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| Compress | CompressBuffer | CompressFile |
| UnCompress | UnCompressBuffer | UnCompressFile |
TYPE
LoadBuffer = PROCEDURE (CONST SYSTEM.ADDRESS, (* buffer *)
VAR CARDINAL);
(* totalIn *)
PutBuffer = PROCEDURE (CONST SYSTEM.ADDRESS, (* buffer *)
CONST CARDINAL, (* totalOut *)
VAR BOOLEAN);
(* success *)
PROCEDURE Compress
(CONST compression : CARDINAL;
CONST workBuffer : SYSTEM.ADDRESS;
CONST workLength : CARDINAL;
CONST inputProc : LoadBuffer;
CONST outputProc : PutBuffer;
CONST showProgress : BOOLEAN;
VAR Status : CARDINAL);
(**
Compress - Compress data from and to buffers.
This procedure begins the process of compressing data. The data
compression method used is a sliding dictionary method to reduce
repeated byte sequences. The size of the dictionary depends on
compression factor. Valid compression factors are :
1 - 512 byte buffer, minimum compression, least time
2 - 1024 byte buffer, better compression, more time
3 - 2048 byte buffer, better compression, more time
4 - 4096 byte buffer, best compression, longest time
Compression factors outside this range will default to a factor of
2.
"inputProc" will be called by the program when more data is
needed. The user is required to fill in the "Buffer" to the the
"totalIn" value received from compress and pass the total number
of bytes loaded back in "totalIn". A value of zero will end
compress processing signaling the end of data.
"outputProc" will be called when there is no room to output more
data or at the conclusion of the program. "totalOut", the number of
bytes in the output buffer, is passed to you. Process this buffer
as needed. When control is passed back to the compression program
data will again be written to the buffer from the first. "success"
set to FALSE will indicate an error and processing will quit.
CALLING SEQUENCE -
Compress (compression, workBuffer, workLength,
inputProc, outputProc,
showProgress, status);
ENTRY -
compression : CARDINAL
Compression factor (1 .. 4).
workBuffer : SYSTEM.ADDRESS
Address of a working buffer. Must be at least four times
bigger than the search buffer size indicated by the
compression factor.
workLength : CARDINAL
Total length of workbuffer in bytes.
inputProc : LoadBuffer
Procedure to load buffer when needed;
outputProc : PutBuffer
Procedure to put buffer when needed;
showProgress : BOOLEAN
Show a device (propeller) which indicates compression in
progress.
EXIT -
status : CARDINAL
Number indicating the status of the compression result.
0 - No error occurred
4 - Error putting output buffer
5 - Work buffer too small
EXAMPLE -
PROCEDURE LoadInput
( buffer : SYSTEM.ADDRESS;
VAR totalIn : CARDINAL);
BEGIN
ReadData (buffer, totalIn);
END LoadInput;
PROCEDURE PutOutputBuffer
( buffer : SYSTEM.ADDRESS;
totalOut : CARDINAL;
VAR success : BOOLEAN);
BEGIN
success := WriteData (buffer, totalOut);
END PutOutput;
PROCEDURE MyProgram;
BEGIN
.
.
Compress.Compress (compression, SYSTEM.ADR (workBuffer), workLength,
LoadInput, PutOutputBuffer,
showProgress, status);
.
.
END MyProgram;
*)
PROCEDURE UnCompress
(CONST workBuffer : SYSTEM.ADDRESS;
CONST workLength : CARDINAL;
CONST inputProc : LoadBuffer;
CONST outputProc : PutBuffer;
CONST showProgress : BOOLEAN;
VAR Status : CARDINAL);
(**
UnCompress - Uncompress data from and to buffers.
This procedure reverses the process of compressing data. The data
must have been compressed using this compression package.
"inputProc" will be called by the program when more data is
needed. The user is required to fill in the buffer up to the the
"totalIn" value received from compress and pass the total number
of bytes loaded back in "totalIn". A value of zero will end
compress processing signaling the end of data.
"outputProc" will be called when there is no room to output more
data or at the conclusion of the program. "totalOut", the total
number of bytes in the output buffer, is passed to you. Process
this buffer as needed. When control is passed back to the
compression program data will again be written to the buffer from
the first. "success" set to FALSE will indicate an error and
processing will quit.
CALLING SEQUENCE -
Compress.UnCompress (workBuffer, workLength,
inputProc, outputProc,
showProgress, status);
ENTRY -
workBuffer : SYSTEM.ADDRESS
Address of a working buffer. Must be at least four times
bigger than the search buffer size indicated by the
compression factor used to compress the data.
workLength : CARDINAL
Total length of workbuffer in bytes.
inputProc : LoadBuffer
Procedure to load buffer when needed;
outputProc : PutBuffer
Procedure to put buffer when needed;
showProgress : BOOLEAN
Show a device (propeller) which indicates compression in
progress.
EXIT -
status : CARDINAL
Number indicating the status of the uncompression result.
0 - No error occurred
4 - Error putting output buffer
5 - Work buffer too small
EXAMPLE -
PROCEDURE LoadInput
( buffer : SYSTEM.ADDRESS;
VAR totalIn : CARDINAL);
BEGIN
ReadData (buffer, totalIn);
END LoadInput;
PROCEDURE PutOutputBuffer
( buffer : SYSTEM.ADDRESS;
totalOut : CARDINAL;
success : BOOLEAN);
BEGIN
success := WriteData (buffer, totalOut);
END PutOutput;
PROCEDURE MyProgram;
BEGIN
.
.
Compress.UnCompress (workBuffer'address, workLength,
LoadInput, PutOutputBuffer,
showProgress, status);
.
.
end MyProgram;
*)
PROCEDURE CompressBuffer
(CONST compression : CARDINAL;
CONST inBuffer : SYSTEM.ADDRESS;
CONST inBufLength : CARDINAL;
CONST outBuffer : SYSTEM.ADDRESS;
CONST outBufLength : CARDINAL;
CONST showProgress : BOOLEAN;
VAR resultLength : CARDINAL;
VAR Status : CARDINAL);
(**
CompressBuffer - Compress a memory buffer.
This routine will use the Compress procedure to compress an input
buffer and write the compressed data to an output buffer.
The size of the dictionary depends on compression factor. Valid
compression factors are :
1 - 512 byte buffer, minimum compression, least time
2 - 1024 byte buffer, better compression, more time
3 - 2048 byte buffer, better compression, more time
4 - 4096 byte buffer, best compression, longest time
Compression factors outside this range will default to a factor of
2.
CALLING SEQUENCE -
CompressBuffer (compression,
inBuffer, inBufLength,
outBuffer, outBufLength,
showProgress,
resultLength, status);
ENTRY -
compression : CARDINAL
Compression factor (1 .. 4).
inBuffer : SYSTEM.ADDRESS
Address of the buffer containing the input data to be
compressed.
inBufLength : CARDINAL
Length of the input buffer;
outBuffer : SYSTEM.ADDRESS
Address of the buffer where compressed input buffer data is
to be stored.
outBufLength : CARDINAL
Length of the output buffer;
showProgress : BOOLEAN
Show a device (propeller) which indicates compression in
progress.
resultLength : CARDINAL
The valid length of the resluting compressed data stored in
the output buffer.
EXIT -
status : CARDINAL
Number indicating the status of the compression result.
0 - No error occurred
4 - Error putting output buffer
5 - Work buffer too small
*)
PROCEDURE UnCompressBuffer
(CONST inBuffer : SYSTEM.ADDRESS;
CONST inBufLength : CARDINAL;
CONST outBuffer : SYSTEM.ADDRESS;
CONST outBufLength : CARDINAL;
CONST showProgress : BOOLEAN;
VAR resultLength : CARDINAL;
VAR Status : CARDINAL);
(**
UnCompressBuffer - Uncompress a memory buffer.
This routine will use the Uncompress procedure to uncompress an
input buffer and write the uncompressed data to an output buffer.
This procedure reverses the process of compressing data. The data
must have been compressed using this compression package.
CALLING SEQUENCE -
UnCompressBuffer (inBuffer, inBufLength,
outBuffer, outBufLength,
showProgress,
resultLength, status);
ENTRY -
inBuffer : SYSTEM.ADDRESS
Address of the buffer containing the input data to be
uncompressed.
inBufLength : CARDINAL
Length of the input buffer.
outBuffer : SYSTEM.ADDRESS
Address of the buffer where uncompressed input buffer data is
to be stored.
outBufLength : CARDINAL
Length of the output buffer.
showProgress : BOOLEAN
Show a device (propeller) which indicates compression in
progress.
EXIT -
resultLength : CARDINAL
The valid length of the resluting compressed data stored in
the output buffer.
status : CARDINAL
Number indicating the status of the uncompression result.
0 - No error occurred
4 - Error putting output buffer
5 - Work buffer too small
*)
PROCEDURE CompressFile
(CONST fileIn : ARRAY OF CHAR;
CONST fileOut : ARRAY OF CHAR;
CONST compression : CARDINAL;
CONST showProgress : BOOLEAN;
VAR bytesIn : ModSys.INT32;
VAR bytesOut : ModSys.INT32;
VAR Status : CARDINAL);
(**
CompressFile - Compress a DOS file to another file.
This routine will use the Compress procedure, read the input file,
compress the data and write the compressed data to another file.
CALLING SEQUENCE -
CompressFile (fileIn, fileOut, compression,
bytesIn, bytesOut, status);
ENTRY -
fileIn : ARRAY OF CHAR
File name of file to be compressed. Must include any path
information if needed.
fileOut : ARRAY OF CHAR
File name of the comressed file. Must include any path
information if needed. The compressed file cannot be the same
as the input file name. The file is tagged with a special
sequence of characters to indicate that it is a compressed
file and the compression used.
compression : CARDINAL
Compression factor (1 .. 4); (See Compress for info).
showProgress : BOOLEAN
Show a device (propeller) which indicates compression in
progress.
EXIT -
bytesIn : ModSys.INT32
Number of bytes compressed from the input file. (File size)
bytesOut : ModSys.INT32
Number of bytes in the compressed file. A compression ratio
can be calculated from this information.
status : CARDINAL
Number indicating the status of the compression result.
0 - No error occurred
1 - Could not open input file
2 - Could not open output file
4 - Error putting output buffer
5 - Work buffer too small
*)
PROCEDURE UnCompressFile
(CONST fileIn : ARRAY OF CHAR;
CONST fileOut : ARRAY OF CHAR;
CONST showProgress : BOOLEAN;
VAR Status : CARDINAL);
(**
UnCompressFile - Uncompress a compressed file to another file.
This routine will use the UnCompress procedure, read the input
compressed file, uncompress the data and write the uncompressed
data to another file.
CALLING SEQUENCE -
UnCompressFile (fileIn, fileOut, status);
ENTRY -
fileIn : ARRAY OF CHAR
File name of file to be uncompressed. Must include any path
information if needed. The file must be a file compressed
using the CompressFile routine above.
fileOut : ARRAY OF CHAR
File name of the uncomressed file. Must include any path
information if needed.
showProgress : BOOLEAN
Show a device (propeller) which indicates compression in
progress.
EXIT -
status : CARDINAL
Number indicating the status of the uncompression result.
0 - No error occurred
1 - Could not open input file
2 - Could not open output file
3 - Not a compressed file
4 - Error putting output buffer
5 - Work buffer too small
*)
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