diff options
Diffstat (limited to 'src/libflate/deflatezlibblock.c')
-rw-r--r-- | src/libflate/deflatezlibblock.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/src/libflate/deflatezlibblock.c b/src/libflate/deflatezlibblock.c new file mode 100644 index 00000000..1c030dc3 --- /dev/null +++ b/src/libflate/deflatezlibblock.c @@ -0,0 +1,34 @@ +#include <u.h> +#include <libc.h> +#include <flate.h> +#include "zlib.h" + +int +deflatezlibblock(uchar *dst, int dsize, uchar *src, int ssize, int level, int debug) +{ + ulong adler; + int n; + + if(dsize < 6) + return FlateOutputFail; + + n = deflateblock(dst + 2, dsize - 6, src, ssize, level, debug); + if(n < 0) + return n; + + dst[0] = ZlibDeflate | ZlibWin32k; + + /* bogus zlib encoding of compression level */ + dst[1] = ((level > 2) + (level > 5) + (level > 8)) << 6; + + /* header check field */ + dst[1] |= 31 - ((dst[0] << 8) | dst[1]) % 31; + + adler = adler32(1, src, ssize); + dst[n + 2] = adler >> 24; + dst[n + 3] = adler >> 16; + dst[n + 4] = adler >> 8; + dst[n + 5] = adler; + + return n + 6; +} |