[Boost-commit] svn:boost r64410 - in sandbox/SOC/2010/bits_and_ints: boost/integer libs/integer/test

Subject: [Boost-commit] svn:boost r64410 - in sandbox/SOC/2010/bits_and_ints: boost/integer libs/integer/test
From: muriloufg_at_[hidden]
Date: 2010-07-28 09:24:38

Author: murilov
Date: 2010-07-28 09:24:37 EDT (Wed, 28 Jul 2010)
New Revision: 64410
URL: http://svn.boost.org/trac/boost/changeset/64410

Log:
Added find_first_one_string function wich finds the first string of ones in an integral value of a given length
Added:
   sandbox/SOC/2010/bits_and_ints/boost/integer/find_first_one_string.hpp   (contents, props changed)
   sandbox/SOC/2010/bits_and_ints/libs/integer/test/find_first_one_string_test.cpp   (contents, props changed)

Added: sandbox/SOC/2010/bits_and_ints/boost/integer/find_first_one_string.hpp
==============================================================================
--- (empty file)
+++ sandbox/SOC/2010/bits_and_ints/boost/integer/find_first_one_string.hpp	2010-07-28 09:24:37 EDT (Wed, 28 Jul 2010)
@@ -0,0 +1,74 @@
+//  Boost integer/isqrt.hpp header file  ------------------------------//
+
+//  (C) Copyright Murilo Adriano Vasconcelos 2010.
+//  Distributed under the Boost Software License, Version 1.0. (See
+//  accompanying file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt
+
+//  See http://www.boost.org for updates, documentation, and revision history. 
+
+#ifndef BOOST_FFOS_INCLUDED
+#define BOOST_FFOS_INCLUDED
+
+#include <boost/utility/enable_if.hpp>
+#include <boost/type_traits/is_unsigned.hpp>
+#include <boost/math/policies/policy.hpp>
+#include <boost/math/policies/error_handling.hpp>
+#include <boost/integer/count_leading_zeros.hpp>
+
+namespace boost {
+	
+/*
+ *	This function finds the first occurrence of a string of 
+ *		ones in `value` with a given lenght `size`.
+ *
+ *	`size` must be greater than 0 and less than or equal the
+ *		length in bits of type `T`. If these requirements are
+ *		no met, one error is raised according to the policy
+ *		used.
+ *
+ *	See the math::policies documentation for more details about
+ *		policies.
+ *
+ *	`T` must be an unsigned type.
+ */
+
+template <typename T, typename Policy>
+typename enable_if<is_unsigned<T>, int>::type 
+find_first_one_string(T value, unsigned size, const Policy& pol)
+{
+	
+	if (size == 0 || size > (sizeof(T) << 3)) {
+		return math::policies::raise_domain_error(
+			"boost::find_first_one_string(%1%, %1%)",
+			"find_first_one_string requires size greater than 0 "
+			"and less than or equal the size in bits of value "
+			"size=%1% given,",
+			size, pol
+		);
+	}
+	
+	int shift;
+	while (size > 1) {
+		shift = size >> 1;
+		value &= (value << shift);
+		size -= shift;
+	}
+	
+	unsigned ret = count_leading_zeros(value);
+	
+	if (ret < (sizeof(T) << 3)) return ret;
+	
+	return -1; // not found
+}
+	
+template <typename T>
+typename enable_if<is_unsigned<T>, int>::type 
+find_first_one_string(T value, int size)
+{
+	return find_first_one_string(value, size, math::policies::policy<>());
+}
+	
+}
+
+#endif
\ No newline at end of file

Added: sandbox/SOC/2010/bits_and_ints/libs/integer/test/find_first_one_string_test.cpp
==============================================================================
--- (empty file)
+++ sandbox/SOC/2010/bits_and_ints/libs/integer/test/find_first_one_string_test.cpp	2010-07-28 09:24:37 EDT (Wed, 28 Jul 2010)
@@ -0,0 +1,43 @@
+//  Boost integer/find_first_one_string.hpp test program  -------//
+//  (C) Copyright Murilo Adriano Vasconcelos 2010.
+//  Distributed under the Boost Software License, Version 1.0. (See
+//  accompanying file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt
+
+
+#include <iostream>
+#include <cmath>
+#include <limits>
+#include <boost/cstdint.hpp>
+#include <boost/detail/lightweight_test.hpp>
+#include <boost/integer/find_first_one_string.hpp>
+
+int main()
+{
+	using boost::find_first_one_string;
+	
+	BOOST_TEST((find_first_one_string((uint32_t)0, 1) == -1));
+	BOOST_TEST((find_first_one_string((uint32_t)0, 2) == -1));
+	BOOST_TEST((find_first_one_string((uint32_t)0, 3) == -1));
+	BOOST_TEST((find_first_one_string((uint32_t)0, 30) == -1));
+	BOOST_TEST((find_first_one_string((uint32_t)0, 31) == -1));
+	BOOST_TEST((find_first_one_string((uint32_t)0x0F, 4) == 28));
+	BOOST_TEST((find_first_one_string((uint32_t)0x1F, 4) == 27));
+	BOOST_TEST((find_first_one_string((uint32_t)0xFFFFFFFF, 1) == 0));
+	BOOST_TEST((find_first_one_string((uint32_t)0xFFFFFFFF, 10) == 0));
+	BOOST_TEST((find_first_one_string((uint32_t)0xFFFFFFFF, 31) == 0));
+	BOOST_TEST((find_first_one_string((uint32_t)0xFFFFFFFF, 32) == 0));
+	BOOST_TEST((find_first_one_string((uint32_t)0x0000FFFF, 16) == 16));
+	BOOST_TEST((find_first_one_string((uint32_t)0x0000FFFF, 20) == -1));
+	
+#ifndef BOOST_HAS_NO_INT64_T
+	BOOST_TEST((find_first_one_string((uint64_t)0, 1) == -1));
+	BOOST_TEST((find_first_one_string((uint64_t)0, 20) == -1));
+	BOOST_TEST((find_first_one_string((uint64_t)0xFFFF0000FFFF, 16) == 16));
+	BOOST_TEST((find_first_one_string((uint64_t)0xFFFF0000FF0FFFFF, 17) == 44));
+	BOOST_TEST((find_first_one_string((uint64_t)0xFFFFFFFFFFFFFFFF, 64) == 0));
+	BOOST_TEST((find_first_one_string((uint64_t)0xFFFFFFFFFFFFFFFF, 63) == 0));
+#endif
+	
+	return boost::report_errors();
+}
\ No newline at end of file