gecko-dev/xpcom/ds/nsByteBuffer.cpp

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3.4 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
#include "nsIByteBuffer.h"
#include "nsIInputStream.h"
#include "nsCRT.h"
#define MIN_BUFFER_SIZE 32
class ByteBufferImpl : public nsIByteBuffer {
public:
ByteBufferImpl(PRInt32 aBufferSize);
~ByteBufferImpl();
NS_DECL_ISUPPORTS
virtual PRInt32 GetLength() const;
virtual PRInt32 GetBufferSize() const;
virtual char* GetBuffer() const;
virtual PRBool Grow(PRInt32 aNewSize);
virtual PRInt32 Fill(PRInt32* aErrorCode, nsIInputStream* aStream,
PRInt32 aKeep);
char* mBuffer;
PRInt32 mSpace;
PRInt32 mLength;
};
ByteBufferImpl::ByteBufferImpl(PRInt32 aBufferSize)
{
if (PRUint32(aBufferSize) < MIN_BUFFER_SIZE) {
aBufferSize = MIN_BUFFER_SIZE;
}
mSpace = aBufferSize;
mBuffer = new char[aBufferSize];
mLength = 0;
NS_INIT_REFCNT();
}
NS_DEFINE_IID(kByteBufferIID,NS_IBYTE_BUFFER_IID);
NS_IMPL_ISUPPORTS(ByteBufferImpl,kByteBufferIID)
ByteBufferImpl::~ByteBufferImpl()
{
if (nsnull != mBuffer) {
delete mBuffer;
mBuffer = nsnull;
}
mLength = 0;
}
PRInt32 ByteBufferImpl::GetLength() const
{
return mLength;
}
PRInt32 ByteBufferImpl::GetBufferSize() const
{
return mSpace;
}
char* ByteBufferImpl::GetBuffer() const
{
return mBuffer;
}
PRBool ByteBufferImpl::Grow(PRInt32 aNewSize)
{
if (PRUint32(aNewSize) < MIN_BUFFER_SIZE) {
aNewSize = MIN_BUFFER_SIZE;
}
char* newbuf = new char[aNewSize];
if (nsnull != newbuf) {
if (0 != mLength) {
nsCRT::memcpy(newbuf, mBuffer, mLength);
}
delete mBuffer;
mBuffer = newbuf;
return PR_TRUE;
}
return PR_FALSE;
}
PRInt32 ByteBufferImpl::Fill(PRInt32* aErrorCode, nsIInputStream* aStream,
PRInt32 aKeep)
{
NS_PRECONDITION(nsnull != aStream, "null stream");
NS_PRECONDITION(PRUint32(aKeep) <= PRUint32(mLength), "illegal keep count");
if ((nsnull == aStream) || (PRUint32(aKeep) > PRUint32(mLength))) {
// whoops
*aErrorCode = NS_INPUTSTREAM_ILLEGAL_ARGS;
return -1;
}
if (0 != aKeep) {
// Slide over kept data
nsCRT::memmove(mBuffer, mBuffer + (mLength - aKeep), aKeep);
}
// Read in some new data
mLength = aKeep;
PRInt32 amount = mSpace - aKeep;
PRInt32 nb = aStream->Read(aErrorCode, mBuffer, aKeep, amount);
if (nb > 0) {
mLength += nb;
}
return nb;
}
NS_BASE nsresult NS_NewByteBuffer(nsIByteBuffer** aInstancePtrResult,
nsISupports* aOuter,
PRInt32 aBufferSize)
{
if (nsnull != aOuter) {
return NS_ERROR_NO_AGGREGATION;
}
ByteBufferImpl* it = new ByteBufferImpl(aBufferSize);
if (nsnull == it) {
return NS_ERROR_OUT_OF_MEMORY;
}
return it->QueryInterface(kByteBufferIID, (void **) aInstancePtrResult);
}