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Don't use reinterpret_cast

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This is a strict-aliasing violation and hence UB
This commit is contained in:
Alexander Grund
2020-01-08 14:23:14 +01:00
parent 983acd5dc0
commit 5bcafbcc3d
1 changed files with 27 additions and 11 deletions
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38
include/boost/nowide/utf8_codecvt.hpp
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@@ -21,6 +21,26 @@ namespace nowide {
// Make sure that mbstate can keep 16 bit of UTF-16 sequence
//
BOOST_STATIC_ASSERT(sizeof(std::mbstate_t) >= 2);
namespace detail {
// Avoid including cstring for std::memcpy
inline void copy_uint16_t(void* dst, const void* src)
{
unsigned char* cdst = static_cast<unsigned char*>(dst);
const unsigned char* csrc = static_cast<const unsigned char*>(src);
cdst[0] = csrc[0];
cdst[1] = csrc[1];
}
inline boost::uint16_t read_state(const std::mbstate_t& src)
{
boost::uint16_t dst;
copy_uint16_t(&dst, &src);
return dst;
}
inline void write_state(std::mbstate_t& dst, const boost::uint16_t src)
{
copy_uint16_t(&dst, &src);
}
} // namespace detail
#if defined _MSC_VER && _MSC_VER < 1700
// MSVC do_length is non-standard it counts wide characters instead of narrow and does not change mbstate
@@ -50,8 +70,7 @@ namespace nowide {
virtual std::codecvt_base::result do_unshift(std::mbstate_t& s, char* from, char* /*to*/, char*& next) const
{
boost::uint16_t& state = *reinterpret_cast<boost::uint16_t*>(&s);
if(state != 0)
if(detail::read_state(s) != 0)
return std::codecvt_base::error;
next = from;
return std::codecvt_base::ok;
@@ -78,12 +97,11 @@ namespace nowide {
const char* from_end,
size_t max) const
{
boost::uint16_t state = detail::read_state(std_state);
#ifndef BOOST_NOWIDE_DO_LENGTH_MBSTATE_CONST
const char* save_from = from;
boost::uint16_t& state = *reinterpret_cast<boost::uint16_t*>(&std_state);
#else
size_t save_max = max;
boost::uint16_t state = *reinterpret_cast<const boost::uint16_t*>(&std_state);
#endif
while(max > 0 && from < from_end)
{
@@ -111,6 +129,7 @@ namespace nowide {
}
}
#ifndef BOOST_NOWIDE_DO_LENGTH_MBSTATE_CONST
detail::write_state(std_state, state);
return static_cast<int>(from - save_from);
#else
return static_cast<int>(save_max - max);
@@ -132,7 +151,7 @@ namespace nowide {
//
// if 0 no code above >0xFFFF observed, of 1 a code above 0xFFFF observed
// and first pair is written, but no input consumed
boost::uint16_t& state = *reinterpret_cast<boost::uint16_t*>(&std_state);
boost::uint16_t state = detail::read_state(std_state);
while(to < to_end && from < from_end)
{
const char* from_saved = from;
@@ -184,6 +203,7 @@ namespace nowide {
to_next = to;
if(r == std::codecvt_base::ok && (from != from_end || state != 0))
r = std::codecvt_base::partial;
detail::write_state(std_state, state);
return r;
}
@@ -203,7 +223,7 @@ namespace nowide {
// State: state!=0 - a first surrogate pair was observed (state = first pair),
// we expect the second one to come and then zero the state
///
boost::uint16_t& state = *reinterpret_cast<boost::uint16_t*>(&std_state);
boost::uint16_t state = detail::read_state(std_state);
while(to < to_end && from < from_end)
{
boost::uint32_t ch = 0;
@@ -264,6 +284,7 @@ namespace nowide {
to_next = to;
if(r == std::codecvt_base::ok && from != from_end)
r = std::codecvt_base::partial;
detail::write_state(std_state, state);
return r;
}
};
@@ -342,11 +363,6 @@ namespace nowide {
{
std::codecvt_base::result r = std::codecvt_base::ok;
// mbstate_t is POD type and should be initialized to 0 (i.a. state = stateT())
// according to standard. We use it to keep a flag 0/1 for surrogate pair writing
//
// if 0 no code above >0xFFFF observed, of 1 a code above 0xFFFF observed
// and first pair is written, but no input consumed
while(to < to_end && from < from_end)
{
const char* from_saved = from;