memory::Copy(ptr, this->buffer + this->position, numBytes);
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this->position += numBytes;
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if (this->position > this->size)
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{
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this->size = this->position;
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}
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}
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//------------------------------------------------------------------------------
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/**
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*/
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Stream::Size
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MemoryStream::Read(void* ptr, Size numBytes)
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{
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n_assert(this->IsOpen());
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n_assert(!this->IsMapped());
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n_assert((ReadAccess == this->accessMode) || (ReadWriteAccess == this->accessMode))
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n_assert((this->position >= 0) && (this->position <= this->size));
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// check if end-of-stream is near
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Size readBytes = numBytes <= this->size - this->position ? numBytes : this->size - this->position;
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n_assert((this->position + readBytes) <= this->size);
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if (readBytes > 0)
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{
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Memory::Copy(this->buffer + this->position, ptr, readBytes);
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this->position += readBytes;
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}
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return readBytes;
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}
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//------------------------------------------------------------------------------
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/**
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*/
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void
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MemoryStream::Seek(Offset offset, SeekOrigin origin)
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{
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n_assert(this->IsOpen());
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n_assert(!this->IsMapped());
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n_assert((this->position >= 0) && (this->position <= this->size));
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switch (origin)
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{
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case Begin:
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this->position = offset;
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break;
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case Current:
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this->position += offset;
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break;
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case End:
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this->position = this->size + offset;
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break;
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}
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// make sure read/write position doesn't become invalid
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this->position = Math::n_iclamp(this->position, 0, this->size);
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}
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//------------------------------------------------------------------------------
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/**
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*/
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bool
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MemoryStream::Eof() const
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{
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n_assert(this->IsOpen());
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n_assert(!this->IsMapped());
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n_assert((this->position >= 0) && (this->position <= this->size));
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return (this->position == this->size);
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}
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//------------------------------------------------------------------------------
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/**
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*/
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bool
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MemoryStream::HasRoom(Size numBytes) const
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{
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return ((this->position + numBytes) <= this->capacity);
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}
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//------------------------------------------------------------------------------
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/**
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This (re-)allocates the memory buffer to a new size. If the new size
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is smaller then the existing size, the buffer contents will be clipped.
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*/
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void
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MemoryStream::Realloc(Size newCapacity)
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{
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unsigned char* newBuffer = (unsigned char*) Memory::Alloc(Memory::StreamDataHeap, newCapacity);
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unsigned char* endOfNewBuffer = newBuffer + newCapacity;
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n_assert(0 != newBuffer);
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int newSize = newCapacity < this->size ? newCapacity : this->size;
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if (0 != this->buffer)
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{
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n_assert((newBuffer + newSize) < endOfNewBuffer);
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Memory::Copy(this->buffer, newBuffer, newSize);
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Memory::Free(Memory::StreamDataHeap, this->buffer);
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}
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this->buffer = newBuffer;
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this->size = newSize;
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this->capacity = newCapacity;
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if (this->position > this->size)
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{
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this->position = this->size;
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}
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}
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//------------------------------------------------------------------------------
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/**
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This method makes room for at least N more bytes. The actually allocated
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memory buffer will be greater then that. This operation involves a copy
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of existing data.
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*/
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void
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MemoryStream::MakeRoom(Size numBytes)
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{
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n_assert(numBytes > 0);
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n_assert((this->size + numBytes) > this->capacity);
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// compute new capacity
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Size oneDotFiveCurrentSize = this->capacity + (this->capacity >> 1);
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Size newCapacity = this->size + numBytes;
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if (oneDotFiveCurrentSize > newCapacity)
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{
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newCapacity = oneDotFiveCurrentSize;
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}
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if (16 > newCapacity)
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{
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newCapacity = 16;
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}
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n_assert(newCapacity > this->capacity);
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// (re-)allocate memory buffer
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this->Realloc(newCapacity);
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}
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//------------------------------------------------------------------------------
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/**
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Map the stream for direct memory access. This is much faster then
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reading/writing, but less flexible. A mapped stream cannot grow, instead
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the allowed memory range is determined by GetSize(). The read/writer must
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take special care to not read or write past the memory buffer boundaries!
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*/
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void*
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MemoryStream::Map()
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{
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n_assert(this->IsOpen());
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Stream::Map();
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n_assert(this->GetSize() > 0);
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return this->buffer;
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}
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//------------------------------------------------------------------------------
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/**
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Unmap a memory-mapped stream.
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*/
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void
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MemoryStream::Unmap()
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{
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n_assert(this->IsOpen());
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Stream::Unmap();
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}
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/// copy data to memory
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Stream::Size
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MemoryStream::Copy( void* ptr, Size numBytes )const
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{
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if ( size<numBytes )
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{
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return 0;
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}
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Memory::Copy(this->buffer, ptr, numBytes);
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return numBytes;
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}
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//------------------------------------------------------------------------------
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/**
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Get a direct pointer to the raw data. This is a convenience method
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and only works for memory streams.
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NOTE: writing new data to the stream may/will result in an invalid
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pointer, don't keep the returned pointer around between writes!
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*/
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void*
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MemoryStream::GetRawPointer() const
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{
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n_assert(0 != this->buffer);
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return this->buffer;
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}
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bool
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MemoryStream::IsHeader( void* headPtr, Size numBytes )
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{
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return (0 == memcmp(headPtr,this->buffer,numBytes));
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}
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} // namespace IO
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