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https://github.com/HDFGroup/hdf5.git
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151 lines
3.4 KiB
C
151 lines
3.4 KiB
C
/*
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* This example creates a group in the file and dataset in the group.
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* Hard link to the group object is created and the dataset is accessed
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* under different names.
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* Iterator function is used to find the object names in the root group.
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*/
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#include "hdf5.h"
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#define FILE "group.h5"
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#define RANK 2
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herr_t file_info(hid_t loc_id, const char *name, void *opdata);
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/* Operator function */
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int
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main(void)
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{
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hid_t file;
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hid_t grp;
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hid_t dataset, dataspace;
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hid_t plist;
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herr_t status;
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hsize_t dims[2];
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hsize_t cdims[2];
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int idx;
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/*
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* Create a file.
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*/
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file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
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/*
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* Create a group in the file.
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*/
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grp = H5Gcreate(file, "/Data", 0);
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/*
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* Create dataset "Compressed Data" in the group using absolute
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* name. Dataset creation property list is modified to use
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* GZIP compression with the compression effort set to 6.
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* Note that compression can be used only when dataset is chunked.
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*/
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dims[0] = 1000;
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dims[1] = 20;
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cdims[0] = 20;
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cdims[1] = 20;
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dataspace = H5Screate_simple(RANK, dims, NULL);
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plist = H5Pcreate(H5P_DATASET_CREATE);
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H5Pset_chunk(plist, 2, cdims);
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H5Pset_deflate( plist, 6);
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dataset = H5Dcreate(file, "/Data/Compressed_Data", H5T_NATIVE_INT,
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dataspace, plist);
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/*
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* Close the dataset and the file.
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*/
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H5Sclose(dataspace);
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H5Dclose(dataset);
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H5Fclose(file);
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/*
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* Now reopen the file and group in the file.
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*/
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file = H5Fopen(FILE, H5F_ACC_RDWR, H5P_DEFAULT);
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grp = H5Gopen(file, "Data");
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/*
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* Access "Compressed_Data" dataset in the group.
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*/
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dataset = H5Dopen(grp, "Compressed_Data");
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if( dataset < 0) printf(" Dataset is not found. \n");
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printf("\"/Data/Compressed_Data\" dataset is open \n");
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/*
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* Close the dataset.
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*/
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status = H5Dclose(dataset);
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/*
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* Create hard link to the Data group.
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*/
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status = H5Glink(file, H5G_LINK_HARD, "Data", "Data_new");
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/*
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* We can access "Compressed_Data" dataset using created
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* hard link "Data_new".
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*/
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dataset = H5Dopen(file, "/Data_new/Compressed_Data");
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if( dataset < 0) printf(" Dataset is not found. \n");
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printf("\"/Data_new/Compressed_Data\" dataset is open \n");
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/*
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* Close the dataset.
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*/
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status = H5Dclose(dataset);
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/*
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* Use iterator to see the names of the objects in the file
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* root directory.
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*/
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idx = H5Giterate(file, "/", NULL, file_info, NULL);
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/*
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* Unlink name "Data" and use iterator to see the names
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* of the objects in the file root direvtory.
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*/
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if (H5Gunlink(file, "Data") < 0)
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printf(" H5Gunlink failed \n");
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else
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printf("\"Data\" is unlinked \n");
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idx = H5Giterate(file, "/", NULL, file_info, NULL);
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/*
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* Close the file.
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*/
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status = H5Fclose(file);
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return 0;
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}
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/*
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* Operator function.
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*/
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herr_t
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file_info(hid_t loc_id, const char *name, void *opdata)
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{
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hid_t grp;
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/*
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* Open the group using its name.
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*/
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grp = H5Gopen(loc_id, name);
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/*
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* Display group name.
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*/
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printf("\n");
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printf("Name : ");
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puts(name);
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H5Gclose(grp);
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return 0;
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}
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