cpp-json/json_parser.cpp

//
//  json_parser.cpp
//  json
//
//  Created by Sam Jaffe on 4/24/16.
//

#include <iostream>

#include "json.hpp"

#include "json_common.hpp"

namespace json { namespace {
  void parse_object(value& json, char const*& data);
  void parse_array(value& json, char const*& data);
  void parse_one_token(value& json, char const*& data);
  
  void parse_one_token(value& json, char const*& data) {
    const char ch = helper::get_next_element(data);
    if (ch == '{') {
      parse_object(json, ++data);
    } else if (ch == '[') {
      parse_array(json, ++data);
    } else if (ch == '"') {
      helper::parse_string(json, ++data);
    } else if (!strncmp(data, "true", 4)) {
      json = true;
    } else if (!strncmp(data, "false", 5)) {
      json = false;
    } else {
      helper::parse_numeric(json, data);
    }
  }
      
  void parse_object(value& json, char const*& data) {
    std::string key;
    while (*data && *data != '}') {
      helper::parse_string(key, data);
      if (helper::get_next_element(data) != ':') {
        throw malformed_json_exception(std::string("Expected key:value pair delimited by ':', got '") + *data + "' instead");
      }
      parse_one_token(json[key], ++data);
      helper::advance_to_boundary('}', data);
    }
    if (*data) ++data;
    else throw malformed_json_exception("Reached end of parse string without finding object end");
  }
  
  void parse_array(value& json, char const*& data) {
    size_t current_idx = 0;
    while (*data && *data != ']') {
      parse_one_token(json[current_idx++], data);
      helper::advance_to_boundary(']', data);
    }
    if (*data) ++data;
    else throw malformed_json_exception("Reached end of parse string without finding array end");
  }
} }

namespace json {
  namespace parser {
    void parse(json::value& json, char const* data) {
      parse_one_token(json, data);
      if (*data) throw malformed_json_exception("Expected a single json token in top-level parse");
    }
    
    void parse(json::value& json, std::istream & in) {
      in.seekg(0, std::ios_base::end);
      std::istream::pos_type end = in.tellg();
      std::unique_ptr<char[]> data{new char[end]};
      in.seekg(0);
      in.read(data.get(), end);
      parse(json, data.get());
    }
  }
}

void json::value::parse(char const* data) {
  json::parser::parse(*this, data);
}

void json::value::parse(std::string const& str) {
  json::parser::parse(*this, str.c_str());
}

void json::value::parse(std::istream & in) {
  json::parser::parse(*this, in);
}