Package org.bitcoinj.base.internal

Class Buffers

  • public class Buffers
extends java.lang.Object
    Utility methods for common operations on Bitcoin P2P message buffers.

    • Constructor Summary

      Constructors 
      Constructor Description
      Buffers()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static byte[] readBytes​(java.nio.ByteBuffer buf, int length)
      Read given number of bytes from the buffer.
      static byte[] readLengthPrefixedBytes​(java.nio.ByteBuffer buf)
      First read a VarInt from the buffer and use it to determine the number of bytes to be read.
      static java.lang.String readLengthPrefixedString​(java.nio.ByteBuffer buf)
      First read a VarInt from the buffer and use it to determine the number of bytes to read.
      static java.nio.ByteBuffer skipBytes​(java.nio.ByteBuffer buf, int numBytes)
      Advance buffer position by a given number of bytes.
      static java.nio.ByteBuffer writeLengthPrefixedBytes​(java.nio.ByteBuffer buf, byte[] bytes)
      First write the length of the byte array as a VarInt.
      static java.nio.ByteBuffer writeLengthPrefixedString​(java.nio.ByteBuffer buf, java.lang.String str)
      Encode a given string using UTF-8.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • Buffers

        public Buffers()

    • Method Detail

      • readBytes

        public static byte[] readBytes​(java.nio.ByteBuffer buf,
                               int length)
                        throws java.nio.BufferUnderflowException
        Read given number of bytes from the buffer.
        Parameters:
        buf - buffer to read from
        length - number of bytes to read
        Returns:
        bytes read
        Throws:
        java.nio.BufferUnderflowException - if the read value extends beyond the remaining bytes of the buffer

      • readLengthPrefixedBytes

        public static byte[] readLengthPrefixedBytes​(java.nio.ByteBuffer buf)
                                      throws java.nio.BufferUnderflowException
        First read a VarInt from the buffer and use it to determine the number of bytes to be read. Then read that many bytes into the byte array to be returned. This construct is frequently used by Bitcoin protocols.
        Parameters:
        buf - buffer to read from
        Returns:
        read bytes
        Throws:
        java.nio.BufferUnderflowException - if the read value extends beyond the remaining bytes of the buffer

      • writeLengthPrefixedBytes

        public static java.nio.ByteBuffer writeLengthPrefixedBytes​(java.nio.ByteBuffer buf,
                                                           byte[] bytes)
                                                    throws java.nio.BufferOverflowException
        First write the length of the byte array as a VarInt. Then write the array contents.
        Parameters:
        buf - buffer to write to
        bytes - bytes to write
        Returns:
        the buffer
        Throws:
        java.nio.BufferOverflowException - if the value doesn't fit the remaining buffer

      • readLengthPrefixedString

        public static java.lang.String readLengthPrefixedString​(java.nio.ByteBuffer buf)
                                                 throws java.nio.BufferUnderflowException
        First read a VarInt from the buffer and use it to determine the number of bytes to read. Then read that many bytes and interpret it as an UTF-8 encoded string to be returned. This construct is frequently used by Bitcoin protocols.
        Parameters:
        buf - buffer to read from
        Returns:
        read string
        Throws:
        java.nio.BufferUnderflowException - if the read value extends beyond the remaining bytes of the buffer

      • writeLengthPrefixedString

        public static java.nio.ByteBuffer writeLengthPrefixedString​(java.nio.ByteBuffer buf,
                                                            java.lang.String str)
                                                     throws java.nio.BufferOverflowException
        Encode a given string using UTF-8. Then write the lnegth of the encoded bytes as a VarInt. Then write the bytes themselves.
        Parameters:
        buf - buffer to write to
        str - string to write
        Returns:
        the buffer
        Throws:
        java.nio.BufferOverflowException - if the value doesn't fit the remaining buffer

      • skipBytes

        public static java.nio.ByteBuffer skipBytes​(java.nio.ByteBuffer buf,
                                            int numBytes)
                                     throws java.nio.BufferUnderflowException
        Advance buffer position by a given number of bytes.
        Parameters:
        buf - buffer to skip bytes on
        numBytes - number of bytes to skip
        Returns:
        the buffer
        Throws:
        java.nio.BufferUnderflowException - if the read value extends beyond the remaining bytes of the buffer