pub/ImplabNet: Implab/Formats/Json/JsonReader.cs comparison

comparison Implab/Formats/Json/JsonReader.cs @ 232:133ba4444acc v2

Слияние

author	cin
date	Thu, 21 Sep 2017 01:14:27 +0300
parents	3e26338eb977
children	302ca905c19e

comparison

equal deleted inserted replaced

-:3eaa9372c754
+:133ba4444acc
+using System;
+using System.Diagnostics;
+using System.IO;
+using Implab.Automaton;
+using Implab.Automaton.RegularExpressions;
+using System.Linq;
+using Implab.Components;
+using System.Collections.Generic;
+using System.Text;
+using System.Globalization;
+namespace Implab.Formats.Json {
+/// <summary>
+/// Pull парсер JSON данных.
+/// </summary>
+/// <remarks>
+/// Следует отметить отдельную интерпретацию свойства <see cref="Level"/>,
+/// оно означает текущий уровень вложенности объектов, однако закрывающий
+/// элемент объекта и массива имеет уровень меньше, чем сам объект.
+/// <code>
+/// { // Level = 1
+///     "name" : "Peter", // Level = 1
+///     "address" : { // Level = 2
+///         city : "Stern" // Level = 2
+///     } // Level = 1
+/// } // Level = 0
+/// </code>
+/// </remarks>
+public class JsonReader : Disposable {
+enum MemberContext {
+MemberName,
+MemberValue
+}
+#region Parser rules
+struct ParserContext {
+readonly int[,] m_dfa;
+int m_state;
+readonly JsonElementContext m_elementContext;
+public ParserContext(int[,] dfa, int state, JsonElementContext context) {
+m_dfa = dfa;
+m_state = state;
+m_elementContext = context;
+}
+public bool Move(JsonTokenType token) {
+var next = m_dfa[m_state, (int)token];
+if (next == AutomatonConst.UNREACHABLE_STATE)
+return false;
+m_state = next;
+return true;
+}
+public JsonElementContext ElementContext {
+get { return m_elementContext; }
+}
+}
+static readonly ParserContext _jsonContext;
+static readonly ParserContext _objectContext;
+static readonly ParserContext _arrayContext;
+static JsonReader() {
+var valueExpression = MakeToken(JsonTokenType.BeginArray, JsonTokenType.BeginObject, JsonTokenType.Literal, JsonTokenType.Number, JsonTokenType.String);
+var memberExpression = MakeToken(JsonTokenType.String).Cat(MakeToken(JsonTokenType.NameSeparator)).Cat(valueExpression);
+var objectExpression = memberExpression
+.Cat(
+MakeToken(JsonTokenType.ValueSeparator)
+.Cat(memberExpression)
+.EClosure()
+)
+.Optional()
+.Cat(MakeToken(JsonTokenType.EndObject))
+.End();
+var arrayExpression = valueExpression
+.Cat(
+MakeToken(JsonTokenType.ValueSeparator)
+.Cat(valueExpression)
+.EClosure()
+)
+.Optional()
+.Cat(MakeToken(JsonTokenType.EndArray))
+.End();
+var jsonExpression = valueExpression.End();
+_jsonContext = CreateParserContext(jsonExpression, JsonElementContext.None);
+_objectContext = CreateParserContext(objectExpression, JsonElementContext.Object);
+_arrayContext = CreateParserContext(arrayExpression, JsonElementContext.Array);
+}
+static Token MakeToken(params JsonTokenType[] input) {
+return Token.New( input.Select(t => (int)t).ToArray() );
+}
+static ParserContext CreateParserContext(Token expr, JsonElementContext context) {
+var dfa = new DFATable();
+var builder = new RegularExpressionVisitor(dfa);
+expr.Accept(builder);
+builder.BuildDFA();
+return new ParserContext(dfa.CreateTransitionTable(), dfa.InitialState, context);
+}
+#endregion
+readonly JsonScanner m_scanner;
+// json starts from the value context and may content even a single literal
+MemberContext m_memberContext = MemberContext.MemberValue;
+JsonElementType m_elementType;
+object m_elementValue;
+string m_memberName = String.Empty;
+Stack<ParserContext> m_stack = new Stack<ParserContext>();
+ParserContext m_context = _jsonContext;
+/// <summary>
+/// Создает новый парсер на основе строки, содержащей JSON
+/// </summary>
+/// <param name="text"></param>
+JsonReader(JsonScanner scanner) {
+m_scanner = scanner;
+}
+public int Level {
+get { return m_stack.Count; }
+}
+/// <summary>
+/// Тип текущего элемента на котором стоит парсер.
+/// </summary>
+public JsonElementType ElementType {
+get { return m_elementType; }
+}
+/// <summary>
+/// Имя элемента - имя свойства родительского контейнера. Для элементов массивов и корневого всегда
+/// пустая строка.
+/// </summary>
+public string ElementName {
+get { return m_memberName; }
+}
+/// <summary>
+/// Значение элемента. Только для элементов типа <see cref="JsonElementType.Value"/>, для остальных <c>null</c>
+/// </summary>
+public object ElementValue {
+get { return m_elementValue; }
+}
+/// <summary>
+/// Читает слеюудущий объект из потока
+/// </summary>
+/// <returns><c>true</c> - операция чтения прошла успешно, <c>false</c> - конец данных</returns>
+public bool Read() {
+string tokenValue;
+JsonTokenType tokenType;
+m_memberName = String.Empty;
+while (m_scanner.ReadToken(out tokenValue, out tokenType)) {
+if(!m_context.Move(tokenType))
+UnexpectedToken(tokenValue, tokenType);
+switch (tokenType) {
+case JsonTokenType.BeginObject:
+m_stack.Push(m_context);
+m_context = _objectContext;
+m_elementValue = null;
+m_memberContext = MemberContext.MemberName;
+m_elementType = JsonElementType.BeginObject;
+return true;
+case JsonTokenType.EndObject:
+if (m_stack.Count == 0)
+UnexpectedToken(tokenValue, tokenType);
+m_context = m_stack.Pop();
+m_elementValue = null;
+m_elementType = JsonElementType.EndObject;
+return true;
+case JsonTokenType.BeginArray:
+m_stack.Push(m_context);
+m_context = _arrayContext;
+m_elementValue = null;
+m_memberContext = MemberContext.MemberValue;
+m_elementType = JsonElementType.BeginArray;
+return true;
+case JsonTokenType.EndArray:
+if (m_stack.Count == 0)
+UnexpectedToken(tokenValue, tokenType);
+m_context = m_stack.Pop();
+m_elementValue = null;
+m_elementType = JsonElementType.EndArray;
+return true;
+case JsonTokenType.String:
+if (m_memberContext == MemberContext.MemberName) {
+m_memberName = tokenValue;
+break;
+}
+m_elementType = JsonElementType.Value;
+m_elementValue = tokenValue;
+return true;
+case JsonTokenType.Number:
+m_elementType = JsonElementType.Value;
+m_elementValue = double.Parse(tokenValue, CultureInfo.InvariantCulture);
+return true;
+case JsonTokenType.Literal:
+m_elementType = JsonElementType.Value;
+m_elementValue = ParseLiteral(tokenValue);
+return true;
+case JsonTokenType.NameSeparator:
+m_memberContext = MemberContext.MemberValue;
+break;
+case JsonTokenType.ValueSeparator:
+m_memberContext = m_context.ElementContext == JsonElementContext.Object ? MemberContext.MemberName : MemberContext.MemberValue;
+break;
+default:
+UnexpectedToken(tokenValue, tokenType);
+break;
+}
+}
+if (m_context.ElementContext != JsonElementContext.None)
+throw new ParserException("Unexpedted end of data");
+Eof = true;
+return false;
+}
+object ParseLiteral(string literal) {
+switch (literal) {
+case "null":
+return null;
+case "false":
+return false;
+case "true":
+return true;
+default:
+UnexpectedToken(literal, JsonTokenType.Literal);
+return null; // avoid compliler error
+}
+}
+void UnexpectedToken(object value, JsonTokenType tokenType) {
+throw new ParserException(String.Format("Unexpected token {0}: '{1}'", tokenType, value));
+}
+/// <summary>
+/// Признак конца потока
+/// </summary>
+public bool Eof {
+get;
+private set;
+}
+protected override void Dispose(bool disposing) {
+if (disposing)
+m_scanner.Dispose();
+}
+/// <summary>
+/// Переходит в конец текущего объекта.
+/// </summary>
+public void SeekElementEnd() {
+var level = Level - 1;
+Debug.Assert(level >= 0);
+while (Level != level)
+Read();
+}
+public static JsonReader Create(string file, Encoding encoding) {
+return new JsonReader(JsonTextScanner.Create(file, encoding));
+}
+public static JsonReader Create(string file) {
+return new JsonReader(JsonTextScanner.Create(file));
+}
+public static JsonReader Create(Stream stream, Encoding encoding) {
+return new JsonReader(JsonTextScanner.Create(stream, encoding));
+}
+public static JsonReader Create(Stream stream) {
+return new JsonReader(JsonTextScanner.Create(stream));
+}
+public static JsonReader Create(TextReader reader) {
+return new JsonReader(JsonTextScanner.Create(reader));
+}
+public static JsonReader ParseString(string data) {
+return new JsonReader(JsonStringScanner.Create(data));
+}
+public static JsonReader ParseString(string data, int offset, int length) {
+return new JsonReader(JsonStringScanner.Create(data, offset, length));
+}
+public static JsonReader ParseString(char[] data, int offset, int lenght) {
+return new JsonReader(JsonStringScanner.Create(data, offset, lenght));
+}
+}
+}

Mercurial > pub > ImplabNet

comparison Implab/Formats/Json/JsonReader.cs @ 232:133ba4444acc v2