/*
* 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 utils.h
*
* \brief General purpose utility functions.
*
* \author Mike Becker
* \author Olaf Wintermann
* \copyright 2-Clause BSD License
*/
#ifndef UCX_UTILS_H
#define UCX_UTILS_H
#include "common.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* Convenience macro for a for loop that counts from zero to n-1.
*/
#define cx_for_n(varname, n) for (size_t varname = 0 ; (varname) < (n) ; (varname)++)
/**
* Convenience macro for swapping two pointers.
*/
#ifdef __cplusplus
#define cx_swap_ptr(left, right) do {auto cx_tmp_swap_var = left; left = right; right = cx_tmp_swap_var;} while(0)
#else
#define cx_swap_ptr(left, right) do {void *cx_tmp_swap_var = left; left = right; right = cx_tmp_swap_var;} while(0)
#endif
// cx_szmul() definition
#if (__GNUC__ >= 5 || defined(__clang__)) && !defined(CX_NO_SZMUL_BUILTIN)
#define CX_SZMUL_BUILTIN
/**
* Alias for \c __builtin_mul_overflow.
*
* Performs a multiplication of size_t values and checks for overflow.
*
* @param a first operand
* @param b second operand
* @param result a pointer to a size_t, where the result should
* be stored
* @return zero, if no overflow occurred and the result is correct, non-zero
* otherwise
*/
#define cx_szmul(a, b, result) __builtin_mul_overflow(a, b, result)
#else // no GNUC or clang bultin
/**
* Performs a multiplication of size_t values and checks for overflow.
*
* @param a first operand
* @param b second operand
* @param result a pointer to a size_t, where the result should
* be stored
* @return zero, if no overflow occurred and the result is correct, non-zero
* otherwise
*/
#define cx_szmul(a, b, result) cx_szmul_impl(a, b, result)
/**
* Performs a multiplication of size_t values and checks for overflow.
*
* This is a custom implementation in case there is no compiler builtin
* available.
*
* @param a first operand
* @param b second operand
* @param result a pointer to a size_t where the result should be stored
* @return zero, if no overflow occurred and the result is correct, non-zero
* otherwise
*/
int cx_szmul_impl(size_t a, size_t b, size_t *result);
#endif // cx_szmul
/**
* Reads data from a stream and writes it to another stream.
*
* @param src the source stream
* @param dest the destination stream
* @param rfnc the read function
* @param wfnc the write function
* @param buf a pointer to the copy buffer or \c NULL if a buffer
* shall be implicitly created on the heap
* @param bufsize the size of the copy buffer - if \p buf is \c NULL you can
* set this to zero to let the implementation decide
* @param n the maximum number of bytes that shall be copied.
* If this is larger than \p bufsize, the content is copied over multiple
* iterations.
* @return the total number of bytes copied
*/
__attribute__((__nonnull__(1, 2, 3, 4)))
size_t cx_stream_bncopy(
void *src,
void *dest,
cx_read_func rfnc,
cx_write_func wfnc,
char *buf,
size_t bufsize,
size_t n
);
/**
* Reads data from a stream and writes it to another stream.
*
* @param src the source stream
* @param dest the destination stream
* @param rfnc the read function
* @param wfnc the write function
* @param buf a pointer to the copy buffer or \c NULL if a buffer
* shall be implicitly created on the heap
* @param bufsize the size of the copy buffer - if \p buf is \c NULL you can
* set this to zero to let the implementation decide
* @return total number of bytes copied
*/
#define cx_stream_bcopy(src, dest, rfnc, wfnc, buf, bufsize) \
cx_stream_bncopy(src, dest, rfnc, wfnc, buf, bufsize, SIZE_MAX)
/**
* Reads data from a stream and writes it to another stream.
*
* The data is temporarily stored in a stack allocated buffer.
*
* @param src the source stream
* @param dest the destination stream
* @param rfnc the read function
* @param wfnc the write function
* @param n the maximum number of bytes that shall be copied.
* @return total number of bytes copied
*/
__attribute__((__nonnull__))
size_t cx_stream_ncopy(
void *src,
void *dest,
cx_read_func rfnc,
cx_write_func wfnc,
size_t n
);
/**
* Reads data from a stream and writes it to another stream.
*
* The data is temporarily stored in a stack allocated buffer.
*
* @param src the source stream
* @param dest the destination stream
* @param rfnc the read function
* @param wfnc the write function
* @return total number of bytes copied
*/
#define cx_stream_copy(src, dest, rfnc, wfnc) \
cx_stream_ncopy(src, dest, rfnc, wfnc, SIZE_MAX)
#ifdef __cplusplus
}
#endif
#endif // UCX_UTILS_H