Added CCHARW_MAX (limit on total characters in a cell)

The total characters in a cell (base character plus combining characters),
plus a '\0' terminator,  will be less than CCHARW_MAX (currently set to
20,  which should be much more than sufficient for most purposes).  This
value is available on ncurses (and apparently not elsewhere),  but any
ncurses implementation really ought to have such a limit.

Further work will be needed here.  You can,  for example,  (still) use
waddch( ) to add an arbitrary number of combining characters;  this needs
to be revised so that waddch( ) returns ERR when needed.  Also,  if any
of the characters are in the Supplemental Multilingual Plane (SMP),  they
will actually be translated into _two_ wchar_t values using Unicode
surrogates on Microsoft Windows (and,  theoretically,  any other platform
similarly bedeviled by 16-bit wchar_t values).

Fix follows from some points made by Robin Haberkorn on the bug-ncurses
mailing list.

Author: Bill-Gray

curses.h

@@ -45,7 +45,7 @@ Defined by this header:
 #define PDC_VER_CHANGE   4
 #define PDC_VER_YEAR   2026
 #define PDC_VER_MONTH   01
-#define PDC_VER_DAY     07
+#define PDC_VER_DAY     31
 
 #define PDC_STRINGIZE( x) #x
 #define PDC_stringize( x) PDC_STRINGIZE( x)
@@ -148,6 +148,7 @@ typedef unsigned char bool;
    #define PDC_LONG_MMASK
    #ifdef PDC_WIDE
       #define USING_COMBINING_CHARACTER_SCHEME
+      #define CCHARW_MAX   20
    #endif
 #endif
 

pdcurses/util.c

@@ -274,7 +274,7 @@ static int _int32_to_wchar_array( wchar_t *obuff, const int obuffsize, const int
 int getcchar(const cchar_t *wcval, wchar_t *wch, attr_t *attrs,
              short *color_pair, void *opts)
 {
-    int32_t c[20];
+    int32_t c[CCHARW_MAX];
     int n = 0;
 
     assert( wcval);
@@ -285,7 +285,7 @@ int getcchar(const cchar_t *wcval, wchar_t *wch, attr_t *attrs,
             fullwidth character to its left.  If c[0] > 0x110001,  it's
             a marker for a combining character string. */
 #ifdef USING_COMBINING_CHARACTER_SCHEME
-    while( n < 10 && c[n] >= COMBINED_CHAR_START)
+    while( n < CCHARW_MAX - 1 && c[n] >= COMBINED_CHAR_START)
     {
         cchar_t added;
 
@@ -308,7 +308,7 @@ int getcchar(const cchar_t *wcval, wchar_t *wch, attr_t *attrs,
             c[i] = c[j];
             c[j] = swap_val;
         }
-        _int32_to_wchar_array( wch, 20, c);
+        _int32_to_wchar_array( wch, CCHARW_MAX, c);
         assert( attrs);
         assert( color_pair);
         if (!attrs || !color_pair)
@@ -325,17 +325,18 @@ int getcchar(const cchar_t *wcval, wchar_t *wch, attr_t *attrs,
 int setcchar(cchar_t *wcval, const wchar_t *wch, const attr_t attrs,
              short color_pair, const void *opts)
 {
-    int32_t ochar[20], rval;
+    int32_t ochar[CCHARW_MAX], rval;
+    const int integer_color_pair = (opts ? *(int *)opts : (int)color_pair);
 #ifdef USING_COMBINING_CHARACTER_SCHEME
     int i;
 #endif
 
-    const int integer_color_pair = (opts ? *(int *)opts : (int)color_pair);
     assert( wcval);
     assert( wch);
     if (!wcval || !wch)
         return ERR;
-    _wchar_to_int32_array( ochar, 20, wch);
+    if( _wchar_to_int32_array( ochar, CCHARW_MAX, wch) < 0)
+        return ERR;
     rval = ochar[0];
          /* If len_out > 1,  we have combining characters.  See */
          /* 'addch.c' for a discussion of how we handle those.  */