IndexedAlphabetBase.cs
108 lines
| 3.9 KiB
| text/x-csharp
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r162 | using Implab; | ||
| using System; | ||||
| using System.Collections.Generic; | ||||
| using System.Diagnostics; | ||||
| using System.Linq; | ||||
| namespace Implab.Automaton { | ||||
| /// <summary> | ||||
| /// Indexed alphabet is the finite set of symbols where each symbol has a zero-based unique index. | ||||
| /// </summary> | ||||
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r167 | /// <remarks> | ||
| /// Indexed alphabets are usefull in bulting efficient translations from source alphabet | ||||
| /// to the input alphabet of the automaton. It's assumed that the index to the symbol match | ||||
| /// is well known and documented. | ||||
| /// </remarks> | ||||
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r162 | public abstract class IndexedAlphabetBase<T> : IAlphabetBuilder<T> { | ||
| int m_nextId = 1; | ||||
| readonly int[] m_map; | ||||
| public int Count { | ||||
| get { return m_nextId; } | ||||
| } | ||||
| protected IndexedAlphabetBase(int mapSize) { | ||||
| m_map = new int[mapSize]; | ||||
| } | ||||
| protected IndexedAlphabetBase(int[] map) { | ||||
| Debug.Assert(map != null); | ||||
| m_map = map; | ||||
| m_nextId = map.Max() + 1; | ||||
| } | ||||
| public int DefineSymbol(T symbol) { | ||||
| var index = GetSymbolIndex(symbol); | ||||
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r164 | if (m_map[index] == DFAConst.UNCLASSIFIED_INPUT) | ||
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r162 | m_map[index] = m_nextId++; | ||
| return m_map[index]; | ||||
| } | ||||
| public int DefineClass(IEnumerable<T> symbols) { | ||||
| Safe.ArgumentNotNull(symbols, "symbols"); | ||||
| symbols = symbols.Distinct(); | ||||
| foreach (var symbol in symbols) { | ||||
| var index = GetSymbolIndex(symbol); | ||||
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r164 | if (m_map[index] == DFAConst.UNCLASSIFIED_INPUT) | ||
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r162 | m_map[GetSymbolIndex(symbol)] = m_nextId; | ||
| else | ||||
| throw new InvalidOperationException(String.Format("Symbol '{0}' already in use", symbol)); | ||||
| } | ||||
| return m_nextId++; | ||||
| } | ||||
| public List<T>[] CreateReverseMap() { | ||||
| return | ||||
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r164 | Enumerable.Range(0, Count) | ||
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r162 | .Select( | ||
| i => InputSymbols | ||||
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r164 | .Where(x => i != DFAConst.UNCLASSIFIED_INPUT && m_map[GetSymbolIndex(x)] == i) | ||
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r162 | .ToList() | ||
| ) | ||||
| .ToArray(); | ||||
| } | ||||
| public int[] Reclassify(IAlphabetBuilder<T> newAlphabet, IEnumerable<IEnumerable<int>> classes) { | ||||
| Safe.ArgumentNotNull(newAlphabet, "newAlphabet"); | ||||
| Safe.ArgumentNotNull(classes, "classes"); | ||||
| var reverseMap = CreateReverseMap(); | ||||
| var translationMap = new int[Count]; | ||||
| foreach (var scl in classes) { | ||||
| // skip if the supper class contains the unclassified element | ||||
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r164 | if (scl.Contains(DFAConst.UNCLASSIFIED_INPUT)) | ||
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r162 | continue; | ||
| var range = new List<T>(); | ||||
| foreach (var cl in scl) { | ||||
| if (cl < 0 || cl >= reverseMap.Length) | ||||
| throw new ArgumentOutOfRangeException(String.Format("Class {0} is not valid for the current alphabet", cl)); | ||||
| range.AddRange(reverseMap[cl]); | ||||
| } | ||||
| var newClass = newAlphabet.DefineClass(range); | ||||
| foreach (var cl in scl) | ||||
| translationMap[cl] = newClass; | ||||
| } | ||||
| return translationMap; | ||||
| } | ||||
| public virtual int Translate(T symbol) { | ||||
| return m_map[GetSymbolIndex(symbol)]; | ||||
| } | ||||
| public abstract int GetSymbolIndex(T symbol); | ||||
| public abstract IEnumerable<T> InputSymbols { get; } | ||||
| /// <summary> | ||||
| /// Gets the translation map from the index of the symbol to it's class this is usefull for the optimized input symbols transtaion. | ||||
| /// </summary> | ||||
| /// <returns>The translation map.</returns> | ||||
| public int[] GetTranslationMap() { | ||||
| return m_map; | ||||
| } | ||||
| } | ||||
| } | ||||