diff options
Diffstat (limited to 'abseil-cpp/absl/strings/match.cc')
-rw-r--r-- | abseil-cpp/absl/strings/match.cc | 96 |
1 files changed, 93 insertions, 3 deletions
diff --git a/abseil-cpp/absl/strings/match.cc b/abseil-cpp/absl/strings/match.cc index 8127cb0..3b81b2c 100644 --- a/abseil-cpp/absl/strings/match.cc +++ b/abseil-cpp/absl/strings/match.cc @@ -14,27 +14,117 @@ #include "absl/strings/match.h" +#include <algorithm> +#include <cstdint> + +#include "absl/base/internal/endian.h" +#include "absl/numeric/bits.h" +#include "absl/strings/ascii.h" #include "absl/strings/internal/memutil.h" namespace absl { ABSL_NAMESPACE_BEGIN -bool EqualsIgnoreCase(absl::string_view piece1, absl::string_view piece2) { +bool EqualsIgnoreCase(absl::string_view piece1, + absl::string_view piece2) noexcept { return (piece1.size() == piece2.size() && 0 == absl::strings_internal::memcasecmp(piece1.data(), piece2.data(), piece1.size())); // memcasecmp uses absl::ascii_tolower(). } -bool StartsWithIgnoreCase(absl::string_view text, absl::string_view prefix) { +bool StrContainsIgnoreCase(absl::string_view haystack, + absl::string_view needle) noexcept { + while (haystack.size() >= needle.size()) { + if (StartsWithIgnoreCase(haystack, needle)) return true; + haystack.remove_prefix(1); + } + return false; +} + +bool StrContainsIgnoreCase(absl::string_view haystack, + char needle) noexcept { + char upper_needle = absl::ascii_toupper(static_cast<unsigned char>(needle)); + char lower_needle = absl::ascii_tolower(static_cast<unsigned char>(needle)); + if (upper_needle == lower_needle) { + return StrContains(haystack, needle); + } else { + const char both_cstr[3] = {lower_needle, upper_needle, '\0'}; + return haystack.find_first_of(both_cstr) != absl::string_view::npos; + } +} + +bool StartsWithIgnoreCase(absl::string_view text, + absl::string_view prefix) noexcept { return (text.size() >= prefix.size()) && EqualsIgnoreCase(text.substr(0, prefix.size()), prefix); } -bool EndsWithIgnoreCase(absl::string_view text, absl::string_view suffix) { +bool EndsWithIgnoreCase(absl::string_view text, + absl::string_view suffix) noexcept { return (text.size() >= suffix.size()) && EqualsIgnoreCase(text.substr(text.size() - suffix.size()), suffix); } +absl::string_view FindLongestCommonPrefix(absl::string_view a, + absl::string_view b) { + const absl::string_view::size_type limit = std::min(a.size(), b.size()); + const char* const pa = a.data(); + const char* const pb = b.data(); + absl::string_view::size_type count = (unsigned) 0; + + if (ABSL_PREDICT_FALSE(limit < 8)) { + while (ABSL_PREDICT_TRUE(count + 2 <= limit)) { + uint16_t xor_bytes = absl::little_endian::Load16(pa + count) ^ + absl::little_endian::Load16(pb + count); + if (ABSL_PREDICT_FALSE(xor_bytes != 0)) { + if (ABSL_PREDICT_TRUE((xor_bytes & 0xff) == 0)) ++count; + return absl::string_view(pa, count); + } + count += 2; + } + if (ABSL_PREDICT_TRUE(count != limit)) { + if (ABSL_PREDICT_TRUE(pa[count] == pb[count])) ++count; + } + return absl::string_view(pa, count); + } + + do { + uint64_t xor_bytes = absl::little_endian::Load64(pa + count) ^ + absl::little_endian::Load64(pb + count); + if (ABSL_PREDICT_FALSE(xor_bytes != 0)) { + count += static_cast<uint64_t>(absl::countr_zero(xor_bytes) >> 3); + return absl::string_view(pa, count); + } + count += 8; + } while (ABSL_PREDICT_TRUE(count + 8 < limit)); + + count = limit - 8; + uint64_t xor_bytes = absl::little_endian::Load64(pa + count) ^ + absl::little_endian::Load64(pb + count); + if (ABSL_PREDICT_TRUE(xor_bytes != 0)) { + count += static_cast<uint64_t>(absl::countr_zero(xor_bytes) >> 3); + return absl::string_view(pa, count); + } + return absl::string_view(pa, limit); +} + +absl::string_view FindLongestCommonSuffix(absl::string_view a, + absl::string_view b) { + const absl::string_view::size_type limit = std::min(a.size(), b.size()); + if (limit == 0) return absl::string_view(); + + const char* pa = a.data() + a.size() - 1; + const char* pb = b.data() + b.size() - 1; + absl::string_view::size_type count = (unsigned) 0; + while (count < limit && *pa == *pb) { + --pa; + --pb; + ++count; + } + + return absl::string_view(++pa, count); +} + ABSL_NAMESPACE_END } // namespace absl |