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-rw-r--r--src/libdnssec/shared/bignum.c64
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..921a1e6
--- /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 <http://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);
+}