ucx: src/cx/utils.h@08539b8273fa

     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  */

    29 /**

    30  * \file utils.h

    31  *

    32  * \brief General purpose utility functions.

    33  *

    34  * \author Mike Becker

    35  * \author Olaf Wintermann

    36  * \version 3.0

    37  * \copyright 2-Clause BSD License

    38  */

    40 #ifndef UCX_UTILS_H

    41 #define UCX_UTILS_H

    43 #include "common.h"

    45 #ifdef __cplusplus

    46 extern "C" {

    47 #endif

    49 /**

    50  * Convenience macro for a for loop that counts from zero to n-1.

    51  */

    52 #define cx_for_n(varname, n) for (size_t varname = 0 ; (varname) < (n) ; (varname)++)

    54 /* ----------------------

    55  * cx_szmul() definition.

    56  * ---------------------- */

    58 #if (__GNUC__ >= 5 || defined(__clang__)) && !defined(CX_NO_SZMUL_BUILTIN)

    59 #define CX_SZMUL_BUILTIN

    61 #if __WORDSIZE == 32

    62 /**

    63  * Alias for \c __builtin_umul_overflow.

    64  *

    65  * Performs a multiplication of size_t values and checks for overflow.

    66  *

    67  * @param a first operand

    68  * @param b second operand

    69  * @param result a pointer to a size_t, where the result should

    70  * be stored

    71  * @return zero, if no overflow occurred and the result is correct, non-zero

    72  * otherwise

    73  */

    74 #define cx_szmul(a, b, result) __builtin_umul_overflow(a, b, result)

    75 #else /* __WORDSIZE != 32 */

    76 /**

    77  * Alias for \c __builtin_umull_overflow.

    78  *

    79  * Performs a multiplication of size_t values and checks for overflow.

    80  *

    81  * @param a first operand

    82  * @param b second operand

    83  * @param result a pointer to a size_t, where the result should

    84  * be stored

    85  * @return zero, if no overflow occurred and the result is correct, non-zero

    86  * otherwise

    87  */

    88 #define cx_szmul(a, b, result) __builtin_umull_overflow(a, b, result)

    89 #endif /* __WORDSIZE */

    91 #else /* no GNUC or clang bultin */

    93 /**

    94  * Performs a multiplication of size_t values and checks for overflow.

    95   *

    96  * @param a first operand

    97  * @param b second operand

    98  * @param result a pointer to a size_t, where the result should

    99  * be stored

   100  * @return zero, if no overflow occurred and the result is correct, non-zero

   101  * otherwise

   102  */

   103 #define cx_szmul(a, b, result) cx_szmul_impl(a, b, result)

   105 /**

   106  * Performs a multiplication of size_t values and checks for overflow.

   107  *

   108  * This is a custom implementation in case there is no compiler builtin

   109  * available.

   110  *

   111  * @param a first operand

   112  * @param b second operand

   113  * @param result a pointer to a size_t where the result should be stored

   114  * @return zero, if no overflow occurred and the result is correct, non-zero

   115  * otherwise

   116  */

   117 int cx_szmul_impl(size_t a, size_t b, size_t *result);

   119 #endif

   121 #ifdef __cplusplus

   122 }

   123 #endif

   125 #endif /* UCX_UTILS_H */

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