1 | /* |
---|
2 | * Copyright 1996, University Corporation for Atmospheric Research |
---|
3 | * See netcdf/COPYRIGHT file for copying and redistribution conditions. |
---|
4 | */ |
---|
5 | /* $Id: ncio.h,v 1.27 2006/01/03 04:56:28 russ Exp $ */ |
---|
6 | |
---|
7 | #ifndef _NCIO_H_ |
---|
8 | #define _NCIO_H_ |
---|
9 | |
---|
10 | #include <stddef.h> /* size_t */ |
---|
11 | #include <sys/types.h> /* off_t */ |
---|
12 | #include "netcdf.h" |
---|
13 | |
---|
14 | typedef struct ncio ncio; /* forward reference */ |
---|
15 | |
---|
16 | /* |
---|
17 | * A value which is an invalid off_t |
---|
18 | */ |
---|
19 | #define OFF_NONE ((off_t)(-1)) |
---|
20 | |
---|
21 | /* |
---|
22 | * Flags used by the region layer, |
---|
23 | * 'rflags' argument to ncio.rel() and ncio.get(). |
---|
24 | */ |
---|
25 | #define RGN_NOLOCK 0x1 /* Don't lock region. |
---|
26 | * Used when contention control handled |
---|
27 | * elsewhere. |
---|
28 | */ |
---|
29 | #define RGN_NOWAIT 0x2 /* return immediate if can't lock, else wait */ |
---|
30 | |
---|
31 | #define RGN_WRITE 0x4 /* we intend to modify, else read only */ |
---|
32 | |
---|
33 | #define RGN_MODIFIED 0x8 /* we did modify, else, discard */ |
---|
34 | |
---|
35 | |
---|
36 | /* |
---|
37 | * The next four typedefs define the signatures |
---|
38 | * of function pointers in struct ncio below. |
---|
39 | * They are not used outside of this file and ncio.h, |
---|
40 | * They just make some casts in the ncio.c more readable. |
---|
41 | */ |
---|
42 | /* |
---|
43 | * Indicate that you are done with the region which begins |
---|
44 | * at offset. Only reasonable flag value is RGN_MODIFIED. |
---|
45 | */ |
---|
46 | typedef int ncio_relfunc(ncio *const nciop, |
---|
47 | off_t offset, int rflags); |
---|
48 | |
---|
49 | /* |
---|
50 | * Request that the region (offset, extent) |
---|
51 | * be made available through *vpp. |
---|
52 | */ |
---|
53 | typedef int ncio_getfunc(ncio *const nciop, |
---|
54 | off_t offset, size_t extent, |
---|
55 | int rflags, |
---|
56 | void **const vpp); |
---|
57 | |
---|
58 | /* |
---|
59 | * Like memmove(), safely move possibly overlapping data. |
---|
60 | * Only reasonable flag value is RGN_NOLOCK. |
---|
61 | */ |
---|
62 | typedef int ncio_movefunc(ncio *const nciop, off_t to, off_t from, |
---|
63 | size_t nbytes, int rflags); |
---|
64 | |
---|
65 | /* |
---|
66 | * Write out any dirty buffers to disk and |
---|
67 | * ensure that next read will get data from disk. |
---|
68 | */ |
---|
69 | typedef int ncio_syncfunc(ncio *const nciop); |
---|
70 | |
---|
71 | /* |
---|
72 | * Sync any changes to disk, then truncate or extend file so its size |
---|
73 | * is length. This is only intended to be called before close, if the |
---|
74 | * file is open for writing and the actual size does not match the |
---|
75 | * calculated size, perhaps as the result of having been previously |
---|
76 | * written in NOFILL mode. |
---|
77 | */ |
---|
78 | typedef int ncio_pad_lengthfunc(ncio* nciop, off_t length); |
---|
79 | |
---|
80 | /* |
---|
81 | * Get file size in bytes. |
---|
82 | */ |
---|
83 | typedef int ncio_filesizefunc(ncio *nciop, off_t *filesizep); |
---|
84 | |
---|
85 | /* Write out any dirty buffers and |
---|
86 | ensure that next read will not get cached data. |
---|
87 | Sync any changes, then close the open file associated with the ncio |
---|
88 | struct, and free its memory. |
---|
89 | nciop - pointer to ncio to close. |
---|
90 | doUnlink - if true, unlink file |
---|
91 | */ |
---|
92 | typedef int ncio_closefunc(ncio *nciop, int doUnlink); |
---|
93 | |
---|
94 | /* Get around cplusplus "const xxx in class ncio without constructor" error */ |
---|
95 | #if defined(__cplusplus) |
---|
96 | #define NCIO_CONST |
---|
97 | #else |
---|
98 | #define NCIO_CONST const |
---|
99 | #endif |
---|
100 | |
---|
101 | /* |
---|
102 | * netcdf i/o abstraction |
---|
103 | */ |
---|
104 | struct ncio { |
---|
105 | /* |
---|
106 | * A copy of the ioflags argument passed in to ncio_open() |
---|
107 | * or ncio_create(). |
---|
108 | */ |
---|
109 | int ioflags; |
---|
110 | |
---|
111 | /* |
---|
112 | * The file descriptor of the netcdf file. |
---|
113 | * This gets handed to the user as the netcdf id. |
---|
114 | */ |
---|
115 | NCIO_CONST int fd; |
---|
116 | |
---|
117 | /* member functions do the work */ |
---|
118 | |
---|
119 | ncio_relfunc *NCIO_CONST rel; |
---|
120 | |
---|
121 | ncio_getfunc *NCIO_CONST get; |
---|
122 | |
---|
123 | ncio_movefunc *NCIO_CONST move; |
---|
124 | |
---|
125 | ncio_syncfunc *NCIO_CONST sync; |
---|
126 | |
---|
127 | ncio_pad_lengthfunc *NCIO_CONST pad_length; |
---|
128 | |
---|
129 | ncio_filesizefunc *NCIO_CONST filesize; |
---|
130 | |
---|
131 | ncio_closefunc *NCIO_CONST close; |
---|
132 | |
---|
133 | /* |
---|
134 | * A copy of the 'path' argument passed in to ncio_open() |
---|
135 | * or ncio_create(). Used by ncabort() to remove (unlink) |
---|
136 | * the file and by error messages. |
---|
137 | */ |
---|
138 | const char *path; |
---|
139 | |
---|
140 | /* implementation private stuff */ |
---|
141 | void *pvt; |
---|
142 | }; |
---|
143 | |
---|
144 | #undef NCIO_CONST |
---|
145 | |
---|
146 | /* Define wrappers around the ncio dispatch table */ |
---|
147 | |
---|
148 | extern int ncio_rel(ncio* const, off_t, int); |
---|
149 | extern int ncio_get(ncio* const, off_t, size_t, int, void** const); |
---|
150 | extern int ncio_move(ncio* const, off_t, off_t, size_t, int); |
---|
151 | extern int ncio_sync(ncio* const); |
---|
152 | extern int ncio_filesize(ncio* const, off_t*); |
---|
153 | extern int ncio_pad_length(ncio* const, off_t); |
---|
154 | extern int ncio_close(ncio* const, int); |
---|
155 | |
---|
156 | extern int ncio_create(const char *path, int ioflags, size_t initialsz, |
---|
157 | off_t igeto, size_t igetsz, size_t *sizehintp, |
---|
158 | ncio** nciopp, void** const mempp); |
---|
159 | |
---|
160 | extern int ncio_open(const char *path, int ioflags, |
---|
161 | off_t igeto, size_t igetsz, size_t *sizehintp, |
---|
162 | ncio** nciopp, void** const mempp); |
---|
163 | |
---|
164 | /* With the advent of diskless io, we need to provide |
---|
165 | for multiple ncio packages at the same time, |
---|
166 | so we have multiple versions of ncio_create. |
---|
167 | If you create a new package, the you must do the following. |
---|
168 | 1. add an extern definition for it in ncio.c |
---|
169 | 2. modify ncio_create and ncio_open in ncio.c to invoke |
---|
170 | the new package when appropriate. |
---|
171 | */ |
---|
172 | |
---|
173 | |
---|
174 | |
---|
175 | #endif /* _NCIO_H_ */ |
---|