ucx: src/cx/hash_key.h@378578666c83

     1 /*

     2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

     3  *

     4  * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.

     5  *

     6  * Redistribution and use in source and binary forms, with or without

     7  * modification, are permitted provided that the following conditions are met:

     8  *

     9  *   1. Redistributions of source code must retain the above copyright

    10  *      notice, this list of conditions and the following disclaimer.

    11  *

    12  *   2. Redistributions in binary form must reproduce the above copyright

    13  *      notice, this list of conditions and the following disclaimer in the

    14  *      documentation and/or other materials provided with the distribution.

    15  *

    16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

    17  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

    18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

    19  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE

    20  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

    21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

    22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

    23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

    24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

    25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

    26  * POSSIBILITY OF SUCH DAMAGE.

    27  */

    28 /**

    29  * \file hash_key.h

    30  * \brief Interface for map implementations.

    31  * \author Mike Becker

    32  * \author Olaf Wintermann

    33  * \version 3.0

    34  * \copyright 2-Clause BSD License

    35  */

    38 #ifndef UCX_HASH_KEY_H

    39 #define UCX_HASH_KEY_H

    41 #include "common.h"

    43 #ifdef __cplusplus

    44 extern "C" {

    45 #endif

    47 /** Internal structure for a key within a hash map. */

    48 struct cx_hash_key_s {

    49     /** The key data. */

    50     void const *data;

    51     /**

    52      * The key data length.

    53      */

    54     size_t len;

    55     /** The hash value of the key data. */

    56     unsigned hash;

    57 };

    59 /**

    60  * Type for a hash key.

    61  */

    62 typedef struct cx_hash_key_s CxHashKey;

    64 /**

    65  * Computes a murmur2 32 bit hash.

    66  *

    67  * You need to initialize \c data and \c len in the key struct.

    68  * The hash is then directly written to that struct.

    69  *

    70  * \note If \c data is \c NULL, the hash is defined as 1574210520.

    71  *

    72  * @param key the key, the hash shall be computed for

    73  */

    74 void cx_hash_murmur(CxHashKey *key);

    76 /**

    77  * Computes a hash key from a string.

    78  *

    79  * The string needs to be zero-terminated.

    80  *

    81  * @param str the string

    82  * @return the hash key

    83  */

    84 __attribute__((__warn_unused_result__))

    85 CxHashKey cx_hash_key_str(char const *str);

    87 /**

    88  * Computes a hash key from a byte array.

    89  *

    90  * @param bytes the array

    91  * @param len the length

    92  * @return the hash key

    93  */

    94 __attribute__((__warn_unused_result__))

    95 CxHashKey cx_hash_key_bytes(

    96         unsigned char const *bytes,

    97         size_t len

    98 );

   100 /**

   101  * Computes a hash key for an arbitrary object.

   102  *

   103  * The computation uses the in-memory representation that might not be

   104  * the same on different platforms. Therefore, this hash should not be

   105  * used for data exchange with different machines.

   106  *

   107  * @param obj a pointer to an arbitrary object

   108  * @param len the length of object in memory

   109  * @return the hash key

   110  */

   111 __attribute__((__warn_unused_result__))

   112 CxHashKey cx_hash_key(

   113         void const *obj,

   114         size_t len

   115 );

   117 /**

   118  * Computes a hash key from a UCX string.

   119  *

   120  * @param str the string

   121  * @return the hash key

   122  */

   123 #define cx_hash_key_cxstr(str) cx_hash_key((void*)(str).ptr, (str).length)

   125 #ifdef __cplusplus

   126 } // extern "C"

   127 #endif

   129 #endif // UCX_HASH_KEY_H

Mercurial > hg > ucx / file revision