Difference between revisions of "LMD VCL - ZLib support"
From LMD
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| Line 39: | Line 39: | ||
LDataStream := TLMDCompressionStream.Create(clDefault, LFileStream); | LDataStream := TLMDCompressionStream.Create(clDefault, LFileStream); | ||
try | try | ||
| − | LDataStream(FSomeData, FSizeOfSomeData); | + | LDataStream.Write(FSomeData, FSizeOfSomeData); |
finally | finally | ||
LDestStream.Free; | LDestStream.Free; | ||
| Line 49: | Line 49: | ||
... | ... | ||
</delphi> | </delphi> | ||
| + | |||
| + | TLMDDecompressionStream can be used as decompression layer for stream with compressed data. Example: | ||
| + | |||
| + | <delphi> | ||
| + | uses | ||
| + | ..., LMDZLib, ...; | ||
| + | |||
| + | // old code | ||
| + | ... | ||
| + | var | ||
| + | LDataStream: TFileStream; | ||
| + | begin | ||
| + | LDataStream := TFileStream.Create(FileName, fmOpenRead); | ||
| + | try | ||
| + | LDataStream.Read(FSomeData, FSizeOfSomeData); | ||
| + | finally | ||
| + | LDataStream.Free; | ||
| + | end; | ||
| + | end; | ||
| + | ... | ||
| + | |||
| + | // code with TLMDDecompressionStream | ||
| + | ... | ||
| + | var | ||
| + | LDataStream: TLMDDecompressionStream; | ||
| + | LFileStream: TFileStream; | ||
| + | begin | ||
| + | LFileStream := TFileStream.Create(FileName, fmOpenRead); | ||
| + | try | ||
| + | LDataStream := TLMDDecompressionStream.Create(LFileStream); | ||
| + | try | ||
| + | LDataStream.Read(FSomeData, FSizeOfSomeData); | ||
| + | finally | ||
| + | LDestStream.Free; | ||
| + | end; | ||
| + | finally | ||
| + | LFileStream.Free; | ||
| + | end; | ||
| + | end; | ||
| + | ... | ||
| + | </delphi> | ||
| + | |||
| + | As you can see changes in code are minimal. | ||
Revision as of 14:10, 17 July 2007
Introduction
LMD 2k7 has built in ZLib library to compress/decompress any data. This is native pascal solution it doesn't require any external obj or dll files.
Units
- LMDZCommonUnit.pas - Common code and types for compress/decompress routines (raw ZLib api)
- LMDZCompressUnit.pas - Unit that contain compression code (raw ZLib api)
- LMDZUncompressUnit.pas - Unit with uncompression code (raw ZLib api)
- LMDZLib.pas - TStream wrappers that provide interface to compress/decompress data directly into any TStream descendants.
LMDZLib interface
TLMDCompressionStream wrapper class that compress data directly to any TStream descendant, and has transparent interface that compatible with TStream, so you can easily add compression for exists application. Example:
<delphi> uses
..., LMDZLib, ...;
// old code ... var
LDataStream: TFileStream;
begin
LDataStream := TFileStream.Create(FileName, fmCreate); try LDataStream(FSomeData, FSizeOfSomeData); finally LDataStream.Free; end;
end; ...
// code with TLMDCompressionStream ... var
LDataStream: TLMDCompressionStream; LFileStream: TFileStream;
begin
LFileStream := TFileStream.Create(FileName, fmCreate);
try
LDataStream := TLMDCompressionStream.Create(clDefault, LFileStream);
try
LDataStream.Write(FSomeData, FSizeOfSomeData);
finally
LDestStream.Free;
end;
finally
LFileStream.Free;
end;
end; ... </delphi>
TLMDDecompressionStream can be used as decompression layer for stream with compressed data. Example:
<delphi> uses
..., LMDZLib, ...;
// old code ... var
LDataStream: TFileStream;
begin
LDataStream := TFileStream.Create(FileName, fmOpenRead); try LDataStream.Read(FSomeData, FSizeOfSomeData); finally LDataStream.Free; end;
end; ...
// code with TLMDDecompressionStream ... var
LDataStream: TLMDDecompressionStream; LFileStream: TFileStream;
begin
LFileStream := TFileStream.Create(FileName, fmOpenRead);
try
LDataStream := TLMDDecompressionStream.Create(LFileStream);
try
LDataStream.Read(FSomeData, FSizeOfSomeData);
finally
LDestStream.Free;
end;
finally
LFileStream.Free;
end;
end; ... </delphi>
As you can see changes in code are minimal.
