jellyfin-server/BDInfo/BitVector32.cs
2016-10-26 15:29:56 -04:00

315 lines
8.5 KiB
C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace BDInfo
{
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("Bit vector full");
}
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 ArgumentOutOfRangeException("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("Bit vector full");
}
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);
}
}
}
}