Provides implementation of a random access and input and output streams where gamma, unary and binary, delta Golomb encoded integers can be read or written.
Writing and reading of streams of compressed integers can be made using BitOutputStream and BitInputStream classes, while the general contracts are specified using the BitOut and BitIn interfaces.
//Golomb coding parameter final int GOLOM_B = 10; //write a bit compressed stream to the file test.bf BitOut out = new BitOutputStream("test" + BitIn.USUAL_EXTENSION); //note that the numbers written must be greater than 0. The result for writing numbers less //than 1 is undefined for(int i=1;i<number;i++) { //unary, gamma, delta, and int write compressed integers out.writeUnary(i); out.writeGamma(i); out.writeDelta(i); out.writeInt(i); //write a number given knowledge of how large it can be out.writeMinimalBinary(i, number); out.writeGolomb(i, GOLOM_B); out.writeSkewedGolomb(i, GOLOM_B); //get the position. This is used for creating pointers into the bit file long byteOffset = out.getByteOffset(); byte bitOffset = out.getBitOffset(); } out.close(); //now read in the compressed stream BitIn in = new BitInputStream("test" + BitIn.USUAL_EXTENSION); for(int i=1;i<number;i++) { int num; //unary, gamma, delta, and int write compressed integers num = in.readUnary(); num = in.readGamma(); num = in.readDelta(); num = in.writeInt(); //write a number given knowledge of how large it can be num = in.writeMinimalBinary(number); num = in.writeGolomb(GOLOM_B); num = in.writeSkewedGolomb(GOLOM_B); //get the position. This is used for creating pointers into the bit file long byteOffset = in.getByteOffset(); byte bitOffset = in.getBitOffset(); //save or write the pointer for later use } in.close();
BitInSeekable bitFile = new BitFileBuffered("test" + BitIn.USUAL_EXTENSION); //position to seek to long byteOffset = ?; byte bitOffset = ?; BitIn in = bitFile.readReset(byteOffset, bitOffset); int num; num = in.readUnary(); num = in.readGamma(); num = in.readDelta(); num = in.writeInt(); //write a number given knowledge of how large it can be num = in.writeMinimalBinary(number); num = in.writeGolomb(GOLOM_B); num = in.writeSkewedGolomb(GOLOM_B);