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Use std::allocator_traits (#3804)
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Signed-off-by: Vladislav Shchapov <[email protected]>
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phprus authored Jan 13, 2024
1 parent df6a356 commit 21b0458
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Showing 2 changed files with 30 additions and 28 deletions.
23 changes: 9 additions & 14 deletions include/fmt/format.h
Original file line number Diff line number Diff line change
Expand Up @@ -43,9 +43,13 @@
#include <cstring> // std::memcpy
#include <initializer_list> // std::initializer_list
#include <limits> // std::numeric_limits
#include <stdexcept> // std::runtime_error
#include <string> // std::string
#include <system_error> // std::system_error
#if defined(__GLIBCXX__) && !defined(_GLIBCXX_USE_DUAL_ABI)
// Workaround for pre gcc 5 libstdc++.
# include <memory> // std::allocator_traits
#endif
#include <stdexcept> // std::runtime_error
#include <string> // std::string
#include <system_error> // std::system_error

#include "base.h"

Expand Down Expand Up @@ -509,14 +513,6 @@ FMT_INLINE void assume(bool condition) {
#endif
}

template <typename Allocator, typename Enable = void> struct allocator_size {
using type = size_t;
};
template <typename Allocator>
struct allocator_size<Allocator, void_t<typename Allocator::size_type>> {
using type = typename Allocator::size_type;
};

template <typename Char, typename InputIt>
auto copy_str(InputIt begin, InputIt end, appender out) -> appender {
get_container(out).append(begin, end);
Expand Down Expand Up @@ -915,9 +911,8 @@ class basic_memory_buffer : public detail::buffer<T> {
static FMT_CONSTEXPR20 void grow(detail::buffer<T>& buf, size_t size) {
detail::abort_fuzzing_if(size > 5000);
auto& self = static_cast<basic_memory_buffer&>(buf);
constexpr size_t max_size =
detail::max_value<typename detail::allocator_size<Allocator>::type>() /
sizeof(T);
const size_t max_size =
std::allocator_traits<Allocator>::max_size(self.alloc_);
size_t old_capacity = buf.capacity();
size_t new_capacity = old_capacity + old_capacity / 2;
if (size > new_capacity)
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35 changes: 21 additions & 14 deletions test/format-test.cc
Original file line number Diff line number Diff line change
Expand Up @@ -413,30 +413,37 @@ TEST(memory_buffer_test, exception_in_deallocate) {
EXPECT_CALL(alloc, deallocate(&mem2[0], 2 * size));
}

class smol_allocator : public std::allocator<char> {
template <typename Allocator, size_t MaxSize>
class max_size_allocator : public Allocator {
public:
using size_type = unsigned char;

auto allocate(size_t n) -> value_type* {
if (n > fmt::detail::max_value<size_type>())
using typename Allocator::value_type;
size_t max_size() const noexcept { return MaxSize; }
value_type* allocate(size_t n) {
if (n > max_size()) {
throw std::length_error("size > max_size");
return std::allocator<char>::allocate(n);
}
return std::allocator_traits<Allocator>::allocate(
*static_cast<Allocator*>(this), n);
}
void deallocate(value_type* p, size_t n) {
std::allocator<char>::deallocate(p, n);
std::allocator_traits<Allocator>::deallocate(*static_cast<Allocator*>(this),
p, n);
}
};

TEST(memory_buffer_test, max_size_allocator) {
basic_memory_buffer<char, 10, smol_allocator> buffer;
buffer.resize(200);
// new_capacity = 200 + 200/2 = 300 > 256
buffer.resize(255); // Shouldn't throw.
// 160 = 128 + 32
using test_allocator = max_size_allocator<std::allocator<char>, 160>;
basic_memory_buffer<char, 10, test_allocator> buffer;
buffer.resize(128);
// new_capacity = 128 + 128/2 = 192 > 160
buffer.resize(160); // Shouldn't throw.
}

TEST(memory_buffer_test, max_size_allocator_overflow) {
basic_memory_buffer<char, 10, smol_allocator> buffer;
EXPECT_THROW(buffer.resize(256), std::exception);
using test_allocator = max_size_allocator<std::allocator<char>, 160>;
basic_memory_buffer<char, 10, test_allocator> buffer;
EXPECT_THROW(buffer.resize(161), std::exception);
}

TEST(format_test, exception_from_lib) {
Expand Down Expand Up @@ -2152,7 +2159,7 @@ TEST(format_int_test, format_int) {
EXPECT_EQ(fmt::format_int(42ul).str(), "42");
EXPECT_EQ(fmt::format_int(-42l).str(), "-42");
EXPECT_EQ(fmt::format_int(42ull).str(), "42");
EXPECT_EQ(fmt::format_int(-42ll).str(), "-42");\
EXPECT_EQ(fmt::format_int(-42ll).str(), "-42");
EXPECT_EQ(fmt::format_int(max_value<int64_t>()).str(),
std::to_string(max_value<int64_t>()));
}
Expand Down

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