ObjectToIdCache.cs source code in C# .NET

                        Code:
                         / WCF / WCF / 3.5.30729.1 / untmp / Orcas / SP / ndp / cdf / src / WCF / Serialization / System / Runtime / Serialization / ObjectToIdCache.cs / 1 / ObjectToIdCache.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------------------------
namespace System.Runtime.Serialization
{ 
    using System.Collections;
    using System.Collections.Generic; 
    using System.Runtime.CompilerServices; 
    using System.Security;
 
    class ObjectToIdCache
    {
        internal int m_currentCount;
        internal int []m_ids; 
        internal Object []m_objs;
 
        public ObjectToIdCache() 
        {
            m_currentCount=1; 
            m_ids = new int[GetPrime(1)];
            m_objs = new Object[m_ids.Length];
        }
 
        public int GetId(object obj, ref bool newId)
        { 
            bool isEmpty; 
            int pos = FindElement(obj, out isEmpty);
            if(!isEmpty) 
            {
                newId = false;
                return m_ids[pos];
            } 
            if(!newId)
                return -1; 
            int id = m_currentCount++; 
            m_objs[pos]=obj;
            m_ids[pos]= id; 
            if (m_currentCount >= (m_objs.Length-1))
                Rehash();
            return id;
        } 

#if NotUsed 
        public bool Remove(object obj) 
        {
            bool isEmpty; 
            int pos = FindElement(obj, out isEmpty);
            if(isEmpty)
                return false;
            RemoveAt(pos); 
            return true;
        } 
#endif 

        // (oldObjId, oldObj-id, newObj-newObjId) => (oldObj-oldObjId, newObj-id, newObjId ) 
        public int ReassignId(int oldObjId, object oldObj, object newObj)
        {
            bool isEmpty;
            int pos = FindElement(oldObj, out isEmpty); 
            if(isEmpty)
                return 0; 
            int id = m_ids[pos]; 
            if (oldObjId > 0)
                m_ids[pos] = oldObjId; 
            else
                RemoveAt(pos);
            pos = FindElement(newObj, out isEmpty);
            int newObjId = 0; 
            if (!isEmpty)
                newObjId = m_ids[pos]; 
            m_objs[pos] = newObj; 
            m_ids[pos] = id;
            return newObjId; 
        }

        private int FindElement(object obj, out bool isEmpty)
        { 
            int hashcode = RuntimeHelpers.GetHashCode(obj);
            int pos = ((hashcode&0x7FFFFFFF)%m_objs.Length); 
            for(int i = pos; i != (pos-1); i++) 
            {
                if (m_objs[i] == null) 
                {
                    isEmpty=true;
                    return i;
                } 
                if (m_objs[i] == obj)
                { 
                    isEmpty=false; 
                    return i;
                } 
                if(i == (m_objs.Length-1))
                    i = -1;
            }
            // m_obj must ALWAYS have atleast one slot empty (null). 
            DiagnosticUtility.DebugAssert("Object table overflow");
            throw System.Runtime.Serialization.DiagnosticUtility.ExceptionUtility.ThrowHelperError(XmlObjectSerializer.CreateSerializationException(SR.GetString(SR.ObjectTableOverflow))); 
        } 

        private void RemoveAt(int pos) 
        {
            int hashcode = RuntimeHelpers.GetHashCode(m_objs[pos]);
            for (int i = pos, j;i != (pos-1); i = j)
            { 
                j = (i+1) % m_objs.Length;
                if (m_objs[j] == null || RuntimeHelpers.GetHashCode(m_objs[j]) != hashcode) 
                { 
                    m_objs[pos] = m_objs[i];
                    m_ids[pos] = m_ids[i]; 
                    m_objs[i] = null;
                    m_ids[i] = 0;
                    return;
                } 
            }
            // m_obj must ALWAYS have atleast one slot empty (null). 
            DiagnosticUtility.DebugAssert("Object table overflow"); 
            throw System.Runtime.Serialization.DiagnosticUtility.ExceptionUtility.ThrowHelperError(XmlObjectSerializer.CreateSerializationException(SR.GetString(SR.ObjectTableOverflow)));
        } 

        private void Rehash()
        {
            int size = GetPrime(m_objs.Length * 2); 
            int[] oldIds = m_ids;
            object[] oldObjs = m_objs; 
            m_ids = new int[size]; 
            m_objs = new Object[size];
 
            for (int j=0; j= min) return prime;
            }
 
            //outside of our predefined table.
            //compute the hard way. 
            for (int i = (min | 1); i < Int32.MaxValue;i+=2) 
            {
                if (IsPrime(i)) 
                    return i;
            }
            return min;
        } 

        static bool IsPrime(int candidate) 
        { 
            if ((candidate & 1) != 0)
            { 
                int limit = (int)Math.Sqrt (candidate);
                for (int divisor = 3; divisor <= limit; divisor+=2)
                {
                    if ((candidate % divisor) == 0) 
                        return false;
                } 
                return true; 
            }
            return (candidate == 2); 
        }

        /// 
        /// Review - Static fields are marked SecurityCritical or readonly to prevent 
        ///          data from being modified or leaked to other components in appdomain.
        ///  
        [SecurityRequiresReview] 
        internal static readonly int[] primes =
        { 
            3, 7, 17, 37, 89, 197, 431, 919, 1931, 4049, 8419, 17519, 36353,
            75431, 156437, 324449, 672827, 1395263, 2893249, 5999471,
        };
 
    }
} 
 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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ObjectToIdCache.cs source code in C# .NET

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