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Diffstat (limited to 'c++/examples/compound.C')
| -rw-r--r-- | c++/examples/compound.C | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/c++/examples/compound.C b/c++/examples/compound.C new file mode 100644 index 0000000..ba7f68f --- /dev/null +++ b/c++/examples/compound.C @@ -0,0 +1,194 @@ +/* + * This example shows how to create a compound datatype, + * write an array which has the compound datatype to the file, + * and read back fields' subsets. + */ + +#include <string> +#ifndef H5_NO_NAMESPACE +using namespace std; +#endif + +#ifdef OLD_HEADER_FILENAME +#include <iostream.h> +#else +#include <iostream> +#endif +#include "H5Cpp.h" + +#ifndef H5_NO_NAMESPACE +using namespace H5; +#endif + +const string FILE_NAME( "SDScompound.h5" ); +const string DATASET_NAME( "ArrayOfStructures" ); +const string MEMBER1( "a_name" ); +const string MEMBER2( "b_name" ); +const string MEMBER3( "c_name" ); +const int LENGTH = 10; +const int RANK = 1; + +int main(void) +{ + /* First structure and dataset*/ + typedef struct s1_t { + int a; + float b; + double c; + } s1_t; + + /* Second structure (subset of s1_t) and dataset*/ + typedef struct s2_t { + double c; + int a; + } s2_t; + + // Try block to detect exceptions raised by any of the calls inside it + try + { + /* + * Initialize the data + */ + int i; + s1_t s1[LENGTH]; + for (i = 0; i< LENGTH; i++) + { + s1[i].a = i; + s1[i].b = i*i; + s1[i].c = 1./(i+1); + } + + /* + * Create the data space. + */ + hsize_t dim[] = {LENGTH}; /* Dataspace dimensions */ + DataSpace space( RANK, dim ); + + /* + * Create the file. + */ + H5File* file = new H5File( FILE_NAME, H5F_ACC_TRUNC ); + + /* + * Create the memory datatype. + */ + CompType mtype1( sizeof(s1_t) ); + mtype1.insertMember( MEMBER1, HOFFSET(s1_t, a), PredType::NATIVE_INT); + mtype1.insertMember( MEMBER3, HOFFSET(s1_t, c), PredType::NATIVE_DOUBLE); + mtype1.insertMember( MEMBER2, HOFFSET(s1_t, b), PredType::NATIVE_FLOAT); + + /* + * Create the dataset. + */ + DataSet* dataset; + dataset = new DataSet( file->createDataSet( DATASET_NAME, mtype1, space )); + + /* + * Wtite data to the dataset; + */ + dataset->write( s1, mtype1 ); + + /* + * Release resources + */ + delete dataset; + delete file; + + // Get the class of the first member in mtype1, then get its type + H5T_class_t member1_class = mtype1.getMemberClass( 2 ); + if( member1_class == H5T_FLOAT ) + { + FloatType member2 = mtype1.getMemberFloatType( 2 ); + string norm_string; + H5T_norm_t norm = member2.getNorm( norm_string ); + cout << "Normalization type is " << norm_string << endl; + } + + /* + * Open the file and the dataset. + */ + file = new H5File( FILE_NAME, H5F_ACC_RDONLY ); + dataset = new DataSet (file->openDataSet( DATASET_NAME )); + + /* + * Create a datatype for s2 + */ + CompType mtype2( sizeof(s2_t) ); + + mtype2.insertMember( MEMBER3, HOFFSET(s2_t, c), PredType::NATIVE_DOUBLE); + mtype2.insertMember( MEMBER1, HOFFSET(s2_t, a), PredType::NATIVE_INT); + + /* + * Read two fields c and a from s1 dataset. Fields in the file + * are found by their names "c_name" and "a_name". + */ + s2_t s2[LENGTH]; + dataset->read( s2, mtype2 ); + + /* + * Display the fields + */ + cout << endl << "Field c : " << endl; + for( i = 0; i < LENGTH; i++) + cout << s2[i].c << " "; + cout << endl; + + cout << endl << "Field a : " << endl; + for( i = 0; i < LENGTH; i++) + cout << s2[i].a << " "; + cout << endl; + + /* + * Create a datatype for s3. + */ + CompType mtype3( sizeof(float) ); + + mtype3.insertMember( MEMBER2, 0, PredType::NATIVE_FLOAT); + + /* + * Read field b from s1 dataset. Field in the file is found by its name. + */ + float s3[LENGTH]; // Third "structure" - used to read float field of s1) + dataset->read( s3, mtype3 ); + + /* + * Display the field + */ + cout << endl << "Field b : " << endl; + for( i = 0; i < LENGTH; i++) + cout << s3[i] << " "; + cout << endl; + + /* + * Release resources + */ + delete dataset; + delete file; + } // end of try block + + // catch failure caused by the H5File operations + catch( FileIException error ) + { + error.printError(); + } + + // catch failure caused by the DataSet operations + catch( DataSetIException error ) + { + error.printError(); + } + + // catch failure caused by the DataSpace operations + catch( DataSpaceIException error ) + { + error.printError(); + } + + // catch failure caused by the DataSpace operations + catch( DataTypeIException error ) + { + error.printError(); + } + + return 0; +} |