Is it possible to read/write bits from a file using JAVA?

Question

To read/write binary files, I am using DataInputStream/DataOutputStream, they have this method writeByte()/readByte(), but what I want to do is read/write bits? Is it possib

Answer 1

Please take a look at my bit-io library https://github.com/jinahya/bit-io, which can read and write non-octet-aligned values such as a 1-bit boolean or 17-bit unsigned integer.

  
  com.googlecode.jinahya
  bit-io
  1.0-alpha-13

This library reads and writes arbitrary-length bits.

final InputStream stream;
final BitInput input = new BitInput(new BitInput.StreamInput(stream));

final int b = input.readBoolean(); // reads a 1-bit boolean value
final int i = input.readUnsignedInt(3); // reads a 3-bit unsigned int
final long l = input.readLong(47); // reads a 47-bit signed long

input.align(1); // 8-bit byte align; padding


final WritableByteChannel channel;
final BitOutput output = new BitOutput(new BitOutput.ChannelOutput(channel));

output.writeBoolean(true); // writes a 1-bit boolean value
output.writeInt(17, 0x00); // writes a 17-bit signed int
output.writeUnsignedLong(54, 0x00L); // writes a 54-bit unsigned long

output.align(4); // 32-bit byte align; discarding