| // 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_replace.h" |
| |
| #include "absl/strings/str_cat.h" |
| |
| namespace absl { |
| namespace strings_internal { |
| |
| using FixedMapping = |
| std::initializer_list<std::pair<absl::string_view, absl::string_view>>; |
| |
| // Applies the ViableSubstitutions in subs_ptr to the absl::string_view s, and |
| // stores the result in *result_ptr. Returns the number of substitutions that |
| // occurred. |
| int ApplySubstitutions( |
| absl::string_view s, |
| std::vector<strings_internal::ViableSubstitution>* subs_ptr, |
| std::string* result_ptr) { |
| auto& subs = *subs_ptr; |
| int substitutions = 0; |
| size_t pos = 0; |
| while (!subs.empty()) { |
| auto& sub = subs.back(); |
| if (sub.offset >= pos) { |
| if (pos <= s.size()) { |
| StrAppend(result_ptr, s.substr(pos, sub.offset - pos), sub.replacement); |
| } |
| pos = sub.offset + sub.old.size(); |
| substitutions += 1; |
| } |
| sub.offset = s.find(sub.old, pos); |
| if (sub.offset == s.npos) { |
| subs.pop_back(); |
| } else { |
| // Insertion sort to ensure the last ViableSubstitution continues to be |
| // before all the others. |
| size_t index = subs.size(); |
| while (--index && subs[index - 1].OccursBefore(subs[index])) { |
| std::swap(subs[index], subs[index - 1]); |
| } |
| } |
| } |
| result_ptr->append(s.data() + pos, s.size() - pos); |
| return substitutions; |
| } |
| |
| } // namespace strings_internal |
| |
| // We can implement this in terms of the generic StrReplaceAll, but |
| // we must specify the template overload because C++ cannot deduce the type |
| // of an initializer_list parameter to a function, and also if we don't specify |
| // the type, we just call ourselves. |
| // |
| // Note that we implement them here, rather than in the header, so that they |
| // aren't inlined. |
| |
| std::string StrReplaceAll(absl::string_view s, |
| strings_internal::FixedMapping replacements) { |
| return StrReplaceAll<strings_internal::FixedMapping>(s, replacements); |
| } |
| |
| int StrReplaceAll(strings_internal::FixedMapping replacements, |
| std::string* target) { |
| return StrReplaceAll<strings_internal::FixedMapping>(replacements, target); |
| } |
| |
| } // namespace absl |