 The codes from 0 to 255 represent 1-character sequences consisting of the corresponding 8-bit character, and the codes 256 through 4095 are created in a dictionary for sequences encountered in the data as it is encoded.At each stage in compression, input bytes are gathered into a sequence until the next character would make a sequence with no code yet in the dictionary.The code for the sequence (without that character) is added to the output, and a new code (for the sequence with that character) is added to the dictionary.