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//------------------------------------------------------------------------------
// <copyright file="BitVector32.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Collections.Specialized {
using System.Diagnostics;
using System.Text;
using System;
using Microsoft.Win32;
/// <devdoc>
/// <para>Provides a simple light bit vector with easy integer or Boolean access to
/// a 32 bit storage.</para>
/// </devdoc>
public struct BitVector32 {
private uint data;
/// <devdoc>
/// <para>Initializes a new instance of the BitVector32 structure with the specified internal data.</para>
/// </devdoc>
public BitVector32(int data) {
this.data = (uint)data;
}
/// <devdoc>
/// <para>Initializes a new instance of the BitVector32 structure with the information in the specified
/// value.</para>
/// </devdoc>
public BitVector32(BitVector32 value) {
this.data = value.data;
}
/// <devdoc>
/// <para>Gets or sets a value indicating whether all the specified bits are set.</para>
/// </devdoc>
public bool this[int bit] {
get {
return (data & bit) == (uint)bit;
}
set {
if (value) {
data |= (uint)bit;
}
else {
data &= ~(uint)bit;
}
}
}
/// <devdoc>
/// <para>Gets or sets the value for the specified section.</para>
/// </devdoc>
public int this[Section section] {
get {
return (int)((data & (uint)(section.Mask << section.Offset)) >> section.Offset);
}
set {
#if DEBUG
if ((value & section.Mask) != value) {
Debug.Fail("Value out of bounds on BitVector32 Section Set!");
}
#endif
value <<= section.Offset;
int offsetMask = (0xFFFF & (int)section.Mask) << section.Offset;
data = (data & ~(uint)offsetMask) | ((uint)value & (uint)offsetMask);
}
}
/// <devdoc>
/// returns the raw data stored in this bit vector...
/// </devdoc>
public int Data {
get {
return (int)data;
}
}
private static short CountBitsSet(short mask) {
// yes, I know there are better algorithms, however, we know the
// bits are always right aligned, with no holes (i.e. always 00000111,
// never 000100011), so this is just fine...
//
short value = 0;
while ((mask & 0x1) != 0) {
value++;
mask >>= 1;
}
return value;
}
/// <devdoc>
/// <para> Creates the first mask in a series.</para>
/// </devdoc>
public static int CreateMask() {
return CreateMask(0);
}
/// <devdoc>
/// Creates the next mask in a series.
/// </devdoc>
public static int CreateMask(int previous) {
if (previous == 0) {
return 1;
}
if (previous == unchecked((int)0x80000000)) {
throw new InvalidOperationException(SR.GetString(SR.BitVectorFull));
}
return previous << 1;
}
/// <devdoc>
/// Given a highValue, creates the mask
/// </devdoc>
private static short CreateMaskFromHighValue(short highValue) {
short required = 16;
while ((highValue & 0x8000) == 0) {
required--;
highValue <<= 1;
}
ushort value = 0;
while (required > 0) {
required--;
value <<= 1;
value |= 0x1;
}
return unchecked((short) value);
}
/// <devdoc>
/// <para>Creates the first section in a series, with the specified maximum value.</para>
/// </devdoc>
public static Section CreateSection(short maxValue) {
return CreateSectionHelper(maxValue, 0, 0);
}
/// <devdoc>
/// <para>Creates the next section in a series, with the specified maximum value.</para>
/// </devdoc>
public static Section CreateSection(short maxValue, Section previous) {
return CreateSectionHelper(maxValue, previous.Mask, previous.Offset);
}
private static Section CreateSectionHelper(short maxValue, short priorMask, short priorOffset) {
if (maxValue < 1) {
throw new ArgumentException(SR.GetString(SR.Argument_InvalidValue, "maxValue", 0), "maxValue");
}
#if DEBUG
int maskCheck = CreateMaskFromHighValue(maxValue);
int offsetCheck = priorOffset + CountBitsSet(priorMask);
Debug.Assert(maskCheck <= short.MaxValue && offsetCheck < 32, "Overflow on BitVector32");
#endif
short offset = (short)(priorOffset + CountBitsSet(priorMask));
if (offset >= 32) {
throw new InvalidOperationException(SR.GetString(SR.BitVectorFull));
}
return new Section(CreateMaskFromHighValue(maxValue), offset);
}
public override bool Equals(object o) {
if (!(o is BitVector32)) {
return false;
}
return data == ((BitVector32)o).data;
}
public override int GetHashCode() {
return base.GetHashCode();
}
/// <devdoc>
/// </devdoc>
public static string ToString(BitVector32 value) {
StringBuilder sb = new StringBuilder(/*"BitVector32{".Length*/12 + /*32 bits*/32 + /*"}".Length"*/1);
sb.Append("BitVector32{");
int locdata = (int)value.data;
for (int i=0; i<32; i++) {
if ((locdata & 0x80000000) != 0) {
sb.Append("1");
}
else {
sb.Append("0");
}
locdata <<= 1;
}
sb.Append("}");
return sb.ToString();
}
/// <devdoc>
/// </devdoc>
public override string ToString() {
return BitVector32.ToString(this);
}
/// <devdoc>
/// <para>
/// Represents an section of the vector that can contain a integer number.</para>
/// </devdoc>
public struct Section {
private readonly short mask;
private readonly short offset;
internal Section(short mask, short offset) {
this.mask = mask;
this.offset = offset;
}
public short Mask {
get {
return mask;
}
}
public short Offset {
get {
return offset;
}
}
public override bool Equals(object o) {
if (o is Section)
return Equals((Section)o);
else
return false;
}
public bool Equals(Section obj)
{
return obj.mask == mask && obj.offset == offset;
}
public static bool operator ==(Section a, Section b)
{
return a.Equals(b);
}
public static bool operator !=(Section a, Section b)
{
return !(a == b);
}
public override int GetHashCode() {
return base.GetHashCode();
}
/// <devdoc>
/// </devdoc>
public static string ToString(Section value) {
return "Section{0x" + Convert.ToString(value.Mask, 16) + ", 0x" + Convert.ToString(value.Offset, 16) + "}";
}
/// <devdoc>
/// </devdoc>
public override string ToString() {
return Section.ToString(this);
}
}
}
}
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