LookupTable.cs


1:	// LookupTable.cs
2:	// Copyright (c) 2000 Mike Krueger
3:	//
4:	// This program is free software; you can redistribute it and/or modify
5:	// it under the terms of the GNU General Public License as published by
6:	// the Free Software Foundation; either version 2 of the License, or
7:	// (at your option) any later version.
8:	//
9:	// This program is distributed in the hope that it will be useful,
10:	// but WITHOUT ANY WARRANTY; without even the implied warranty of
11:	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12:	// GNU General Public License for more details.
13:	//
14:	// You should have received a copy of the GNU General Public License
15:	// along with this program; if not, write to the Free Software
16:	// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17:
18:	using System;
19:	using System.Collections;
20:	using System.Drawing;
21:	using SharpDevelop.DefaultEditor.Text;
22:
23:	namespace SharpDevelop.DefaultEditor.Util {
24:
25:	/// <summary>
26:	/// This class implements a keyword map. It implements a digital search trees (tries) to find
27:	/// a word.
28:	/// </summary>
29:	public class LookupTable
30:	{
31:	Node root = new Node(null, null);
32:	bool casesensitive;
33:	int length;
34:
35:	public int Length {
36:	get {
37:	return length;
38:	}
39:	}
40:
41:	/// <summary>
42:	/// Get the object, which was inserted under the keyword (line, at offset, with length length),
43:	/// returns null, if no such keyword was inserted.
44:	/// </summary>
45:	public object this[IDocument document, LineSegment line, int offset, int length] {
46:	get {
47:	if(length == 0) {
48:	return null;
49:	}
50:	Node next = root;
51:
52:	int wordOffset = line.Offset + offset;
53:	if (casesensitive) {
54:	for (int i = 0; i < length; ++i) {
55:	int index = ((int)document.GetCharAt(wordOffset + i)) % 256;
56:	next = next.leaf[index];
57:
58:	if (next == null) {
59:	return null;
60:	}
61:
62:	if (next.color != null && SharpDevelop.DefaultEditor.Util.TextUtility.RegionMatches(document, wordOffset, length, next.word)) {
63:	return next.color;
64:	}
65:	}
66:	} else {
67:	for (int i = 0; i < length; ++i) {
68:	int index = ((int)Char.ToUpper(document.GetCharAt(wordOffset + i))) % 256;
69:
70:	next = next.leaf[index];
71:
72:	if (next == null) {
73:	return null;
74:	}
75:
76:	if (next.color != null && SharpDevelop.DefaultEditor.Util.TextUtility.RegionMatches(document, casesensitive, wordOffset, length, next.word)) {
77:	return next.color;
78:	}
79:	}
80:	}
81:	return null;
82:	}
83:	}
84:
85:	/// <summary>
86:	/// Inserts an object in the tree, under keyword
87:	/// </summary>
88:	public object this[string keyword] {
89:	set {
90:	Node node = root;
91:	Node next = root;
92:	if (!casesensitive) {
93:	keyword = keyword.ToUpper();
94:	}
95:	++length;
96:
97:	// insert word into the tree
98:	for (int i = 0; i < keyword.Length; ++i) {
99:	int index = ((int)keyword[i]) % 256; // index of curchar
100:	bool d = keyword[i] == '\\';
101:
102:	next = next.leaf[index]; // get node to this index
103:
104:	if (next == null) { // no node created -> insert word here
105:	node.leaf[index] = new Node(value, keyword);
106:	break;
107:	}
108:
109:	if (next.word != null && next.word.Length != i) { // node there, take node content and insert them again
110:	string tmpword = next.word; // this word will be inserted 1 level deeper (better, don't need too much
111:	object tmpcolor = next.color; // string comparisons for finding.)
112:	next.color = next.word = null;
113:	this[tmpword] = tmpcolor;
114:	}
115:
116:	if (i == keyword.Length - 1) { // end of keyword reached, insert node there, if a node was here it was
117:	next.word = keyword; // reinserted, if it has the same length (keyword EQUALS this word) it will be overwritten
118:	next.color = value;
119:	break;
120:	}
121:
122:	node = next;
123:	}
124:	}
125:	}
126:
127:	public LookupTable(bool casesensitive)
128:	{
129:	this.casesensitive = casesensitive;
130:	}
131:
132:	class Node
133:	{
134:	public Node(object color, string word)
135:	{
136:	this.word = word;
137:	this.color = color;
138:	}
139:
140:	public string word;
141:	public object color;
142:
143:	public Node[] leaf = new Node[256];
144:	}
145:	}
146:	}