ucx: src/cx/utils.h@dfd0403ff8b6

     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  * Convenience macro for swapping two pointers.

    56  */

    57 #ifdef __cplusplus

    58 #define cx_swap_ptr(left, right) do {auto cx_tmp_swap_var = left; left = right; right = cx_tmp_swap_var;} while(0)

    59 #else

    60 #define cx_swap_ptr(left, right) do {void *cx_tmp_swap_var = left; left = right; right = cx_tmp_swap_var;} while(0)

    61 #endif

    63 // cx_szmul() definition

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

    66 #define CX_SZMUL_BUILTIN

    68 #if __WORDSIZE == 32

    69 /**

    70  * Alias for \c __builtin_umul_overflow.

    71  *

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

    73  *

    74  * @param a first operand

    75  * @param b second operand

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

    77  * be stored

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

    79  * otherwise

    80  */

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

    82 #else // __WORDSIZE != 32

    83 /**

    84  * Alias for \c __builtin_umull_overflow.

    85  *

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

    87  *

    88  * @param a first operand

    89  * @param b second operand

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

    91  * be stored

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

    93  * otherwise

    94  */

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

    96 #endif // __WORDSIZE

    98 #else // no GNUC or clang bultin

   100 /**

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

   102   *

   103  * @param a first operand

   104  * @param b second operand

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

   106  * be stored

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

   108  * otherwise

   109  */

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

   112 /**

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

   114  *

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

   116  * available.

   117  *

   118  * @param a first operand

   119  * @param b second operand

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

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

   122  * otherwise

   123  */

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

   126 #endif

   128 #ifdef __cplusplus

   129 }

   130 #endif

   132 #endif // UCX_UTILS_H

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