1 files changed, 60 insertions, 0 deletions
diff --git a/shared/c-siphash/src/c-siphash.h b/shared/c-siphash/src/c-siphash.h
new file mode 100644
index 00000000..c0cfc1e0
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+++ b/shared/c-siphash/src/c-siphash.h
@@ -0,0 +1,60 @@
+#pragma once
+
+/**
+ * Streaming-capable SipHash Implementation
+ *
+ * This library provides a SipHash API, that is fully implemented in ISO-C11
+ * and has no external dependencies. The library performs no memory allocation,
+ * and provides a streaming API where data to be hashed can be appended
+ * piecemeal.
+ *
+ * A streaming-capable hash state is represented by the "CSipHash" structure,
+ * which should be initialized with a unique seed before use. If streaming
+ * capabilities are not required, c_siphash_hash() provides a simple one-shot
+ * API.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stddef.h>
+#include <stdint.h>
+
+typedef struct CSipHash CSipHash;
+
+/**
+ * struct CSipHash - SipHash state object
+ * @v0-@v3:             internal state
+ * @padding:            pending bytes that were not a multiple of 8
+ * @n_bytes:            number of hashed bytes
+ *
+ * The state of an inflight hash is represenetd by a CSipHash object. Before
+ * hashing, it must be initialized with c_siphash_init(), providing a unique
+ * random hash seed. Data is hashed by appending it to the state object, using
+ * c_siphash_append(). Finally, the hash is read out by calling
+ * c_siphash_finalize().
+ *
+ * This state object has no allocated resources. It is safe to release its
+ * backing memory without any further action.
+ */
+struct CSipHash {
+        uint64_t v0;
+        uint64_t v1;
+        uint64_t v2;
+        uint64_t v3;
+        uint64_t padding;
+        size_t n_bytes;
+};
+
+#define C_SIPHASH_NULL {}
+
+void c_siphash_init(CSipHash *state, const uint8_t seed[16]);
+void c_siphash_append(CSipHash *state, const uint8_t *bytes, size_t n_bytes);
+uint64_t c_siphash_finalize(CSipHash *state);
+
+uint64_t c_siphash_hash(const uint8_t seed[16], const uint8_t *bytes, size_t n_bytes);
+
+#ifdef __cplusplus
+}
+#endif