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author | rsc <devnull@localhost> | 2003-11-23 18:19:18 +0000 |
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committer | rsc <devnull@localhost> | 2003-11-23 18:19:18 +0000 |
commit | b6afd33e2f23953f00c6fac6b5d45946a9113654 (patch) | |
tree | 300478ec8ac939d1b7aa0c1b987367a49a4e47ce /src/libflate/deflatezlib.c | |
parent | 8a708fb239f4272ac7e4f16f437093c56b2cab39 (diff) | |
download | plan9port-b6afd33e2f23953f00c6fac6b5d45946a9113654.tar.gz plan9port-b6afd33e2f23953f00c6fac6b5d45946a9113654.tar.bz2 plan9port-b6afd33e2f23953f00c6fac6b5d45946a9113654.zip |
add libflate
Diffstat (limited to 'src/libflate/deflatezlib.c')
-rw-r--r-- | src/libflate/deflatezlib.c | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/src/libflate/deflatezlib.c b/src/libflate/deflatezlib.c new file mode 100644 index 00000000..037c355a --- /dev/null +++ b/src/libflate/deflatezlib.c @@ -0,0 +1,60 @@ +#include <u.h> +#include <libc.h> +#include <flate.h> +#include "zlib.h" + +typedef struct ZRead ZRead; + +struct ZRead +{ + ulong adler; + void *rr; + int (*r)(void*, void*, int); +}; + +static int +zlread(void *vzr, void *buf, int n) +{ + ZRead *zr; + + zr = vzr; + n = (*zr->r)(zr->rr, buf, n); + if(n <= 0) + return n; + zr->adler = adler32(zr->adler, buf, n); + return n; +} + +int +deflatezlib(void *wr, int (*w)(void*, void*, int), void *rr, int (*r)(void*, void*, int), int level, int debug) +{ + ZRead zr; + uchar buf[4]; + int ok; + + buf[0] = ZlibDeflate | ZlibWin32k; + + /* bogus zlib encoding of compression level */ + buf[1] = ((level > 2) + (level > 5) + (level > 8)) << 6; + + /* header check field */ + buf[1] |= 31 - ((buf[0] << 8) | buf[1]) % 31; + if((*w)(wr, buf, 2) != 2) + return FlateOutputFail; + + zr.rr = rr; + zr.r = r; + zr.adler = 1; + ok = deflate(wr, w, &zr, zlread, level, debug); + if(ok != FlateOk) + return ok; + + buf[0] = zr.adler >> 24; + buf[1] = zr.adler >> 16; + buf[2] = zr.adler >> 8; + buf[3] = zr.adler; + if((*w)(wr, buf, 4) != 4) + return FlateOutputFail; + + return FlateOk; +} |