1 files changed, 64 insertions, 0 deletions
diff --git a/src/libdnssec/shared/bignum.c b/src/libdnssec/shared/bignum.c
new file mode 100644
index 0000000..3b347a6
--- /dev/null
+++ b/src/libdnssec/shared/bignum.c
@@ -0,0 +1,64 @@
+/*  Copyright (C) 2018 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <assert.h>
+#include <string.h>
+
+#include "libdnssec/shared/bignum.h"
+
+static void skip_leading_zeroes(dnssec_binary_t *value)
+{
+	while (value->size > 0 && value->data[0] == 0) {
+		value->data += 1;
+		value->size -= 1;
+	}
+}
+
+size_t bignum_size_u(const dnssec_binary_t *_value)
+{
+	dnssec_binary_t value = *_value;
+	skip_leading_zeroes(&value);
+
+	if (value.size == 0) {
+		return value.size + 1;
+	} else {
+		return value.size;
+	}
+}
+
+size_t bignum_size_s(const dnssec_binary_t *_value)
+{
+	dnssec_binary_t value = *_value;
+	skip_leading_zeroes(&value);
+
+	if (value.size == 0 || value.data[0] & 0x80) {
+		return value.size + 1;
+	} else {
+		return value.size;
+	}
+}
+
+void bignum_write(wire_ctx_t *ctx, size_t width, const dnssec_binary_t *_value)
+{
+	dnssec_binary_t value = *_value;
+	skip_leading_zeroes(&value);
+
+	size_t padding_len = width - value.size;
+	if (padding_len > 0) {
+		wire_ctx_clear(ctx, padding_len);
+	}
+	wire_ctx_write(ctx, value.data, value.size);
+}