[groff] 03/23: [libgroff]: Use C++98 null pointer constant.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 639db8495b6ec7a7550a7cacfce4fa7a8236d2d5
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Tue Sep 21 17:25:53 2021 +1000

    [libgroff]: Use C++98 null pointer constant.
    
    * src/include/font.h (UNDEFINED_GLYPH): Use idiomatic C++98 null pointer
      constant.
    
    Update some comments.
---
 ChangeLog          |  5 +++++
 src/include/font.h | 64 ++++++++++++++++++++++++++++--------------------------
 2 files changed, 38 insertions(+), 31 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 75664be..a107e00 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2021-09-21  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       * src/include/font.h (UNDEFINED_GLYPH): Use idiomatic C++98 null
+       pointer constant.
+
 2021-09-19  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        [grohtml]: Fix compiler warning and dead store.
diff --git a/src/include/font.h b/src/include/font.h
index f5c07c9..f3f6bed 100644
--- a/src/include/font.h
+++ b/src/include/font.h
@@ -24,8 +24,8 @@ typedef void (*FONT_COMMAND_HANDLER)(const char *,    // 
command
                                     const char *,      // file
                                     int);              // lineno
 
-// A glyph is represented by a font-independent 'glyph *' pointer.
-// The functions name_to_glyph and number_to_glyph return such a pointer.
+// A glyph is represented by a font-independent 'glyph *' pointer.  The
+// functions name_to_glyph and number_to_glyph return such a pointer.
 //
 // There are two types of glyphs:
 //
@@ -38,9 +38,10 @@ typedef void (*FONT_COMMAND_HANDLER)(const char *,   // 
command
 
 // The statically allocated information about a glyph.
 //
-// This is an abstract class; only its subclass 'charinfo' is instantiated.
-// 'charinfo' exists in two versions: one in roff/troff/input.cpp for troff,
-// and one in libs/libgroff/nametoindex.cpp for the preprocessors and the
+// This is an abstract class; only its subclass 'charinfo' is
+// instantiated.  'charinfo' exists in two versions: one in
+// roff/troff/input.cpp for troff, and one in
+// libs/libgroff/nametoindex.cpp for the preprocessors and the
 // postprocessors.
 struct glyph {
   int index;                   // A font-independent integer value.
@@ -48,7 +49,7 @@ struct glyph {
   friend class character_indexer;
 };
 
-#define UNDEFINED_GLYPH ((glyph *) NULL)
+#define UNDEFINED_GLYPH ((glyph *) 0)
 
 // The next three functions exist in two versions: one in
 // roff/troff/input.cpp for troff, and one in
@@ -64,9 +65,9 @@ extern glyph *number_to_glyph(int);   // Convert the 
font-dependent glyph
                        // object.  This has the same semantics as the groff
                        // escape sequence \N'number'.  If such a 'glyph'
                        // object does not yet exist, a new one is allocated.
-extern const char *glyph_to_name(glyph *);     // Convert the given glyph
-                       // back to its name.  Return NULL if the glyph
-                       // doesn't have a name.
+extern const char *glyph_to_name(glyph *);     // Convert the given
+                       // glyph back to its name.  Return null pointer
+                       // if the glyph doesn't have a name.
 inline int glyph_to_number(glyph *);   // Convert the given glyph back to
                        // its number.  Return -1 if it does not designate
                        // a numbered character.
@@ -183,17 +184,17 @@ public:
   int get_zoom();      // Return the font's zoom factor * 1000.
   int get_code(glyph *);       // Return the code point in the physical
                        // font of the given glyph.
-  const char *get_special_device_encoding(glyph *);    // Return special
-                       // device dependent information about the given
-                       // glyph.  Return NULL if there is no special
-                       // information.
+  const char *get_special_device_encoding(glyph *);    // Return
+                       // special device-dependent information about
+                       // the given glyph.  Return null pointer if
+                       // there is no special information.
   const char *get_name();      // Return the name of this font.
   const char *get_internal_name();     // Return the 'internalname'
-                       // attribute of this font.  Return NULL if it has
-                       // none.
+                       // attribute of this font or null pointer if it
+                       // has none.
   const char *get_image_generator();   // Return the 'image_generator'
-                       // attribute of this font.  Return NULL if it has
-                       // none.
+                       // attribute of this font or null pointer if it
+                       // has none.
   static bool scan_papersize(const char *, const char **,
                             double *, double *); // Parse the
                        // 'papersize' directive in the DESC file name
@@ -211,13 +212,14 @@ public:
   static void command_line_font_dir(const char *);     // Prepend given
                        // path (arg1) to the list of directories in which
                        // to look up fonts.
-  static FILE *open_file(const char *, char **);       // Open a font file
-                       // with the given name (arg1), searching along the
-                       // current font path.  If arg2 points to a string
-                       // pointer, set it to the found file name (this
-                       // depends on the device also).  Return the opened
-                       // file.  If not found, arg2 is unchanged, and NULL
-                       // is returned.
+  static FILE *open_file(const char *, char **);       // Open
+                       // a font file with the given name (arg1),
+                       // searching along the current font path.  If
+                       // arg2 points to a string pointer, set it to
+                       // the found file name (this depends on the
+                       // device also).  Return the opened file.  If
+                       // not found, arg2 is unchanged, and a null
+                       // pointer is returned.
 
   // Open the DESC file (depending on the device) and initialize some
   // static variables with info from there.
@@ -252,12 +254,12 @@ public:
   static bool is_unicode; // DESC file has the 'unicode' directive.
   static const char *image_generator;  // The 'image_generator' attribute
                        // given in the DESC file.
-  static const char **font_name_table; // The 'fonts' attribute given in
-                       // the DESC file, as a NULL-terminated array of
-                       // strings.
-  static const char **style_table;     // The 'styles' attribute given in
-                       // the DESC file, as a NULL-terminated array of
-                       // strings.
+  static const char **font_name_table; // The 'fonts' attribute given
+                       // in the DESC file, as a null
+                       // pointer-terminated array of strings.
+  static const char **style_table;     // The 'styles' attribute given
+                       // in the DESC file, as a null
+                       // pointer-terminated array of strings.
   static const char *family;   // The 'family' attribute given in the DESC
                        // file.
   static int *sizes;   // The 'sizes' attribute given in the DESC file, as
@@ -274,7 +276,7 @@ private:
   bool special;                // See public is_special() above.
   char *name;          // The name of this font.  Used by get_name().
   char *internalname;  // The 'internalname' attribute of this font, or
-                       // NULL.  Used by get_internal_name().
+                       // a null pointer.  Used by get_internal_name().
   double slant;                // The natural slant angle (in degrees) of this 
font.
   int zoom;            // The font's magnification, multiplied by 1000.
                        // Used by scale().  A zero value means 'no zoom'.