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/* This may look like C, but it's really -*- C++ -*- */
// $Id$
// ============================================================================
//
// = LIBRARY
// ACE
//
// = DESCRIPTION
// Template to encapsulate getting a value from an environment variable
// and using a supplied default value if not in the environment.
//
// = AUTHOR
// Chris Cleeland (derived from work by Carlos O'Ryan)
//
// ============================================================================
#ifndef ACE_ENV_VALUE_T_H
#define ACE_ENV_VALUE_T_H
#include "ace/OS.h" // Need to get ACE_static_cast definition
#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
template <class T>
class ACE_Env_Value
{
// = TITLE
// Enviroment Variable Value
//
// = DESCRIPTION
// Reads a variable from the user enviroment, providing a default
// value.
//
// = AUTHOR
// Chris Cleeland, Carlos O'Ryan
public:
ACE_Env_Value (void);
// Default constructor which isn't bound to a specific environment
// variable name or a default value. Before being useful it must
// <open()>ed.
ACE_Env_Value (const char *varname,
const T &vardefault);
// Constructor that calls <open>.
~ACE_Env_Value (void);
// Destroy the value.
operator T (void);
// Returns the value as type T.
void open (const char *varname, const T &defval);
// The constructor, read <varname> from the enviroment, using
// <vardefault> as its value if it is not defined.
const char *varname (void) const;
// Returns the name of the variable being tracked.
private:
ACE_UNIMPLEMENTED_FUNC (ACE_Env_Value(const ACE_Env_Value<T> &))
ACE_UNIMPLEMENTED_FUNC (ACE_Env_Value<T> operator=(const ACE_Env_Value<T> &))
// Disallow copying and assignment.
void fetch_value (void);
const char *varname_;
T value_;
};
template <class T> void ACE_Convert (const char *s, T &t);
// Function to convert a string <s> into type <T>.
#if defined (__ACE_INLINE__)
#include "ace/Env_Value_T.i"
#endif /* __ACE_INLINE__ */
#if defined (ACE_TEMPLATES_REQUIRE_SOURCE)
#include "ace/Env_Value_T.cpp"
#endif /* ACE_TEMPLATES_REQUIRE_SOURCE */
// Default calls a CTOR on type T of the form 'T::T(const char*)', but
// users can feel free to create their own specialized conversion
// functions if necessary, as shown below. Note that for 'char*' the
// default is used because a simple cast will be performed and no
// conversion will be necessary.
template <class T> inline void
ACE_Convert (const char *s, T &t)
{
t = T (s);
}
inline void
ACE_Convert (const char *s, char *&v)
{
v = (char *) s;
}
inline void
ACE_Convert (const char *s, short &si)
{
si = ACE_static_cast (short, ACE_OS::strtol (s, 0, 10));
}
inline void
ACE_Convert (const char *s, u_short &us)
{
us = ACE_static_cast (u_short, ACE_OS::strtol (s, 0, 10));
}
inline void
ACE_Convert (const char *s, u_int &i)
{
i = ACE_static_cast (u_int,
ACE_OS::strtol (s, 0, 10));
}
inline void
ACE_Convert (const char *s, long &l)
{
l = ACE_OS::strtol (s, 0, 10);
}
inline void
ACE_Convert (const char *s, int &i)
{
i = ACE_static_cast (int, ACE_OS::strtol (s, 0, 10));
}
inline void
ACE_Convert (const char *s, u_long &ul)
{
ul = ACE_OS::strtoul (s, 0, 10);
}
inline void
ACE_Convert (const char *s, double &d)
{
d = ACE_OS::strtod (s, 0);
}
#if defined (ACE_TEMPLATES_REQUIRE_PRAGMA)
#pragma implementation "Env_Value_T.cpp"
#endif /* ACE_TEMPLATES_REQUIRE_PRAGMA */
#endif /* ACE_ENV_VALUE_T_H */
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