1// Copyright 2017 The Abseil Authors.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// https://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15#include "absl/strings/str_replace.h"
16
17#include "absl/strings/str_cat.h"
18
19namespace absl {
20namespace strings_internal {
21
22using FixedMapping =
23 std::initializer_list<std::pair<absl::string_view, absl::string_view>>;
24
25// Applies the ViableSubstitutions in subs_ptr to the absl::string_view s, and
26// stores the result in *result_ptr. Returns the number of substitutions that
27// occurred.
28int ApplySubstitutions(
29 absl::string_view s,
30 std::vector<strings_internal::ViableSubstitution>* subs_ptr,
31 std::string* result_ptr) {
32 auto& subs = *subs_ptr;
33 int substitutions = 0;
34 size_t pos = 0;
35 while (!subs.empty()) {
36 auto& sub = subs.back();
37 if (sub.offset >= pos) {
38 if (pos <= s.size()) {
39 StrAppend(result_ptr, s.substr(pos, sub.offset - pos), sub.replacement);
40 }
41 pos = sub.offset + sub.old.size();
42 substitutions += 1;
43 }
44 sub.offset = s.find(sub.old, pos);
45 if (sub.offset == s.npos) {
46 subs.pop_back();
47 } else {
48 // Insertion sort to ensure the last ViableSubstitution continues to be
49 // before all the others.
50 size_t index = subs.size();
51 while (--index && subs[index - 1].OccursBefore(subs[index])) {
52 std::swap(subs[index], subs[index - 1]);
53 }
54 }
55 }
56 result_ptr->append(s.data() + pos, s.size() - pos);
57 return substitutions;
58}
59
60} // namespace strings_internal
61
62// We can implement this in terms of the generic StrReplaceAll, but
63// we must specify the template overload because C++ cannot deduce the type
64// of an initializer_list parameter to a function, and also if we don't specify
65// the type, we just call ourselves.
66//
67// Note that we implement them here, rather than in the header, so that they
68// aren't inlined.
69
70std::string StrReplaceAll(absl::string_view s,
71 strings_internal::FixedMapping replacements) {
72 return StrReplaceAll<strings_internal::FixedMapping>(s, replacements);
73}
74
75int StrReplaceAll(strings_internal::FixedMapping replacements,
76 std::string* target) {
77 return StrReplaceAll<strings_internal::FixedMapping>(replacements, target);
78}
79
80} // namespace absl
81