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Shifting a negative number is an -fsanitize=undefined violation, use the unsigned type

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Peter Dimov
2017-12-22 16:24:21 +02:00
parent 69f5b950a2
commit 134b225378
1 changed files with 15 additions and 4 deletions
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19
include/boost/endian/buffers.hpp
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@@ -38,6 +38,10 @@
#include <boost/predef/detail/endian_compat.h> #include <boost/predef/detail/endian_compat.h>
#include <boost/endian/conversion.hpp> #include <boost/endian/conversion.hpp>
#include <boost/type_traits/is_signed.hpp> #include <boost/type_traits/is_signed.hpp>
#include <boost/type_traits/make_unsigned.hpp>
#include <boost/type_traits/conditional.hpp>
#include <boost/type_traits/is_integral.hpp>
#include <boost/type_traits/type_identity.hpp>
#include <boost/cstdint.hpp> #include <boost/cstdint.hpp>
#include <boost/static_assert.hpp> #include <boost/static_assert.hpp>
#include <boost/core/scoped_enum.hpp> #include <boost/core/scoped_enum.hpp>
@@ -221,20 +225,27 @@ namespace endian
{ {
typedef unrolled_byte_loops<T, n_bytes - 1, sign> next; typedef unrolled_byte_loops<T, n_bytes - 1, sign> next;
// shifting a negative number is flagged by -fsanitize=undefined
// so use the corresponding unsigned type for the shifts
typedef typename boost::conditional<
boost::is_integral<T>::value,
boost::make_unsigned<T>, boost::type_identity<T> >::type::type U;
static T load_big(const unsigned char* bytes) BOOST_NOEXCEPT static T load_big(const unsigned char* bytes) BOOST_NOEXCEPT
{ return static_cast<T>(*(bytes - 1) | (next::load_big(bytes - 1) << 8)); } { return static_cast<T>(*(bytes - 1) | (static_cast<U>(next::load_big(bytes - 1)) << 8)); }
static T load_little(const unsigned char* bytes) BOOST_NOEXCEPT static T load_little(const unsigned char* bytes) BOOST_NOEXCEPT
{ return static_cast<T>(*bytes | (next::load_little(bytes + 1) << 8)); } { return static_cast<T>(*bytes | (static_cast<U>(next::load_little(bytes + 1)) << 8)); }
static void store_big(char* bytes, T value) BOOST_NOEXCEPT static void store_big(char* bytes, T value) BOOST_NOEXCEPT
{ {
*(bytes - 1) = static_cast<char>(value); *(bytes - 1) = static_cast<char>(value);
next::store_big(bytes - 1, static_cast<T>(value >> 8)); next::store_big(bytes - 1, static_cast<T>(static_cast<U>(value) >> 8));
} }
static void store_little(char* bytes, T value) BOOST_NOEXCEPT static void store_little(char* bytes, T value) BOOST_NOEXCEPT
{ {
*bytes = static_cast<char>(value); *bytes = static_cast<char>(value);
next::store_little(bytes + 1, static_cast<T>(value >> 8)); next::store_little(bytes + 1, static_cast<T>(static_cast<U>(value) >> 8));
} }
}; };