1 #include <u.h>
2 #include <libc.h>
3 #include <flate.h>
4 #include "zlib.h"
5
6 typedef struct ZWrite ZWrite;
7
8 struct ZWrite
9 {
10 ulong adler;
11 void *wr;
12 int (*w)(void*, void*, int);
13 };
14
15 static int
zlwrite(void * vzw,void * buf,int n)16 zlwrite(void *vzw, void *buf, int n)
17 {
18 ZWrite *zw;
19
20 zw = vzw;
21 zw->adler = adler32(zw->adler, buf, n);
22 n = (*zw->w)(zw->wr, buf, n);
23 if(n <= 0)
24 return n;
25 return n;
26 }
27
28 int
inflatezlib(void * wr,int (* w)(void *,void *,int),void * getr,int (* get)(void *))29 inflatezlib(void *wr, int (*w)(void*, void*, int), void *getr, int (*get)(void*))
30 {
31 ZWrite zw;
32 ulong v;
33 int c, i;
34
35 c = (*get)(getr);
36 if(c < 0)
37 return FlateInputFail;
38 i = (*get)(getr);
39 if(i < 0)
40 return FlateInputFail;
41
42 if(((c << 8) | i) % 31)
43 return FlateCorrupted;
44 if((c & ZlibMeth) != ZlibDeflate
45 || (c & ZlibCInfo) > ZlibWin32k)
46 return FlateCorrupted;
47
48 zw.wr = wr;
49 zw.w = w;
50 zw.adler = 1;
51 i = inflate(&zw, zlwrite, getr, get);
52 if(i != FlateOk)
53 return i;
54
55 v = 0;
56 for(i = 0; i < 4; i++){
57 c = (*get)(getr);
58 if(c < 0)
59 return FlateInputFail;
60 v = (v << 8) | c;
61 }
62 if(zw.adler != v)
63 return FlateCorrupted;
64
65 return FlateOk;
66 }
67