1 | /** \file |
---|
2 | Attribute functions |
---|
3 | |
---|
4 | These functions read and write attributes. |
---|
5 | |
---|
6 | Copyright 2010 University Corporation for Atmospheric |
---|
7 | Research/Unidata. See \ref copyright file for more info. */ |
---|
8 | |
---|
9 | #include "ncdispatch.h" |
---|
10 | |
---|
11 | /** \name Getting Attributes |
---|
12 | |
---|
13 | Functions to get the values of attributes. |
---|
14 | */ |
---|
15 | /*! \{ */ |
---|
16 | |
---|
17 | /*! |
---|
18 | \ingroup attributes |
---|
19 | Get an attribute of any type. |
---|
20 | |
---|
21 | The nc_get_att() functions works for any type of attribute, and must |
---|
22 | be used to get attributes of user-defined type. We recommend that they |
---|
23 | type safe versions of this function be used where possible. |
---|
24 | |
---|
25 | \param ncid NetCDF or group ID, from a previous call to nc_open(), |
---|
26 | nc_create(), nc_def_grp(), or associated inquiry functions such as |
---|
27 | nc_inq_ncid(). |
---|
28 | |
---|
29 | \param varid Variable ID of the attribute's variable, or ::NC_GLOBAL |
---|
30 | for a global attribute. |
---|
31 | |
---|
32 | \param name Attribute \ref object_name. |
---|
33 | |
---|
34 | \param value Pointer to location for returned attribute value(s). All |
---|
35 | elements of the vector of attribute values are returned, so you must |
---|
36 | allocate enough space to hold them. Before using the value as a C |
---|
37 | string, make sure it is null-terminated. Call nc_inq_attlen() first to |
---|
38 | find out the length of the attribute. |
---|
39 | */ |
---|
40 | int |
---|
41 | nc_get_att(int ncid, int varid, const char *name, void *value) |
---|
42 | { |
---|
43 | NC* ncp; |
---|
44 | int stat = NC_NOERR; |
---|
45 | nc_type xtype; |
---|
46 | |
---|
47 | if ((stat = NC_check_id(ncid, &ncp))) |
---|
48 | return stat; |
---|
49 | |
---|
50 | /* Need to get the type */ |
---|
51 | if ((stat = nc_inq_atttype(ncid, varid, name, &xtype))) |
---|
52 | return stat; |
---|
53 | |
---|
54 | return ncp->dispatch->get_att(ncid, varid, name, value, xtype); |
---|
55 | } |
---|
56 | /*! \} */ |
---|
57 | |
---|
58 | /*! |
---|
59 | \ingroup attributes |
---|
60 | Get an attribute. |
---|
61 | |
---|
62 | This function gets an attribute from the netCDF file. The nc_get_att() |
---|
63 | function works with any type of data, including user defined types. |
---|
64 | |
---|
65 | \note The netCDF library reads all attributes into memory when the |
---|
66 | file is opened with nc_open(). Getting an attribute copies the value |
---|
67 | from the in-memory store, and does not incure any file I/O penalties. |
---|
68 | |
---|
69 | \param ncid NetCDF or group ID, from a previous call to nc_open(), |
---|
70 | nc_create(), nc_def_grp(), or associated inquiry functions such as |
---|
71 | nc_inq_ncid(). |
---|
72 | |
---|
73 | \param varid Variable ID of the attribute's variable, or ::NC_GLOBAL |
---|
74 | for a global attribute. |
---|
75 | |
---|
76 | \param name Attribute \ref object_name. |
---|
77 | |
---|
78 | \param value Pointer to location for returned attribute value(s). All |
---|
79 | elements of the vector of attribute values are returned, so you must |
---|
80 | allocate enough space to hold them. If you don't know how much |
---|
81 | space to reserve, call nc_inq_attlen() first to find out the length of |
---|
82 | the attribute. |
---|
83 | |
---|
84 | <h1>Example</h1> |
---|
85 | |
---|
86 | Here is an example using nc_get_att_double() to determine the values |
---|
87 | of a variable attribute named valid_range for a netCDF variable named |
---|
88 | rh and using nc_get_att_text() to read a global attribute named title |
---|
89 | in an existing netCDF dataset named foo.nc. |
---|
90 | |
---|
91 | In this example, it is assumed that we don't know how many values will |
---|
92 | be returned, but that we do know the types of the attributes. Hence, |
---|
93 | to allocate enough space to store them, we must first inquire about |
---|
94 | the length of the attributes. |
---|
95 | |
---|
96 | \code |
---|
97 | #include <netcdf.h> |
---|
98 | ... |
---|
99 | int status; |
---|
100 | int ncid; |
---|
101 | int rh_id; |
---|
102 | int vr_len, t_len; |
---|
103 | double *vr_val; |
---|
104 | char *title; |
---|
105 | extern char *malloc() |
---|
106 | |
---|
107 | ... |
---|
108 | status = nc_open("foo.nc", NC_NOWRITE, &ncid); |
---|
109 | if (status != NC_NOERR) handle_error(status); |
---|
110 | ... |
---|
111 | status = nc_inq_varid (ncid, "rh", &rh_id); |
---|
112 | if (status != NC_NOERR) handle_error(status); |
---|
113 | ... |
---|
114 | status = nc_inq_attlen (ncid, rh_id, "valid_range", &vr_len); |
---|
115 | if (status != NC_NOERR) handle_error(status); |
---|
116 | status = nc_inq_attlen (ncid, NC_GLOBAL, "title", &t_len); |
---|
117 | if (status != NC_NOERR) handle_error(status); |
---|
118 | |
---|
119 | vr_val = (double *) malloc(vr_len * sizeof(double)); |
---|
120 | title = (char *) malloc(t_len + 1); |
---|
121 | |
---|
122 | status = nc_get_att_double(ncid, rh_id, "valid_range", vr_val); |
---|
123 | if (status != NC_NOERR) handle_error(status); |
---|
124 | status = nc_get_att_text(ncid, NC_GLOBAL, "title", title); |
---|
125 | if (status != NC_NOERR) handle_error(status); |
---|
126 | title[t_len] = '\0'; |
---|
127 | ... |
---|
128 | \endcode |
---|
129 | */ |
---|
130 | /*! \{ */ |
---|
131 | int |
---|
132 | nc_get_att_text(int ncid, int varid, const char *name, char *value) |
---|
133 | { |
---|
134 | NC* ncp; |
---|
135 | int stat = NC_check_id(ncid, &ncp); |
---|
136 | if(stat != NC_NOERR) return stat; |
---|
137 | return ncp->dispatch->get_att(ncid, varid, name, (void *)value, NC_CHAR); |
---|
138 | } |
---|
139 | |
---|
140 | int |
---|
141 | nc_get_att_schar(int ncid, int varid, const char *name, signed char *value) |
---|
142 | { |
---|
143 | NC* ncp; |
---|
144 | int stat = NC_check_id(ncid, &ncp); |
---|
145 | if(stat != NC_NOERR) return stat; |
---|
146 | return ncp->dispatch->get_att(ncid, varid, name, (void *)value, NC_BYTE); |
---|
147 | } |
---|
148 | |
---|
149 | int |
---|
150 | nc_get_att_uchar(int ncid, int varid, const char *name, unsigned char *value) |
---|
151 | { |
---|
152 | NC* ncp; |
---|
153 | int stat = NC_check_id(ncid, &ncp); |
---|
154 | if(stat != NC_NOERR) return stat; |
---|
155 | return ncp->dispatch->get_att(ncid, varid, name, (void *)value, NC_UBYTE); |
---|
156 | } |
---|
157 | |
---|
158 | int |
---|
159 | nc_get_att_short(int ncid, int varid, const char *name, short *value) |
---|
160 | { |
---|
161 | NC* ncp; |
---|
162 | int stat = NC_check_id(ncid, &ncp); |
---|
163 | if(stat != NC_NOERR) return stat; |
---|
164 | return ncp->dispatch->get_att(ncid, varid, name, (void *)value, NC_SHORT); |
---|
165 | } |
---|
166 | |
---|
167 | int |
---|
168 | nc_get_att_int(int ncid, int varid, const char *name, int *value) |
---|
169 | { |
---|
170 | NC* ncp; |
---|
171 | int stat = NC_check_id(ncid, &ncp); |
---|
172 | if(stat != NC_NOERR) return stat; |
---|
173 | return ncp->dispatch->get_att(ncid, varid, name, (void *)value, NC_INT); |
---|
174 | } |
---|
175 | |
---|
176 | int |
---|
177 | nc_get_att_long(int ncid, int varid, const char *name, long *value) |
---|
178 | { |
---|
179 | NC* ncp; |
---|
180 | int stat = NC_check_id(ncid, &ncp); |
---|
181 | if(stat != NC_NOERR) return stat; |
---|
182 | return ncp->dispatch->get_att(ncid, varid, name, (void *)value, longtype); |
---|
183 | } |
---|
184 | |
---|
185 | int |
---|
186 | nc_get_att_float(int ncid, int varid, const char *name, float *value) |
---|
187 | { |
---|
188 | NC* ncp; |
---|
189 | int stat = NC_check_id(ncid, &ncp); |
---|
190 | if(stat != NC_NOERR) return stat; |
---|
191 | return ncp->dispatch->get_att(ncid, varid, name, (void *)value, NC_FLOAT); |
---|
192 | } |
---|
193 | |
---|
194 | int |
---|
195 | nc_get_att_double(int ncid, int varid, const char *name, double *value) |
---|
196 | { |
---|
197 | NC* ncp; |
---|
198 | int stat = NC_check_id(ncid, &ncp); |
---|
199 | if(stat != NC_NOERR) return stat; |
---|
200 | return ncp->dispatch->get_att(ncid, varid, name, (void *)value, NC_DOUBLE); |
---|
201 | } |
---|
202 | |
---|
203 | int |
---|
204 | nc_get_att_ubyte(int ncid, int varid, const char *name, unsigned char *value) |
---|
205 | { |
---|
206 | NC* ncp; |
---|
207 | int stat = NC_check_id(ncid, &ncp); |
---|
208 | if(stat != NC_NOERR) return stat; |
---|
209 | return ncp->dispatch->get_att(ncid, varid, name, (void *)value, NC_UBYTE); |
---|
210 | } |
---|
211 | |
---|
212 | int |
---|
213 | nc_get_att_ushort(int ncid, int varid, const char *name, unsigned short *value) |
---|
214 | { |
---|
215 | NC* ncp; |
---|
216 | int stat = NC_check_id(ncid, &ncp); |
---|
217 | if(stat != NC_NOERR) return stat; |
---|
218 | return ncp->dispatch->get_att(ncid, varid, name, (void *)value, NC_USHORT); |
---|
219 | } |
---|
220 | |
---|
221 | int |
---|
222 | nc_get_att_uint(int ncid, int varid, const char *name, unsigned int *value) |
---|
223 | { |
---|
224 | NC* ncp; |
---|
225 | int stat = NC_check_id(ncid, &ncp); |
---|
226 | if(stat != NC_NOERR) return stat; |
---|
227 | return ncp->dispatch->get_att(ncid, varid, name, (void *)value, NC_UINT); |
---|
228 | } |
---|
229 | |
---|
230 | int |
---|
231 | nc_get_att_longlong(int ncid, int varid, const char *name, long long *value) |
---|
232 | { |
---|
233 | NC* ncp; |
---|
234 | int stat = NC_check_id(ncid, &ncp); |
---|
235 | if(stat != NC_NOERR) return stat; |
---|
236 | return ncp->dispatch->get_att(ncid, varid, name, (void *)value, NC_INT64); |
---|
237 | } |
---|
238 | |
---|
239 | int |
---|
240 | nc_get_att_ulonglong(int ncid, int varid, const char *name, unsigned long long *value) |
---|
241 | { |
---|
242 | NC *ncp; |
---|
243 | int stat = NC_check_id(ncid, &ncp); |
---|
244 | if(stat != NC_NOERR) return stat; |
---|
245 | return ncp->dispatch->get_att(ncid, varid, name, (void *)value, NC_UINT64); |
---|
246 | } |
---|
247 | |
---|
248 | int |
---|
249 | nc_get_att_string(int ncid, int varid, const char *name, char **value) |
---|
250 | { |
---|
251 | NC *ncp; |
---|
252 | int stat = NC_check_id(ncid, &ncp); |
---|
253 | if(stat != NC_NOERR) return stat; |
---|
254 | return ncp->dispatch->get_att(ncid,varid,name,(void*)value, NC_STRING); |
---|
255 | } |
---|
256 | /*! \} */ |
---|