internal Packed8ThreeBlocks(int packedIntsVersion, DataInput @in, int valueCount)
: this(valueCount)
{
@in.ReadBytes(Blocks, 0, 3 * valueCount);
// because packed ints have not always been byte-aligned
var remaining = (int)(PackedInts.Format.PACKED.ByteCount(packedIntsVersion, valueCount, 24) - 3L * valueCount * 1);
for (int i = 0; i < remaining; ++i)
{
@in.ReadByte();
}
}
internal Direct32(int packedIntsVersion, DataInput @in, int valueCount)
: this(valueCount)
{
for (int i = 0; i < valueCount; ++i)
{
Values[i] = @in.ReadInt();
}
// because packed ints have not always been byte-aligned
int remaining = (int)(PackedInts.Format.PACKED.ByteCount(packedIntsVersion, valueCount, 32) - 4L * valueCount);
for (int i = 0; i < remaining; ++i)
{
@in.ReadByte();
}
}
internal Packed16ThreeBlocks(int packedIntsVersion, DataInput @in, int valueCount)
: this(valueCount)
{
for (int i = 0; i < 3 * valueCount; ++i)
{
Blocks[i] = @in.ReadShort();
}
// because packed ints have not always been byte-aligned
int remaining = (int)(PackedInts.Format.PACKED.ByteCount(packedIntsVersion, valueCount, 48) - 3L * valueCount * 2);
for (int i = 0; i < remaining; ++i)
{
@in.ReadByte();
}
}
/// <summary>
/// Decompress at least <code>decompressedLen</code> bytes into
/// <code>dest[dOff:]</code>. Please note that <code>dest</code> must be large
/// enough to be able to hold <b>all</b> decompressed data (meaning that you
/// need to know the total decompressed length).
/// </summary>
public static int Decompress(DataInput compressed, int decompressedLen, byte[] dest, int dOff)
{
int destEnd = dest.Length;
do
{
// literals
int token = compressed.ReadByte() & 0xFF;
int literalLen = (int)(((uint)token) >> 4);
if (literalLen != 0)
{
if (literalLen == 0x0F)
{
byte len;
while ((len = compressed.ReadByte()) == 0xFF)
{
literalLen += 0xFF;
}
literalLen += len & 0xFF;
}
compressed.ReadBytes(dest, dOff, literalLen);
dOff += literalLen;
}
if (dOff >= decompressedLen)
{
break;
}
// matchs
var byte1 = compressed.ReadByte();
var byte2 = compressed.ReadByte();
int matchDec = (byte1 & 0xFF) | ((byte2 & 0xFF) << 8);
Debug.Assert(matchDec > 0);
int matchLen = token & 0x0F;
if (matchLen == 0x0F)
{
int len;
while ((len = compressed.ReadByte()) == 0xFF)
{
matchLen += 0xFF;
}
matchLen += len & 0xFF;
}
matchLen += MIN_MATCH;
// copying a multiple of 8 bytes can make decompression from 5% to 10% faster
int fastLen = (int)((matchLen + 7) & 0xFFFFFFF8);
if (matchDec < matchLen || dOff + fastLen > destEnd)
{
// overlap -> naive incremental copy
for (int @ref = dOff - matchDec, end = dOff + matchLen; dOff < end; ++@ref, ++dOff)
{
dest[dOff] = dest[@ref];
}
}
else
{
// no overlap -> arraycopy
Array.Copy(dest, dOff - matchDec, dest, dOff, fastLen);
dOff += matchLen;
}
} while (dOff < decompressedLen);
return dOff;
}