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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 "y_absl/strings/str_split.h"
- #include <algorithm>
- #include <cassert>
- #include <cstdint>
- #include <cstdlib>
- #include <cstring>
- #include <iterator>
- #include <limits>
- #include <memory>
- #include "y_absl/base/internal/raw_logging.h"
- #include "y_absl/strings/ascii.h"
- namespace y_absl {
- Y_ABSL_NAMESPACE_BEGIN
- namespace {
- // This GenericFind() template function encapsulates the finding algorithm
- // shared between the ByString and ByAnyChar delimiters. The FindPolicy
- // template parameter allows each delimiter to customize the actual find
- // function to use and the length of the found delimiter. For example, the
- // Literal delimiter will ultimately use y_absl::string_view::find(), and the
- // AnyOf delimiter will use y_absl::string_view::find_first_of().
- template <typename FindPolicy>
- y_absl::string_view GenericFind(y_absl::string_view text,
- y_absl::string_view delimiter, size_t pos,
- FindPolicy find_policy) {
- if (delimiter.empty() && text.length() > 0) {
- // Special case for empty string delimiters: always return a zero-length
- // y_absl::string_view referring to the item at position 1 past pos.
- return y_absl::string_view(text.data() + pos + 1, 0);
- }
- size_t found_pos = y_absl::string_view::npos;
- y_absl::string_view found(text.data() + text.size(),
- 0); // By default, not found
- found_pos = find_policy.Find(text, delimiter, pos);
- if (found_pos != y_absl::string_view::npos) {
- found = y_absl::string_view(text.data() + found_pos,
- find_policy.Length(delimiter));
- }
- return found;
- }
- // Finds using y_absl::string_view::find(), therefore the length of the found
- // delimiter is delimiter.length().
- struct LiteralPolicy {
- static size_t Find(y_absl::string_view text, y_absl::string_view delimiter,
- size_t pos) {
- return text.find(delimiter, pos);
- }
- static size_t Length(y_absl::string_view delimiter) {
- return delimiter.length();
- }
- };
- // Finds using y_absl::string_view::find_first_of(), therefore the length of the
- // found delimiter is 1.
- struct AnyOfPolicy {
- static size_t Find(y_absl::string_view text, y_absl::string_view delimiter,
- size_t pos) {
- return text.find_first_of(delimiter, pos);
- }
- static size_t Length(y_absl::string_view /* delimiter */) { return 1; }
- };
- } // namespace
- //
- // ByString
- //
- ByString::ByString(y_absl::string_view sp) : delimiter_(sp) {}
- y_absl::string_view ByString::Find(y_absl::string_view text, size_t pos) const {
- if (delimiter_.length() == 1) {
- // Much faster to call find on a single character than on an
- // y_absl::string_view.
- size_t found_pos = text.find(delimiter_[0], pos);
- if (found_pos == y_absl::string_view::npos)
- return y_absl::string_view(text.data() + text.size(), 0);
- return text.substr(found_pos, 1);
- }
- return GenericFind(text, delimiter_, pos, LiteralPolicy());
- }
- //
- // ByChar
- //
- y_absl::string_view ByChar::Find(y_absl::string_view text, size_t pos) const {
- size_t found_pos = text.find(c_, pos);
- if (found_pos == y_absl::string_view::npos)
- return y_absl::string_view(text.data() + text.size(), 0);
- return text.substr(found_pos, 1);
- }
- //
- // ByAnyChar
- //
- ByAnyChar::ByAnyChar(y_absl::string_view sp) : delimiters_(sp) {}
- y_absl::string_view ByAnyChar::Find(y_absl::string_view text, size_t pos) const {
- return GenericFind(text, delimiters_, pos, AnyOfPolicy());
- }
- //
- // ByLength
- //
- ByLength::ByLength(ptrdiff_t length) : length_(length) {
- Y_ABSL_RAW_CHECK(length > 0, "");
- }
- y_absl::string_view ByLength::Find(y_absl::string_view text, size_t pos) const {
- pos = std::min(pos, text.size()); // truncate `pos`
- y_absl::string_view substr = text.substr(pos);
- // If the string is shorter than the chunk size we say we
- // "can't find the delimiter" so this will be the last chunk.
- if (substr.length() <= static_cast<size_t>(length_))
- return y_absl::string_view(text.data() + text.size(), 0);
- return y_absl::string_view(substr.data() + length_, 0);
- }
- Y_ABSL_NAMESPACE_END
- } // namespace y_absl
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