Added ntassert() mechanism for Windows based port use.

include/ntconf.h

@@ -246,4 +246,14 @@ extern int FDECL(set_win32_option, (const char *, const char *));
 extern int FDECL(alternative_palette, (char *));
 #endif
 
+#ifdef NDEBUG
+#define ntassert(expression) ((void)0)
+#else
+extern void FDECL(ntassert_failed, (const char * exp, const char * file,
+                                    int line));
+
+#define ntassert(expression) (void)((!!(expression)) || \
+        (ntassert_failed(#expression, __FILE__, __LINE__), 0))
+#endif
+
 #endif /* NTCONF_H */

sys/winnt/nttty.c

@@ -322,6 +322,10 @@ static void check_buffer_size(int width, int height)
 
 static cell_t * buffer_get_cell(console_buffer_t * buffer, int x, int y)
 {
+    ntassert(x >= 0 && x < buffer_width);
+    ntassert(y >= 0 && ((y < buffer_height) ||
+                        (y == buffer_height && x == 0)));
+
     return buffer->cells + (buffer_width * y) + x;
 }
 
@@ -363,6 +367,9 @@ static void back_buffer_flip()
 static void buffer_fill_to_end(console_buffer_t * buffer, cell_t * src,
                                 int x, int y)
 {
+    ntassert(x >= 0 && x < buffer_width);
+    ntassert(y >= 0 && y < buffer_height);
+
     cell_t * dst = buffer_get_cell(buffer, x, y);
     cell_t * sentinel = buffer_get_cell(buffer, 0, buffer_height);
     while (dst != sentinel)
@@ -374,6 +381,9 @@ static void buffer_fill_to_end(console_buffer_t * buffer, cell_t * src,
 
 static void back_buffer_write(cell_t * cell, int x, int y)
 {
+    ntassert(x >= 0 && x < buffer_width);
+    ntassert(y >= 0 && y < buffer_height);
+
     cell_t * dst = buffer_get_cell(&back_buffer, x, y);
     *dst = *cell;
 
@@ -383,6 +393,9 @@ static void back_buffer_write(cell_t * cell, int x, int y)
 
 static void back_buffer_clear_to_end_of_line(int x, int y)
 {
+    ntassert(x >= 0 && x < buffer_width);
+    ntassert(y >= 0 && y < buffer_height);
+
     cell_t * cell;
     cell_t *sentinel;
 
@@ -834,6 +847,9 @@ int in_ch;
 void
 cl_end()
 {
+    ntassert(ttyDisplay->curx >= 0 && ttyDisplay->curx < buffer_width);
+    ntassert(ttyDisplay->cury >= 0 && ttyDisplay->cury < buffer_height);
+
     console.cursor.X = ttyDisplay->curx;
     console.cursor.Y = ttyDisplay->cury;
 

sys/winnt/winnt.c

@@ -461,6 +461,21 @@ char *buf;
 }
 #endif /* RUNTIME_PORT_ID */
 
+/* ntassert_failed is called when an ntassert's condition is false */
+void ntassert_failed(const char * exp, const char * file, int line)
+{
+    char message[128];
+    _snprintf(message, sizeof(message),
+                "NHASSERT(%s) in '%s' at line %d\n", exp, file, line);
+
+    if (IsDebuggerPresent()) {
+        OutputDebugStringA(message);
+        DebugBreak();
+    }
+
+    error(message);
+}
+
 #endif /* WIN32 */
 
 /*winnt.c*/