XmlReaderEx (Initial Draft)

gistfile1.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Text.RegularExpressions;

namespace PServiceBus.Serializer.Xml {
    public unsafe class XmlReaderEx : IDisposable {

        private char* _chrs;
        private string _elementName, _attributeTypeValue;
        private bool _disposed, _isEndElement, _hasValue, _hasTypeAttribute;
        private StringBuilder sb;
        const int DefaultSBCapacity = 1024 << 1;
        const string TypeStr = "Type";
        const char SpaceStr = ' ', GreaterStr = '>', LessStr = '<', BackSlash = '/', Null = '\0';
        private static Regex _typeRegex = new Regex(@"type=""(?<Type>[^""]+)""", RegexOptions.Compiled);

        public XmlReaderEx(string xml) {
            _chrs = (char*)Marshal.StringToHGlobalUni(xml);
            sb = new StringBuilder(DefaultSBCapacity);
        }

        public string ElementName { get { return _elementName; } }
        public string TypeAttribute { get { return _attributeTypeValue; } }
        public bool IsEndElement { get { return _isEndElement; } }

        public string GetValue() {
            if (_isEndElement) return string.Empty;
            sb.Clear().Append(*_chrs);
            do {
                ++_chrs;
                if (*_chrs == Null || *_chrs == LessStr) break;
                sb.Append(*_chrs);
            } while (true);
            return sb.ToString();
        }

        public bool Read(){
            if (*_chrs == Null) return false;
            _elementName = _attributeTypeValue = null;
            _hasTypeAttribute = _hasValue = _isEndElement = false;
            sb.Clear();
            do {
                ++_chrs;
                if (*_chrs == GreaterStr || *_chrs == Null) {
                    if (*_chrs != Null) ++_chrs;
                    break;
                }
                if (*_chrs == SpaceStr && _elementName == null) {
                    _elementName = sb.ToString();
                    sb.Clear();
                    _hasTypeAttribute = true;
                    _hasValue = false;
                    continue;
                }
                if (*_chrs != LessStr) {
                    sb.Append(*_chrs);
                    _hasValue = true;
                }
            } while (true);
            if (_hasValue) {
                var text = sb.ToString();
                if (_hasTypeAttribute)
                    _attributeTypeValue = _typeRegex.Match(text).Groups[TypeStr].Value;
                else if (_elementName == null)
                    _elementName = text;
                if (_elementName[0] == BackSlash) {
                    _isEndElement = true;
                    _elementName = _elementName.Substring(1);
                }
            }
            return _hasValue;
        }

        public void MoveToEndElement(string name) {
            do {
                if (_elementName == name && _isEndElement) break;
            } while (Read());
        }

        protected void Dispose(bool disposing) {
            if (_disposed) return;
            if (disposing)
                GC.SuppressFinalize(this);
            _chrs = default(char*);
            _disposed = true;
        }

        #region IDisposable Members
        public void Dispose() {
            Dispose(true);
        }
        #endregion

        ~XmlReaderEx() {
            Dispose(false);
        }
    }
}