1 #include <u.h>
2 #include <libc.h>
3 #include <diskfs.h>
4 
5 int nfilereads;
6 void _nfilereads_darwin_sucks(void) { }
7 
8 typedef struct DiskFile DiskFile;
9 struct DiskFile
10 {
11 	Disk disk;
12 	int fd;
13 };
14 
15 static long
16 preadn(int fd, void *vdata, u32int ulen, u64int offset)
17 {
18 	long n;
19 	uchar *data;
20 	long len;
21 
22 	nfilereads++;
23 	len = ulen;
24 	data = vdata;
25 /*	fprint(2, "readn 0x%llux 0x%ux\n", offset, ulen); */
26 	while(len > 0){
27 		n = pread(fd, data, len, offset);
28 		if(n <= 0)
29 			break;
30 		data += n;
31 		offset += n;
32 		len -= n;
33 	}
34 	return data-(uchar*)vdata;
35 }
36 
37 static void
38 diskfileblockput(Block *b)
39 {
40 	free(b);
41 }
42 
43 uvlong nreadx;
44 static Block*
45 diskfileread(Disk *dd, u32int len, u64int offset)
46 {
47 	int n;
48 	Block *b;
49 	DiskFile *d = (DiskFile*)dd;
50 
51 	b = mallocz(sizeof(Block)+len, 1);
52 	if(b == nil)
53 		return nil;
54 	b->data = (uchar*)&b[1];
55 nreadx += len;
56 	n = preadn(d->fd, b->data, len, offset);
57 	if(n <= 0){
58 		free(b);
59 		return nil;
60 	}
61 	b->_close = diskfileblockput;
62 	b->len = n;
63 	return b;
64 }
65 
66 static int
67 diskfilesync(Disk *dd)
68 {
69 	USED(dd);
70 	return 0;
71 }
72 
73 static void
74 diskfileclose(Disk *dd)
75 {
76 	DiskFile *d = (DiskFile*)dd;
77 
78 	close(d->fd);
79 	free(d);
80 }
81 
82 Disk*
83 diskopenfile(char *file)
84 {
85 	int fd;
86 	DiskFile *d;
87 
88 	if((fd = open(file, OREAD)) < 0)
89 		return nil;
90 	d = mallocz(sizeof(DiskFile), 1);
91 	if(d == nil){
92 		close(fd);
93 		return nil;
94 	}
95 	d->disk._read = diskfileread;
96 	d->disk._sync = diskfilesync;
97 	d->disk._close = diskfileclose;
98 	d->fd = fd;
99 	return &d->disk;
100 }