* ace/Env_Value_T.*: Added a new template (ACE_Env_Value) which is

  a typesafe encapsulation of environment variables with the ability
  to provide a value to be used as a default if the variable isn't
  set.  An example of its use can be seen in the corresponding test,
  tests/Env_Value_Test.cpp.

* tests/Env_Value_Test.cpp: Added test for the new template added
  above.

* tests/Makefile: Added new Env_Value_Test test to the Makefile.

8 files changed, 307 insertions, 5 deletions

diff --git a/ChangeLog-98a b/ChangeLog-98a
index 00d2da38f9b..b09c68946ea 100644
--- a/ChangeLog-98a
+++ b/ChangeLog-98a
@@ -1,3 +1,20 @@
+Wed Dec 31 16:25:16 1997  Chris Cleeland  <cleeland@cs.wustl.edu>
+
+	* ace/Env_Value_T.*: Added a new template (ACE_Env_Value) which is
+ 	  a typesafe encapsulation of environment variables with the ability
+ 	  to provide a value to be used as a default if the variable isn't
+ 	  set.  An example of its use can be seen in the corresponding test,
+ 	  tests/Env_Value_Test.cpp.  Thanks to Carlos O'Ryan for giving me
+ 	  the seed that started this.
+
+	* tests/Env_Value_Test.cpp: Added test for the new template added
+ 	  above.
+
+	* tests/Makefile: Added new Env_Value_Test test to the Makefile.
+	
+	* ace/OS.{h,i} (strtod): Added new function for converting strings
+ 	  to doubles.
+
 Wed Dec 31 14:56:06 1997  Douglas C. Schmidt  <schmidt@flamenco.cs.wustl.edu>
 
 	* examples/Reactor/Dgram/: Enhanced the examples to make sure they
diff --git a/ace/Env_Value_T.cpp b/ace/Env_Value_T.cpp
new file mode 100644
index 00000000000..25a2efed4d1
--- /dev/null
+++ b/ace/Env_Value_T.cpp
@@ -0,0 +1,12 @@
+// $Id$
+
+#if ! defined (__ACE_INLINE__)
+#include "ace/Env_Value_T.i"
+#endif /* __ACE_INLINE__ */
+
+#if defined (ACE_HAS_EXPLICIT_TEMPLATE_INSTANTIATION)
+template void ACE_Convert(const char*, char*&);
+#elif defined (ACE_HAS_TEMPLATE_INSTANTIATION_PRAGMA)
+#pragma instantiate void ACE_Convert (const char*, char*&)
+#endif
+
diff --git a/ace/Env_Value_T.h b/ace/Env_Value_T.h
new file mode 100644
index 00000000000..dbce975361e
--- /dev/null
+++ b/ace/Env_Value_T.h
@@ -0,0 +1,85 @@
+// 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)
+// 
+// ============================================================================
+
+#if !defined (ACE_ENV_VALUE_T_H)
+#  define ACE_ENV_VALUE_T_H
+
+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 which calls <open()>.
+  
+  ~ACE_Env_Value (void);
+  // Destroy the value.
+
+  operator const T (void) const;
+  // 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&))
+  ACE_UNIMPLEMENTED_FUNC(ACE_Env_Value& operator= (const ACE_Env_Value&))
+  // Disallow copying and assignment.
+
+private:
+  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 */
+
+#if defined (ACE_TEMPLATES_REQUIRE_PRAGMA)
+#pragma implementation ("Env_Value_T.cpp")
+#endif /* ACE_TEMPLATES_REQUIRE_PRAGMA */
+
+#endif
diff --git a/ace/Env_Value_T.i b/ace/Env_Value_T.i
new file mode 100644
index 00000000000..0770f86c79c
--- /dev/null
+++ b/ace/Env_Value_T.i
@@ -0,0 +1,91 @@
+// $Id$
+
+template <class T> ACE_INLINE
+ACE_Env_Value<T>::operator const T (void) const
+{
+  return value_;
+}
+
+template <class T> ACE_INLINE
+ACE_Env_Value<T>::ACE_Env_Value (void)
+  : varname_ (0)
+{}
+
+template <class T> ACE_INLINE
+ACE_Env_Value<T>::ACE_Env_Value (const char* varname, const T& defval)
+  : varname_ (varname), value_(defval)
+{
+  this->fetch_value ();
+}
+
+
+template <class T> ACE_INLINE void
+ACE_Env_Value<T>::open (const char* varname, const T& defval)
+{
+  varname_ = varname;
+  value_ = defval;
+  this->fetch_value ();
+}
+
+template <class T> ACE_INLINE void
+ACE_Env_Value<T>::fetch_value ()
+{
+  const char* env = ACE_OS::getenv (varname_);
+  if (env != 0)
+    ACE_Convert (env, value_);
+}
+
+
+template <class T> ACE_INLINE
+ACE_Env_Value<T>::~ACE_Env_Value (void)
+{
+}
+
+
+// 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> ACE_INLINE void
+ACE_Convert (const char* s, T& t)
+{
+  t = T(s);
+}
+
+ACE_INLINE void
+ACE_Convert (const char* s, char*& v)
+{
+  v = (char*)s;
+}
+
+ACE_INLINE void
+ACE_Convert (const char* s, short& si)
+{
+  si = ACE_OS::strtol (s, 0, 10);
+}
+
+ACE_INLINE void
+ACE_Convert (const char* s, long& l)
+{
+  l = ACE_OS::strtol (s, 0, 10);
+}
+
+ACE_INLINE void
+ACE_Convert (const char* s, int& i)
+{
+  i = ACE_OS::strtol (s, 0, 10);
+}
+
+ACE_INLINE void
+ACE_Convert (const char* s, unsigned long& ul)
+{
+  ul = ACE_OS::strtoul (s, 0, 10);
+}
+
+ACE_INLINE void
+ACE_Convert (const char* s, double& d)
+{
+  d = ACE_OS::strtod (s, 0);
+}
diff --git a/ace/OS.h b/ace/OS.h
index ac4e4eb94ed..15a0d21df90 100644
--- a/ace/OS.h
+++ b/ace/OS.h
@@ -4533,9 +4533,11 @@ public:
   static long strtol (const char *s,
                       char **ptr,
                       int base);
-  static u_long strtoul(const char *s,
-                        char **ptr,
-                        int base);
+  static u_long strtoul (const char *s,
+                         char **ptr,
+                         int base);
+  static double strtod (const char *s,
+                        char **endptr);
 
 #if !defined (ACE_HAS_WCHAR_TYPEDEFS_CHAR)
   // = These go here since they are needed for TAO.
diff --git a/ace/OS.i b/ace/OS.i
index f0705cb9922..efd98c3afbd 100644
--- a/ace/OS.i
+++ b/ace/OS.i
@@ -1259,10 +1259,17 @@ ACE_OS::strtol (const char *s, char **ptr, int base)
 ACE_INLINE unsigned long
 ACE_OS::strtoul (const char *s, char **ptr, int base)
 {
-  // ACE_TRACE ("ACE_OS::strtol");
+  // ACE_TRACE ("ACE_OS::strtoul");
   return ::strtoul (s, ptr, base);
 }
 
+ACE_INLINE double
+ACE_OS::strtod (const char *s, char **endptr)
+{
+  // ACE_TRACE ("ACE_OS::strtod");
+  return ::strtod (s, endptr);
+}
+
 ACE_INLINE long
 ACE_OS::sysconf (int name)
 {
diff --git a/tests/Env_Value_Test.cpp b/tests/Env_Value_Test.cpp
new file mode 100644
index 00000000000..13b51ec65df
--- /dev/null
+++ b/tests/Env_Value_Test.cpp
@@ -0,0 +1,87 @@
+// $Id$
+
+// ============================================================================
+//
+// = LIBRARY
+//    tests
+//
+// = DESCRIPTION
+//      This is a simple test to make sure the Env_Value template is
+//      working correctly.
+//
+// = AUTHOR
+//    Chris Cleeland
+//
+// ============================================================================
+
+#include "test_config.h"
+#include "ace/OS.h"
+#include "ace/Process.h"
+#include "ace/Env_Value_T.h"
+
+int
+main (int argc, char *argv[], char* environ[])
+{
+  if (argc == 1)
+    {
+      // No arguments means we're the initial test
+      ACE_Process_Options options (1);
+      options.setenv (environ);
+      
+      char* const* envargv;
+
+      options.command_line ("Env_Value_Test run_as_test");
+
+      options.setenv("TEST_VALUE_POSITIVE", "%s", "10.2");
+      options.setenv("TEST_VALUE_NEGATIVE", "%s", "-10.2");
+
+      ACE_Process p;
+      ACE_ASSERT (p.spawn (options) != -1);
+      p.wait ();
+    }
+  else
+    {
+      // In this case we're the child
+      ACE_START_TEST ("Env_Value");
+
+#define TEST_THIS(type,varname,defval,expval) \
+      do { \
+        ACE_Env_Value<type> val(varname, (defval));\
+        ACE_ASSERT (val == (expval)); \
+      } while (0)
+
+          ;
+      
+      TEST_THIS (int, "TEST_VALUE_POSITIVE", 4, 10);
+      TEST_THIS (double, "TEST_VALUE_POSITIVE", -1.0, 10.2);
+      TEST_THIS (unsigned long, "TEST_VALUE_POSITIVE", 0, 10);
+      TEST_THIS (short, "TEST_VALUE_POSITIVE", 0, 10);
+
+      TEST_THIS (int, "TEST_VALUE_NEGATIVE", 4, -10);
+      TEST_THIS (double, "TEST_VALUE_NEGATIVE", -1.0, -10.2);
+      TEST_THIS (unsigned long, "TEST_VALUE_NEGATIVE", 0, -10);
+      TEST_THIS (short, "TEST_VALUE_NEGATIVE", 0, -10);
+
+      char* defstr = "Sarah Cleeland is Two!";
+      ACE_Env_Value<char*> sval("This_Shouldnt_Be_Set_Hopefully", defstr);
+      ACE_ASSERT (ACE_OS::strcmp (sval, defstr) == 0);
+
+      ACE_END_TEST;
+    }
+  
+  return 0;
+}
+
+#if defined (ACE_HAS_EXPLICIT_TEMPLATE_INSTANTIATION)
+template class ACE_Env_Value<int>;
+template class ACE_Env_Value<double>;
+template class ACE_Env_Value<unsigned long>;
+template class ACE_Env_Value<short>;
+template class ACE_Env_Value<char*>;
+#elif defined (ACE_HAS_TEMPLATE_INSTANTIATION_PRAGMA)
+#pragma instantiate  ACE_Env_Value<int>
+#pragma instantiate  ACE_Env_Value<double>
+#pragma instantiate  ACE_Env_Value<unsigned long>
+#pragma instantiate  ACE_Env_Value<short>
+#pragma instantiate  ACE_Env_Value<char*>
+#endif
diff --git a/tests/Makefile b/tests/Makefile
index 56a8b1fc9a3..3a508f65f13 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -9,7 +9,8 @@
 #	Local macros
 #----------------------------------------------------------------------------
 
-BIN =	Atomic_Op_Test \
+BIN =	Env_Value_Test \
+	Atomic_Op_Test \
 	Barrier_Test \
 	Basic_Types_Test \
 	Buffer_Stream_Test \