Calling a Micro Focus Compression Routine

For data file compression the File Handler calls the compression routine that you specify in the DATACOMPRESS Compiler directive.

To call a Micro Focus data compression routine use the syntax:

COBOL:

call "CBLDCnnn" using input-buffer,
                      input-buffer-size,
                      output-buffer,
                      output-buffer-size,
                      compression-type

CBLDCnnn(input_buffer, &input_buffer_size,  
         output_buffer, &output_buffer_size,
         &compression-type);

where the parameters are:

`nnn`	A data compression routine in the range 001 to 127.
`input_buffer`	A PIC X(`size`) data item. On entry to the routine it must contain the data to compress or decompress; maximum size is 65535.
`input_buffer_size`	A two-byte (int in C, PIC XX COMP-5 in COBOL) data item. On entry it must contain the length of data in the input buffer.
`output_buffer`	A PIC X(`size`) data item. On exit it contains the resulting data.
`output_buffer_size`	A two-byte (int in C, PIC XX COMP-5 in COBOL) data item. On entry it must contain the size of the output buffer available; on exit it contains the length of the data in the buffer.
`compression-type`	A one-byte (char in C, PIC X COMP-X in COBOL) data item. On entry this must specify if the input data is to be compressed or decompressed: 0 - compress 1 - decompress.

The RETURN-CODE special register indicates whether the operation succeeded or not. Compression or decompression fails only if the output buffer is too small to accept the results. 0 indicates success and 1 indicates failure.