80 lines
2.7 KiB
C++
80 lines
2.7 KiB
C++
// 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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