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David_L_6
Beginner
101 Views

igzip for VS10 C++?

I was searching for a zlib-compatible compressor but faster, and came cross the paper describing igzip --

High Performance DEFLATE Compression on Intel Architecture Processors

igzip looks like exactly (!) what I am looking for.  Compatible with zlib, but faster.

However, the downloadable source was for Linux.  I need it for a VS10 C++ project.  I have successfully (I think) compiled and assembled the desired modules (common, crc, crc_utils, hufftables, hufftables_c.cpp, igzip0c_body, igzip0c_finish, init_stream) into a .lib. 

But when I attempt to link the library into my project, I get error LNK2019: unresolved external symbol fast_lz (and init_stream) from where they are called.  I also have a "C" lz4 compression library linked into the project, and it works fine.  I have spent 3 days playing with it, looking for the clue that will unlock the symbols, but no luck so far.

I get no other warnings and/or errors during the compiling/assembling of the library or project.  Any help (especially if anybody has done the work to create a VS10 lib igzip project) would be appreciated! 

 

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David_L_6
Beginner
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Update:

I was able to build the igzip library in my VC2010 C/C++ project.  Yay!

1)  I needed to invoke the YASM assembler in the project (thanks to Brian Gladman's "Building YASM with Microsoft Visual Studio 2010 - C/C++ v10") for the .ASM modules.

2)  There were a few things to change between GCC and MSVC in the C (called .cpp, but they were C) modules.  Ie:  adding "typedef" to structure definitions and pulling the functions out of an .h file and creating a separate .c(pp) file for them.

But now I ran into an unrelated issue - the code uses the pclmulqdq instruction which my processor does not support.

I have looked for a .ASM macro to replace it (one supposedly resides in GAS, but I downloaded binutils 2.24 and did not find a reference to the instruction outside of the disassembler) but have had no luck.  I do have the psuedo code and can build a 'C' version, but that is not optimal (and of course there will be no bugs in my code.... ya, right...).

Anybody out there with code/guidance?

Thanks,

Dave

 

 

 

gvollant
Beginner
101 Views

very good news.

 

Is it possible you upload , send email or post on forum the full project?

David_L_6
Beginner
101 Views

I zipped up the VS10 igzip library files and attached it (also put the zip at: http://www.cruzinsb.com/igzip_VS10/).

My focus was to use igzip to create zlib (not gzip) compressed files.  So far I have been unsuccessful in replacing the gzip header/CRC with a zlib header/adler32.  Getting closer though.

I believe the files zipped here have been returned to the successful gzip state with the zlib logic commented out.

If anyone has zlib-compatible versions of igzip, I'm all ears!

 

gvollant
Beginner
101 Views

 

thankyou a lot

igzip can create deflate (without header) or gzip 

 

You probably need your code to add the (small) zlib header, which contain, I believe adler32 checksum

 

Any news to a fallback for older CPU (core 2 duo before 2009, I believe) with incompatible instruction  ?

gvollant
Beginner
101 Views

 

 

By reading RFC950 and http://stackoverflow.com/questions/9050260/what-does-a-zlib-header-look-like

 

Just begin by 0x78 0x01 (ou 0x78 0x9c) then deflate data then adler32 checkum

 

gvollant
Beginner
101 Views

 

 

By reading RFC950 and http://stackoverflow.com/questions/9050260/what-does-a-zlib-header-look-like

 

Just begin by 0x78 0x01 (ou 0x78 0x9c) then deflate data then adler32 checkum

 

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