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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

C:

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

where the parameters for routines CBLDC001 and CBLDC003 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.

and for routines CBLDC101 and CBLDC103 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 256 megabytes.
input_buffer_size A four-byte (int in C, PIC XXXX 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 four-byte (int in C, PIC XXXX 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.

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