using System; using System.Collections; using System.Globalization; using System.Text; namespace Procurios.Public { /// /// This class encodes and decodes JSON strings. /// Spec. details, see http://www.json.org/ /// /// JSON uses Arrays and Objects. These correspond here to the datatypes ArrayList and Hashtable. /// All numbers are parsed to doubles. /// public class JSON { public const int TOKEN_NONE = 0; public const int TOKEN_CURLY_OPEN = 1; public const int TOKEN_CURLY_CLOSE = 2; public const int TOKEN_SQUARED_OPEN = 3; public const int TOKEN_SQUARED_CLOSE = 4; public const int TOKEN_COLON = 5; public const int TOKEN_COMMA = 6; public const int TOKEN_STRING = 7; public const int TOKEN_NUMBER = 8; public const int TOKEN_TRUE = 9; public const int TOKEN_FALSE = 10; public const int TOKEN_NULL = 11; private const int BUILDER_CAPACITY = 2000; /// /// Parses the string json into a value /// /// A JSON string. /// An ArrayList, a Hashtable, a double, a string, null, true, or false public static object JsonDecode(string json) { bool success = true; return JsonDecode(json, ref success); } /// /// Parses the string json into a value; and fills 'success' with the successfullness of the parse. /// /// A JSON string. /// Successful parse? /// An ArrayList, a Hashtable, a double, a string, null, true, or false public static object JsonDecode(string json, ref bool success) { success = true; if (json != null) { char[] charArray = json.ToCharArray(); int index = 0; object value = ParseValue(charArray, ref index, ref success); return value; } else { return null; } } /// /// Converts a Hashtable / ArrayList object into a JSON string /// /// A Hashtable / ArrayList /// A JSON encoded string, or null if object 'json' is not serializable public static string JsonEncode(object json) { StringBuilder builder = new StringBuilder(BUILDER_CAPACITY); bool success = SerializeValue(json, builder); return (success ? builder.ToString() : null); } protected static Hashtable ParseObject(char[] json, ref int index, ref bool success) { Hashtable table = new Hashtable(); int token; // { NextToken(json, ref index); bool done = false; while (!done) { token = LookAhead(json, index); if (token == JSON.TOKEN_NONE) { success = false; return null; } else if (token == JSON.TOKEN_COMMA) { NextToken(json, ref index); } else if (token == JSON.TOKEN_CURLY_CLOSE) { NextToken(json, ref index); return table; } else { // name string name = ParseString(json, ref index, ref success); if (!success) { success = false; return null; } // : token = NextToken(json, ref index); if (token != JSON.TOKEN_COLON) { success = false; return null; } // value object value = ParseValue(json, ref index, ref success); if (!success) { success = false; return null; } table[name] = value; } } return table; } protected static ArrayList ParseArray(char[] json, ref int index, ref bool success) { ArrayList array = new ArrayList(); // [ NextToken(json, ref index); bool done = false; while (!done) { int token = LookAhead(json, index); if (token == JSON.TOKEN_NONE) { success = false; return null; } else if (token == JSON.TOKEN_COMMA) { NextToken(json, ref index); } else if (token == JSON.TOKEN_SQUARED_CLOSE) { NextToken(json, ref index); break; } else { object value = ParseValue(json, ref index, ref success); if (!success) { return null; } array.Add(value); } } return array; } protected static object ParseValue(char[] json, ref int index, ref bool success) { switch (LookAhead(json, index)) { case JSON.TOKEN_STRING: return ParseString(json, ref index, ref success); case JSON.TOKEN_NUMBER: return ParseNumber(json, ref index, ref success); case JSON.TOKEN_CURLY_OPEN: return ParseObject(json, ref index, ref success); case JSON.TOKEN_SQUARED_OPEN: return ParseArray(json, ref index, ref success); case JSON.TOKEN_TRUE: NextToken(json, ref index); return true; case JSON.TOKEN_FALSE: NextToken(json, ref index); return false; case JSON.TOKEN_NULL: NextToken(json, ref index); return null; case JSON.TOKEN_NONE: break; } success = false; return null; } protected static string ParseString(char[] json, ref int index, ref bool success) { StringBuilder s = new StringBuilder(BUILDER_CAPACITY); char c; EatWhitespace(json, ref index); // " c = json[index++]; bool complete = false; while (!complete) { if (index == json.Length) { break; } c = json[index++]; if (c == '"') { complete = true; break; } else if (c == '\\') { if (index == json.Length) { break; } c = json[index++]; if (c == '"') { s.Append('"'); } else if (c == '\\') { s.Append('\\'); } else if (c == '/') { s.Append('/'); } else if (c == 'b') { s.Append('\b'); } else if (c == 'f') { s.Append('\f'); } else if (c == 'n') { s.Append('\n'); } else if (c == 'r') { s.Append('\r'); } else if (c == 't') { s.Append('\t'); } else if (c == 'u') { int remainingLength = json.Length - index; if (remainingLength >= 4) { // parse the 32 bit hex into an integer codepoint uint codePoint; if (!(success = UInt32.TryParse(new string(json, index, 4), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out codePoint))) { return ""; } // convert the integer codepoint to a unicode char and add to string s.Append(Char.ConvertFromUtf32((int)codePoint)); // skip 4 chars index += 4; } else { break; } } } else { s.Append(c); } } if (!complete) { success = false; return null; } return s.ToString(); } protected static double ParseNumber(char[] json, ref int index, ref bool success) { EatWhitespace(json, ref index); int lastIndex = GetLastIndexOfNumber(json, index); int charLength = (lastIndex - index) + 1; double number; success = Double.TryParse(new string(json, index, charLength), NumberStyles.Any, CultureInfo.InvariantCulture, out number); index = lastIndex + 1; return number; } protected static int GetLastIndexOfNumber(char[] json, int index) { int lastIndex; for (lastIndex = index; lastIndex < json.Length; lastIndex++) { if ("0123456789+-.eE".IndexOf(json[lastIndex]) == -1) { break; } } return lastIndex - 1; } protected static void EatWhitespace(char[] json, ref int index) { for (; index < json.Length; index++) { if (" \t\n\r".IndexOf(json[index]) == -1) { break; } } } protected static int LookAhead(char[] json, int index) { int saveIndex = index; return NextToken(json, ref saveIndex); } protected static int NextToken(char[] json, ref int index) { EatWhitespace(json, ref index); if (index == json.Length) { return JSON.TOKEN_NONE; } char c = json[index]; index++; switch (c) { case '{': return JSON.TOKEN_CURLY_OPEN; case '}': return JSON.TOKEN_CURLY_CLOSE; case '[': return JSON.TOKEN_SQUARED_OPEN; case ']': return JSON.TOKEN_SQUARED_CLOSE; case ',': return JSON.TOKEN_COMMA; case '"': return JSON.TOKEN_STRING; case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': case '-': return JSON.TOKEN_NUMBER; case ':': return JSON.TOKEN_COLON; } index--; int remainingLength = json.Length - index; // false if (remainingLength >= 5) { if (json[index] == 'f' && json[index + 1] == 'a' && json[index + 2] == 'l' && json[index + 3] == 's' && json[index + 4] == 'e') { index += 5; return JSON.TOKEN_FALSE; } } // true if (remainingLength >= 4) { if (json[index] == 't' && json[index + 1] == 'r' && json[index + 2] == 'u' && json[index + 3] == 'e') { index += 4; return JSON.TOKEN_TRUE; } } // null if (remainingLength >= 4) { if (json[index] == 'n' && json[index + 1] == 'u' && json[index + 2] == 'l' && json[index + 3] == 'l') { index += 4; return JSON.TOKEN_NULL; } } return JSON.TOKEN_NONE; } protected static bool SerializeValue(object value, StringBuilder builder) { bool success = true; if (value is string) { success = SerializeString((string)value, builder); } else if (value is Hashtable) { success = SerializeObject((Hashtable)value, builder); } else if (value is ArrayList) { success = SerializeArray((ArrayList)value, builder); } else if ((value is Boolean) && ((Boolean)value == true)) { builder.Append("true"); } else if ((value is Boolean) && ((Boolean)value == false)) { builder.Append("false"); } else if (value is ValueType) { // thanks to ritchie for pointing out ValueType to me success = SerializeNumber(Convert.ToDouble(value), builder); } else if (value == null) { builder.Append("null"); } else { success = false; } return success; } protected static bool SerializeObject(Hashtable anObject, StringBuilder builder) { builder.Append("{"); IDictionaryEnumerator e = anObject.GetEnumerator(); bool first = true; while (e.MoveNext()) { string key = e.Key.ToString(); object value = e.Value; if (!first) { builder.Append(", "); } SerializeString(key, builder); builder.Append(":"); if (!SerializeValue(value, builder)) { return false; } first = false; } builder.Append("}"); return true; } protected static bool SerializeArray(ArrayList anArray, StringBuilder builder) { builder.Append("["); bool first = true; for (int i = 0; i < anArray.Count; i++) { object value = anArray[i]; if (!first) { builder.Append(", "); } if (!SerializeValue(value, builder)) { return false; } first = false; } builder.Append("]"); return true; } protected static bool SerializeString(string aString, StringBuilder builder) { builder.Append("\""); char[] charArray = aString.ToCharArray(); for (int i = 0; i < charArray.Length; i++) { char c = charArray[i]; if (c == '"') { builder.Append("\\\""); } else if (c == '\\') { builder.Append("\\\\"); } else if (c == '\b') { builder.Append("\\b"); } else if (c == '\f') { builder.Append("\\f"); } else if (c == '\n') { builder.Append("\\n"); } else if (c == '\r') { builder.Append("\\r"); } else if (c == '\t') { builder.Append("\\t"); } else { int codepoint = Convert.ToInt32(c); if ((codepoint >= 32) && (codepoint <= 126)) { builder.Append(c); } else { builder.Append("\\u" + Convert.ToString(codepoint, 16).PadLeft(4, '0')); } } } builder.Append("\""); return true; } protected static bool SerializeNumber(double number, StringBuilder builder) { builder.Append(Convert.ToString(number, CultureInfo.InvariantCulture)); return true; } } }