JSON Encoder/Decoder (original by game_guy)

[DiviBurrito]

Sometimes it can be useful to be able to read and write data in JSON format.
I use it to define custom data sets in my projects, and then to compile it into .rxdata files.


I found this script that can read and write certain objects to and from JSON on the chaos-projects boards.
It was written by game_guy, so if anything give credits to him.
I enhanced his script a little bit to be able to correctly parse whitespaces. In the original script, everything had to be on one line and there where no other whitespaces allowed anywhere (except in strings).

Code:

#===============================================================================
# JSON Encoder/Decoder
# Version 1.2
# Author: game_guy
#-------------------------------------------------------------------------------
# Intro:
# JSON (JavaScript Object Notation) is a lightweight data-interchange
# format. It is easy for humans to read and write. It is easy for machines to
# parse and generate.
# This is a simple JSON Parser or Decoder. It'll take JSON thats been
# formatted into a string and decode it into the proper object.
# This script can also encode certain ruby objects into JSON.
#
# Features:
# Decodes JSON format into ruby strings, arrays, hashes, integers, booleans.
#
# Instructions:
# This is a scripters utility. To decode JSON data, call
# JSON.decode("json string")
# -Depending on "json string", this method can return any of the values:
#  -Integer
#  -String
#  -Boolean
#  -Hash
#  -Array
#  -Nil
#
# To Encode objects, use
# JSON.encode(object)
# -This will return a string with JSON. Object can be any one of the following
#  -Integer
#  -String
#  -Boolean
#  -Hash
#  -Array
#  -Nil
#
# Version 1.2 (DiviBurrito)
#  Ability to parse whitespaces (space, newline, etc)
#
# Credits:
# game_guy ~ Creating it.
#===============================================================================
module JSON
 
  TOKEN_NONE = 0;
  TOKEN_CURLY_OPEN = 1;
  TOKEN_CURLY_CLOSED = 2;
  TOKEN_SQUARED_OPEN = 3;
  TOKEN_SQUARED_CLOSED = 4;
  TOKEN_COLON = 5;
  TOKEN_COMMA = 6;
  TOKEN_STRING = 7;
  TOKEN_NUMBER = 8;
  TOKEN_TRUE = 9;
  TOKEN_FALSE = 10;
  TOKEN_NULL = 11;
  TOKEN_WHITESPACE = 12;
 
  @index = 0
  @json = ""
  @length = 0
 
  def self.decode(json)
    @json = json
    @index = 0
    @length = @json.length
    return self.parse
  end
 
  def self.encode(obj)
    if obj.is_a?(Hash)
      return self.encode_hash(obj)
    elsif obj.is_a?(Array)
      return self.encode_array(obj)
    elsif obj.is_a?(Fixnum) || obj.is_a?(Float)
      return self.encode_integer(obj)
    elsif obj.is_a?(String)
      return self.encode_string(obj)
    elsif obj.is_a?(TrueClass) || obj.is_a?(FalseClass)
      return self.encode_bool(obj)
    elsif obj.is_a?(NilClass)
      return "null"
    end
    return nil
  end
 
  def self.encode_hash(hash)
    string = "{"
    hash.each_key {|key|
      string += "\"#{key}\":" + self.encode(hash[key]).to_s + ","
    }
    string[string.size - 1, 1] = "}"
    return string
  end
 
  def self.encode_array(array)
    string = "["
    array.each {|i|
      string += self.encode(i).to_s + ","
    }
    string[string.size - 1, 1] = "]"
    return string
  end
 
  def self.encode_string(string)
    return "\"#{string}\""
  end
 
  def self.encode_integer(int)
    return int.to_s
  end
 
  def self.encode_bool(bool)
    return (bool.is_a?(TrueClass) ? "true" : "false")
  end
 
  def self.next_token(debug = 0)
    char = @json[@index, 1]
    @index += 1
    case char
    when '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-'
      return TOKEN_NUMBER
    when '{'
      return TOKEN_CURLY_OPEN
    when '}'
      return TOKEN_CURLY_CLOSED
    when '"'
      return TOKEN_STRING
    when ','
      return TOKEN_COMMA
    when '['
      return TOKEN_SQUARED_OPEN
    when ']'
      return TOKEN_SQUARED_CLOSED
    when ':'
      return TOKEN_COLON
    when /\s/
      return TOKEN_WHITESPACE
    end
    @index -= 1
    if @json[@index, 5] == "false"
      @index += 5
      return TOKEN_FALSE
    elsif @json[@index, 4] == "true"
      @index += 4
      return TOKEN_TRUE
    elsif @json[@index, 4] == "null"
      @index += 4
      return TOKEN_NULL
    end
    return TOKEN_NONE
  end
 
  def self.parse(debug = 0)
    complete = false
    while !complete
      if @index >= @length
        break
      end
      token = self.next_token
      case token
      when TOKEN_NONE
        return nil
      when TOKEN_NUMBER
        return self.parse_number
      when TOKEN_CURLY_OPEN
        return self.parse_object
      when TOKEN_STRING
        return self.parse_string
      when TOKEN_SQUARED_OPEN
        return self.parse_array
      when TOKEN_TRUE
        return true
      when TOKEN_FALSE
        return false
      when TOKEN_NULL
        return nil
      end
    end
  end
 
  def self.parse_object
    obj = {}
    complete = false
    while !complete
      token = self.next_token
      if token == TOKEN_CURLY_CLOSED
        complete = true
        break
      elsif token == TOKEN_NONE
        return nil
      elsif token == TOKEN_COMMA
      elsif token == TOKEN_WHITESPACE
      else
        name = self.parse_string
        return nil if name == nil
        token = self.next_token
        return nil if token != TOKEN_COLON
        value = self.parse
        obj[name] = value
      end
    end
    return obj
  end
 
  def self.parse_string
    complete = false
    string = ""
    while !complete
      break if @index >= @length
      char = @json[@index, 1]
      @index += 1
      case char
      when '"'
        complete = true
        break
      else
        string += char.to_s
      end
    end
    if !complete
      return nil
    end
    return string
  end
 
  def self.parse_number
    @index -= 1
    negative = @json[@index, 1] == "-" ? true : false
    string = ""
    complete = false
    while !complete
      break if @index >= @length
      char = @json[@index, 1]
      @index += 1
      case char
      when "{", "}", ":", ",", "[", "]"
        @index -= 1
        complete = true
        break
      when "0", "1", "2", '3', '4', '5', '6', '7', '8', '9'
        string += char.to_s
      end
    end
    return string.to_i
  end
 
  def self.parse_array
    obj = []
    complete = false
    while !complete
      token = self.next_token(1)
      if token == TOKEN_SQUARED_CLOSED
        complete = true
        break
      elsif token == TOKEN_NONE
        return nil
      elsif token == TOKEN_COMMA
      elsif token == TOKEN_WHITESPACE
      else
        @index -= 1
        value = self.parse
        obj.push(value)
      end
    end
    return obj
  end
 
end

There isn't a whole lot to this script. Everything is documented in the script itself.
Hope this helps someone.