diff options
Diffstat (limited to 'src/ProtocolBuffers/Serialization/JsonTextCursor.cs')
| -rw-r--r-- | src/ProtocolBuffers/Serialization/JsonTextCursor.cs | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/src/ProtocolBuffers/Serialization/JsonTextCursor.cs b/src/ProtocolBuffers/Serialization/JsonTextCursor.cs new file mode 100644 index 00000000..a2a5b73d --- /dev/null +++ b/src/ProtocolBuffers/Serialization/JsonTextCursor.cs @@ -0,0 +1,270 @@ +using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
+using System.Text;
+
+namespace Google.ProtocolBuffers.Serialization
+{
+ /// <summary>
+ /// JSon Tokenizer used by JsonFormatReader
+ /// </summary>
+ class JsonTextCursor
+ {
+ public enum JsType { String, Number, Object, Array, True, False, Null }
+
+ private readonly char[] _buffer;
+ private int _bufferPos;
+ private readonly TextReader _input;
+ private int _lineNo, _linePos;
+
+ public JsonTextCursor(char[] input)
+ {
+ _input = null;
+ _buffer = input;
+ _bufferPos = 0;
+ _next = Peek();
+ _lineNo = 1;
+ }
+
+ public JsonTextCursor(TextReader input)
+ {
+ _input = input;
+ _next = Peek();
+ _lineNo = 1;
+ }
+
+ private int Peek()
+ {
+ if (_input != null)
+ return _input.Peek();
+ else if (_bufferPos < _buffer.Length)
+ return _buffer[_bufferPos];
+ else
+ return -1;
+ }
+
+ private int Read()
+ {
+ if (_input != null)
+ return _input.Read();
+ else if (_bufferPos < _buffer.Length)
+ return _buffer[_bufferPos++];
+ else
+ return -1;
+ }
+
+ int _next;
+ public Char NextChar { get { SkipWhitespace(); return (char)_next; } }
+
+ #region Assert(...)
+ [System.Diagnostics.DebuggerNonUserCode]
+ private string CharDisplay(int ch)
+ {
+ return ch == -1 ? "EOF" :
+ (ch > 32 && ch < 127) ? String.Format("'{0}'", (char)ch) :
+ String.Format("'\\u{0:x4}'", ch);
+ }
+ [System.Diagnostics.DebuggerNonUserCode]
+ private void Assert(bool cond, char expected)
+ {
+ if (!cond)
+ {
+ throw new FormatException(
+ String.Format(CultureInfo.InvariantCulture,
+ "({0}:{1}) error: Unexpected token {2}, expected: {3}.",
+ _lineNo, _linePos,
+ CharDisplay(_next),
+ CharDisplay(expected)
+ ));
+ }
+ }
+ [System.Diagnostics.DebuggerNonUserCode]
+ public void Assert(bool cond, string message)
+ {
+ if (!cond)
+ {
+ throw new FormatException(
+ String.Format(CultureInfo.InvariantCulture,
+ "({0},{1}) error: {2}", _lineNo, _linePos, message));
+ }
+ }
+ [System.Diagnostics.DebuggerNonUserCode]
+ public void Assert(bool cond, string format, params object[] args)
+ {
+ if (!cond)
+ {
+ if (args != null && args.Length > 0)
+ format = String.Format(format, args);
+ throw new FormatException(
+ String.Format(CultureInfo.InvariantCulture,
+ "({0},{1}) error: {2}", _lineNo, _linePos, format));
+ }
+ }
+ #endregion
+
+ private char ReadChar()
+ {
+ int ch = Read();
+ Assert(ch != -1, "Unexpected end of file.");
+ if (ch == '\n')
+ {
+ _lineNo++;
+ _linePos = 0;
+ }
+ else if (ch != '\r')
+ {
+ _linePos++;
+ }
+ _next = Peek();
+ return (char)ch;
+ }
+
+ public void Consume(char ch) { Assert(TryConsume(ch), ch); }
+ public bool TryConsume(char ch)
+ {
+ SkipWhitespace();
+ if (_next == ch)
+ {
+ ReadChar();
+ return true;
+ }
+ return false;
+ }
+
+ public void Consume(string sequence)
+ {
+ SkipWhitespace();
+
+ foreach (char ch in sequence)
+ Assert(ch == ReadChar(), "Expected token '{0}'.", sequence);
+ }
+
+ public void SkipWhitespace()
+ {
+ int chnext = _next;
+ while (chnext != -1)
+ {
+ if (!Char.IsWhiteSpace((char)chnext))
+ break;
+ ReadChar();
+ chnext = _next;
+ }
+ }
+
+ public string ReadString()
+ {
+ SkipWhitespace();
+ Consume('"');
+ StringBuilder sb = new StringBuilder();
+ while (_next != '"')
+ {
+ if (_next == '\\')
+ {
+ Consume('\\');//skip the escape
+ char ch = ReadChar();
+ switch (ch)
+ {
+ case 'b': sb.Append('\b'); break;
+ case 'f': sb.Append('\f'); break;
+ case 'n': sb.Append('\n'); break;
+ case 'r': sb.Append('\r'); break;
+ case 't': sb.Append('\t'); break;
+ case 'u':
+ {
+ string hex = new string(new char[] { ReadChar(), ReadChar(), ReadChar(), ReadChar() });
+ int result;
+ Assert(int.TryParse(hex, NumberStyles.AllowHexSpecifier, CultureInfo.InvariantCulture, out result),
+ "Expected a 4-character hex specifier.");
+ sb.Append((char)result);
+ break;
+ }
+ default:
+ sb.Append(ch); break;
+ }
+ }
+ else
+ {
+ Assert(_next != '\n' && _next != '\r' && _next != '\f' && _next != -1, '"');
+ sb.Append(ReadChar());
+ }
+ }
+ Consume('"');
+ return sb.ToString();
+ }
+
+ public string ReadNumber()
+ {
+ SkipWhitespace();
+
+ StringBuilder sb = new StringBuilder();
+ if (_next == '-')
+ sb.Append(ReadChar());
+ Assert(_next >= '0' && _next <= '9', "Expected a numeric type.");
+ while ((_next >= '0' && _next <= '9') || _next == '.')
+ sb.Append(ReadChar());
+ if (_next == 'e' || _next == 'E')
+ {
+ sb.Append(ReadChar());
+ if (_next == '-' || _next == '+')
+ sb.Append(ReadChar());
+ Assert(_next >= '0' && _next <= '9', "Expected a numeric type.");
+ while (_next >= '0' && _next <= '9')
+ sb.Append(ReadChar());
+ }
+ return sb.ToString();
+ }
+
+ public JsType ReadVariant(out object value)
+ {
+ SkipWhitespace();
+ switch (_next)
+ {
+ case 'n': Consume("null"); value = null; return JsType.Null;
+ case 't': Consume("true"); value = true; return JsType.True;
+ case 'f': Consume("false"); value = false; return JsType.False;
+ case '"': value = ReadString(); return JsType.String;
+ case '{':
+ {
+ Consume('{');
+ while (NextChar != '}')
+ {
+ ReadString();
+ Consume(':');
+ object tmp;
+ ReadVariant(out tmp);
+ if (!TryConsume(','))
+ break;
+ }
+ Consume('}');
+ value = null;
+ return JsType.Object;
+ }
+ case '[':
+ {
+ Consume('[');
+ List<object> values = new List<object>();
+ while (NextChar != ']')
+ {
+ object tmp;
+ ReadVariant(out tmp);
+ values.Add(tmp);
+ if (!TryConsume(','))
+ break;
+ }
+ Consume(']');
+ value = values.ToArray();
+ return JsType.Array;
+ }
+ default:
+ if ((_next >= '0' && _next <= '9') || _next == '-')
+ {
+ value = ReadNumber();
+ return JsType.Number;
+ }
+ Assert(false, "Expected a value.");
+ throw new FormatException();
+ }
+ }
+ }
+}
\ No newline at end of file |