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Fix swprintf checks

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This commit is contained in:
Krystian Stasiowski
2020-02-22 17:44:57 -05:00
parent 4850c6f50a
commit 74e2395a2f
1 changed files with 12 additions and 13 deletions
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25
include/boost/static_string/static_string.hpp
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@ -469,8 +469,6 @@ to_static_string_float_impl(double value) noexcept
{ {
// extra one needed for null terminator // extra one needed for null terminator
char buffer[N + 1]; char buffer[N + 1];
const auto write_count =
std::snprintf(buffer, N + 1, "%f", value);
// since our buffer has a fixed size, if the number of characters // since our buffer has a fixed size, if the number of characters
// that would be written exceeds the size of the buffer, // that would be written exceeds the size of the buffer,
// we need touse scientific notation instead. // we need touse scientific notation instead.
@ -482,7 +480,9 @@ to_static_string_float_impl(double value) noexcept
// and the potential sign of the integral part, total of 6 chars. // and the potential sign of the integral part, total of 6 chars.
// we will reserve 7 characters just in case the size of the exponent // we will reserve 7 characters just in case the size of the exponent
// is 3 characters. // is 3 characters.
if (write_count > N) // snprintf returns the number of characters
// that would have been written
if (std::snprintf(buffer, N + 1, "%f", value) > N)
{ {
const auto period = const auto period =
std::char_traits<char>::find(buffer, N, '.'); std::char_traits<char>::find(buffer, N, '.');
@ -501,10 +501,9 @@ to_static_string_float_impl(long double value) noexcept
{ {
// extra one needed for null terminator // extra one needed for null terminator
char buffer[N + 1]; char buffer[N + 1];
// number of characters written // snprintf returns the number of characters
const auto write_count = // that would have been written
std::snprintf(buffer, N + 1, "%Lf", value); if (std::snprintf(buffer, N + 1, "%Lf", value) > N)
if (write_count > N)
{ {
const auto period = const auto period =
std::char_traits<char>::find(buffer, N, '.'); std::char_traits<char>::find(buffer, N, '.');
@ -523,9 +522,9 @@ to_static_wstring_float_impl(double value) noexcept
{ {
// extra one needed for null terminator // extra one needed for null terminator
wchar_t buffer[N + 1]; wchar_t buffer[N + 1];
const auto write_count = // swprintf returns a negative number if it can't
std::swprintf(buffer, N + 1, L"%f", value); // fit all the characters in the buffer
if (write_count > N) if (std::swprintf(buffer, N + 1, L"%f", value) < 0)
{ {
const auto period = const auto period =
std::char_traits<wchar_t>::find(buffer, N, '.'); std::char_traits<wchar_t>::find(buffer, N, '.');
@ -544,9 +543,9 @@ to_static_wstring_float_impl(long double value) noexcept
{ {
// extra one needed for null terminator // extra one needed for null terminator
wchar_t buffer[N + 1]; wchar_t buffer[N + 1];
const auto write_count = // swprintf returns a negative number if it can't
std::swprintf(buffer, N + 1, L"%Lf", value); // fit all the characters in the buffer
if (write_count > N) if (std::swprintf(buffer, N + 1, L"%Lf", value) < 0)
{ {
const auto period = const auto period =
std::char_traits<wchar_t>::find(buffer, N, '.'); std::char_traits<wchar_t>::find(buffer, N, '.');