add hackish _snprintf() and _vsnprintf()

Clean-ups are welcome. :)

kernel/dyninit.c

@@ -65,7 +65,7 @@ far_t DynAlloc(const char *what, unsigned num, unsigned size)
   if ((ULONG) total + Dynp->Allocated > 0xffff)
   {
     char buf[256];
-    snprintf(buf, sizeof(buf), "Dyn %u\n", (ULONG) total + Dynp->Allocated);
+    _snprintf(buf, sizeof(buf), "Dyn %u\n", (ULONG) total + Dynp->Allocated);
     panic(buf);
   }
 

kernel/main.c

@@ -653,7 +653,7 @@ STATIC void InitIO(void)
 VOID init_fatal(const BYTE * err_msg)
 {
   char buf[256];
-  snprintf(buf, sizeof(buf), "\nInternal kernel error - %s\nSystem halted\n", err_msg);
+  _snprintf(buf, sizeof(buf), "\nInternal kernel error - %s\nSystem halted\n", err_msg);
   panic(buf);
 }
 

kernel/prf.c

@@ -144,7 +144,8 @@ static BYTE SSFAR *charp = 0;
 
 STATIC VOID handle_char(COUNT);
 STATIC void ltob(LONG, BYTE SSFAR *, COUNT);
-STATIC void do_printf(const char *, REG va_list);
+STATIC void do_printf(CONST BYTE *, va_list);
+STATIC void do_printf_n(size_t size, CONST BYTE * fmt, va_list arg);
 
 /* special handler to switch between sprintf and printf */
 STATIC VOID handle_char(COUNT c)
@@ -251,19 +252,40 @@ int _vsprintf(char * buff, CONST char * fmt, va_list arg)
   return 0;
 }
 
-STATIC void do_printf(CONST BYTE * fmt, va_list arg)
+PRINTF(3)
+int VA_CDECL _snprintf(char * buff, size_t size, CONST char * fmt, ...)
 {
-  int base;
-  BYTE s[11], * p;
-  int size;
-  unsigned char flags;
+  va_list arg;
+
+  va_start(arg, fmt);
+  charp = buff;
+  do_printf_n(size, fmt, arg);
+  va_end(arg);
+  handle_char('\0');
+  return 0;
+}
+
+int _vsnprintf(char * buff, size_t size, CONST char * fmt, va_list arg)
+{
+  charp = buff;
+  do_printf_n(size, fmt, arg);
+  handle_char('\0');
+  return 0;
+}
+
+enum { RET_CONT, RET_RET };
+STATIC int printf_handle_char(CONST BYTE ** _fmt, va_list arg)
+{
+#define fmt (*_fmt)
+    int base;
+    BYTE s[11], * p;
+    int size;
+    unsigned char flags;
 
-  for (;*fmt != '\0'; fmt++)
-  {
     if (*fmt != '%')
     {
       handle_char(*fmt);
-      continue;
+      return RET_CONT;
     }
 
     fmt++;
@@ -300,11 +322,11 @@ STATIC void do_printf(CONST BYTE * fmt, va_list arg)
     switch (*fmt)
     {
       case '\0':
-        return;
+        return RET_RET;
 
       case 'c':
         handle_char(va_arg(arg, int));
-        continue;
+        return RET_CONT;
 
       case 'P':
         {
@@ -369,7 +391,7 @@ STATIC void do_printf(CONST BYTE * fmt, va_list arg)
       case '%':
 
         handle_char(*fmt);
-        continue;
+        return RET_CONT;
 
     }
     {
@@ -390,6 +412,34 @@ STATIC void do_printf(CONST BYTE * fmt, va_list arg)
 
     for (; size > 0; size--)
       handle_char(' ');
+
+    return RET_CONT;
+#undef fmt
+}
+
+STATIC void do_printf(CONST BYTE * fmt, va_list arg)
+{
+  for (;*fmt != '\0'; fmt++)
+  {
+    switch (printf_handle_char(&fmt, arg)) {
+    case RET_CONT:
+      continue;
+    case RET_RET:
+      return;
+    }
+  }
+}
+
+STATIC void do_printf_n(size_t size, CONST BYTE * fmt, va_list arg)
+{
+  for (;*fmt != '\0' && size > 0; fmt++, size--)
+  {
+    switch (printf_handle_char(&fmt, arg)) {
+    case RET_CONT:
+      continue;
+    case RET_RET:
+      return;
+    }
   }
 }
 

kernel/proto.h

@@ -282,8 +282,10 @@ UWORD ASMCFUNC SEGM(HMA_TEXT) syscall_MUX14(__FAR(iregs) regs);
 #ifdef DEBUG
 int VA_CDECL _printf(CONST char * fmt, ...) PRINTF(1);
 int VA_CDECL _sprintf(char * buff, CONST char * fmt, ...) PRINTF(2);
+int VA_CDECL _snprintf(char * buff, size_t size, CONST char * fmt, ...) PRINTF(3);
 int _vprintf(CONST char *fmt, va_list arg);
 int _vsprintf(char * buff, CONST char * fmt, va_list arg);
+int _vsnprintf(char * buff, size_t size, CONST char * fmt, va_list arg);
 #endif
 VOID hexd(const char *title,__FAR(VOID) p, COUNT numBytes);
 void put_unsigned(unsigned n, int base, int width);