hunyadi-dev commented on a change in pull request #797: URL: https://github.com/apache/nifi-minifi-cpp/pull/797#discussion_r431260169
########## File path: libminifi/include/utils/ValueUtils.h ########## @@ -0,0 +1,203 @@ +/** + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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/licenseas/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. + */ + +#ifndef NIFI_MINIFI_CPP_VALUEUTILS_H +#define NIFI_MINIFI_CPP_VALUEUTILS_H + +#include <exception> +#include <string> +#include <cstring> +#include <vector> +#include <cstdlib> +#include "PropertyErrors.h" +#include <type_traits> +#include <limits> + +namespace org { +namespace apache { +namespace nifi { +namespace minifi { +namespace utils { + +class ValueParser { + private: + template< class... > + using void_t = void; + + template<typename From, typename To, typename = void> + struct is_non_narrowing_convertible: std::false_type { + static_assert(std::is_integral<From>::value && std::is_integral<To>::value, "Checks only integral values"); + }; + + template<typename From, typename To> + struct is_non_narrowing_convertible<From, To, void_t<decltype(To{std::declval<From>()})>>: std::true_type{ + static_assert(std::is_integral<From>::value && std::is_integral<To>::value, "Checks only integral values"); + }; + + public: + ValueParser(const std::string& str, std::size_t offset = 0): str(str), offset(offset) {} + + template<typename Out> + ValueParser& parseInt(Out& out) { + static_assert(is_non_narrowing_convertible<int, Out>::value, "Expected lossless conversion from int"); + try { + char *end; + long result{std::strtol(str.c_str() + offset, &end, 10)}; + offset = end - str.c_str(); + if (result < (std::numeric_limits<int>::min)() || result > (std::numeric_limits<int>::max)()) { + throw ParseException("Cannot convert long to int"); + } + out = {static_cast<int>(result)}; + return *this; + }catch(...){ + throw ParseException("Could not parse int"); + } + } + + template<typename Out> + ValueParser& parseLong(Out& out) { + static_assert(is_non_narrowing_convertible<long, Out>::value, "Expected lossless conversion from long"); + try { + char *end; + long result{std::strtol(str.c_str() + offset, &end, 10)}; + offset = end - str.c_str(); + out = {result}; + return *this; + }catch(...){ + throw ParseException("Could not parse long"); + } + } + + template<typename Out> + ValueParser& parseLongLong(Out& out) { + static_assert(is_non_narrowing_convertible<long long, Out>::value, "Expected lossless conversion from long long"); + try { + char *end; + long long result{std::strtoll(str.c_str() + offset, &end, 10)}; + offset = end - str.c_str(); + out = {result}; + return *this; + }catch(...){ + throw ParseException("Could not parse long long"); + } + } + + template<typename Out> + ValueParser& parseUInt32(Out& out) { + static_assert(is_non_narrowing_convertible<uint32_t, Out>::value, "Expected lossless conversion from uint32_t"); + try { + parseSpace(); + if (offset < str.length() && str[offset] == '-') { + throw ParseException("Not an unsigned long"); + } + char *end; + unsigned long result{std::strtoul(str.c_str() + offset, &end, 10)}; + offset = end - str.c_str(); + if (result > (std::numeric_limits<uint32_t>::max)()) { + throw ParseException("Cannot convert unsigned long to uint32_t"); + } + out = {static_cast<uint32_t>(result)}; + return *this; + }catch(...){ + throw ParseException("Could not parse unsigned long"); + } + } + + template<typename Out> + ValueParser& parseUnsignedLongLong(Out& out) { + static_assert(is_non_narrowing_convertible<unsigned long long, Out>::value, "Expected lossless conversion from unsigned long long"); + try { + parseSpace(); + if (offset < str.length() && str[offset] == '-') { + throw ParseException("Not an unsigned long"); + } + char *end; + unsigned long long result{std::strtoull(str.c_str() + offset, &end, 10)}; + offset = end - str.c_str(); + out = {result}; + return *this; + }catch(...){ + throw ParseException("Could not parse unsigned long long"); + } + } + + template<typename Out> + ValueParser& parseBool(Out& out){ + const char* options[] = {"false", "true"}; + const bool values[] = {false, true}; + auto index = parseAny(options); + if(index == -1)throw ParseException("Couldn't parse bool"); + out = values[index]; + return *this; + } + + int parseAny(const std::vector<std::string> &options) { + parseSpace(); + for (std::size_t optionIdx = 0; optionIdx < options.size(); ++optionIdx) { + const auto &option = options[optionIdx]; + if (offset + option.length() <= str.length()) { + if (std::equal(option.begin(), option.end(), str.begin() + offset)) { + offset += option.length(); + return optionIdx; + } + } + } + return -1; + } + + template<std::size_t N> + int parseAny(const char* (&options)[N]) { Review comment: Looks awfully complicated for something that should be an `std::strncmp`. What exactly is `offset` and why do we add the match length to it? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
