Make Fl_String and Fl_Int_Vector private (#789)

- add CMake option 'OPTION_USE_STD'
- add configure option '--enable-use_std'
- move FL/Fl_String.H to src/Fl_String.H
- move FL/Fl_Int_Vector.H to src/Fl_Int_Vector.H
- remove Fl_String from demo program examples/callbacks.cxx
- remove Fl_Int_Vector from public header FL/Fl_Table.H
- some methods of Fl_Table are no longer inline
- add CMake option OPTION_USE_STD to allow std::string in some
  selected functions and methods

Experimental, may be removed before release:

- use either Fl_Int_Vector or std::vector in Fl_Table depending
  on CMake OPTION_USE_STD or configure --enable-use_std

Move all fl_filename* functions that use Fl_String to fluid

Main changes in fluid:
 - add fluid_filename.h and .cxx
 - include "fluid_filename.h" rather than <FL/filename.H>

Update fl_input(), fl_password() and test/ask

- add maxchar parameter to fl_input() and fl_password()
- fl_input_str() and fl_password_str() are optional and return
  std::string if enabled (FLTK_USE_STD)

1 files changed, 50 insertions, 40 deletions

diff --git a/src/Fl_Preferences.cxx b/src/Fl_Preferences.cxx
index 6a6150fad..f4a769d69 100644
--- a/src/Fl_Preferences.cxx
+++ b/src/Fl_Preferences.cxx
@@ -1,8 +1,8 @@
 //
 // Preferences methods for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2011-2022 by Bill Spitzak and others.
 // Copyright 2002-2010 by Matthias Melcher.
+// Copyright 2011-2023 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -28,6 +28,9 @@
 #include <stdlib.h>
 #include <stdarg.h>
 
+#if (FLTK_USE_STD)
+#include <string>
+#endif
 
 char Fl_Preferences::nameBuffer[128];
 char Fl_Preferences::uuidBuffer[40];
@@ -844,46 +847,36 @@ char Fl_Preferences::get( const char *key, char *&text, const char *defaultValue
   return ( v != defaultValue );
 }
 
-// /**
-// Reads an entry from the group. A default value must be
-// supplied. The return value indicates if the value was available
-// (non-zero) or the default was used (0).
-//
-// \param[in] key name of entry
-// \param[out] value returned from preferences or default value if none was set
-// \param[in] defaultValue default value to be used if no preference was set
-// \return 0 if the default value was used
-// */
-//char Fl_Preferences::get( const char *key, Fl_String &value, const Fl_String &defaultValue ) {
-//  const char *v = node->get( key );
-//  if (v) {
-//    if ( strchr( v, '\\' ) ) {
-//      char *text = decodeText( v );
-//      value = text;
-//      ::free(text);
-//    } else {
-//      value = v;
-//    }
-//    return 1;
-//  } else {
-//    value = defaultValue;
-//    return 0;
-//  }
-//}
-
-// /**
-// Sets an entry (name/value pair). The return value indicates if there
-// was a problem storing the data in memory. However it does not
-// reflect if the value was actually stored in the preference file.
-//
-// \param[in] entry name of entry
-// \param[in] value set this entry to value (stops at the first nul character).
-// \return 0 if setting the value failed
-// */
-//char Fl_Preferences::set( const char *entry, const Fl_String &value ) {
-//  return set(entry, value.c_str());
-//}
+#if (FLTK_USE_STD)
 
+/**
+ Reads an entry from the group. A default value must be
+ supplied. The return value indicates if the value was available
+ (non-zero) or the default was used (0).
+
+ \param[in] key name of entry
+ \param[out] value returned from preferences or default value if none was set
+ \param[in] defaultValue default value to be used if no preference was set
+ \return 0 if the default value was used
+ */
+char Fl_Preferences::get( const char *key, std::string &value, const std::string &defaultValue ) {
+  const char *v = node->get( key );
+  if (v) {
+    if ( strchr( v, '\\' ) ) {
+      char *text = decodeText( v );
+      value = text;
+      ::free(text);
+    } else {
+      value = v;
+    }
+    return 1;
+  } else {
+    value = defaultValue;
+    return 0;
+  }
+}
+
+#endif
 
 /**
  Sets an entry (name/value pair). The return value indicates if there
@@ -1055,6 +1048,23 @@ char Fl_Preferences::set( const char *key, const void *data, int dsize ) {
   return 1;
 }
 
+#if (FLTK_USE_STD)
+
+/**
+ Sets an entry (name/value pair). The return value indicates if there
+ was a problem storing the data in memory. However it does not
+ reflect if the value was actually stored in the preference file.
+
+ \param[in] entry name of entry
+ \param[in] value set this entry to value (stops at the first nul character).
+ \return 0 if setting the value failed
+ */
+char Fl_Preferences::set( const char *entry, const std::string &value ) {
+  return set(entry, value.c_str());
+}
+
+#endif // FLTK_USE_STD
+
 /**
  Returns the size of the value part of an entry.