Add Fletcher-16.

fletcher16.h

@@ -0,0 +1,34 @@
+/*
+ * This file is part of the Aaru Data Preservation Suite.
+ * Copyright (c) 2019-2021 Natalia Portillo.
+ *
+ * This library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of the
+ * License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef AARU_CHECKSUMS_NATIVE_FLETCHER16_H
+#define AARU_CHECKSUMS_NATIVE_FLETCHER16_H
+
+#define FLETCHER16_MODULE 0xFF
+
+typedef struct {
+    uint8_t sum1;
+    uint8_t sum2;
+} fletcher16_ctx;
+
+AARU_EXPORT fletcher16_ctx* AARU_CALL fletcher16_init();
+AARU_EXPORT int AARU_CALL fletcher16_update(fletcher16_ctx* ctx, const uint8_t* data, uint32_t len);
+AARU_EXPORT int AARU_CALL fletcher16_final(fletcher16_ctx* ctx, uint16_t* checksum);
+AARU_EXPORT void AARU_CALL fletcher16_free(fletcher16_ctx* ctx);
+
+#endif//AARU_CHECKSUMS_NATIVE_FLETCHER16_H