ucx: src/cx/utils.h@12c2b10b51a9

     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 // cx_szmul() definition

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

    57 #define CX_SZMUL_BUILTIN

    59 #if __WORDSIZE == 32

    60 /**

    61  * Alias for \c __builtin_umull_overflow.

    62  *

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

    64  *

    65  * @param a first operand

    66  * @param b second operand

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

    68  * be stored

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

    70  * otherwise

    71  */

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

    73 #else // __WORDSIZE != 32

    74 /**

    75  * Alias for \c __builtin_umulll_overflow.

    76  *

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

    78  *

    79  * @param a first operand

    80  * @param b second operand

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

    82  * be stored

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

    84  * otherwise

    85  */

    86 #define cx_szmul(a, b, result) __builtin_umulll_overflow(a, b, result)

    87 #endif // __WORDSIZE

    89 #else // no GNUC or clang bultin

    91 /**

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

    93   *

    94  * @param a first operand

    95  * @param b second operand

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

    97  * be stored

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

    99  * otherwise

   100  */

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

   103 /**

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

   105  *

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

   107  * available.

   108  *

   109  * @param a first operand

   110  * @param b second operand

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

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

   113  * otherwise

   114  */

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

   117 #endif

   119 #ifdef __cplusplus

   120 }

   121 #endif

   123 #endif // UCX_UTILS_H

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