csharp/404Lcc/Lcc/Assets/Plugins/LitJson/Lexer.cs

Lexer.cs
#region Header
/**
 * Lexer.cs
 *   JSON lexer implementation based on a finite state machine.
 *
 * The authors disclaim copyright to this source code. For more details, see
 * the COPYING file included with this distribution.
 **/
#endregion


using System;
using System.Collections.Generic;
using System.IO;
using System.Text;


namespace LitJson
{
    internal clast FsmContext
    {
        public bool  Return;
        public int   NextState;
        public Lexer L;
        public int   StateStack;
    }


    internal clast Lexer
    {
        #region Fields
        private delegate bool StateHandler (FsmContext ctx);

        private static int[]          fsm_return_table;
        private static StateHandler[] fsm_handler_table;

        private bool          allow_comments;
        private bool          allow_single_quoted_strings;
        private bool          end_of_input;
        private FsmContext    fsm_context;
        private int           input_buffer;
        private int           input_char;
        private TextReader    reader;
        private int           state;
        private StringBuilder string_buffer;
        private string        string_value;
        private int           token;
        private int           unichar;
        #endregion


        #region Properties
        public bool AllowComments {
            get { return allow_comments; }
            set { allow_comments = value; }
        }

        public bool AllowSingleQuotedStrings {
            get { return allow_single_quoted_strings; }
            set { allow_single_quoted_strings = value; }
        }

        public bool EndOfInput {
            get { return end_of_input; }
        }

        public int Token {
            get { return token; }
        }

        public string StringValue {
            get { return string_value; }
        }
        #endregion


        #region Constructors
        static Lexer ()
        {
            PopulateFsmTables ();
        }

        public Lexer (TextReader reader)
        {
            allow_comments = true;
            allow_single_quoted_strings = true;

            input_buffer = 0;
            string_buffer = new StringBuilder (128);
            state = 1;
            end_of_input = false;
            this.reader = reader;

            fsm_context = new FsmContext ();
            fsm_context.L = this;
        }
        #endregion


        #region Static Methods
        private static int HexValue (int digit)
        {
            switch (digit) {
            case 'a':
            case 'A':
                return 10;

            case 'b':
            case 'B':
                return 11;

            case 'c':
            case 'C':
                return 12;

            case 'd':
            case 'D':
                return 13;

            case 'e':
            case 'E':
                return 14;

            case 'f':
            case 'F':
                return 15;

            default:
                return digit - '0';
            }
        }

        private static void PopulateFsmTables ()
        {
            // See section A.1. of the manual for details of the finite
            // state machine.
            fsm_handler_table = new StateHandler[28] {
                State1,
                State2,
                State3,
                State4,
                State5,
                State6,
                State7,
                State8,
                State9,
                State10,
                State11,
                State12,
                State13,
                State14,
                State15,
                State16,
                State17,
                State18,
                State19,
                State20,
                State21,
                State22,
                State23,
                State24,
                State25,
                State26,
                State27,
                State28
            };

            fsm_return_table = new int[28] {
                (int) ParserToken.Char,
                0,
                (int) ParserToken.Number,
                (int) ParserToken.Number,
                0,
                (int) ParserToken.Number,
                0,
                (int) ParserToken.Number,
                0,
                0,
                (int) ParserToken.True,
                0,
                0,
                0,
                (int) ParserToken.False,
                0,
                0,
                (int) ParserToken.Null,
                (int) ParserToken.CharSeq,
                (int) ParserToken.Char,
                0,
                0,
                (int) ParserToken.CharSeq,
                (int) ParserToken.Char,
                0,
                0,
                0,
                0
            };
        }

        private static char ProcessEscChar (int esc_char)
        {
            switch (esc_char) {
            case '"':
            case '\'':
            case '\\':
            case '/':
                return Convert.ToChar (esc_char);

            case 'n':
                return '\n';

            case 't':
                return '\t';

            case 'r':
                return '\r';

            case 'b':
                return '\b';

            case 'f':
                return '\f';

            default:
                // Unreachable
                return '?';
            }
        }

        private static bool State1 (FsmContext ctx)
        {
            while (ctx.L.GetChar ()) {
                if (ctx.L.input_char == ' ' ||
                    ctx.L.input_char >= '\t' && ctx.L.input_char = '1' && ctx.L.input_char = '0' && ctx.L.input_char = 'A' && ctx.L.input_char = 'a' && ctx.L.input_char