ref: c8b187f9db503465460d8bafa2d7a758bbcf59ca
dir: /libflate/deflatezlibblock.c/
#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; }