1 /*
2 * Copyright (C) 2018 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #ifndef NLP_SAFT_COMPONENTS_COMMON_MOBILE_LITE_STRINGS_STR_CAT_H_
18 #define NLP_SAFT_COMPONENTS_COMMON_MOBILE_LITE_STRINGS_STR_CAT_H_
19
20 // Less efficient but more compact versions of several absl string utils.
21 //
22 // "More compact" means "pulls in fewer code dependencies". That's useful if
23 // one tries to minimize the code size.
24 //
25 // Note: the name and the signature of the functions from this header were
26 // chosen to minimize the effort of converting code that uses absl::LiteStrCat &
27 // co to our more compact functions.
28
29 #include <string>
30
31 #ifdef COMPILER_MSVC
32 #include <sstream>
33 #endif // COMPILER_MSVC
34
35 namespace libtextclassifier3 {
36 namespace mobile {
37
38 // Less efficient but more compact version of absl::LiteStrCat().
39 //
40 // Given a value v (see supported types below) LiteStrCat(v) returns a new
41 // string that contains the representation of v. For examples, see
42 // str-cat_test.cc.
43 template <typename T>
LiteStrCat(T v)44 inline std::string LiteStrCat(T v) {
45 #ifdef COMPILER_MSVC
46 std::stringstream stream;
47 stream << v;
48 return stream.str();
49 #else
50 return std::to_string(v);
51 #endif
52 }
53
54 template <>
LiteStrCat(const char * v)55 inline std::string LiteStrCat(const char *v) {
56 return std::string(v);
57 }
58
59 // TODO(salcianu): use a reference type (const std::string &). For some reason,
60 // I couldn't get that to work on a first try.
61 template <>
LiteStrCat(std::string v)62 inline std::string LiteStrCat(std::string v) {
63 return v;
64 }
65
66 template <>
LiteStrCat(char v)67 inline std::string LiteStrCat(char v) {
68 return std::string(1, v);
69 }
70
71 // Less efficient but more compact version of absl::LiteStrAppend().
72 template <typename T>
LiteStrAppend(std::string * dest,T v)73 inline void LiteStrAppend(std::string *dest, T v) {
74 dest->append(LiteStrCat(v)); // NOLINT
75 }
76
77 template <typename T1, typename T2>
LiteStrAppend(std::string * dest,T1 v1,T2 v2)78 inline void LiteStrAppend(std::string *dest, T1 v1, T2 v2) {
79 dest->append(LiteStrCat(v1)); // NOLINT
80 dest->append(LiteStrCat(v2)); // NOLINT
81 }
82
83 template <typename T1, typename T2, typename T3>
LiteStrAppend(std::string * dest,T1 v1,T2 v2,T3 v3)84 inline void LiteStrAppend(std::string *dest, T1 v1, T2 v2, T3 v3) {
85 LiteStrAppend(dest, v1, v2);
86 dest->append(LiteStrCat(v3)); // NOLINT
87 }
88
89 template <typename T1, typename T2, typename T3, typename T4>
LiteStrAppend(std::string * dest,T1 v1,T2 v2,T3 v3,T4 v4)90 inline void LiteStrAppend(std::string *dest, T1 v1, T2 v2, T3 v3, T4 v4) {
91 LiteStrAppend(dest, v1, v2, v3);
92 dest->append(LiteStrCat(v4)); // NOLINT
93 }
94
95 } // namespace mobile
96 } // namespace nlp_saft
97
98 #endif // NLP_SAFT_COMPONENTS_COMMON_MOBILE_LITE_STRINGS_STR_CAT_H_
99