Abseil Common Libraries (C++) (grcp 依赖)
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80 lines
2.7 KiB
80 lines
2.7 KiB
// Copyright 2017 The Abseil Authors. |
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// |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// https://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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#include "absl/strings/str_replace.h" |
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#include "absl/strings/str_cat.h" |
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namespace absl { |
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namespace strings_internal { |
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using FixedMapping = |
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std::initializer_list<std::pair<absl::string_view, absl::string_view>>; |
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// Applies the ViableSubstitutions in subs_ptr to the absl::string_view s, and |
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// stores the result in *result_ptr. Returns the number of substitutions that |
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// occurred. |
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int ApplySubstitutions( |
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absl::string_view s, |
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std::vector<strings_internal::ViableSubstitution>* subs_ptr, |
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std::string* result_ptr) { |
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auto& subs = *subs_ptr; |
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int substitutions = 0; |
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size_t pos = 0; |
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while (!subs.empty()) { |
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auto& sub = subs.back(); |
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if (sub.offset >= pos) { |
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if (pos <= s.size()) { |
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StrAppend(result_ptr, s.substr(pos, sub.offset - pos), sub.replacement); |
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} |
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pos = sub.offset + sub.old.size(); |
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substitutions += 1; |
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} |
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sub.offset = s.find(sub.old, pos); |
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if (sub.offset == s.npos) { |
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subs.pop_back(); |
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} else { |
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// Insertion sort to ensure the last ViableSubstitution continues to be |
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// before all the others. |
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size_t index = subs.size(); |
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while (--index && subs[index - 1].OccursBefore(subs[index])) { |
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std::swap(subs[index], subs[index - 1]); |
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} |
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} |
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} |
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result_ptr->append(s.data() + pos, s.size() - pos); |
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return substitutions; |
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} |
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} // namespace strings_internal |
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// We can implement this in terms of the generic StrReplaceAll, but |
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// we must specify the template overload because C++ cannot deduce the type |
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// of an initializer_list parameter to a function, and also if we don't specify |
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// the type, we just call ourselves. |
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// |
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// Note that we implement them here, rather than in the header, so that they |
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// aren't inlined. |
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std::string StrReplaceAll(absl::string_view s, |
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strings_internal::FixedMapping replacements) { |
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return StrReplaceAll<strings_internal::FixedMapping>(s, replacements); |
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} |
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int StrReplaceAll(strings_internal::FixedMapping replacements, |
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std::string* target) { |
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return StrReplaceAll<strings_internal::FixedMapping>(replacements, target); |
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} |
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} // namespace absl
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