#region Header
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/**
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* Lexer.cs
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* JSON lexer implementation based on a finite state machine.
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*
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* The authors disclaim copyright to this source code. For more details, see
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* the COPYING file included with this distribution.
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**/
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#endregion
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|
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using System;
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using System.Collections.Generic;
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using System.IO;
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using System.Text;
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|
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namespace LitJson
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{
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internal class FsmContext
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{
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public bool Return;
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public int NextState;
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public Lexer L;
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public int StateStack;
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}
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|
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internal class Lexer
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{
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#region Fields
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private delegate bool StateHandler (FsmContext ctx);
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private static readonly int[] fsm_return_table;
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private static readonly StateHandler[] fsm_handler_table;
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private bool allow_comments;
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private bool allow_single_quoted_strings;
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private bool end_of_input;
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private FsmContext fsm_context;
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private int input_buffer;
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private int input_char;
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private TextReader reader;
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private int state;
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private StringBuilder string_buffer;
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private string string_value;
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private int token;
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private int unichar;
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#endregion
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|
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#region Properties
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public bool AllowComments {
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get { return allow_comments; }
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set { allow_comments = value; }
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}
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public bool AllowSingleQuotedStrings {
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get { return allow_single_quoted_strings; }
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set { allow_single_quoted_strings = value; }
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}
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public bool EndOfInput {
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get { return end_of_input; }
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}
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public int Token {
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get { return token; }
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}
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public string StringValue {
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get { return string_value; }
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}
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#endregion
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#region Constructors
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static Lexer ()
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{
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PopulateFsmTables (out fsm_handler_table, out fsm_return_table);
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}
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public Lexer (TextReader reader)
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{
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allow_comments = true;
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allow_single_quoted_strings = true;
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input_buffer = 0;
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string_buffer = new StringBuilder (128);
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state = 1;
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end_of_input = false;
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this.reader = reader;
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fsm_context = new FsmContext ();
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fsm_context.L = this;
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}
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#endregion
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#region Static Methods
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private static int HexValue (int digit)
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{
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switch (digit) {
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case 'a':
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case 'A':
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return 10;
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case 'b':
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case 'B':
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return 11;
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case 'c':
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case 'C':
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return 12;
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case 'd':
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case 'D':
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return 13;
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case 'e':
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case 'E':
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return 14;
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case 'f':
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case 'F':
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return 15;
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default:
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return digit - '0';
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}
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}
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private static void PopulateFsmTables (out StateHandler[] fsm_handler_table, out int[] fsm_return_table)
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{
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// See section A.1. of the manual for details of the finite
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// state machine.
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fsm_handler_table = new StateHandler[28] {
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State1,
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State2,
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State3,
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State4,
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State5,
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State6,
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State7,
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State8,
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State9,
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State10,
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State11,
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State12,
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State13,
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State14,
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State15,
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State16,
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State17,
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State18,
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State19,
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State20,
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State21,
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State22,
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State23,
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State24,
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State25,
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State26,
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State27,
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State28
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};
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fsm_return_table = new int[28] {
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(int) ParserToken.Char,
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0,
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(int) ParserToken.Number,
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(int) ParserToken.Number,
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0,
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(int) ParserToken.Number,
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0,
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(int) ParserToken.Number,
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0,
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0,
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(int) ParserToken.True,
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0,
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0,
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0,
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(int) ParserToken.False,
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0,
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0,
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(int) ParserToken.Null,
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(int) ParserToken.CharSeq,
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(int) ParserToken.Char,
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0,
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0,
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(int) ParserToken.CharSeq,
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(int) ParserToken.Char,
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0,
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0,
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0,
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0
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};
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}
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private static char ProcessEscChar (int esc_char)
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{
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switch (esc_char) {
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case '"':
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case '\'':
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case '\\':
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case '/':
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return Convert.ToChar (esc_char);
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case 'n':
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return '\n';
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case 't':
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return '\t';
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case 'r':
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return '\r';
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case 'b':
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return '\b';
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case 'f':
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return '\f';
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default:
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// Unreachable
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return '?';
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}
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}
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private static bool State1 (FsmContext ctx)
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{
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while (ctx.L.GetChar ()) {
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if (ctx.L.input_char == ' ' ||
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ctx.L.input_char >= '\t' && ctx.L.input_char <= '\r')
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continue;
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if (ctx.L.input_char >= '1' && ctx.L.input_char <= '9') {
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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ctx.NextState = 3;
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return true;
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}
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switch (ctx.L.input_char) {
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case '"':
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ctx.NextState = 19;
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ctx.Return = true;
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return true;
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case ',':
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case ':':
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case '[':
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case ']':
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case '{':
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case '}':
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ctx.NextState = 1;
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ctx.Return = true;
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return true;
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case '-':
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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ctx.NextState = 2;
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return true;
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case '0':
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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ctx.NextState = 4;
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return true;
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case 'f':
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ctx.NextState = 12;
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return true;
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case 'n':
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ctx.NextState = 16;
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return true;
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case 't':
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ctx.NextState = 9;
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return true;
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case '\'':
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if (! ctx.L.allow_single_quoted_strings)
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return false;
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ctx.L.input_char = '"';
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ctx.NextState = 23;
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ctx.Return = true;
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return true;
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case '/':
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if (! ctx.L.allow_comments)
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return false;
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ctx.NextState = 25;
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return true;
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default:
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return false;
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}
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}
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return true;
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}
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private static bool State2 (FsmContext ctx)
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{
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ctx.L.GetChar ();
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if (ctx.L.input_char >= '1' && ctx.L.input_char<= '9') {
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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ctx.NextState = 3;
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return true;
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}
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switch (ctx.L.input_char) {
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case '0':
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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ctx.NextState = 4;
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return true;
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default:
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return false;
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}
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}
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private static bool State3 (FsmContext ctx)
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{
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while (ctx.L.GetChar ()) {
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if (ctx.L.input_char >= '0' && ctx.L.input_char <= '9') {
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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continue;
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}
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if (ctx.L.input_char == ' ' ||
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ctx.L.input_char >= '\t' && ctx.L.input_char <= '\r') {
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ctx.Return = true;
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ctx.NextState = 1;
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return true;
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}
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switch (ctx.L.input_char) {
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case ',':
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case ']':
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case '}':
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ctx.L.UngetChar ();
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ctx.Return = true;
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ctx.NextState = 1;
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return true;
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case '.':
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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ctx.NextState = 5;
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return true;
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case 'e':
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case 'E':
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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ctx.NextState = 7;
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return true;
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default:
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return false;
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}
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}
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return true;
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}
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private static bool State4 (FsmContext ctx)
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{
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ctx.L.GetChar ();
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if (ctx.L.input_char == ' ' ||
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ctx.L.input_char >= '\t' && ctx.L.input_char <= '\r') {
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ctx.Return = true;
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ctx.NextState = 1;
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return true;
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}
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switch (ctx.L.input_char) {
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case ',':
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case ']':
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case '}':
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ctx.L.UngetChar ();
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ctx.Return = true;
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ctx.NextState = 1;
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return true;
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case '.':
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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ctx.NextState = 5;
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return true;
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case 'e':
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case 'E':
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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ctx.NextState = 7;
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return true;
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default:
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return false;
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}
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}
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private static bool State5 (FsmContext ctx)
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{
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ctx.L.GetChar ();
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if (ctx.L.input_char >= '0' && ctx.L.input_char <= '9') {
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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ctx.NextState = 6;
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return true;
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}
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return false;
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}
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private static bool State6 (FsmContext ctx)
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{
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while (ctx.L.GetChar ()) {
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if (ctx.L.input_char >= '0' && ctx.L.input_char <= '9') {
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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continue;
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}
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if (ctx.L.input_char == ' ' ||
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ctx.L.input_char >= '\t' && ctx.L.input_char <= '\r') {
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ctx.Return = true;
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ctx.NextState = 1;
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return true;
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}
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switch (ctx.L.input_char) {
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case ',':
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case ']':
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case '}':
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ctx.L.UngetChar ();
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ctx.Return = true;
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ctx.NextState = 1;
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return true;
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case 'e':
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case 'E':
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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ctx.NextState = 7;
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return true;
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default:
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return false;
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}
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}
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return true;
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}
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private static bool State7 (FsmContext ctx)
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{
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ctx.L.GetChar ();
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if (ctx.L.input_char >= '0' && ctx.L.input_char<= '9') {
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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ctx.NextState = 8;
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return true;
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}
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switch (ctx.L.input_char) {
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case '+':
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case '-':
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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ctx.NextState = 8;
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return true;
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default:
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return false;
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}
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}
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private static bool State8 (FsmContext ctx)
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{
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while (ctx.L.GetChar ()) {
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if (ctx.L.input_char >= '0' && ctx.L.input_char<= '9') {
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ctx.L.string_buffer.Append ((char) ctx.L.input_char);
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continue;
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}
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if (ctx.L.input_char == ' ' ||
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ctx.L.input_char >= '\t' && ctx.L.input_char<= '\r') {
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ctx.Return = true;
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ctx.NextState = 1;
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return true;
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}
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switch (ctx.L.input_char) {
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case ',':
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case ']':
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case '}':
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ctx.L.UngetChar ();
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ctx.Return = true;
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ctx.NextState = 1;
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return true;
|
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default:
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return false;
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}
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}
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return true;
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}
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private static bool State9 (FsmContext ctx)
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{
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ctx.L.GetChar ();
|
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switch (ctx.L.input_char) {
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case 'r':
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ctx.NextState = 10;
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return true;
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default:
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return false;
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}
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}
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private static bool State10 (FsmContext ctx)
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{
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ctx.L.GetChar ();
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switch (ctx.L.input_char) {
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case 'u':
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ctx.NextState = 11;
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return true;
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default:
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return false;
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}
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}
|
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private static bool State11 (FsmContext ctx)
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{
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ctx.L.GetChar ();
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switch (ctx.L.input_char) {
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case 'e':
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ctx.Return = true;
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ctx.NextState = 1;
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return true;
|
|
default:
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return false;
|
}
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}
|
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private static bool State12 (FsmContext ctx)
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{
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ctx.L.GetChar ();
|
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switch (ctx.L.input_char) {
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case 'a':
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ctx.NextState = 13;
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return true;
|
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default:
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return false;
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}
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}
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private static bool State13 (FsmContext ctx)
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{
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ctx.L.GetChar ();
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switch (ctx.L.input_char) {
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case 'l':
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ctx.NextState = 14;
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return true;
|
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default:
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return false;
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}
|
}
|
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private static bool State14 (FsmContext ctx)
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{
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ctx.L.GetChar ();
|
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switch (ctx.L.input_char) {
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case 's':
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ctx.NextState = 15;
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return true;
|
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default:
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return false;
|
}
|
}
|
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private static bool State15 (FsmContext ctx)
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{
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ctx.L.GetChar ();
|
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switch (ctx.L.input_char) {
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case 'e':
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ctx.Return = true;
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ctx.NextState = 1;
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return true;
|
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default:
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return false;
|
}
|
}
|
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private static bool State16 (FsmContext ctx)
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{
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ctx.L.GetChar ();
|
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switch (ctx.L.input_char) {
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case 'u':
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ctx.NextState = 17;
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return true;
|
|
default:
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return false;
|
}
|
}
|
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private static bool State17 (FsmContext ctx)
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{
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ctx.L.GetChar ();
|
|
switch (ctx.L.input_char) {
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case 'l':
|
ctx.NextState = 18;
|
return true;
|
|
default:
|
return false;
|
}
|
}
|
|
private static bool State18 (FsmContext ctx)
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{
|
ctx.L.GetChar ();
|
|
switch (ctx.L.input_char) {
|
case 'l':
|
ctx.Return = true;
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ctx.NextState = 1;
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return true;
|
|
default:
|
return false;
|
}
|
}
|
|
private static bool State19 (FsmContext ctx)
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{
|
while (ctx.L.GetChar ()) {
|
switch (ctx.L.input_char) {
|
case '"':
|
ctx.L.UngetChar ();
|
ctx.Return = true;
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ctx.NextState = 20;
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return true;
|
|
case '\\':
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ctx.StateStack = 19;
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ctx.NextState = 21;
|
return true;
|
|
default:
|
ctx.L.string_buffer.Append ((char) ctx.L.input_char);
|
continue;
|
}
|
}
|
|
return true;
|
}
|
|
private static bool State20 (FsmContext ctx)
|
{
|
ctx.L.GetChar ();
|
|
switch (ctx.L.input_char) {
|
case '"':
|
ctx.Return = true;
|
ctx.NextState = 1;
|
return true;
|
|
default:
|
return false;
|
}
|
}
|
|
private static bool State21 (FsmContext ctx)
|
{
|
ctx.L.GetChar ();
|
|
switch (ctx.L.input_char) {
|
case 'u':
|
ctx.NextState = 22;
|
return true;
|
|
case '"':
|
case '\'':
|
case '/':
|
case '\\':
|
case 'b':
|
case 'f':
|
case 'n':
|
case 'r':
|
case 't':
|
ctx.L.string_buffer.Append (
|
ProcessEscChar (ctx.L.input_char));
|
ctx.NextState = ctx.StateStack;
|
return true;
|
|
default:
|
return false;
|
}
|
}
|
|
private static bool State22 (FsmContext ctx)
|
{
|
int counter = 0;
|
int mult = 4096;
|
|
ctx.L.unichar = 0;
|
|
while (ctx.L.GetChar ()) {
|
|
if (ctx.L.input_char >= '0' && ctx.L.input_char <= '9' ||
|
ctx.L.input_char >= 'A' && ctx.L.input_char <= 'F' ||
|
ctx.L.input_char >= 'a' && ctx.L.input_char <= 'f') {
|
|
ctx.L.unichar += HexValue (ctx.L.input_char) * mult;
|
|
counter++;
|
mult /= 16;
|
|
if (counter == 4) {
|
ctx.L.string_buffer.Append (
|
Convert.ToChar (ctx.L.unichar));
|
ctx.NextState = ctx.StateStack;
|
return true;
|
}
|
|
continue;
|
}
|
|
return false;
|
}
|
|
return true;
|
}
|
|
private static bool State23 (FsmContext ctx)
|
{
|
while (ctx.L.GetChar ()) {
|
switch (ctx.L.input_char) {
|
case '\'':
|
ctx.L.UngetChar ();
|
ctx.Return = true;
|
ctx.NextState = 24;
|
return true;
|
|
case '\\':
|
ctx.StateStack = 23;
|
ctx.NextState = 21;
|
return true;
|
|
default:
|
ctx.L.string_buffer.Append ((char) ctx.L.input_char);
|
continue;
|
}
|
}
|
|
return true;
|
}
|
|
private static bool State24 (FsmContext ctx)
|
{
|
ctx.L.GetChar ();
|
|
switch (ctx.L.input_char) {
|
case '\'':
|
ctx.L.input_char = '"';
|
ctx.Return = true;
|
ctx.NextState = 1;
|
return true;
|
|
default:
|
return false;
|
}
|
}
|
|
private static bool State25 (FsmContext ctx)
|
{
|
ctx.L.GetChar ();
|
|
switch (ctx.L.input_char) {
|
case '*':
|
ctx.NextState = 27;
|
return true;
|
|
case '/':
|
ctx.NextState = 26;
|
return true;
|
|
default:
|
return false;
|
}
|
}
|
|
private static bool State26 (FsmContext ctx)
|
{
|
while (ctx.L.GetChar ()) {
|
if (ctx.L.input_char == '\n') {
|
ctx.NextState = 1;
|
return true;
|
}
|
}
|
|
return true;
|
}
|
|
private static bool State27 (FsmContext ctx)
|
{
|
while (ctx.L.GetChar ()) {
|
if (ctx.L.input_char == '*') {
|
ctx.NextState = 28;
|
return true;
|
}
|
}
|
|
return true;
|
}
|
|
private static bool State28 (FsmContext ctx)
|
{
|
while (ctx.L.GetChar ()) {
|
if (ctx.L.input_char == '*')
|
continue;
|
|
if (ctx.L.input_char == '/') {
|
ctx.NextState = 1;
|
return true;
|
}
|
|
ctx.NextState = 27;
|
return true;
|
}
|
|
return true;
|
}
|
#endregion
|
|
|
private bool GetChar ()
|
{
|
if ((input_char = NextChar ()) != -1)
|
return true;
|
|
end_of_input = true;
|
return false;
|
}
|
|
private int NextChar ()
|
{
|
if (input_buffer != 0) {
|
int tmp = input_buffer;
|
input_buffer = 0;
|
|
return tmp;
|
}
|
|
return reader.Read ();
|
}
|
|
public bool NextToken ()
|
{
|
StateHandler handler;
|
fsm_context.Return = false;
|
|
while (true) {
|
handler = fsm_handler_table[state - 1];
|
|
if (! handler (fsm_context))
|
throw new JsonException (input_char);
|
|
if (end_of_input)
|
return false;
|
|
if (fsm_context.Return) {
|
string_value = string_buffer.ToString ();
|
string_buffer.Remove (0, string_buffer.Length);
|
token = fsm_return_table[state - 1];
|
|
if (token == (int) ParserToken.Char)
|
token = input_char;
|
|
state = fsm_context.NextState;
|
|
return true;
|
}
|
|
state = fsm_context.NextState;
|
}
|
}
|
|
private void UngetChar ()
|
{
|
input_buffer = input_char;
|
}
|
}
|
}
|
