| // 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/str_split.h" |
| |
| #include <algorithm> |
| #include <cassert> |
| #include <cstdint> |
| #include <cstdlib> |
| #include <cstring> |
| #include <iterator> |
| #include <limits> |
| #include <memory> |
| |
| #include "absl/base/internal/raw_logging.h" |
| #include "absl/strings/ascii.h" |
| |
| namespace absl { |
| |
| 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 absl::string_view::find(), and the |
| // AnyOf delimiter will use absl::string_view::find_first_of(). |
| template <typename FindPolicy> |
| absl::string_view GenericFind(absl::string_view text, |
| absl::string_view delimiter, size_t pos, |
| FindPolicy find_policy) { |
| if (delimiter.empty() && text.length() > 0) { |
| // Special case for empty std::string delimiters: always return a zero-length |
| // absl::string_view referring to the item at position 1 past pos. |
| return absl::string_view(text.data() + pos + 1, 0); |
| } |
| size_t found_pos = absl::string_view::npos; |
| absl::string_view found(text.data() + text.size(), |
| 0); // By default, not found |
| found_pos = find_policy.Find(text, delimiter, pos); |
| if (found_pos != absl::string_view::npos) { |
| found = absl::string_view(text.data() + found_pos, |
| find_policy.Length(delimiter)); |
| } |
| return found; |
| } |
| |
| // Finds using absl::string_view::find(), therefore the length of the found |
| // delimiter is delimiter.length(). |
| struct LiteralPolicy { |
| size_t Find(absl::string_view text, absl::string_view delimiter, size_t pos) { |
| return text.find(delimiter, pos); |
| } |
| size_t Length(absl::string_view delimiter) { return delimiter.length(); } |
| }; |
| |
| // Finds using absl::string_view::find_first_of(), therefore the length of the |
| // found delimiter is 1. |
| struct AnyOfPolicy { |
| size_t Find(absl::string_view text, absl::string_view delimiter, size_t pos) { |
| return text.find_first_of(delimiter, pos); |
| } |
| size_t Length(absl::string_view /* delimiter */) { return 1; } |
| }; |
| |
| } // namespace |
| |
| // |
| // ByString |
| // |
| |
| ByString::ByString(absl::string_view sp) : delimiter_(sp) {} |
| |
| absl::string_view ByString::Find(absl::string_view text, size_t pos) const { |
| if (delimiter_.length() == 1) { |
| // Much faster to call find on a single character than on an |
| // absl::string_view. |
| size_t found_pos = text.find(delimiter_[0], pos); |
| if (found_pos == absl::string_view::npos) |
| return absl::string_view(text.data() + text.size(), 0); |
| return text.substr(found_pos, 1); |
| } |
| return GenericFind(text, delimiter_, pos, LiteralPolicy()); |
| } |
| |
| // |
| // ByChar |
| // |
| |
| absl::string_view ByChar::Find(absl::string_view text, size_t pos) const { |
| size_t found_pos = text.find(c_, pos); |
| if (found_pos == absl::string_view::npos) |
| return absl::string_view(text.data() + text.size(), 0); |
| return text.substr(found_pos, 1); |
| } |
| |
| // |
| // ByAnyChar |
| // |
| |
| ByAnyChar::ByAnyChar(absl::string_view sp) : delimiters_(sp) {} |
| |
| absl::string_view ByAnyChar::Find(absl::string_view text, size_t pos) const { |
| return GenericFind(text, delimiters_, pos, AnyOfPolicy()); |
| } |
| |
| // |
| // ByLength |
| // |
| ByLength::ByLength(ptrdiff_t length) : length_(length) { |
| ABSL_RAW_CHECK(length > 0, ""); |
| } |
| |
| absl::string_view ByLength::Find(absl::string_view text, |
| size_t pos) const { |
| pos = std::min(pos, text.size()); // truncate `pos` |
| absl::string_view substr = text.substr(pos); |
| // If the std::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 absl::string_view(text.data() + text.size(), 0); |
| |
| return absl::string_view(substr.data() + length_, 0); |
| } |
| |
| } // namespace absl |