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extdef.h [2017/12/06 11:18] (current)
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| | ====== extdef.h ====== |
| | <code> |
| | /** |
| | * extdef.h - A header of macros to augment the C standard headers. |
| | * |
| | * v1.0 - 10/06/2012 - Initial release |
| | * |
| | * Copyright (C) 2012 - Joel Holdsworth |
| | * |
| | * 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 AUTHOR ``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 AUTHOR 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. |
| | **/ |
| | |
| | #ifndef _EXTDEF_H |
| | #define _EXTDEF_H |
| | |
| | #define countof(x) (sizeof(x)/sizeof(x[0])) |
| | |
| | #define begin_element(x) (&x[0]) |
| | #define end_element(x) (&x[countof(x)]) |
| | |
| | #endif /* _EXTDEF_H */ |
| | </code> |
| | |
| | ===== Overview ===== |
| | extdef.h is a companion header to add extra macros to augment the C/C++ standard set. The header is released under the BSD license. |
| | ===== Reference ===== |
| | ==== countof() ==== |
| | This macro is a a companion to the ''sizeof()'' keyword and the [[http://cplusplus.com/reference/clibrary/cstddef/offsetof/|offsetof()]] macro in stddef.h. ''countof'' returns the number of elements in a C style array. The value returned is an unsigned integral value of type ''size_t'' with the amount of bytes between the specified member and the beginning of its structure. |
| | ==== begin_element() & end_element() ==== |
| | ''begin_element()'' returns a pointer to the first element of an array. ''end_element()'' returns a pointer to the first address after the end of the array. |
| | |
| | These two macros are provided so that C style array can neatly integrate with [[http://cplusplus.com/reference/algorithm/|STL algorithms]]. This is possible because STL iterators have the same semantic properties. These provide an elegant way to easily search and transform sequence data types. |
| | |
| | === Example === |
| | Finding the maximum value in an array. |
| | <code> |
| | const int a[] = {1, 3, 2, 5, 4}; |
| | const int max = max_element(begin_element(a), end_element(a)); |
| | </code> |
| |