126 lines
2.6 KiB
C++
126 lines
2.6 KiB
C++
/*
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* \brief Helpers for non-ordinary RPC arguments
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* \author Norman Feske
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* \date 2011-04-06
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*/
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/*
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* Copyright (C) 2011-2013 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__RPC_ARGS_H_
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#define _INCLUDE__BASE__RPC_ARGS_H_
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#include <util/string.h>
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#include <base/stdint.h>
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namespace Genode {
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class Rpc_in_buffer_base;
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template <size_t> class Rpc_in_buffer;
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}
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/**
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* Base class of 'Rpc_in_buffer'
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*/
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class Genode::Rpc_in_buffer_base
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{
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protected:
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const char *_base;
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size_t _size;
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/**
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* Construct buffer from null-terminated string
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*/
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explicit Rpc_in_buffer_base(const char *str)
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: _base(str), _size(strlen(str) + 1) { }
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/**
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* Construct an empty buffer by default
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*/
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Rpc_in_buffer_base(): _base(0), _size(0) { }
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public:
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/**
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* Construct buffer
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*/
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Rpc_in_buffer_base(const char *base, size_t size)
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: _base(base), _size(size) { }
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const char *base() const { return _base; }
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size_t size() const { return _size; }
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};
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/**
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* Buffer with size constrain
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*/
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template <Genode::size_t MAX>
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class Genode::Rpc_in_buffer : public Rpc_in_buffer_base
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{
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private:
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/*
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* This member is only there to pump up the size of the object such
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* that 'sizeof()' returns the maximum buffer size when queried by
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* the RPC framework.
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*/
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char _balloon[MAX];
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public:
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enum { MAX_SIZE = MAX };
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/**
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* Construct buffer
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*/
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Rpc_in_buffer(const char *base, size_t size)
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: Rpc_in_buffer_base(base, min(size, (size_t)MAX_SIZE)) { }
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/**
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* Construct buffer from null-terminated string
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*/
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Rpc_in_buffer(const char *str) : Rpc_in_buffer_base(str)
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{
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if (_size >= MAX_SIZE)
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_size = MAX_SIZE;
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}
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/**
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* Default constructor creates invalid buffer
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*/
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Rpc_in_buffer() { }
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void operator = (Rpc_in_buffer<MAX_SIZE> const &from)
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{
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_base = from.base();
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_size = from.size();
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}
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/**
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* Return true if buffer contains a valid null-terminated string
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*/
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bool is_valid_string() const {
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return (_size <= MAX_SIZE) && (_size > 0) && (_base[_size - 1] == '\0'); }
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/**
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* Return buffer content as null-terminated string
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*
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* \return pointer to null-terminated string
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*
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* The method returns an empty string if the buffer does not hold
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* a valid null-terminated string. To distinguish a buffer holding
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* an invalid string from a buffer holding a valid empty string,
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* the function 'is_valid_string' can be used.
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*/
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char const *string() const { return is_valid_string() ? base() : ""; }
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};
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#endif /* _INCLUDE__BASE__RPC_ARGS_H_ */
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