XmlNormalizationState.cs

using System.Collections.Generic;
using System.Text;
 
namespace Waher.Content.Xml
{
    public class XmlNormalizationState
    {
        private readonly StringBuilder output = new StringBuilder();
        private readonly Dictionary<string, string> namespceByPrefix = new Dictionary<string, string>();
        private readonly LinkedList<LinkedList<KeyValuePair<string, string>>> prefixStack = new LinkedList<LinkedList<KeyValuePair<string, string>>>();
        private LinkedList<KeyValuePair<string, string>> newPrefixes = null;
 
        public XmlNormalizationState()
        {
        }
 
        public void Append(string s)
        {
            this.output.Append(s);
        }
 
        public void Append(char ch)
        {
            this.output.Append(ch);
        }
 
        public override string ToString()
        {
            return this.output.ToString();
        }
 
        public bool RegisterPrefix(string Prefix, string Namespace)
        {
            if (this.namespceByPrefix.TryGetValue(Prefix, out string PrevNamespace))
            {
                if (PrevNamespace == Namespace)
                    return false;
            }
            else
                PrevNamespace = null;
 
            if (this.newPrefixes is null)
                this.newPrefixes = new LinkedList<KeyValuePair<string, string>>();
 
            this.newPrefixes.AddLast(new KeyValuePair<string, string>(Prefix, PrevNamespace));
            this.namespceByPrefix[Prefix] = Namespace;
 
            return true;
        }
 
        public void PushPrefixes()
        {
            this.prefixStack.AddLast(this.newPrefixes);
            this.newPrefixes = null;
        }
 
        public void PopPrefixes()
        {
            if (this.prefixStack.Last is null)
                return;
 
            LinkedList<KeyValuePair<string, string>> ToRemove = this.prefixStack.Last.Value;
            this.prefixStack.RemoveLast();
 
            if (!(ToRemove is null))
            {
                foreach (KeyValuePair<string, string> P in ToRemove)
                {
                    if (P.Value is null)
                        this.namespceByPrefix.Remove(P.Key);
                    else
                        this.namespceByPrefix[P.Key] = P.Value;
                }
            }
        }
    }
}