haiku/headers/private/net/NetBufferUtilities.h

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/*
* Copyright 2006-2007, Haiku, Inc. All Rights Reserved.
* Distributed under the terms of the MIT License.
*/
#ifndef NET_BUFFER_UTILITIES_H
#define NET_BUFFER_UTILITIES_H
#include <net_buffer.h>
extern net_buffer_module_info *gBufferModule;
class NetBufferModuleGetter {
public:
static net_buffer_module_info *Get() { return gBufferModule; }
};
//! A class to access a field safely across node boundaries
template<typename Type, int Offset, typename Module = NetBufferModuleGetter>
class NetBufferFieldReader {
public:
NetBufferFieldReader(net_buffer *buffer)
:
fBuffer(buffer)
{
fStatus = Module::Get()->direct_access(fBuffer, Offset,
sizeof(Type), (void **)&fData);
if (fStatus != B_OK) {
fStatus = Module::Get()->read(fBuffer, Offset,
&fDataBuffer, sizeof(Type));
fData = &fDataBuffer;
}
}
status_t
Status() const
{
return fStatus;
}
Type &
Data() const
{
return *fData;
}
Type *
operator->() const
{
return fData;
}
Type &
operator*() const
{
return *fData;
}
void
Sync()
{
if (fBuffer == NULL || fStatus < B_OK)
return;
if (fData == &fDataBuffer)
Module::Get()->write(fBuffer, Offset, fData, sizeof(Type));
fBuffer = NULL;
}
protected:
NetBufferFieldReader() {}
net_buffer *fBuffer;
status_t fStatus;
Type *fData;
Type fDataBuffer;
};
template<typename Type, int Offset, typename Module = NetBufferModuleGetter>
class NetBufferField : public NetBufferFieldReader<Type, Offset, Module> {
public:
NetBufferField(net_buffer *buffer)
: NetBufferFieldReader<Type, Offset, Module>(buffer)
{}
~NetBufferField()
{
this->Sync();
}
};
template<typename Type, typename Module = NetBufferModuleGetter>
class NetBufferHeaderReader : public NetBufferFieldReader<Type, 0, Module> {
public:
NetBufferHeaderReader(net_buffer *buffer)
: NetBufferFieldReader<Type, 0, Module>(buffer)
{}
void
Remove()
{
this->Remove(sizeof(Type));
}
void
Remove(size_t bytes)
{
if (this->fBuffer != NULL) {
Module::Get()->remove_header(this->fBuffer, bytes);
this->fBuffer = NULL;
}
}
};
template<typename Type, typename Module = NetBufferModuleGetter>
class NetBufferHeaderRemover : public NetBufferHeaderReader<Type, Module> {
public:
NetBufferHeaderRemover(net_buffer *buffer)
: NetBufferHeaderReader<Type, Module>(buffer)
{}
~NetBufferHeaderRemover()
{
this->Remove();
}
};
//! A class to add a header to a buffer
template<typename Type, typename Module = NetBufferModuleGetter>
class NetBufferPrepend : public NetBufferFieldReader<Type, 0, Module> {
public:
NetBufferPrepend(net_buffer *buffer, size_t size = sizeof(Type))
{
this->fBuffer = buffer;
this->fStatus = Module::Get()->prepend_size(buffer, size,
(void **)&(this->fData));
if (this->fStatus == B_OK && this->fData == NULL)
this->fData = &this->fDataBuffer;
}
~NetBufferPrepend()
{
this->Sync();
}
};
#endif // NET_BUFFER_UTILITIES_H