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Fixes Undefined Behavior in LaneTupel (Strict Aliasing), resolves 2665

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It's complicated :sigh: read this please:
http://dbp-consulting.com/tutorials/StrictAliasing.html

tl;dr: has to go through a memcpy (in C++) as in:
184cc11cee/src/support/utilities.h (L29-L40)
This commit is contained in:
Daniel J. Hofmann 2016-07-18 12:32:25 +02:00
parent 50cbba1620
commit 130d5298fc
1 changed files with 5 additions and 8 deletions
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13
src/util/guidance/turn_lanes.cpp
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@ -2,6 +2,7 @@
#include <algorithm>
#include <iostream>
#include <tuple>
#include <boost/assert.hpp>
@ -24,10 +25,8 @@ LaneTupel::LaneTupel(const LaneID lanes_in_turn, const LaneID first_lane_from_th
// comparation based on interpretation as unsigned 32bit integer
bool LaneTupel::operator==(const LaneTupel other) const
{
static_assert(sizeof(LaneTupel) == sizeof(std::uint16_t),
"Comparation requires LaneTupel to be the of size 16Bit");
return *reinterpret_cast<const std::uint16_t *>(this) ==
*reinterpret_cast<const std::uint16_t *>(&other);
return std::tie(lanes_in_turn, first_lane_from_the_right) ==
std::tie(other.lanes_in_turn, other.first_lane_from_the_right);
}
bool LaneTupel::operator!=(const LaneTupel other) const { return !(*this == other); }
@ -35,10 +34,8 @@ bool LaneTupel::operator!=(const LaneTupel other) const { return !(*this == othe
// comparation based on interpretation as unsigned 32bit integer
bool LaneTupel::operator<(const LaneTupel other) const
{
static_assert(sizeof(LaneTupel) == sizeof(std::uint16_t),
"Comparation requires LaneTupel to be the of size 16Bit");
return *reinterpret_cast<const std::uint16_t *>(this) <
*reinterpret_cast<const std::uint16_t *>(&other);
return std::tie(lanes_in_turn, first_lane_from_the_right) <
std::tie(other.lanes_in_turn, other.first_lane_from_the_right);
}
} // namespace guidance