xref: /inferno-os/os/boot/libflate/inflateblock.c (revision 74a4d8c26dd3c1e9febcb717cfd6cb6512991a7a)
1*74a4d8c2SCharles.Forsyth #include "lib9.h"
2*74a4d8c2SCharles.Forsyth #include <flate.h>
3*74a4d8c2SCharles.Forsyth 
4*74a4d8c2SCharles.Forsyth typedef struct Block	Block;
5*74a4d8c2SCharles.Forsyth 
6*74a4d8c2SCharles.Forsyth struct Block
7*74a4d8c2SCharles.Forsyth {
8*74a4d8c2SCharles.Forsyth 	uchar	*pos;
9*74a4d8c2SCharles.Forsyth 	uchar	*limit;
10*74a4d8c2SCharles.Forsyth };
11*74a4d8c2SCharles.Forsyth 
12*74a4d8c2SCharles.Forsyth static int
blgetc(void * vb)13*74a4d8c2SCharles.Forsyth blgetc(void *vb)
14*74a4d8c2SCharles.Forsyth {
15*74a4d8c2SCharles.Forsyth 	Block *b;
16*74a4d8c2SCharles.Forsyth 
17*74a4d8c2SCharles.Forsyth 	b = vb;
18*74a4d8c2SCharles.Forsyth 	if(b->pos >= b->limit)
19*74a4d8c2SCharles.Forsyth 		return -1;
20*74a4d8c2SCharles.Forsyth 	return *b->pos++;
21*74a4d8c2SCharles.Forsyth }
22*74a4d8c2SCharles.Forsyth 
23*74a4d8c2SCharles.Forsyth static int
blwrite(void * vb,void * buf,int n)24*74a4d8c2SCharles.Forsyth blwrite(void *vb, void *buf, int n)
25*74a4d8c2SCharles.Forsyth {
26*74a4d8c2SCharles.Forsyth 	Block *b;
27*74a4d8c2SCharles.Forsyth 
28*74a4d8c2SCharles.Forsyth 	b = vb;
29*74a4d8c2SCharles.Forsyth 
30*74a4d8c2SCharles.Forsyth 	if(n > b->limit - b->pos)
31*74a4d8c2SCharles.Forsyth 		n = b->limit - b->pos;
32*74a4d8c2SCharles.Forsyth 	memmove(b->pos, buf, n);
33*74a4d8c2SCharles.Forsyth 	b->pos += n;
34*74a4d8c2SCharles.Forsyth 	return n;
35*74a4d8c2SCharles.Forsyth }
36*74a4d8c2SCharles.Forsyth 
37*74a4d8c2SCharles.Forsyth int
inflateblock(uchar * dst,int dsize,uchar * src,int ssize)38*74a4d8c2SCharles.Forsyth inflateblock(uchar *dst, int dsize, uchar *src, int ssize)
39*74a4d8c2SCharles.Forsyth {
40*74a4d8c2SCharles.Forsyth 	Block bd, bs;
41*74a4d8c2SCharles.Forsyth 	int ok;
42*74a4d8c2SCharles.Forsyth 
43*74a4d8c2SCharles.Forsyth 	bs.pos = src;
44*74a4d8c2SCharles.Forsyth 	bs.limit = src + ssize;
45*74a4d8c2SCharles.Forsyth 
46*74a4d8c2SCharles.Forsyth 	bd.pos = dst;
47*74a4d8c2SCharles.Forsyth 	bd.limit = dst + dsize;
48*74a4d8c2SCharles.Forsyth 
49*74a4d8c2SCharles.Forsyth 	ok = inflate(&bd, blwrite, &bs, blgetc);
50*74a4d8c2SCharles.Forsyth 	if(ok != FlateOk)
51*74a4d8c2SCharles.Forsyth 		return ok;
52*74a4d8c2SCharles.Forsyth 	return bd.pos - dst;
53*74a4d8c2SCharles.Forsyth }
54