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/*
* Copyright (C) 2018 The Android Open Source Project
*
* 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 "utils/strings/substitute.h"
#include <algorithm>
#include "utils/base/logging.h"
namespace libtextclassifier3 {
namespace strings {
bool Substitute(const StringPiece format, const std::vector<StringPiece>& args,
std::string* output) {
// Determine total size needed.
size_t size = 0;
for (size_t i = 0; i < format.size(); i++) {
if (format[i] == '$') {
if (i + 1 >= format.size()) {
TC3_LOG(ERROR) << "Invalid format string: " << format.ToString();
return false;
} else if (isdigit(format[i + 1])) {
int index = format[i + 1] - '0';
if (static_cast<size_t>(index) >= args.size()) {
TC3_LOG(ERROR) << "Asked for " << index << ", but only "
<< args.size() << " arguments given";
return false;
}
size += args[index].size();
++i; // Skip next char.
} else if (format[i + 1] == '$') {
++size;
++i; // Skip next char.
} else {
TC3_LOG(ERROR) << "Invalid format string: " << format.ToString();
return false;
}
} else {
++size;
}
}
if (size == 0) {
output->clear();
return true;
}
// Build the string.
output->resize(size);
char* target = &(*output)[0];
for (size_t i = 0; i < format.size(); i++) {
if (format[i] == '$') {
if (isdigit(format[i + 1])) {
const StringPiece src = args[format[i + 1] - '0'];
target = std::copy(src.data(), src.data() + src.size(), target);
++i; // Skip next char.
} else if (format[i + 1] == '$') {
*target++ = '$';
++i; // Skip next char.
}
} else {
*target++ = format[i];
}
}
return true;
}
std::string Substitute(const StringPiece format,
const std::vector<StringPiece>& args) {
std::string result;
if (!Substitute(format, args, &result)) {
return "";
}
return result;
}
} // namespace strings
} // namespace libtextclassifier3