X-Git-Url: https://develop.uap-core.de/gitweb/uwplayer.git/blobdiff_plain/83d9f3aaf8206aa081ead0ff630a1c33ed670d71..848befbcc166fff6fdde6a635cf7a31f9f9185e0:/ucx/cx/hash_key.h

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+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+/**
+ * \file hash_key.h
+ * \brief Interface for map implementations.
+ * \author Mike Becker
+ * \author Olaf Wintermann
+ * \version 3.0
+ * \copyright 2-Clause BSD License
+ */
+
+
+#ifndef UCX_HASH_KEY_H
+#define UCX_HASH_KEY_H
+
+#include "stddef.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Internal structure for a key within a hash map. */
+struct cx_hash_key_s {
+    /** The key data. */
+    union {
+        unsigned char *bytes;
+        unsigned char const *cbytes;
+        char *str;
+        char const *cstr;
+        void *obj;
+        void const *cobj;
+    } data;
+    /**
+     * The key data length.
+     */
+    size_t len;
+    /** The hash value of the key data. */
+    unsigned hash;
+};
+
+/**
+ * Type for a hash key.
+ */
+typedef struct cx_hash_key_s CxHashKey;
+
+/**
+ * Computes a murmur2 32 bit hash.
+ *
+ * You need to initialize \c data and \c len in the key struct.
+ * The hash is then directly written to that struct.
+ *
+ * \note If \c data is \c NULL, the hash is defined as 1574210520.
+ *
+ * @param key the key, the hash shall be computed for
+ */
+void cx_hash_murmur(CxHashKey *key);
+
+/**
+ * Computes a hash key from a string.
+ *
+ * The string needs to be zero-terminated.
+ *
+ * @param str the string
+ * @return the hash key
+ */
+__attribute__((__warn_unused_result__))
+CxHashKey cx_hash_key_str(char const *str);
+
+/**
+ * Computes a hash key from a byte array.
+ *
+ * @param bytes the array
+ * @param len the length
+ * @return the hash key
+ */
+__attribute__((__warn_unused_result__))
+CxHashKey cx_hash_key_bytes(
+        unsigned char const *bytes,
+        size_t len
+);
+
+/**
+ * Computes a hash key for an arbitrary object.
+ *
+ * The computation uses the in-memory representation that might not be
+ * the same on different platforms. Therefore, this hash should not be
+ * used for data exchange with different machines.
+ *
+ * @param obj a pointer to an arbitrary object
+ * @param len the length of object in memory
+ * @return the hash key
+ */
+__attribute__((__warn_unused_result__))
+CxHashKey cx_hash_key(
+        void const *obj,
+        size_t len
+);
+
+/**
+ * Computes a hash key from a UCX string.
+ *
+ * @param str the string
+ * @return the hash key
+ */
+#define cx_hash_key_cxstr(str) cx_hash_key((void*)(str).ptr, (str).length)
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif // UCX_HASH_KEY_H