143 lines
3.3 KiB
C#
143 lines
3.3 KiB
C#
// StringHelper.cs
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// Author: Sergey Chaban (serge@wildwestsoftware.com)
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using System;
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using System.Text;
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namespace Mono.ILASM {
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/// <summary>
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/// </summary>
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internal class StringHelper : StringHelperBase {
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private static readonly string startIdChars = "#$@_";
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private static readonly string idChars = "_$@?`";
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/// <summary>
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/// </summary>
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/// <param name="host"></param>
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public StringHelper (ILTokenizer host) : base (host)
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{
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}
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/// <summary>
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/// </summary>
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/// <returns></returns>
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public override bool Start (char ch)
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{
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mode = Token.UNKNOWN;
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if (Char.IsLetter (ch) || startIdChars.IndexOf (ch) != -1) {
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mode = Token.ID;
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} else if (ch == '\'') {
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mode = Token.SQSTRING;
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} else if (ch == '"') {
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mode = Token.QSTRING;
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}
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return (mode != Token.UNKNOWN);
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}
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private static bool IsIdChar (int c)
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{
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char ch = (char) c;
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return (Char.IsLetterOrDigit(ch) || idChars.IndexOf (ch) != -1);
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}
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/// <summary>
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/// </summary>
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/// <returns></returns>
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public override string Build ()
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{
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if (mode == Token.UNKNOWN) return String.Empty;
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int ch = 0;
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ILReader reader = host.Reader;
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StringBuilder idsb = new StringBuilder ();
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if (mode == Token.SQSTRING || mode == Token.QSTRING) {
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int term = (mode == Token.SQSTRING) ? '\'' : '"';
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reader.Read (); // skip quote
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for (ch = reader.Read (); ch != -1; ch = reader.Read ()) {
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if (ch == term) {
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break;
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}
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if (ch == '\\') {
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ch = reader.Read ();
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/*
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* Long string can be broken across multiple lines
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* by using '\' as the last char in line.
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* Any white space chars between '\' and the first
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* char on the next line are ignored.
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*/
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if (ch == '\n') {
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reader.SkipWhitespace ();
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continue;
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}
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int escaped = Escape (reader, ch);
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if (escaped == -1) {
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reader.Unread (ch);
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ch = '\\';
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} else {
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ch = escaped;
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}
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}
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idsb.Append((char)ch);
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}
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} else { // ID
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while ((ch = reader.Read ()) != -1) {
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if (IsIdChar (ch)) {
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idsb.Append ((char) ch);
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} else {
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reader.Unread (ch);
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break;
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}
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}
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}
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return idsb.ToString ();
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}
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/// <summary>
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/// </summary>
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/// <param name="ch"></param>
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/// <returns></returns>
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public static int Escape (ILReader reader, int ch)
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{
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int res = -1;
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if (ch >= '0' && ch <='7') {
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StringBuilder octal = new StringBuilder ();
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octal.Append ((char)ch);
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int possibleOctalChar = reader.Peek ();
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if (possibleOctalChar >= '0' && possibleOctalChar <='7') {
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octal.Append ((char)reader.Read ());
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possibleOctalChar = reader.Peek ();
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if (possibleOctalChar >= '0' && possibleOctalChar <='7')
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octal.Append ((char)reader.Read ());
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}
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res = Convert.ToInt32(octal.ToString (), 8);
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} else {
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int id = "abfnrtv\"'\\".IndexOf ((char)ch);
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if (id != -1) {
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res = "\a\b\f\n\r\t\v\"'\\" [id];
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}
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}
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return res;
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}
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}
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}
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