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-rw-r--r--hmac/libkeccak_hmac_copy.c38
1 files changed, 38 insertions, 0 deletions
diff --git a/hmac/libkeccak_hmac_copy.c b/hmac/libkeccak_hmac_copy.c
new file mode 100644
index 0000000..8a4077b
--- /dev/null
+++ b/hmac/libkeccak_hmac_copy.c
@@ -0,0 +1,38 @@
+/* See LICENSE file for copyright and license details. */
+#include "../common.h"
+
+
+/**
+ * Make a copy of an HMAC hashing-state
+ *
+ * @param dest The slot for the duplicate, must not be initialised (memory leak otherwise)
+ * @param src The state to duplicate
+ * @return Zero on success, -1 on error
+ */
+int
+libkeccak_hmac_copy(struct libkeccak_hmac_state *restrict dest, const struct libkeccak_hmac_state *restrict src)
+{
+ size_t size;
+
+ dest->key_opad = NULL;
+ dest->key_ipad = NULL;
+
+ if (libkeccak_state_copy(&dest->sponge, &src->sponge) < 0)
+ return -1;
+
+ dest->key_length = src->key_length;
+ dest->leftover = src->leftover;
+
+ size = (src->key_length + 7) >> 3;
+ dest->key_opad = malloc(2 * size);
+ if (!dest->key_opad) {
+ libkeccak_state_destroy(&dest->sponge);
+ return -1;
+ }
+ dest->key_ipad = dest->key_opad + size;
+
+ memcpy(dest->key_opad, src->key_opad, size);
+ memcpy(dest->key_ipad, src->key_ipad, size);
+
+ return 0;
+}