adding zephyr-im master branch

lib/ZMakeZcode.c

@@ -0,0 +1,80 @@
+/* This file is part of the Project Athena Zephyr Notification System.
+ * It contains source for the ZMakeZcode function.
+ *
+ *	Created by:	Jeffrey Hutzelman
+ *
+ *	$Id$
+ *
+ *	Copyright (c) 1987, 2002 by the Massachusetts Institute of Technology.
+ *	For copying and distribution information, see the file
+ *	"mit-copyright.h". 
+ */
+
+#include <internal.h>
+#include <assert.h>
+
+#ifndef lint
+static const char rcsid_ZMakeZcode_c[] = "$Id$";
+#endif
+
+Code_t
+ZMakeZcode32(char *ptr,
+	     int len,
+	     unsigned long val)
+{
+    unsigned char buf[4];
+    buf[0] = (val >> 24) & 0xff;
+    buf[1] = (val >> 16) & 0xff;
+    buf[2] = (val >>  8) & 0xff;
+    buf[3] =  val        & 0xff;
+    return ZMakeZcode(ptr, len, buf, 4);
+}
+
+Code_t
+ZMakeZcode(register char *ptr,
+	   int len,
+	   unsigned char *field,
+	   int num)
+{
+    int i;
+
+    /*
+     * This optimistic check lets us discover quickly if the buffer
+     * is not even large enough to hold the field without escapes.
+     * It also insures we'll have space for the leading 'Z' and the
+     * trailing NUL.  Note that this does _not_ remove the need for
+     * checking length as we encode.
+     */
+    if (len < num + 2)
+      return ZERR_FIELDLEN;
+    *ptr++ = 'Z';
+    --len;
+    for (i=0;i<num;i++) {
+        switch (field[i]) {
+            case 0x00:
+                if (len < 3)
+                    return ZERR_FIELDLEN;
+                *(unsigned char *)ptr++ = 0xff;
+                *(unsigned char *)ptr++ = 0xf0;
+                len -= 2;
+                continue;
+
+            case 0xff:
+                if (len < 3)
+                    return ZERR_FIELDLEN;
+                *(unsigned char *)ptr++ = 0xff;
+                *(unsigned char *)ptr++ = 0xf1;
+                len -= 2;
+                continue;
+
+            default:
+                if (len < 2)
+                    return ZERR_FIELDLEN;
+                *ptr++ = field[i];
+                len--;
+        }
+    }
+
+    *ptr = '\0';
+    return ZERR_NONE;
+}