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// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#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) noexcept {
return (piece1.size() == piece2.size() &&
0 == absl::strings_internal::memcasecmp(piece1.data(), piece2.data(),
piece1.size()));
// memcasecmp uses absl::ascii_tolower().
}
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) 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
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