1 #include "lib9.h"
2 #include <flate.h>
3 #include "zlib.h"
4
5 typedef struct ZRead ZRead;
6
7 struct ZRead
8 {
9 ulong adler;
10 void *rr;
11 int (*r)(void*, void*, int);
12 };
13
14 static int
zlread(void * vzr,void * buf,int n)15 zlread(void *vzr, void *buf, int n)
16 {
17 ZRead *zr;
18
19 zr = vzr;
20 n = (*zr->r)(zr->rr, buf, n);
21 if(n <= 0)
22 return n;
23 zr->adler = adler32(zr->adler, buf, n);
24 return n;
25 }
26
27 int
deflatezlib(void * wr,int (* w)(void *,void *,int),void * rr,int (* r)(void *,void *,int),int level,int debug)28 deflatezlib(void *wr, int (*w)(void*, void*, int), void *rr, int (*r)(void*, void*, int), int level, int debug)
29 {
30 ZRead zr;
31 uchar buf[4];
32 int ok;
33
34 buf[0] = ZlibDeflate | ZlibWin32k;
35
36 /* bogus zlib encoding of compression level */
37 buf[1] = ((level > 2) + (level > 5) + (level > 8)) << 6;
38
39 /* header check field */
40 buf[1] |= 31 - ((buf[0] << 8) | buf[1]) % 31;
41 if((*w)(wr, buf, 2) != 2)
42 return FlateOutputFail;
43
44 zr.rr = rr;
45 zr.r = r;
46 zr.adler = 1;
47 ok = deflate(wr, w, &zr, zlread, level, debug);
48 if(ok != FlateOk)
49 return ok;
50
51 buf[0] = zr.adler >> 24;
52 buf[1] = zr.adler >> 16;
53 buf[2] = zr.adler >> 8;
54 buf[3] = zr.adler;
55 if((*w)(wr, buf, 4) != 4)
56 return FlateOutputFail;
57
58 return FlateOk;
59 }
60