xref: /inferno-os/os/boot/libflate/deflateblock.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
blread(void * vb,void * buf,int n)13*74a4d8c2SCharles.Forsyth blread(void *vb, void *buf, int n)
14*74a4d8c2SCharles.Forsyth {
15*74a4d8c2SCharles.Forsyth 	Block *b;
16*74a4d8c2SCharles.Forsyth 
17*74a4d8c2SCharles.Forsyth 	b = vb;
18*74a4d8c2SCharles.Forsyth 	if(n > b->limit - b->pos)
19*74a4d8c2SCharles.Forsyth 		n = b->limit - b->pos;
20*74a4d8c2SCharles.Forsyth 	memmove(buf, b->pos, n);
21*74a4d8c2SCharles.Forsyth 	b->pos += n;
22*74a4d8c2SCharles.Forsyth 	return n;
23*74a4d8c2SCharles.Forsyth }
24*74a4d8c2SCharles.Forsyth 
25*74a4d8c2SCharles.Forsyth static int
blwrite(void * vb,void * buf,int n)26*74a4d8c2SCharles.Forsyth blwrite(void *vb, void *buf, int n)
27*74a4d8c2SCharles.Forsyth {
28*74a4d8c2SCharles.Forsyth 	Block *b;
29*74a4d8c2SCharles.Forsyth 
30*74a4d8c2SCharles.Forsyth 	b = vb;
31*74a4d8c2SCharles.Forsyth 
32*74a4d8c2SCharles.Forsyth 	if(n > b->limit - b->pos)
33*74a4d8c2SCharles.Forsyth 		n = b->limit - b->pos;
34*74a4d8c2SCharles.Forsyth 	memmove(b->pos, buf, n);
35*74a4d8c2SCharles.Forsyth 	b->pos += n;
36*74a4d8c2SCharles.Forsyth 	return n;
37*74a4d8c2SCharles.Forsyth }
38*74a4d8c2SCharles.Forsyth 
39*74a4d8c2SCharles.Forsyth int
deflateblock(uchar * dst,int dsize,uchar * src,int ssize,int level,int debug)40*74a4d8c2SCharles.Forsyth deflateblock(uchar *dst, int dsize, uchar *src, int ssize, int level, int debug)
41*74a4d8c2SCharles.Forsyth {
42*74a4d8c2SCharles.Forsyth 	Block bd, bs;
43*74a4d8c2SCharles.Forsyth 	int ok;
44*74a4d8c2SCharles.Forsyth 
45*74a4d8c2SCharles.Forsyth 	bs.pos = src;
46*74a4d8c2SCharles.Forsyth 	bs.limit = src + ssize;
47*74a4d8c2SCharles.Forsyth 
48*74a4d8c2SCharles.Forsyth 	bd.pos = dst;
49*74a4d8c2SCharles.Forsyth 	bd.limit = dst + dsize;
50*74a4d8c2SCharles.Forsyth 
51*74a4d8c2SCharles.Forsyth 	ok = deflate(&bd, blwrite, &bs, blread, level, debug);
52*74a4d8c2SCharles.Forsyth 	if(ok != FlateOk)
53*74a4d8c2SCharles.Forsyth 		return ok;
54*74a4d8c2SCharles.Forsyth 	return bd.pos - dst;
55*74a4d8c2SCharles.Forsyth }
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