AlphabetConverter.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Speech / Src / Internal / AlphabetConverter.cs / 1 / AlphabetConverter.cs
                        
                        
                            //---------------------------------------------------------------------------- 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
//
// 
// Description: 
//      Convert Between phonemes string between SAPI, UPS and IPA
// 
// History:
//      11/15/2005  [....]                      Created interface code.
//      11/17/2005  [....]                      Added conversion methods.
//--------------------------------------------------------------------------- 
using System;
using System.Collections.Generic; 
using System.Globalization; 
using System.Collections;
using System.Reflection; 
using System.IO;
using System.Text;

#pragma warning disable 1634, 1691 // Allows suppression of certain PreSharp messages. 

namespace System.Speech.Internal 
{ 
    internal enum AlphabetType
    { 
        Sapi, Ipa, Ups
    }

    ///  
    /// This class allows conversion between SAPI and IPA phonemes.
    /// Objects of this class are not thread safe for modifying state. 
    ///  
    internal class AlphabetConverter
    { 
        //*******************************************************************
        //
        // Constructors
        // 
        //*******************************************************************
 
        #region Constructors 

        internal AlphabetConverter (int langId) 
        {
            _currentLangId = -1;
            SetLanguageId (langId);
        } 

        #endregion 
 
        //********************************************************************
        // 
        // Internal Methods
        //
        //*******************************************************************
 
        #region internal Methods
 
        ///  
        /// Convert from SAPI phonemes to IPA phonemes.
        ///  
        /// 
        /// 
        /// Return an array of unicode characters each of which represents an IPA phoneme if the SAPI phonemes are valid.
        /// Otherwise, return null. 
        /// 
        internal char [] SapiToIpa (char [] phonemes) 
        { 
            return Convert (phonemes, true);
        } 

        /// 
        /// Convert from IPA phonemes to SAPI phonemes.
        ///  
        /// 
        /// Return an array of unicode characters each of which represents a SAPI phoneme if the IPA phonemes are valid. 
        /// Otherwise, return null. 
        /// 
        internal char [] IpaToSapi (char [] phonemes) 
        {
            return Convert (phonemes, false);
        }
 
        /// 
        /// Determines whether a given string of SAPI ids can be potentially converted using a single 
        /// conversion unit, that is, a prefix of some convertible string. 
        /// 
        /// The string of SAPI or UPS phoneme ids 
        /// To indicate whether parameter phonemes is in SAPI or UPS phonemes
        /// 
        internal bool IsPrefix(string phonemes, bool isSapi)
        { 
            return _phoneMap.IsPrefix(phonemes, isSapi);
        } 
 
        internal bool IsConvertibleUnit(string phonemes, bool isSapi)
        { 
            return _phoneMap.ConvertPhoneme(phonemes, isSapi) != null;
        }

        internal int SetLanguageId (int langId) 
        {
            if (langId < 0) 
            { 
                throw new ArgumentException (SR.Get (SRID.MustBeGreaterThanZero), "langId");
            } 
            if (langId == _currentLangId)
            {
                return _currentLangId;
            } 

            int i; 
            int oldLangId = _currentLangId; 
            for (i = 0; i < _langIds.Length; i++)
            { 
                if (_langIds [i] == langId)
                {
                    break;
                } 
            }
            if (i == _langIds.Length) 
            { 
                _currentLangId = langId;
                _phoneMap = null; 
            }
            else
            {
                lock (_staticLock) 
                {
                    if (_phoneMaps [i] == null) 
                    { 
                        _phoneMaps [i] = CreateMap (_resourceNames [i]);
                    } 
                    _phoneMap = _phoneMaps [i];
                    _currentLangId = langId;
                }
 
            }
            return oldLangId; 
        } 
        #endregion
 
        //********************************************************************
        //
        // Private Methods
        // 
        //********************************************************************
 
        #region Private Methods 

        private char [] Convert (char [] phonemes, bool isSapi) 
        {
            // If the phoneset of the selected language is UPS anyway, that is phone mapping is unnecessary,
            // we return the same phoneme string. But we still need to make a copy.
            if (_phoneMap == null || phonemes.Length == 0) 
            {
                return (char []) phonemes.Clone (); 
            } 

            // 
            // We break the phoneme string into substrings of phonemes, each of which is directly convertible from
            // the mapping table. If there is ambiguity, we always choose the largest substring as we go from left
            // to right.
            // 
            // In order to do this, we check whether a given substring is a potential prefix of a convertible substring.
            // 
 
            StringBuilder result = new StringBuilder ();
            int startIndex; // Starting index of a substring being considered 
            int endIndex;   // The ending index of the last convertible substring
            String token;           // Holds a substring of phonemes that are directly convertible from the mapping table.
            String lastConvert;     // Holds last convertible substring, starting from startIndex.
 
            String tempConvert;
            String source = new String (phonemes); 
            int i; 

            lastConvert = null; 
            startIndex = i = 0;
            endIndex = -1;

#pragma warning disable 56507 

            while (i < source.Length) 
            { 
                token = source.Substring (startIndex, i - startIndex + 1);
                if (_phoneMap.IsPrefix (token, isSapi)) 
                {
                    tempConvert = _phoneMap.ConvertPhoneme (token, isSapi);
                    // Note we may have an empty string for conversion result here
                    if (tempConvert != null) 
                    {
                        lastConvert = tempConvert; 
                        endIndex = i; 
                    }
                } 
                else
                {
                    // If we have not had a convertible substring, the input is not convertible.
                    if (lastConvert == null) 
                    {
                        break; 
                    } 
                    else
                    { 
                        // Use the converted substring, and start over from the last convertible position.
                        result.Append (lastConvert);
                        i = endIndex;
                        startIndex = endIndex + 1; 
                        lastConvert = null;
                    } 
                } 
                i++;
            } 

            if (lastConvert != null && endIndex == phonemes.Length - 1)
            {
                result.Append (lastConvert); 
            }
            else 
            { 
                return null;
            } 
#pragma warning restore 56507

            return result.ToString ().ToCharArray ();
        } 

        private PhoneMapData CreateMap (string resourceName) 
        { 
            Assembly assembly = Assembly.GetAssembly (GetType ());
            Stream stream = assembly.GetManifestResourceStream(resourceName); 
            if (stream == null)
            {
                throw new FileLoadException(SR.Get(SRID.CannotLoadResourceFromManifest, resourceName, assembly.FullName));
            } 
            return new PhoneMapData (new BufferedStream (stream));
        } 
 
        #endregion
 
        //*******************************************************************
        //
        // Private Fields
        // 
        //********************************************************************
 
        #region Private Fields 

        private int _currentLangId; 
        private PhoneMapData _phoneMap;

        private static int[] _langIds = new int[] { 0x804, 0x404, 0x407, 0x409, 0x40A, 0x40C, 0x411};
        private static String[] _resourceNames = 
                    new String[] { "upstable_chs.upsmap", "upstable_cht.upsmap", "upstable_deu.upsmap", "upstable_enu.upsmap",
                                   "upstable_esp.upsmap", "upstable_fra.upsmap", "upstable_jpn.upsmap", 
 
                                        };
        private static PhoneMapData [] _phoneMaps = new PhoneMapData [7]; 
        private static object _staticLock = new object ();

        #endregion
 
        //*******************************************************************
        // 
        // Private Type 
        //
        //******************************************************************* 

        #region Private Type

        internal class PhoneMapData 
        {
            private class ConversionUnit 
            { 
                public String sapi;
                public String ups; 
                public bool isDefault;
            }

            internal PhoneMapData (Stream input) 
            {
                using (BinaryReader reader = new BinaryReader (input, System.Text.Encoding.Unicode)) 
                { 
                    int size = reader.ReadInt32 ();
                    convertTable = new ConversionUnit [size]; 
                    int i;
                    for (i = 0; i < size; i++)
                    {
                        convertTable [i] = new ConversionUnit (); 
                        convertTable [i].sapi = ReadPhoneString (reader);
                        convertTable [i].ups = ReadPhoneString (reader); 
                        convertTable [i].isDefault = reader.ReadInt32 () != 0 ? true : false; 
                    }
 
                    prefixSapiTable = InitializePrefix (true);
                    prefixUpsTable = InitializePrefix (false);
                }
            } 

            internal bool IsPrefix (string prefix, bool isSapi) 
            { 
                if (isSapi)
                { 
                    return prefixSapiTable.ContainsKey (prefix);
                }
                else
                { 
                    return prefixUpsTable.ContainsKey (prefix);
                } 
            } 

            internal string ConvertPhoneme (string phoneme, bool isSapi) 
            {
                ConversionUnit unit;
                if (isSapi)
                { 
                    unit = (ConversionUnit) prefixSapiTable [phoneme];
                } 
                else 
                {
                    unit = (ConversionUnit) prefixUpsTable [phoneme]; 
                }
                if (unit == null)
                {
                    return null; 
                }
                return isSapi ? unit.ups : unit.sapi; 
            } 

            ///  
            /// Create a hash table of all possible prefix substrings for each ConversionUnit
            /// 
            /// Creating a SAPI or UPS prefix table
            ///  
            private Hashtable InitializePrefix (bool isSapi)
            { 
                int i, j; 
                Hashtable prefixTable = Hashtable.Synchronized (new Hashtable ());
                string from, key; 
                for (i = 0; i < convertTable.Length; i++)
                {
                    if (isSapi)
                    { 
                        from = convertTable [i].sapi;
                    } 
                    else 
                    {
                        from = convertTable [i].ups; 
                    }

                    for (j = 0; j + 1 < from.Length; j++)
                    { 
                        key = from.Substring (0, j + 1);
                        if (!prefixTable.ContainsKey (key)) 
                        { 
                            prefixTable [key] = null;
                        } 
                    }

                    if (convertTable [i].isDefault || prefixTable [from] == null)
                    { 
                        prefixTable [from] = convertTable [i];
                    } 
                } 
                return prefixTable;
            } 

            static private string ReadPhoneString (BinaryReader reader)
            {
                int phoneLength; 
                char [] phoneString;
                phoneLength = reader.ReadInt16 () / 2; 
                phoneString = reader.ReadChars (phoneLength); 
                return new String (phoneString, 0, phoneLength - 1);
            } 

            private Hashtable prefixSapiTable, prefixUpsTable;
            private ConversionUnit [] convertTable;
        } 

        #endregion 
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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