From c2e754829628d1e9b7a16b3389cfdace76950fdf Mon Sep 17 00:00:00 2001 From: misterg Date: Tue, 19 Sep 2017 16:54:40 -0400 Subject: Initial Commit --- absl/strings/str_replace.cc | 79 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100644 absl/strings/str_replace.cc (limited to 'absl/strings/str_replace.cc') diff --git a/absl/strings/str_replace.cc b/absl/strings/str_replace.cc new file mode 100644 index 0000000..69efa35 --- /dev/null +++ b/absl/strings/str_replace.cc @@ -0,0 +1,79 @@ +// 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 +// +// http://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>; + +// 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* 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(s, replacements); +} + +int StrReplaceAll(strings_internal::FixedMapping replacements, std::string* target) { + return StrReplaceAll(replacements, target); +} + +} // namespace absl -- cgit v1.2.3