Subversion Repositories planix.SVN

Rev

Rev 2 | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
2 - 1 
/* included by expand and 9boot with different header files */
2 
 
3 
typedef struct Biobuf	Biobuf;
4 
 
5 
struct Biobuf
6 
{
7 
	uchar *bp;
8 
	uchar *p;
9 
	uchar *ep;
10 
};
11 
 
12 
static ulong	Boffset(Biobuf *bp);
13 
static int	crcwrite(void *out, void *buf, int n);
14 
static ulong	get4(Biobuf *b);
15 
static int	getc(void*);
16 
static int	header(Biobuf*);
17 
static ulong	offset(Biobuf*);
18 
static int	trailer(Biobuf*, Biobuf*);
19 
 
20 
/* GZIP flags */
21 
enum {
22 
	Ftext=		(1<<0),
23 
	Fhcrc=		(1<<1),
24 
	Fextra=		(1<<2),
25 
	Fname=		(1<<3),
26 
	Fcomment=	(1<<4),
27 
 
28 
	GZCRCPOLY	= 0xedb88320UL,
29 
};
30 
 
31 
static ulong	*crctab;
32 
static ulong	crc;
33 
 
34 
int
35 
gunzip(uchar *out, int outn, uchar *in, int inn)
36 
{
37 
	Biobuf bin, bout;
38 
	int err;
39 
 
40 
	crc = 0;
41 
	crctab = mkcrctab(GZCRCPOLY);
42 
	err = inflateinit();
43 
	if(err != FlateOk)
44 
		print("inflateinit failed: %s\n", flateerr(err));
45 
 
46 
	bin.bp = bin.p = in;
47 
	bin.ep = in+inn;
48 
	bout.bp = bout.p = out;
49 
	bout.ep = out+outn;
50 
 
51 
	err = header(&bin);
52 
	if(err != FlateOk)
53 
		return err;
54 
 
55 
	err = inflate(&bout, crcwrite, &bin, getc);
56 
	if(err != FlateOk)
57 
		print("inflate failed: %s\n", flateerr(err));
58 
 
59 
	err = trailer(&bout, &bin);
60 
	if(err != FlateOk)
61 
		return err;
62 
 
63 
	return Boffset(&bout);
64 
}
65 
 
66 
static int
67 
header(Biobuf *bin)
68 
{
69 
	int i, flag;
70 
 
71 
	if(getc(bin) != 0x1f || getc(bin) != 0x8b){
72 
		print("bad magic\n");
73 
		return FlateCorrupted;
74 
	}
75 
	if(getc(bin) != 8){
76 
		print("unknown compression type\n");
77 
		return FlateCorrupted;
78 
	}
79 
 
80 
	flag = getc(bin);
81 
 
82 
	/* mod time */
83 
	get4(bin);
84 
 
85 
	/* extra flags */
86 
	getc(bin);
87 
 
88 
	/* OS type */
89 
	getc(bin);
90 
 
91 
	if(flag & Fextra)
92 
		for(i=getc(bin); i>0; i--)
93 
			getc(bin);
94 
 
95 
	/* name */
96 
	if(flag&Fname)
97 
		while(getc(bin) != 0)
98 
			;
99 
 
100 
	/* comment */
101 
	if(flag&Fcomment)
102 
		while(getc(bin) != 0)
103 
			;
104 
 
105 
	/* crc16 */
106 
	if(flag&Fhcrc) {
107 
		getc(bin);
108 
		getc(bin);
109 
	}
110 
 
111 
	return FlateOk;
112 
}
113 
 
114 
static int
115 
trailer(Biobuf *bout, Biobuf *bin)
116 
{
117 
	/* crc32 */
118 
	if(crc != get4(bin)){
119 
		print("crc mismatch\n");
120 
		return FlateCorrupted;
121 
	}
122 
 
123 
	/* length */
124 
	if(get4(bin) != Boffset(bout)){
125 
		print("bad output len\n");
126 
		return FlateCorrupted;
127 
	}
128 
	return FlateOk;
129 
}
130 
 
131 
static ulong
132 
get4(Biobuf *b)
133 
{
134 
	ulong v;
135 
	int i, c;
136 
 
137 
	v = 0;
138 
	for(i = 0; i < 4; i++){
139 
		c = getc(b);
140 
		v |= c << (i * 8);
141 
	}
142 
	return v;
143 
}
144 
 
145 
static int
146 
getc(void *in)
147 
{
148 
	Biobuf *bp = in;
149 
 
150 
//	if((bp->p - bp->bp) % 10000 == 0)
151 
//		print(".");
152 
	if(bp->p >= bp->ep){
153 
		print("EOF");
154 
		return -1;
155 
	}
156 
	return *bp->p++;
157 
}
158 
 
159 
static ulong
160 
Boffset(Biobuf *bp)
161 
{
162 
	return bp->p - bp->bp;
163 
}
164 
 
165 
static int
166 
crcwrite(void *out, void *buf, int n)
167 
{
168 
	Biobuf *bp;
169 
	int nn;
170 
 
171 
	crc = blockcrc(crctab, crc, buf, n);
172 
	bp = out;
173 
	nn = n;
174 
	if(nn > bp->ep-bp->p)
175 
		nn = bp->ep-bp->p;
176 
	if(nn > 0)
177 
		memmove(bp->p, buf, nn);
178 
	bp->p += n;
179 
	return n;
180 
}