1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
|
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Copyright by The HDF Group. *
* Copyright by the Board of Trustees of the University of Illinois. *
* All rights reserved. *
* *
* This file is part of HDF5. The full HDF5 copyright notice, including *
* terms governing use, modification, and redistribution, is contained in *
* the COPYING file, which can be found at the root of the source code *
* distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases. *
* If you do not have access to either file, you may request a copy from *
* help@hdfgroup.org. *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*
* This example illustrates how to create a compressed dataset.
* It is used in the HDF5 Tutorial.
*/
#include <iostream>
using std::cout;
using std::endl;
#include <string>
#include "H5Cpp.h"
using namespace H5;
const H5std_string FILE_NAME("h5tutr_cmprss.h5");
const H5std_string DATASET_NAME("Compressed_Data");
const int DIM0 = 100;
const int DIM1 = 20;
int main (void)
{
hsize_t dims[2] = { DIM0, DIM1 }; // dataset dimensions
hsize_t chunk_dims[2] = { 20, 20 }; // chunk dimensions
int i,j, buf[DIM0][DIM1];
// Try block to detect exceptions raised by any of the calls inside it
try
{
// Turn off the auto-printing when failure occurs so that we can
// handle the errors appropriately
Exception::dontPrint();
// Create a new file using the default property lists.
H5File file(FILE_NAME, H5F_ACC_TRUNC);
// Create the data space for the dataset.
DataSpace *dataspace = new DataSpace(2, dims);
// Modify dataset creation property to enable chunking
DSetCreatPropList *plist = new DSetCreatPropList;
plist->setChunk(2, chunk_dims);
// Set ZLIB (DEFLATE) Compression using level 6.
// To use SZIP compression comment out this line.
plist->setDeflate(6);
// Uncomment these lines to set SZIP Compression
// unsigned szip_options_mask = H5_SZIP_NN_OPTION_MASK;
// unsigned szip_pixels_per_block = 16;
// plist->setSzip(szip_options_mask, szip_pixels_per_block);
// Create the dataset.
DataSet *dataset = new DataSet(file.createDataSet( DATASET_NAME,
PredType::STD_I32BE, *dataspace, *plist) );
for (i = 0; i< DIM0; i++)
for (j=0; j<DIM1; j++)
buf[i][j] = i+j;
// Write data to dataset.
dataset->write(buf, PredType::NATIVE_INT);
// Close objects and file. Either approach will close the HDF5 item.
delete dataspace;
delete dataset;
delete plist;
file.close();
// -----------------------------------------------
// Re-open the file and dataset, retrieve filter
// information for dataset and read the data back.
// -----------------------------------------------
int rbuf[DIM0][DIM1];
int numfilt;
size_t nelmts={1}, namelen={1};
unsigned flags, filter_info, cd_values[1], idx;
char name[1];
H5Z_filter_t filter_type;
// Open the file and the dataset in the file.
file.openFile(FILE_NAME, H5F_ACC_RDONLY);
dataset = new DataSet(file.openDataSet( DATASET_NAME));
// Get the create property list of the dataset.
plist = new DSetCreatPropList(dataset->getCreatePlist ());
// Get the number of filters associated with the dataset.
numfilt = plist->getNfilters();
cout << "Number of filters associated with dataset: " << numfilt << endl;
for (idx=0; idx < numfilt; idx++) {
nelmts = 0;
filter_type = plist->getFilter(idx, flags, nelmts, cd_values, namelen, name , filter_info);
cout << "Filter Type: ";
switch (filter_type) {
case H5Z_FILTER_DEFLATE:
cout << "H5Z_FILTER_DEFLATE" << endl;
break;
case H5Z_FILTER_SZIP:
cout << "H5Z_FILTER_SZIP" << endl;
break;
default:
cout << "Other filter type included." << endl;
}
}
// Read data.
dataset->read(rbuf, PredType::NATIVE_INT);
delete plist;
delete dataset;
file.close(); // can be skipped
} // end of try block
// catch failure caused by the H5File operations
catch(FileIException error)
{
error.printErrorStack();
return -1;
}
// catch failure caused by the DataSet operations
catch(DataSetIException error)
{
error.printErrorStack();
return -1;
}
// catch failure caused by the DataSpace operations
catch(DataSpaceIException error)
{
error.printErrorStack();
return -1;
}
return 0; // successfully terminated
}
|
