Package org.apache.accumulo.core.file.rfile.bcfile

Class Utils

  • public final class Utils
extends Object
    Supporting Utility classes used by TFile, and shared by users of TFile.

    • Method Detail

      • writeVInt

        public static void writeVInt​(DataOutput out,
                             int n)
                      throws IOException
        Encoding an integer into a variable-length encoding format. Synonymous to Utils#writeVLong(out, n).
        Parameters:
        out - output stream
        n - The integer to be encoded
        Throws:
        IOException
        See Also:
        writeVLong(DataOutput, long)

      • writeVLong

        public static void writeVLong​(DataOutput out,
                              long n)
                       throws IOException
        Encoding a Long integer into a variable-length encoding format.
        • if n in [-32, 127): encode in one byte with the actual value. Otherwise,
        • if n in [-20*2^8, 20*2^8): encode in two bytes: byte[0] = n/256 - 52; byte[1]=n&0xff. Otherwise,
        • if n IN [-16*2^16, 16*2^16): encode in three bytes: byte[0]=n/2^16 - 88; byte[1]=(n>>8)&0xff; byte[2]=n&0xff. Otherwise,
        • if n in [-8*2^24, 8*2^24): encode in four bytes: byte[0]=n/2^24 - 112; byte[1] = (n>>16)&0xff; byte[2] = (n>>8)&0xff; byte[3]=n&0xff. Otherwise:
        • if n in [-2^31, 2^31): encode in five bytes: byte[0]=-125; byte[1] = (n>>24)&0xff; byte[2]=(n>>16)&0xff; byte[3]=(n>>8)&0xff; byte[4]=n&0xff;
        • if n in [-2^39, 2^39): encode in six bytes: byte[0]=-124; byte[1] = (n>>32)&0xff; byte[2]=(n>>24)&0xff; byte[3]=(n>>16)&0xff; byte[4]=(n>>8)&0xff; byte[5]=n&0xff
        • if n in [-2^47, 2^47): encode in seven bytes: byte[0]=-123; byte[1] = (n>>40)&0xff; byte[2]=(n>>32)&0xff; byte[3]=(n>>24)&0xff; byte[4]=(n>>16)&0xff; byte[5]=(n>>8)&0xff; byte[6]=n&0xff;
        • if n in [-2^55, 2^55): encode in eight bytes: byte[0]=-122; byte[1] = (n>>48)&0xff; byte[2] = (n>>40)&0xff; byte[3]=(n>>32)&0xff; byte[4]=(n>>24)&0xff; byte[5]=(n>>16)&0xff; byte[6]=(n>>8)&0xff; byte[7]=n&0xff;
        • if n in [-2^63, 2^63): encode in nine bytes: byte[0]=-121; byte[1] = (n>>54)&0xff; byte[2] = (n>>48)&0xff; byte[3] = (n>>40)&0xff; byte[4]=(n>>32)&0xff; byte[5]=(n>>24)&0xff; byte[6]=(n>>16)&0xff; byte[7]=(n>>8)&0xff; byte[8]=n&0xff;
        Parameters:
        out - output stream
        n - the integer number
        Throws:
        IOException

      • readVInt

        public static int readVInt​(DataInput in)
                    throws IOException
        Decoding the variable-length integer. Synonymous to (int)Utils#readVLong(in).
        Parameters:
        in - input stream
        Returns:
        the decoded integer
        Throws:
        IOException
        See Also:
        readVLong(DataInput)

      • readVLong

        public static long readVLong​(DataInput in)
                      throws IOException
        Decoding the variable-length integer. Suppose the value of the first byte is FB, and the following bytes are NB[*].
        • if (FB >= -32), return (long)FB;
        • if (FB in [-72, -33]), return (FB+52)<<8 + NB[0]&0xff;
        • if (FB in [-104, -73]), return (FB+88)<<16 + (NB[0]&0xff)<<8 + NB[1]&0xff;
        • if (FB in [-120, -105]), return (FB+112)<<24 + (NB[0]&0xff)<<16 + (NB[1]&0xff)<<8 + NB[2]&0xff;
        • if (FB in [-128, -121]), return interpret NB[FB+129] as a signed big-endian integer.
        Parameters:
        in - input stream
        Returns:
        the decoded long integer.
        Throws:
        IOException

      • readString

        public static String readString​(DataInput in)
                         throws IOException
        Read a String as a VInt n, followed by n Bytes in Text format.
        Parameters:
        in - The input stream.
        Returns:
        The string
        Throws:
        IOException