Rocco's source code cleanups and #defines for magic values in global_init(). Added die_too_small() function

git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@476 35c25a1d-7b9e-4130-9fde-d3aeb78583b8

ChangeLog

@@ -9,6 +9,8 @@ General
 	- Added message for when keypad goes awry.  Added code in main and
 	  function print_numlock_warning() to notify user, and added an
 	  apropriate section in the faq to refer to this brokenness.
+	- Added macros in nano.h for magic values that might be unclear in
+	  nano.c:global_init().
 - configure.in:
 	- Fix for _use_keypad check breaking slang support (Christian
 	  Weisgerber).
@@ -43,6 +45,12 @@ General
   usage()
 	- Alternate speller option no longer valid if DISABLE_SPELLER is
 	  active. (Rocco)
+  window_init(), handle_sigwinch()
+	- Added check for not having enough LINES to do anything useful,
+	  if so die with an error. (Rocco)
+  die_too_small()
+	- Function to print the window too small error message, avoids
+	  repeated string defs and globals.
 - fi.po:
 	- Update by Pauli Virtanen.
 

nano.c

@@ -141,6 +141,16 @@ void die(char *msg, ...)
     exit(1);			/* We have a problem: exit w/ errorlevel(1) */
 }
 
+/* Die with an error message that the screen was too small if, well, the
+   screen is too small */
+void die_too_small(void)
+{
+    char *too_small_msg = _("Window size is too small for Nano...");
+
+    die(too_small_msg);
+
+}
+
 void print_view_warning(void)
 {
     statusbar(_("Key illegal in VIEW mode"));
@@ -163,7 +173,10 @@ void global_init(void)
     center_y = LINES / 2;
     current_x = 0;
     current_y = 0;
-    editwinrows = LINES - 5 + no_help();
+
+    if ((editwinrows = LINES - 5 + no_help()) < MIN_EDITOR_ROWS)
+	die_too_small();
+
     fileage = NULL;
     cutbuffer = NULL;
     current = NULL;
@@ -171,8 +184,13 @@ void global_init(void)
     editbot = NULL;
     totlines = 0;
     placewewant = 0;
+
     if (!fill)
-	fill = COLS - 8;
+	fill = COLS - CHARS_FROM_EOL;
+
+    if (fill < MIN_FILL_LENGTH)
+	die_too_small();
+
     hblank = nmalloc(COLS + 1);
 
     /* Thanks BG for this bit... */
@@ -1555,8 +1573,12 @@ void handle_sigwinch(int s)
 
     center_x = COLS / 2;
     center_y = LINES / 2;
-    editwinrows = LINES - 5 + no_help();
+
-    fill = COLS - 8;
+    if ((editwinrows = LINES - 5 + no_help()) < MIN_EDITOR_ROWS)
+	die_too_small();
+
+    if ((fill = COLS - CHARS_FROM_EOL) < MIN_FILL_LENGTH)
+	die_too_small();
 
     free(hblank);
     hblank = nmalloc(COLS + 1);
@@ -1629,7 +1651,8 @@ void signal_init(void)
 
 void window_init(void)
 {
-    editwinrows = LINES - 5 + no_help();
+    if ((editwinrows = LINES - 5 + no_help()) < MIN_EDITOR_ROWS)
+	die_too_small();
 
     /* Setup up the main text window */
     edit = newwin(editwinrows, COLS, 2, 0);

nano.h

@@ -266,4 +266,14 @@ know what you're doing */
 #define TOP 2
 #define CENTER 1
 #define BOTTOM 0
-#endif                             
+
+/* Minimum editor window rows required for Nano to work correctly */
+#define MIN_EDITOR_ROWS 3
+
+/* Default number of characters from end-of-line where text wrapping occurs */
+#define CHARS_FROM_EOL 8
+
+/* Minimum fill length (space available for text before wrapping occurs) */
+#define MIN_FILL_LENGTH 10
+
+#endif /* ifndef NANO_H */