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/*
*
* Copyright 2015 gRPC authors.
*
* 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 <algorithm>
#include <cctype>
#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include "route_guide.grpc.pb.h"
namespace routeguide {
std::string GetDbFileContent(int argc, char** argv) {
std::string db_path;
std::string arg_str("--db_path");
if (argc > 1) {
std::string argv_1 = argv[1];
size_t start_position = argv_1.find(arg_str);
if (start_position != std::string::npos) {
start_position += arg_str.size();
if (argv_1[start_position] == ' ' ||
argv_1[start_position] == '=') {
db_path = argv_1.substr(start_position + 1);
}
}
} else {
db_path = "route_guide_db.json";
}
std::ifstream db_file(db_path);
if (!db_file.is_open()) {
std::cout << "Failed to open " << db_path << std::endl;
return "";
}
std::stringstream db;
db << db_file.rdbuf();
return db.str();
}
// A simple parser for the json db file. It requires the db file to have the
// exact form of [{"location": { "latitude": 123, "longitude": 456}, "name":
// "the name can be empty" }, { ... } ... The spaces will be stripped.
class Parser {
public:
explicit Parser(const std::string& db) : db_(db) {
// Remove all spaces.
db_.erase(
std::remove_if(db_.begin(), db_.end(), isspace),
db_.end());
if (!Match("[")) {
SetFailedAndReturnFalse();
}
}
bool Finished() {
return current_ >= db_.size();
}
bool TryParseOne(Feature* feature) {
if (failed_ || Finished() || !Match("{")) {
return SetFailedAndReturnFalse();
}
if (!Match(location_) || !Match("{") || !Match(latitude_)) {
return SetFailedAndReturnFalse();
}
long temp = 0;
ReadLong(&temp);
feature->mutable_location()->set_latitude(temp);
if (!Match(",") || !Match(longitude_)) {
return SetFailedAndReturnFalse();
}
ReadLong(&temp);
feature->mutable_location()->set_longitude(temp);
if (!Match("},") || !Match(name_) || !Match("\"")) {
return SetFailedAndReturnFalse();
}
size_t name_start = current_;
while (current_ != db_.size() && db_[current_++] != '"') {
}
if (current_ == db_.size()) {
return SetFailedAndReturnFalse();
}
feature->set_name(db_.substr(name_start, current_-name_start-1));
if (!Match("},")) {
if (db_[current_ - 1] == ']' && current_ == db_.size()) {
return true;
}
return SetFailedAndReturnFalse();
}
return true;
}
private:
bool SetFailedAndReturnFalse() {
failed_ = true;
return false;
}
bool Match(const std::string& prefix) {
bool eq = db_.substr(current_, prefix.size()) == prefix;
current_ += prefix.size();
return eq;
}
void ReadLong(long* l) {
size_t start = current_;
while (current_ != db_.size() && db_[current_] != ',' && db_[current_] != '}') {
current_++;
}
// It will throw an exception if fails.
*l = std::stol(db_.substr(start, current_ - start));
}
bool failed_ = false;
std::string db_;
size_t current_ = 0;
const std::string location_ = "\"location\":";
const std::string latitude_ = "\"latitude\":";
const std::string longitude_ = "\"longitude\":";
const std::string name_ = "\"name\":";
};
void ParseDb(const std::string& db, std::vector<Feature>* feature_list) {
feature_list->clear();
std::string db_content(db);
db_content.erase(
std::remove_if(db_content.begin(), db_content.end(), isspace),
db_content.end());
Parser parser(db_content);
Feature feature;
while (!parser.Finished()) {
feature_list->push_back(Feature());
if (!parser.TryParseOne(&feature_list->back())) {
std::cout << "Error parsing the db file";
feature_list->clear();
break;
}
}
std::cout << "DB parsed, loaded " << feature_list->size()
<< " features." << std::endl;
}
} // namespace routeguide
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