--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nss/lib/util/secasn1u.c	Mon Jul 28 10:47:06 2014 +0200
@@ -0,0 +1,97 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Utility routines to complement the ASN.1 encoding and decoding functions.
+ */
+
+#include "secasn1.h"
+
+
+/*
+ * We have a length that needs to be encoded; how many bytes will the
+ * encoding take?
+ *
+ * The rules are that 0 - 0x7f takes one byte (the length itself is the
+ * entire encoding); everything else takes one plus the number of bytes
+ * in the length.
+ */
+int
+SEC_ASN1LengthLength (unsigned long len)
+{
+    int lenlen = 1;
+
+    if (len > 0x7f) {
+	do {
+	    lenlen++;
+	    len >>= 8;
+	} while (len);
+    }
+
+    return lenlen;
+}
+
+
+/*
+ * XXX Move over (and rewrite as appropriate) the rest of the
+ * stuff in dersubr.c!
+ */
+
+
+/*
+ * Find the appropriate subtemplate for the given template.
+ * This may involve calling a "chooser" function, or it may just
+ * be right there.  In either case, it is expected to *have* a
+ * subtemplate; this is asserted in debug builds (in non-debug
+ * builds, NULL will be returned).
+ *
+ * "thing" is a pointer to the structure being encoded/decoded
+ * "encoding", when true, means that we are in the process of encoding
+ *	(as opposed to in the process of decoding)
+ */
+const SEC_ASN1Template *
+SEC_ASN1GetSubtemplate (const SEC_ASN1Template *theTemplate, void *thing,
+			PRBool encoding)
+{
+    const SEC_ASN1Template *subt = NULL;
+
+    PORT_Assert (theTemplate->sub != NULL);
+    if (theTemplate->sub != NULL) {
+	if (theTemplate->kind & SEC_ASN1_DYNAMIC) {
+	    SEC_ASN1TemplateChooserPtr chooserp;
+
+	    chooserp = *(SEC_ASN1TemplateChooserPtr *) theTemplate->sub;
+	    if (chooserp) {
+		if (thing != NULL)
+		    thing = (char *)thing - theTemplate->offset;
+		subt = (* chooserp)(thing, encoding);
+	    }
+	} else {
+	    subt = (SEC_ASN1Template*)theTemplate->sub;
+	}
+    }
+    return subt;
+}
+
+PRBool SEC_ASN1IsTemplateSimple(const SEC_ASN1Template *theTemplate)
+{
+    if (!theTemplate) {
+	return PR_TRUE; /* it doesn't get any simpler than NULL */
+    }
+    /* only templates made of one primitive type or a choice of primitive
+       types are considered simple */
+    if (! (theTemplate->kind & (~SEC_ASN1_TAGNUM_MASK))) {
+	return PR_TRUE; /* primitive type */
+    }
+    if (!(theTemplate->kind & SEC_ASN1_CHOICE)) {
+	return PR_FALSE; /* no choice means not simple */
+    }
+    while (++theTemplate && theTemplate->kind) {
+	if (theTemplate->kind & (~SEC_ASN1_TAGNUM_MASK)) {
+	    return PR_FALSE; /* complex type */
+	}
+    }
+    return PR_TRUE; /* choice of primitive types */
+}
+