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 <cstddef>
18 #include <initializer_list>
19 #include <string>
20 #include <utility>
21 #include <vector>
22
23 #include "absl/base/config.h"
24 #include "absl/base/nullability.h"
25 #include "absl/strings/str_cat.h"
26 #include "absl/strings/string_view.h"
27
28 namespace absl {
29 ABSL_NAMESPACE_BEGIN
30 namespace strings_internal {
31
32 using FixedMapping =
33 std::initializer_list<std::pair<absl::string_view, absl::string_view>>;
34
35 // Applies the ViableSubstitutions in subs_ptr to the absl::string_view s, and
36 // stores the result in *result_ptr. Returns the number of substitutions that
37 // occurred.
ApplySubstitutions(absl::string_view s,absl::Nonnull<std::vector<strings_internal::ViableSubstitution> * > subs_ptr,absl::Nonnull<std::string * > result_ptr)38 int ApplySubstitutions(
39 absl::string_view s,
40 absl::Nonnull<std::vector<strings_internal::ViableSubstitution>*> subs_ptr,
41 absl::Nonnull<std::string*> result_ptr) {
42 auto& subs = *subs_ptr;
43 int substitutions = 0;
44 size_t pos = 0;
45 while (!subs.empty()) {
46 auto& sub = subs.back();
47 if (sub.offset >= pos) {
48 if (pos <= s.size()) {
49 StrAppend(result_ptr, s.substr(pos, sub.offset - pos), sub.replacement);
50 }
51 pos = sub.offset + sub.old.size();
52 substitutions += 1;
53 }
54 sub.offset = s.find(sub.old, pos);
55 if (sub.offset == s.npos) {
56 subs.pop_back();
57 } else {
58 // Insertion sort to ensure the last ViableSubstitution continues to be
59 // before all the others.
60 size_t index = subs.size();
61 while (--index && subs[index - 1].OccursBefore(subs[index])) {
62 std::swap(subs[index], subs[index - 1]);
63 }
64 }
65 }
66 result_ptr->append(s.data() + pos, s.size() - pos);
67 return substitutions;
68 }
69
70 } // namespace strings_internal
71
72 // We can implement this in terms of the generic StrReplaceAll, but
73 // we must specify the template overload because C++ cannot deduce the type
74 // of an initializer_list parameter to a function, and also if we don't specify
75 // the type, we just call ourselves.
76 //
77 // Note that we implement them here, rather than in the header, so that they
78 // aren't inlined.
79
StrReplaceAll(absl::string_view s,strings_internal::FixedMapping replacements)80 std::string StrReplaceAll(absl::string_view s,
81 strings_internal::FixedMapping replacements) {
82 return StrReplaceAll<strings_internal::FixedMapping>(s, replacements);
83 }
84
StrReplaceAll(strings_internal::FixedMapping replacements,absl::Nonnull<std::string * > target)85 int StrReplaceAll(strings_internal::FixedMapping replacements,
86 absl::Nonnull<std::string*> target) {
87 return StrReplaceAll<strings_internal::FixedMapping>(replacements, target);
88 }
89
90 ABSL_NAMESPACE_END
91 } // namespace absl
92