Differences

This shows you the differences between two versions of the page.

@@ Line 1: / Line 1: @@
+====== 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>