diff options
Diffstat (limited to 'libstdc++-v3/src/c++17/floating_from_chars.cc')
| -rw-r--r-- | libstdc++-v3/src/c++17/floating_from_chars.cc | 50 |
1 files changed, 26 insertions, 24 deletions
diff --git a/libstdc++-v3/src/c++17/floating_from_chars.cc b/libstdc++-v3/src/c++17/floating_from_chars.cc index 4aa2483bc28..13de1e346ab 100644 --- a/libstdc++-v3/src/c++17/floating_from_chars.cc +++ b/libstdc++-v3/src/c++17/floating_from_chars.cc @@ -30,6 +30,7 @@ // Prefer to use std::pmr::string if possible, which requires the cxx11 ABI. #define _GLIBCXX_USE_CXX11_ABI 1 +#include <array> #include <charconv> #include <bit> #include <string> @@ -101,7 +102,6 @@ namespace return m_buf + std::__exchange(m_bytes, m_bytes + bytes); __glibcxx_assert(m_ptr == nullptr); - __glibcxx_assert(alignment != 1); m_ptr = operator new(bytes); m_bytes = bytes; @@ -451,30 +451,34 @@ namespace #endif // USE_STRTOD_FOR_FROM_CHARS #if _GLIBCXX_FLOAT_IS_IEEE_BINARY32 && _GLIBCXX_DOUBLE_IS_IEEE_BINARY64 - // If the given ASCII character represents a hexit, return that hexit. - // Otherwise return -1. - int - ascii_to_hexit(char ch) - { - if (ch >= '0' && ch <= '9') - return ch - '0'; - if (ch >= 'a' && ch <= 'f') - return ch - 'a' + 10; - if (ch >= 'A' && ch <= 'F') - return ch - 'A' + 10; - return -1; - } - // Return true iff [FIRST,LAST) begins with PREFIX, ignoring case. + // PREFIX is assumed to not contain any uppercase letters. bool starts_with_ci(const char* first, const char* last, string_view prefix) { __glibcxx_requires_valid_range(first, last); - for (char ch : prefix) + // A lookup table that maps uppercase letters to lowercase and + // is otherwise the identity mapping. + static constexpr auto upper_to_lower_table = [] { + constexpr unsigned char lower_letters[27] = "abcdefghijklmnopqrstuvwxyz"; + constexpr unsigned char upper_letters[27] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; + std::array<unsigned char, (1u << __CHAR_BIT__)> table = {}; + for (unsigned i = 0; i < table.size(); ++i) + table[i] = i; + for (unsigned i = 0; i < 26; ++i) + table[upper_letters[i]] = lower_letters[i]; + return table; + }(); + + if (last - first < static_cast<ptrdiff_t>(prefix.length())) + return false; + + for (const unsigned char pch : prefix) { - __glibcxx_assert(ch >= 'a' && ch <= 'z'); - if (first == last || (*first != ch && *first != ch - 32)) + // __glibcxx_assert(pch == upper_to_lower_table[pch]); + const unsigned char ch = *first; + if (ch != pch && upper_to_lower_table[ch] != pch) return false; ++first; } @@ -550,10 +554,8 @@ namespace ++first; break; } - else if ((ch >= '0' && ch <= '9') - || (ch >= 'a' && ch <= 'z') - || (ch >= 'A' && ch <= 'Z') - || ch == '_') + else if (ch == '_' + || __detail::__from_chars_alnum_to_val(ch) < 127) continue; else { @@ -614,8 +616,8 @@ namespace continue; } - int hexit = ascii_to_hexit(ch); - if (hexit == -1) + int hexit = __detail::__from_chars_alnum_to_val(ch); + if (hexit >= 16) break; seen_hexit = true; |