89 lines
1.6 KiB
C++
89 lines
1.6 KiB
C++
/*
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* \brief Fiasco-specific layout of IPC message buffer
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* \author Norman Feske
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* \date 2006-06-14
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*/
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/*
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* Copyright (C) 2006-2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#ifndef _INCLUDE__BASE__IPC_MSGBUF_H_
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#define _INCLUDE__BASE__IPC_MSGBUF_H_
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#include <base/stdint.h>
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namespace Genode {
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class Ipc_marshaller;
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/**
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* IPC message buffer layout
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*/
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class Msgbuf_base
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{
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private:
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size_t const _capacity;
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protected:
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size_t _data_size = 0;
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friend class Ipc_marshaller;
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Msgbuf_base(size_t capacity) : _capacity(capacity) { }
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struct Headroom { long space[4]; } _headroom;
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char buf[];
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public:
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template <typename T>
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T &header()
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{
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static_assert(sizeof(T) <= sizeof(Headroom),
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"Header size exceeds message headroom");
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return *reinterpret_cast<T *>(buf - sizeof(T));
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}
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unsigned long &word(unsigned i)
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{
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return reinterpret_cast<unsigned long *>(buf)[i];
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}
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/**
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* Return size of message buffer
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*/
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size_t capacity() const { return _capacity; };
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/**
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* Return pointer of message data payload
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*/
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void *data() { return buf; };
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void const *data() const { return buf; };
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size_t data_size() const { return _data_size; }
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};
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/**
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* Instance of IPC message buffer with specified buffer size
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*/
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template <unsigned BUF_SIZE>
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class Msgbuf : public Msgbuf_base
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{
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public:
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char buf[BUF_SIZE];
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Msgbuf() : Msgbuf_base(BUF_SIZE) { }
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};
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}
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#endif /* _INCLUDE__BASE__IPC_MSGBUF_H_ */
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