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Change overlap checks to use pointer comparison

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This commit is contained in:
Krystian Stasiowski
2020-02-23 20:19:21 -05:00
parent 0e11360cf1
commit 6efe1cfbb5
1 changed files with 7 additions and 9 deletions
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16
include/boost/static_string/static_string.hpp
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@ -4993,18 +4993,18 @@ insert(
const auto curr_data = data(); const auto curr_data = data();
const std::size_t count = detail::distance(first, last); const std::size_t count = detail::distance(first, last);
const std::size_t index = pos - curr_data; const std::size_t index = pos - curr_data;
const auto s = &*first; const auto first_addr = &*first;
BOOST_STATIC_STRING_THROW_IF( BOOST_STATIC_STRING_THROW_IF(
count > max_size() - curr_size, std::length_error{"count > max_size() - size()"}); count > max_size() - curr_size, std::length_error{"count > max_size() - size()"});
const bool inside = detail::ptr_in_range(curr_data, curr_data + curr_size, s); const bool inside = detail::ptr_in_range(curr_data, curr_data + curr_size, first_addr);
if (!inside || (inside && ((s - curr_data) + count <= index))) if (!inside || (inside && (first_addr + count <= pos)))
{ {
traits_type::move(&curr_data[index + count], &curr_data[index], curr_size - index + 1); traits_type::move(&curr_data[index + count], &curr_data[index], curr_size - index + 1);
detail::copy_with_traits<Traits>(first, last, &curr_data[index]); detail::copy_with_traits<Traits>(first, last, &curr_data[index]);
} }
else else
{ {
const size_type offset = s - curr_data; const size_type offset = first_addr - curr_data;
traits_type::move(&curr_data[index + count], &curr_data[index], curr_size - index + 1); traits_type::move(&curr_data[index + count], &curr_data[index], curr_size - index + 1);
if (offset < index) if (offset < index)
{ {
@ -5208,12 +5208,10 @@ replace(
curr_size - (std::min)(n1, curr_size - pos) >= max_size() - n2, curr_size - (std::min)(n1, curr_size - pos) >= max_size() - n2,
std::length_error{"replaced string exceeds max_size()"}); std::length_error{"replaced string exceeds max_size()"});
const bool inside = detail::ptr_in_range(curr_data, curr_data + curr_size, first_addr); const bool inside = detail::ptr_in_range(curr_data, curr_data + curr_size, first_addr);
// due to short circuit evaluation, the second operand of the logical if (inside && first_addr == i1 && n1 == n2)
// AND expression will only be evaluated if s is within the string,
// which means that operand of the cast will never be negative.
if (inside && std::size_t(first_addr - curr_data) == pos && n1 == n2)
return *this; return *this;
if (!inside || (inside && ((first_addr - curr_data) + n2 <= pos))) // Short circuit evaluation ensures that the pointer arithmetic is valid
if (!inside || (inside && (first_addr + n2 <= i1)))
{ {
// source outside // source outside
traits_type::move(&curr_data[pos + n2], &curr_data[pos + n1], curr_size - pos - n1 + 1); traits_type::move(&curr_data[pos + n2], &curr_data[pos + n1], curr_size - pos - n1 + 1);