1 #include <u.h>
2 #include <libc.h>
3 #include <diskfs.h>
4 
5 int nfilereads;
6 
7 typedef struct DiskFile DiskFile;
8 struct DiskFile
9 {
10 	Disk disk;
11 	int fd;
12 };
13 
14 static long
15 preadn(int fd, void *vdata, u32int ulen, u64int offset)
16 {
17 	long n;
18 	uchar *data;
19 	long len;
20 
21 	nfilereads++;
22 	len = ulen;
23 	data = vdata;
24 /*	fprint(2, "readn 0x%llux 0x%ux\n", offset, ulen); */
25 	while(len > 0){
26 		n = pread(fd, data, len, offset);
27 		if(n <= 0)
28 			break;
29 		data += n;
30 		offset += n;
31 		len -= n;
32 	}
33 	return data-(uchar*)vdata;
34 }
35 
36 static void
37 diskfileblockput(Block *b)
38 {
39 	free(b);
40 }
41 
42 uvlong nreadx;
43 static Block*
44 diskfileread(Disk *dd, u32int len, u64int offset)
45 {
46 	int n;
47 	Block *b;
48 	DiskFile *d = (DiskFile*)dd;
49 
50 	b = mallocz(sizeof(Block)+len, 1);
51 	if(b == nil)
52 		return nil;
53 	b->data = (uchar*)&b[1];
54 nreadx += len;
55 	n = preadn(d->fd, b->data, len, offset);
56 	if(n <= 0){
57 		free(b);
58 		return nil;
59 	}
60 	b->_close = diskfileblockput;
61 	b->len = n;
62 	return b;
63 }
64 
65 static int
66 diskfilesync(Disk *dd)
67 {
68 	USED(dd);
69 	return 0;
70 }
71 
72 static void
73 diskfileclose(Disk *dd)
74 {
75 	DiskFile *d = (DiskFile*)dd;
76 
77 	close(d->fd);
78 	free(d);
79 }
80 
81 Disk*
82 diskopenfile(char *file)
83 {
84 	int fd;
85 	DiskFile *d;
86 
87 	if((fd = open(file, OREAD)) < 0)
88 		return nil;
89 	d = mallocz(sizeof(DiskFile), 1);
90 	if(d == nil){
91 		close(fd);
92 		return nil;
93 	}
94 	d->disk._read = diskfileread;
95 	d->disk._sync = diskfilesync;
96 	d->disk._close = diskfileclose;
97 	d->fd = fd;
98 	return &d->disk;
99 }