1 #include "lib9.h"
2 #include <flate.h>
3 #include "zlib.h"
4
5 typedef struct Block Block;
6
7 struct Block
8 {
9 uchar *pos;
10 uchar *limit;
11 };
12
13 static int
blgetc(void * vb)14 blgetc(void *vb)
15 {
16 Block *b;
17
18 b = vb;
19 if(b->pos >= b->limit)
20 return -1;
21 return *b->pos++;
22 }
23
24 static int
blwrite(void * vb,void * buf,int n)25 blwrite(void *vb, void *buf, int n)
26 {
27 Block *b;
28
29 b = vb;
30
31 if(n > b->limit - b->pos)
32 n = b->limit - b->pos;
33 memmove(b->pos, buf, n);
34 b->pos += n;
35 return n;
36 }
37
38 int
inflatezlibblock(uchar * dst,int dsize,uchar * src,int ssize)39 inflatezlibblock(uchar *dst, int dsize, uchar *src, int ssize)
40 {
41 Block bd, bs;
42 int ok;
43
44 if(ssize < 6)
45 return FlateInputFail;
46
47 if(((src[0] << 8) | src[1]) % 31)
48 return FlateCorrupted;
49 if((src[0] & ZlibMeth) != ZlibDeflate
50 || (src[0] & ZlibCInfo) > ZlibWin32k)
51 return FlateCorrupted;
52
53 bs.pos = src + 2;
54 bs.limit = src + ssize - 6;
55
56 bd.pos = dst;
57 bd.limit = dst + dsize;
58
59 ok = inflate(&bd, blwrite, &bs, blgetc);
60 if(ok != FlateOk)
61 return ok;
62
63 if(adler32(1, dst, bs.pos - dst) != ((bs.pos[0] << 24) | (bs.pos[1] << 16) | (bs.pos[2] << 8) | bs.pos[3]))
64 return FlateCorrupted;
65
66 return bd.pos - dst;
67 }
68