haiku/headers/private/net/NetBufferUtilities.h

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/*
* Copyright 2006, 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 retrieve and remove a header from a buffer
template<typename Type, typename Module = NetBufferModuleGetter > class NetBufferHeader {
public:
NetBufferHeader(net_buffer *buffer)
:
fBuffer(buffer)
{
}
~NetBufferHeader()
{
Remove();
}
status_t
Status()
{
return fBuffer->size < sizeof(Type) ? B_BAD_VALUE : B_OK;
}
status_t
SetTo(net_buffer *buffer)
{
fBuffer = buffer;
return Status();
}
Type &
Data()
{
Type *data;
if (Module::Get()->direct_access(fBuffer, 0, sizeof(Type),
(void **)&data) == B_OK)
return *data;
Module::Get()->read(fBuffer, 0, &fDataBuffer, sizeof(Type));
return fDataBuffer;
}
void
Remove()
{
Remove(sizeof(Type));
}
void
Remove(size_t bytes)
{
if (fBuffer != NULL) {
Module::Get()->remove_header(fBuffer, bytes);
fBuffer = NULL;
}
}
void
Detach()
{
fBuffer = NULL;
}
private:
net_buffer *fBuffer;
Type fDataBuffer;
};
//! A class to add a header to a buffer
template<typename Type, typename Module = NetBufferModuleGetter > class NetBufferPrepend {
public:
NetBufferPrepend(net_buffer *buffer, size_t size = 0)
:
fBuffer(buffer),
fData(NULL)
{
if (size == 0)
size = sizeof(Type);
fStatus = Module::Get()->prepend_size(buffer, size, (void **)&fData);
}
~NetBufferPrepend()
{
if (fBuffer != NULL)
Detach();
}
status_t
Status()
{
return fStatus;
}
Type &
Data()
{
if (fData != NULL)
return *fData;
return fDataBuffer;
}
// TODO: I'm not sure it's a good idea to have Detach() routines
// in NetBufferHeader and here with such a different outcome...
void
Detach()
{
if (fData == NULL)
Module::Get()->write(fBuffer, 0, &fDataBuffer, sizeof(Type));
fBuffer = NULL;
}
private:
net_buffer *fBuffer;
status_t fStatus;
Type *fData;
Type fDataBuffer;
};
#endif // NET_BUFFER_UTILITIES_H