[svn-r794] Group example was modified to use the H5Glink/unlink and

H5Dopen(grp, dataset) functions.

Tested on SUN Sparc (baldric)

1 files changed, 97 insertions, 65 deletions

diff --git a/examples/h5_group.c b/examples/h5_group.c
index 1c5ab12..2a7ea48 100644
--- a/examples/h5_group.c
+++ b/examples/h5_group.c
@@ -1,25 +1,34 @@
 /*
- * This example shows how to create groups within the file and    
- * datasets within the file and groups.
+ * This example creates a group in the file and dataset in the group. 
+ * Hard link to the group object is created and the dataset is accessed
+ * under different names. 
+ * Iterator function is used to find the object names in the root group.
  */ 
 
 
 #include "hdf5.h"
 
 
-#define FILE    "DIR.h5"
+#define FILE    "group.h5"
 #define RANK    2
 
+ 
+herr_t file_info(hid_t loc_id, const char *name, void *opdata);
+                                     /* Operator function */
 int
 main(void)
 {
 
-    hid_t    file, dir;
+    hid_t    file;
+    hid_t    grp;
     hid_t    dataset, dataspace;
+    hid_t    plist; 
 
     herr_t   status;
     hsize_t  dims[2];
-    hsize_t  size[1];
+    hsize_t  cdims[2];
+ 
+    int      idx;
 
     /*
      * Create a file.
@@ -27,92 +36,115 @@ main(void)
     file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
 
     /*
-     * Create two groups in a file.
+     * Create a group in the file. 
      */
-    dir = H5Gcreate(file, "/IntData", 0);
-    status = H5Gclose(dir);
-
-    dir = H5Gcreate(file,"/FloatData", 0);
-    status = H5Gclose(dir);
+    grp = H5Gcreate(file, "/Data", 0);
 
+    /*
+     * Create dataset "Compressed Data" in the group using absolute
+     * name. Dataset creation property list is modified to use 
+     * GZIP compression with the compression effort set to 6. 
+     * Note that compression can be used only when dataset is chunked. 
+     */
+    dims[0] = 1000;
+    dims[1] = 20;
+    cdims[0] = 20;
+    cdims[1] = 20;
+    dataspace = H5Screate_simple(RANK, dims, NULL);
+    plist     = H5Pcreate(H5P_DATASET_CREATE);
+                H5Pset_chunk(plist, 2, cdims);
+                H5Pset_deflate( plist, 6); 
+    dataset = H5Dcreate(file, "/Data/Compressed_Data", H5T_NATIVE_INT, 
+                        dataspace, plist); 
+ 
     /* 
-     * Create dataspace for the character string
+     * Close the dataset and the file.
      */
-    size[0] = 80;
-    dataspace = H5Screate_simple(1, size, NULL);
+    H5Sclose(dataspace);
+    H5Dclose(dataset);
+    H5Fclose(file);
 
     /*
-     * Create dataset "String" in the root group.  
+     * Now reopen the file and group in the file. 
      */
-    dataset = H5Dcreate(file, "String", H5T_NATIVE_CHAR, dataspace,
-			H5P_DEFAULT);
-    H5Dclose(dataset);
+    file = H5Fopen(FILE, H5F_ACC_RDWR, H5P_DEFAULT);
+    grp  = H5Gopen(file, "Data");
 
-    /*
-     * Create dataset "String" in the /IntData group.  
+    /* 
+     * Access "Compressed_Data" dataset in the group. 
      */
-    dataset = H5Dcreate(file, "/IntData/String", H5T_NATIVE_CHAR, dataspace,
-			H5P_DEFAULT);
-    H5Dclose(dataset);
+    dataset = H5Dopen(grp, "Compressed_Data");
+    if( dataset < 0) printf(" Dataset is not found. \n");
+    printf("\"/Data/Compressed_Data\" dataset is open \n");
 
     /*
-     * Create dataset "String" in the /FloatData group.  
+     * Close the dataset.
      */
-    dataset = H5Dcreate(file, "/FloatData/String", H5T_NATIVE_CHAR, dataspace,
-			H5P_DEFAULT);
-    H5Sclose(dataspace);
-    H5Dclose(dataset);
+    status = H5Dclose(dataset);
 
     /*
-     * Create IntArray dataset in the /IntData group by specifying full path.
+     * Create hard link to the Data group.
      */
-    dims[0] = 2;
-    dims[1] = 3;
-    dataspace = H5Screate_simple(RANK, dims, NULL);
-    dataset = H5Dcreate(file, "/IntData/IntArray", H5T_NATIVE_INT, dataspace,
-			H5P_DEFAULT); 
-    H5Sclose(dataspace);
-    H5Dclose(dataset);
+    status = H5Glink(file, H5G_LINK_HARD, "Data", "Data_new");
 
-    /*
-     * Set current group to /IntData and attach to the dataset String.
+    /* 
+     * We can access "Compressed_Data" dataset using created
+     * hard link "Data_new". 
      */
-    status = H5Gset (file, "/IntData");
-    dataset = H5Dopen(file, "String");
-    if (dataset > 0) printf("String dataset in /IntData group is found\n"); 
-    H5Dclose(dataset);
+    dataset = H5Dopen(file, "/Data_new/Compressed_Data");
+    if( dataset < 0) printf(" Dataset is not found. \n");
+    printf("\"/Data_new/Compressed_Data\" dataset is open \n");
 
     /*
-     * Set current group to /FloatData.
+     * Close the dataset.
      */
-    status = H5Gset (file, "/FloatData");
+    status = H5Dclose(dataset);
 
     /* 
-     * Create two datasets FlatArray and DoubleArray.
+     * Use iterator to see the names of the objects in the file
+     * root directory.
      */
-    dims[0] = 5;
-    dims[1] = 10;
-    dataspace = H5Screate_simple(RANK, dims, NULL);
-    dataset = H5Dcreate(file, "FloatArray", H5T_NATIVE_FLOAT, dataspace,
-			H5P_DEFAULT); 
-    H5Sclose(dataspace);
-    H5Dclose(dataset);
+    idx = H5Giterate(file, "/", NULL, file_info, NULL);
 
-    dims[0] = 4;
-    dims[1] = 6;
-    dataspace = H5Screate_simple(RANK, dims, NULL);
-    dataset = H5Dcreate(file, "DoubleArray", H5T_NATIVE_DOUBLE, dataspace,
-			H5P_DEFAULT); 
-    H5Sclose(dataspace);
-    H5Dclose(dataset);
+    /*
+     * Unlink  name "Data" and use iterator to see the names
+     * of the objects in the file root direvtory.
+     */
+    if (H5Gunlink(file, "Data") < 0)  
+      printf(" H5Gunlink failed \n");
+    else  
+      printf("\"Data\" is unlinked \n");
 
-    /* 
-     * Attach to /FloatData/String dataset.
+    idx = H5Giterate(file, "/", NULL, file_info, NULL);
+    
+
+    /*
+     * Close the file.
      */
-    dataset = H5Dopen(file, "/FloatData/String");
-    if (dataset > 0) printf("/FloatData/String dataset is found\n"); 
-    H5Dclose(dataset);
-    H5Fclose(file);
+     
+    status = H5Fclose(file);
 
     return 0;
 }
+/*
+ * Operator function.
+ */
+herr_t
+file_info(hid_t loc_id, const char *name, void *opdata)
+{
+    hid_t grp;
+    /*
+     * Open the group using its name.
+     */
+    grp = H5Gopen(loc_id, name);
+ 
+    /*
+     * Display group name.
+     */
+    printf("\n");
+    printf("Name : ");
+    puts(name);
+    
+    H5Gclose(grp);
+    return 0;
+ }