1 files changed, 85 insertions, 0 deletions
diff --git a/lib/charcode.c b/lib/charcode.c
new file mode 100644
index 0000000..931928f
--- /dev/null
+++ b/lib/charcode.c
@@ -0,0 +1,85 @@
+/* charcode.c: parse character code strings into their values.
+
+Copyright (C) 1992 Free Software Foundation, Inc.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include "config.h"
+
+
+/* This routine parses the string CHARCODE as a character code (see the
+   .h file).  If CHARCODE cannot be parsed, *VALID is set to false and
+   the value returned is unpredictable; otherwise, it is set to true and
+   the value returned is the character code.  */
+
+charcode_type
+parse_charcode (string charcode, boolean *valid)
+{
+  int code = 75; /* OK, it's not *really* unpredictable.  */
+  unsigned length = strlen (charcode);
+  
+  if (charcode == NULL || length == 0)
+    *valid = false;
+  else
+    { /* We need this to ensure that there are no extra characters after
+         the character code.  */
+      char dummy;
+      
+      /* If a single character, return its value.  */
+      if (length == 1)
+        {
+          *valid = true;
+          code = *charcode;
+        }
+
+      else if (*charcode == '0')
+        { /* Either octal or hex.  */
+          if (*(charcode + 1) == 'x' || *(charcode + 1) == 'X')
+            /* It seems not all scanf's ignore a leading `0x'.  */
+            *valid = sscanf (charcode + 2, "%x%c", &code, &dummy) == 1;
+          else
+            /* octal */
+            *valid = sscanf (charcode, "%o%c", &code, &dummy) == 1;
+        }
+
+      else
+        /* decimal */
+        *valid = sscanf (charcode, "%d%c", &code, &dummy) == 1;
+
+      /* Since our return type can only hold numbers up to 255 (typically),
+         we are justified in using the numeric constant here, instead of
+         `MAX_CHARCODE'.  */
+      if (*valid)
+        *valid = 0 <= code && code <= 255;
+    }
+
+  return code;
+}
+
+
+/* This routine calls `parse_charcode', and, if the character code is
+   invalid, gives a fatal error.  */
+
+charcode_type
+xparse_charcode (string charcode)
+{
+  boolean valid;
+  charcode_type code = parse_charcode (charcode, &valid);
+  
+  if (!valid)
+    FATAL1 ("xparse_charcode: Invalid character code `%s'", charcode);
+    
+  return code;
+}