Abstract: A fast and flexible data decompressor decodes data, such as that encoded by CCITT Group 4 facsimile machines, to produce display data. In the decompressor, a microprocessor controlled by microcode evaluates variable length codes each representing a series of data cells, each data cell in a series having a single value assigned thereto. The variable length codes have a first code type, such as vertical codes and pass codes used in two-dimensional coding schemes, are decoded by the microprocessor. The variable length codes having a second type, such as one-dimensional horizontal codes, are decoded by a pair of loo k-up tables in read only memories (ROM's). One ROM determines the length of the code and the other determines the run length of the series of data cells represented by the code. A shifter which receives encoded data is shifted by the length of the code, whether determined by the code length ROM or the microprocessor.