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 #include "utils/strings/substitute.h" 18 19 #include <algorithm> 20 21 #include "utils/base/logging.h" 22 23 namespace libtextclassifier3 { 24 namespace strings { 25 26 bool Substitute(const StringPiece format, const std::vector<StringPiece>& args, 27 std::string* output) { 28 // Determine total size needed. 29 size_t size = 0; 30 for (size_t i = 0; i < format.size(); i++) { 31 if (format[i] == '$') { 32 if (i + 1 >= format.size()) { 33 TC3_LOG(ERROR) << "Invalid format string: " << format.ToString(); 34 return false; 35 } else if (isdigit(format[i + 1])) { 36 int index = format[i + 1] - '0'; 37 if (static_cast<size_t>(index) >= args.size()) { 38 TC3_LOG(ERROR) << "Asked for " << index << ", but only " 39 << args.size() << " arguments given"; 40 return false; 41 } 42 size += args[index].size(); 43 ++i; // Skip next char. 44 } else if (format[i + 1] == '$') { 45 ++size; 46 ++i; // Skip next char. 47 } else { 48 TC3_LOG(ERROR) << "Invalid format string: " << format.ToString(); 49 return false; 50 } 51 } else { 52 ++size; 53 } 54 } 55 56 if (size == 0) { 57 output->clear(); 58 return true; 59 } 60 61 // Build the string. 62 output->resize(size); 63 char* target = &(*output)[0]; 64 for (size_t i = 0; i < format.size(); i++) { 65 if (format[i] == '$') { 66 if (isdigit(format[i + 1])) { 67 const StringPiece src = args[format[i + 1] - '0']; 68 target = std::copy(src.data(), src.data() + src.size(), target); 69 ++i; // Skip next char. 70 } else if (format[i + 1] == '$') { 71 *target++ = '$'; 72 ++i; // Skip next char. 73 } 74 } else { 75 *target++ = format[i]; 76 } 77 } 78 return true; 79 } 80 81 std::string Substitute(const StringPiece format, 82 const std::vector<StringPiece>& args) { 83 std::string result; 84 if (!Substitute(format, args, &result)) { 85 return ""; 86 } 87 return result; 88 } 89 90 } // namespace strings 91 } // namespace libtextclassifier3 92
