From e22d03eb45fdc504bca3d6227725d45a3ff7d192 Mon Sep 17 00:00:00 2001
From: Brian Wellington <source@isc.org>
Date: Fri, 20 Aug 1999 17:01:06 +0000
Subject: [PATCH] Added dns_name_downcase

---
 lib/dns/include/dns/name.h | 10 ++++++++
 lib/dns/name.c             | 47 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+)

diff --git a/lib/dns/include/dns/name.h b/lib/dns/include/dns/name.h
index d9d9f1f1f5..df9d43a541 100644
--- a/lib/dns/include/dns/name.h
+++ b/lib/dns/include/dns/name.h
@@ -789,6 +789,16 @@ dns_result_t dns_name_totext(dns_name_t *name,
  *	DNS_R_NOSPACE
  */
 
+void
+dns_name_downcase(dns_name_t *name);
+/*
+ * Convert all uppercase letters in name to lowercase.
+ *
+ * Requires:
+ *
+ *	'name' is a valid name that is not read-only.
+ */
+
 dns_result_t dns_name_concatenate(dns_name_t *prefix, dns_name_t *suffix,
 				  dns_name_t *name, isc_buffer_t *target);
 /*
diff --git a/lib/dns/name.c b/lib/dns/name.c
index 2dbcb1b200..4079080002 100644
--- a/lib/dns/name.c
+++ b/lib/dns/name.c
@@ -1724,6 +1724,53 @@ dns_name_totext(dns_name_t *name, isc_boolean_t omit_final_dot,
 	return (DNS_R_SUCCESS);
 }
 
+void
+dns_name_downcase(dns_name_t *name) {
+	unsigned char *ndata;
+	unsigned int nlen, count, bytes, labels;
+ 
+	REQUIRE(VALID_NAME(name));
+	REQUIRE((name->attributes & DNS_NAMEATTR_READONLY) == 0);
+
+	ndata = name->ndata;
+	nlen = name->length;
+	labels = name->labels;
+
+	while (labels > 0 && nlen > 0) {
+		labels--;
+		count = *ndata++;
+		nlen--;
+		if (count < 64) {
+			INSIST(nlen >= count);
+			while (count > 0) {
+				*ndata = maptolower[(*ndata)];
+				ndata++;
+				nlen--;
+				count--;
+			}
+		} else if (count == DNS_LABELTYPE_BITSTRING) {
+			INSIST(nlen > 0);
+			count = *ndata++;
+			if (count == 0)
+				count = 256;
+			nlen--;
+
+			bytes = count / 8;
+			if (count % 8 != 0)
+				bytes++;
+			INSIST(nlen >= bytes);
+
+			/* Skip this label */
+			nlen -= bytes;
+			ndata += bytes;
+		} else {
+			FATAL_ERROR(__FILE__, __LINE__,
+				    "Unexpected label type %02x", count);
+			/* Does not return. */
+		}
+	}
+}
+
 static void
 set_offsets(dns_name_t *name, unsigned char *offsets, isc_boolean_t set_labels,
 	    isc_boolean_t set_length, isc_boolean_t set_absolute)