BitArray.cs

using System.Runtime.InteropServices;
using System.Threading;

namespace System.Collections
{
    [Serializable]
    [ComVisible(true)]
    [__DynamicallyInvokable]
    public sealed class BitArray : ICollection, IEnumerable, ICloneable
    {
        [Serializable]
        private class BitArrayEnumeratorSimple : IEnumerator, ICloneable
        {
            private BitArray bitarray;

            private int index;

            private int version;

            private bool currentElement;

            public virtual object Current
            {
                get
                {
                    if (index == -1)
                    {
                        throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_EnumNotStarted"));
                    }
                    if (index >= bitarray.Count)
                    {
                        throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_EnumEnded"));
                    }
                    return currentElement;
                }
            }

            internal BitArrayEnumeratorSimple(BitArray bitarray)
            {
                this.bitarray = bitarray;
                index = -1;
                version = bitarray._version;
            }

            public object Clone()
            {
                return MemberwiseClone();
            }

            public virtual bool MoveNext()
            {
                if (version != bitarray._version)
                {
                    throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_EnumFailedVersion"));
                }
                if (index < bitarray.Count - 1)
                {
                    index++;
                    currentElement = bitarray.Get(index);
                    return true;
                }
                index = bitarray.Count;
                return false;
            }

            public void Reset()
            {
                if (version != bitarray._version)
                {
                    throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_EnumFailedVersion"));
                }
                index = -1;
            }
        }

        private const int BitsPerInt32 = 32;

        private const int BytesPerInt32 = 4;

        private const int BitsPerByte = 8;

        private int[] m_array;

        private int m_length;

        private int _version;

        [NonSerialized]
        private object _syncRoot;

        private const int _ShrinkThreshold = 256;

        [__DynamicallyInvokable]
        public bool this[int index]
        {
            [__DynamicallyInvokable]
            get
            {
                return Get(index);
            }
            [__DynamicallyInvokable]
            set
            {
                Set(index, value);
            }
        }

        [__DynamicallyInvokable]
        public int Length
        {
            [__DynamicallyInvokable]
            get
            {
                return m_length;
            }
            [__DynamicallyInvokable]
            set
            {
                if (value < 0)
                {
                    throw new ArgumentOutOfRangeException("value", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
                }
                int arrayLength = GetArrayLength(value, 32);
                if (arrayLength > m_array.Length || arrayLength + 256 < m_array.Length)
                {
                    int[] array = new int[arrayLength];
                    Array.Copy(m_array, array, (arrayLength > m_array.Length) ? m_array.Length : arrayLength);
                    m_array = array;
                }
                if (value > m_length)
                {
                    int num = GetArrayLength(m_length, 32) - 1;
                    int num2 = m_length % 32;
                    if (num2 > 0)
                    {
                        m_array[num] &= (1 << num2) - 1;
                    }
                    Array.Clear(m_array, num + 1, arrayLength - num - 1);
                }
                m_length = value;
                _version++;
            }
        }

        public int Count => m_length;

        public object SyncRoot
        {
            get
            {
                if (_syncRoot == null)
                {
                    Interlocked.CompareExchange<object>(ref _syncRoot, new object(), (object)null);
                }
                return _syncRoot;
            }
        }

        public bool IsReadOnly => false;

        public bool IsSynchronized => false;

        private BitArray()
        {
        }

        [__DynamicallyInvokable]
        public BitArray(int length)
            : this(length, defaultValue: false)
        {
        }

        [__DynamicallyInvokable]
        public BitArray(int length, bool defaultValue)
        {
            if (length < 0)
            {
                throw new ArgumentOutOfRangeException("length", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
            }
            m_array = new int[GetArrayLength(length, 32)];
            m_length = length;
            int num = defaultValue ? (-1) : 0;
            for (int i = 0; i < m_array.Length; i++)
            {
                m_array[i] = num;
            }
            _version = 0;
        }

        [__DynamicallyInvokable]
        public BitArray(byte[] bytes)
        {
            if (bytes == null)
            {
                throw new ArgumentNullException("bytes");
            }
            if (bytes.Length > 268435455)
            {
                throw new ArgumentException(Environment.GetResourceString("Argument_ArrayTooLarge", 8), "bytes");
            }
            m_array = new int[GetArrayLength(bytes.Length, 4)];
            m_length = bytes.Length * 8;
            int num = 0;
            int i;
            for (i = 0; bytes.Length - i >= 4; i += 4)
            {
                m_array[num++] = ((bytes[i] & 0xFF) | ((bytes[i + 1] & 0xFF) << 8) | ((bytes[i + 2] & 0xFF) << 16) | ((bytes[i + 3] & 0xFF) << 24));
            }
            switch (bytes.Length - i)
            {
            case 3:
                m_array[num] = (bytes[i + 2] & 0xFF) << 16;
                goto case 2;
            case 2:
                m_array[num] |= (bytes[i + 1] & 0xFF) << 8;
                goto case 1;
            case 1:
                m_array[num] |= (bytes[i] & 0xFF);
                break;
            }
            _version = 0;
        }

        [__DynamicallyInvokable]
        public BitArray(bool[] values)
        {
            if (values == null)
            {
                throw new ArgumentNullException("values");
            }
            m_array = new int[GetArrayLength(values.Length, 32)];
            m_length = values.Length;
            for (int i = 0; i < values.Length; i++)
            {
                if (values[i])
                {
                    m_array[i / 32] |= 1 << i % 32;
                }
            }
            _version = 0;
        }

        [__DynamicallyInvokable]
        public BitArray(int[] values)
        {
            if (values == null)
            {
                throw new ArgumentNullException("values");
            }
            if (values.Length > 67108863)
            {
                throw new ArgumentException(Environment.GetResourceString("Argument_ArrayTooLarge", 32), "values");
            }
            m_array = new int[values.Length];
            m_length = values.Length * 32;
            Array.Copy(values, m_array, values.Length);
            _version = 0;
        }

        [__DynamicallyInvokable]
        public BitArray(BitArray bits)
        {
            if (bits == null)
            {
                throw new ArgumentNullException("bits");
            }
            int arrayLength = GetArrayLength(bits.m_length, 32);
            m_array = new int[arrayLength];
            m_length = bits.m_length;
            Array.Copy(bits.m_array, m_array, arrayLength);
            _version = bits._version;
        }

        [__DynamicallyInvokable]
        public bool Get(int index)
        {
            if (index < 0 || index >= Length)
            {
                throw new ArgumentOutOfRangeException("index", Environment.GetResourceString("ArgumentOutOfRange_Index"));
            }
            return (m_array[index / 32] & (1 << index % 32)) != 0;
        }

        [__DynamicallyInvokable]
        public void Set(int index, bool value)
        {
            if (index < 0 || index >= Length)
            {
                throw new ArgumentOutOfRangeException("index", Environment.GetResourceString("ArgumentOutOfRange_Index"));
            }
            if (value)
            {
                m_array[index / 32] |= 1 << index % 32;
            }
            else
            {
                m_array[index / 32] &= ~(1 << index % 32);
            }
            _version++;
        }

        [__DynamicallyInvokable]
        public void SetAll(bool value)
        {
            int num = value ? (-1) : 0;
            int arrayLength = GetArrayLength(m_length, 32);
            for (int i = 0; i < arrayLength; i++)
            {
                m_array[i] = num;
            }
            _version++;
        }

        [__DynamicallyInvokable]
        public BitArray And(BitArray value)
        {
            if (value == null)
            {
                throw new ArgumentNullException("value");
            }
            if (Length != value.Length)
            {
                throw new ArgumentException(Environment.GetResourceString("Arg_ArrayLengthsDiffer"));
            }
            int arrayLength = GetArrayLength(m_length, 32);
            for (int i = 0; i < arrayLength; i++)
            {
                m_array[i] &= value.m_array[i];
            }
            _version++;
            return this;
        }

        [__DynamicallyInvokable]
        public BitArray Or(BitArray value)
        {
            if (value == null)
            {
                throw new ArgumentNullException("value");
            }
            if (Length != value.Length)
            {
                throw new ArgumentException(Environment.GetResourceString("Arg_ArrayLengthsDiffer"));
            }
            int arrayLength = GetArrayLength(m_length, 32);
            for (int i = 0; i < arrayLength; i++)
            {
                m_array[i] |= value.m_array[i];
            }
            _version++;
            return this;
        }

        [__DynamicallyInvokable]
        public BitArray Xor(BitArray value)
        {
            if (value == null)
            {
                throw new ArgumentNullException("value");
            }
            if (Length != value.Length)
            {
                throw new ArgumentException(Environment.GetResourceString("Arg_ArrayLengthsDiffer"));
            }
            int arrayLength = GetArrayLength(m_length, 32);
            for (int i = 0; i < arrayLength; i++)
            {
                m_array[i] ^= value.m_array[i];
            }
            _version++;
            return this;
        }

        [__DynamicallyInvokable]
        public BitArray Not()
        {
            int arrayLength = GetArrayLength(m_length, 32);
            for (int i = 0; i < arrayLength; i++)
            {
                m_array[i] = ~m_array[i];
            }
            _version++;
            return this;
        }

        public void CopyTo(Array array, int index)
        {
            if (array == null)
            {
                throw new ArgumentNullException("array");
            }
            if (index < 0)
            {
                throw new ArgumentOutOfRangeException("index", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
            }
            if (array.Rank != 1)
            {
                throw new ArgumentException(Environment.GetResourceString("Arg_RankMultiDimNotSupported"));
            }
            if (array is int[])
            {
                Array.Copy(m_array, 0, array, index, GetArrayLength(m_length, 32));
                return;
            }
            if (array is byte[])
            {
                int arrayLength = GetArrayLength(m_length, 8);
                if (array.Length - index < arrayLength)
                {
                    throw new ArgumentException(Environment.GetResourceString("Argument_InvalidOffLen"));
                }
                byte[] array2 = (byte[])array;
                for (int i = 0; i < arrayLength; i++)
                {
                    array2[index + i] = (byte)((m_array[i / 4] >> i % 4 * 8) & 0xFF);
                }
                return;
            }
            if (array is bool[])
            {
                if (array.Length - index < m_length)
                {
                    throw new ArgumentException(Environment.GetResourceString("Argument_InvalidOffLen"));
                }
                bool[] array3 = (bool[])array;
                for (int j = 0; j < m_length; j++)
                {
                    array3[index + j] = (((m_array[j / 32] >> j % 32) & 1) != 0);
                }
                return;
            }
            throw new ArgumentException(Environment.GetResourceString("Arg_BitArrayTypeUnsupported"));
        }

        public object Clone()
        {
            BitArray bitArray = new BitArray(m_array);
            bitArray._version = _version;
            bitArray.m_length = m_length;
            return bitArray;
        }

        [__DynamicallyInvokable]
        public IEnumerator GetEnumerator()
        {
            return new BitArrayEnumeratorSimple(this);
        }

        private static int GetArrayLength(int n, int div)
        {
            if (n <= 0)
            {
                return 0;
            }
            return (n - 1) / div + 1;
        }
    }
}