Hi Laurent,
> # uLong compressBound (uLong sourceLen)
> # int compress2(Bytef *dest, uLongf *destLen, const Bytef *source,
> uLong sourceLen, int level)
I'm afraid I can give only a partial answer, as I don't understand the
exact requirements of these functions well enough.
However, here are some points:
The lines
'(dest `(genCharBuff bufSize) . 0) # *dest
'(destLen (8 . N) . `bufSize) # *destLen
are probably a problem. For one thing, using a read macro (with
backquote) here doesn't do what you expect, because 'bufSize' is not
bound yet when the function 'Zcompress2' is read.
You can check that with (pp 'Zcompress2):
...
(native "libz.so"
...
'(dest (NIL B) . 0)
'(destLen (8 . N))
...
Also, the size and type specifier must be reversed in the cons pairs.
Correct would probably be
(dest (<bufSize> B . <bufSize>)) # Return in 'dest', buffer size, return
<bufSize> bytes
and
(destLen (8 . N) (<bufSize> . 8)) # Pass buffer size as long, return a long
Then I would stay with some naming conventions, define 'Dest' and
'DestLen' as local variables, and get finally:
(de Zcompress2 (InBuf Level)
(let (InBufSize (size InBuf) BufSize (ZcompressBound InBufSize))
(use (Dest DestLen)
(list
(native
"libz.so" # lib file
"compress2" # function
'I # return value (error status)
(list 'Dest # *dest
(cons BufSize 'B BufSize) )
(list 'DestLen # *destLen
(8 . N)
(cons BufSize 8) )
InBuf # *source
InBufSize # sourceLen
Level ) # level
(head DestLen Dest) ) ) ) )
Notes:
- For system libraries, you don't need to pass the full path. Thus,
instead of (native "/usr/lib/libz.so" ..) you can simply write
(native "libz.so" ..)
- I don't know what 'compress2' does with multibyte UTF-8 chars, but
in any case it is better to use (size inBuf) instead of (length
inBuf)
Cheers,
- Alex
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