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- /// Spart License (zlib/png)
- ///
- ///
- /// Copyright (c) 2003 Jonathan de Halleux
- ///
- /// This software is provided 'as-is', without any express or implied warranty.
- /// In no event will the authors be held liable for any damages arising from
- /// the use of this software.
- ///
- /// Permission is granted to anyone to use this software for any purpose,
- /// including commercial applications, and to alter it and redistribute it
- /// freely, subject to the following restrictions:
- ///
- /// 1. The origin of this software must not be misrepresented; you must not
- /// claim that you wrote the original software. If you use this software in a
- /// product, an acknowledgment in the product documentation would be
- /// appreciated but is not required.
- ///
- /// 2. Altered source versions must be plainly marked as such, and must not be
- /// misrepresented as being the original software.
- ///
- /// 3. This notice may not be removed or altered from any source distribution.
- ///
- /// Author: Jonathan de Halleuxnamespace Spart.Parsers.Composite
- namespace Spart.Parsers.Composite
- {
- using System;
- using Spart.Scanners;
- using Spart.Actions;
- using Spart.Parsers.NonTerminal;
- public class RepetitionParser : UnaryTerminalParser
- {
- private uint m_LowerBound;
- private uint m_UpperBound;
- public RepetitionParser(Parser parser, uint lowerBound, uint upperBound)
- :base(parser)
- {
- SetBounds(lowerBound,upperBound);
- }
- public uint LowerBound
- {
- get
- {
- return m_LowerBound;
- }
- }
- public uint UpperBound
- {
- get
- {
- return m_UpperBound;
- }
- }
- public void SetBounds(uint lb, uint ub)
- {
- if (ub < lb)
- throw new ArgumentException("lower bound must be smaller than upper bound");
- m_LowerBound = lb;
- m_UpperBound = ub;
- }
- public override ParserMatch ParseMain(IScanner scanner)
- {
- // save scanner state
- long offset = scanner.Offset;
- ParserMatch m=scanner.EmptyMatch;
- ParserMatch m_temp=null;
- // execution bound
- int count=0;
- // lower bound, minimum number of executions
- while(count < LowerBound && !scanner.AtEnd)
- {
- m_temp = Parser.Parse(scanner);
- // stop if not successful
- if (!m_temp.Success)
- break;
- // increment count and update full match
- ++count;
- m.Concat(m_temp);
- }
-
- if (count == LowerBound)
- {
- while(count < UpperBound && !scanner.AtEnd)
- {
- m_temp = Parser.Parse(scanner);
- // stop if not successful
- if (!m_temp.Success)
- break;
- // increment count
- ++count;
- m.Concat(m_temp);
- }
- }
- else
- {
- m=scanner.NoMatch;
- // restoring parser failed, rewind scanner
- scanner.Seek(offset);
- }
- return m;
- }
-
- public override Parser Clone()
- {
- RepetitionParser clone = base.Clone() as RepetitionParser;
- return clone;
- }
- }
- }
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