[svn-r17238] Purpose: Fix bug and improve readability

Description:
    - Revised DataSet::write to pass in correct string buffer
    - Added member function DataSet::getInMemDataSize() to simplify
      getting the dataset's data size in memory.
    - Added private functions for reading fixed- and variable-length
      string data: p_read_fixed_len and p_read_variable_len.
    - Added tests to write/read array of strings to datasets.

Platforms tested:
    Linux/32 2.6 (jam)
    FreeBSD/64 6.3 (liberty)
    SunOS 5.10 (linew)

7 files changed, 432 insertions, 177 deletions

diff --git a/c++/src/H5AbstractDs.cpp b/c++/src/H5AbstractDs.cpp
index a61cc88..19eeb33 100644
--- a/c++/src/H5AbstractDs.cpp
+++ b/c++/src/H5AbstractDs.cpp
@@ -25,6 +25,11 @@
 #include "H5CommonFG.h"
 #include "H5Alltypes.h"
 
+#include <iostream> // remove when done
+
+    using std::cerr;
+    using std::endl;
+
 #ifndef H5_NO_NAMESPACE
 namespace H5 {
 #endif
diff --git a/c++/src/H5AbstractDs.h b/c++/src/H5AbstractDs.h
index c98e5e1..1d04d6c 100644
--- a/c++/src/H5AbstractDs.h
+++ b/c++/src/H5AbstractDs.h
@@ -51,6 +51,9 @@ class H5_DLLCPP AbstractDs {
 	StrType getStrType() const;
 	VarLenType getVarLenType() const;
 
+	// Gets the size in memory of this abstract dataset.
+	virtual size_t getInMemDataSize() const = 0;
+
 	// Gets the dataspace of this abstract dataset - pure virtual.
 	virtual DataSpace getSpace() const = 0;
 
diff --git a/c++/src/H5Attribute.cpp b/c++/src/H5Attribute.cpp
index b1ab73e..6de5e63 100644
--- a/c++/src/H5Attribute.cpp
+++ b/c++/src/H5Attribute.cpp
@@ -198,35 +198,37 @@ void Attribute::read(const DataType& mem_type, H5std_string& strg) const
 //--------------------------------------------------------------------------
 size_t Attribute::getInMemDataSize() const
 {
+    char *func = "Attribute::getInMemDataSize";
+
     // Get the data type of this attribute
     hid_t mem_type_id = H5Aget_type(id);
-    if (mem_type_id <= 0)
+    if( mem_type_id < 0 )
     {
-	throw AttributeIException("Attribute::getInMemDataSize", "H5Aget_type failed");
+	throw AttributeIException(func, "H5Aget_type failed");
     }
 
     // Get the data type's size
     hid_t native_type = H5Tget_native_type(mem_type_id, H5T_DIR_DEFAULT);
     if (native_type < 0)
     {
-	throw AttributeIException("Attribute::getInMemDataSize", "H5Tget_native_type failed");
+	throw AttributeIException(func, "H5Tget_native_type failed");
     }
     size_t type_size = H5Tget_size(native_type);
     if (type_size == 0)
     {
-	throw AttributeIException("Attribute::getInMemDataSize", "H5Tget_size failed");
+	throw AttributeIException(func, "H5Tget_size failed");
     }
 
     // Get number of elements of the attribute
     hid_t space_id = H5Aget_space(id);
     if (space_id < 0)
     {
-	throw AttributeIException("Attribute::getInMemDataSize", "H5Aget_space failed");
+	throw AttributeIException(func, "H5Aget_space failed");
     }
     hssize_t num_elements = H5Sget_simple_extent_npoints(space_id);
     if (num_elements < 0)
     {
-	throw AttributeIException("Attribute::getInMemDataSize", "H5Sget_simple_extent_npoints failed");
+	throw AttributeIException(func, "H5Sget_simple_extent_npoints failed");
     }
 
     // Calculate and return the size of the data
diff --git a/c++/src/H5Attribute.h b/c++/src/H5Attribute.h
index abece10..284e5bc 100644
--- a/c++/src/H5Attribute.h
+++ b/c++/src/H5Attribute.h
@@ -38,10 +38,10 @@ class H5_DLLCPP Attribute : public AbstractDs, public IdComponent {
 	virtual DataSpace getSpace() const;
 
 	// Returns the amount of storage size required for this attribute.
-	hsize_t getStorageSize() const;
+	virtual hsize_t getStorageSize() const;
 
 	// Returns the in memory size of this attribute's data.
-	size_t getInMemDataSize() const;
+	virtual size_t getInMemDataSize() const;
 
 	// Reads data from this attribute.
 	void read( const DataType& mem_type, void *buf ) const;
@@ -82,7 +82,7 @@ class H5_DLLCPP Attribute : public AbstractDs, public IdComponent {
 	// sub-types
 	virtual hid_t p_get_type() const;
 
-	// Reads variable or fixed len strings
+	// Reads variable or fixed len strings from this attribute.
 	void p_read_variable_len(const DataType& mem_type, H5std_string& strg) const;
 	void p_read_fixed_len(const DataType& mem_type, H5std_string& strg) const;
 
diff --git a/c++/src/H5DataSet.cpp b/c++/src/H5DataSet.cpp
index 494d3ea..cddb5d4 100644
--- a/c++/src/H5DataSet.cpp
+++ b/c++/src/H5DataSet.cpp
@@ -37,6 +37,7 @@
 #include "H5File.h"
 #include "H5Attribute.h"
 #include "H5DataSet.h"
+#include "H5private.h"		// for HDfree
 
 #ifndef H5_NO_NAMESPACE
 namespace H5 {
@@ -220,6 +221,53 @@ hsize_t DataSet::getStorageSize() const
 }
 
 //--------------------------------------------------------------------------
+// Function:	DataSet::getInMemDataSize
+///\brief	Gets the size in memory of the dataset's data.
+///\return	Size of data (in memory)
+///\exception	H5::DataSetIException
+// Programmer	Binh-Minh Ribler - Apr 2009
+//--------------------------------------------------------------------------
+size_t DataSet::getInMemDataSize() const
+{
+    char *func = "DataSet::getInMemDataSize";
+
+    // Get the data type of this dataset
+    hid_t mem_type_id = H5Dget_type(id);
+    if( mem_type_id < 0 )
+    {
+	throw DataSetIException(func, "H5Dget_type failed");
+    }
+
+    // Get the data type's size
+    hid_t native_type = H5Tget_native_type(mem_type_id, H5T_DIR_DEFAULT);
+    if (native_type < 0)
+    {
+	throw DataSetIException(func, "H5Tget_native_type failed");
+    }
+    size_t type_size = H5Tget_size(native_type);
+    if (type_size == 0)
+    {
+	throw DataSetIException(func, "H5Tget_size failed");
+    }
+
+    // Get number of elements of the dataset
+    hid_t space_id = H5Dget_space(id); // first get its data space
+    if (space_id < 0)
+    {
+	throw DataSetIException(func, "H5Dget_space failed");
+    }
+    hssize_t num_elements = H5Sget_simple_extent_npoints(space_id);
+    if (num_elements < 0)
+    {
+	throw DataSetIException(func, "H5Sget_simple_extent_npoints failed");
+    }
+
+    // Calculate and return the size of the data
+    size_t data_size = type_size * num_elements;
+    return(data_size);
+}
+
+//--------------------------------------------------------------------------
 // Function:	DataSet::getOffset
 ///\brief	Returns the address of this dataset in the file.
 ///\return	Address of dataset
@@ -364,20 +412,45 @@ void DataSet::read( void* buf, const DataType& mem_type, const DataSpace& mem_sp
 // Function:	DataSet::read
 ///\brief	This is an overloaded member function, provided for convenience.
 ///		It takes a reference to a \c std::string for the buffer.
+///\param	buf - IN: Buffer for read data
+///\param	mem_type - IN: Memory datatype
+///\param	mem_space - IN: Memory dataspace
+///\param	file_space - IN: Dataset's dataspace in the file
+///\param	xfer_plist - IN: Transfer property list for this I/O operation
+///\exception	H5::DataSetIException
 // Programmer	Binh-Minh Ribler - 2000
-//--------------------------------------------------------------------------
-void DataSet::read( H5std_string& strg, const DataType& mem_type, const DataSpace& mem_space, const DataSpace& file_space, const DSetMemXferPropList& xfer_plist ) const
+// Modification
+//	Jul 2009
+//		Follow the change to Attribute::read and use the following
+//		private functions to read datasets with fixed- and
+//		variable-length string:
+//			DataSet::p_read_fixed_len and
+//			DataSet::p_read_variable_len
+//--------------------------------------------------------------------------
+void DataSet::read(H5std_string& strg, const DataType& mem_type, const DataSpace& mem_space, const DataSpace& file_space, const DSetMemXferPropList& xfer_plist) const
 {
-   // Allocate C character string for reading
-   size_t size = mem_type.getSize();
-   char* strg_C = new char[size+1];  // temporary C-string for C API
+    // Check if this dataset has variable-len string or fixed-len string and
+    // proceed appropriately.
+    htri_t is_variable_len = H5Tis_variable_str(mem_type.getId());
+    if (is_variable_len < 0)
+    {
+        throw DataSetIException("DataSet::read", "H5Tis_variable_str failed");
+    }
 
-   // Use the overloaded member to read
-   read(strg_C, mem_type, mem_space, file_space, xfer_plist);
+    // Obtain identifiers for C API
+    hid_t mem_type_id = mem_type.getId();
+    hid_t mem_space_id = mem_space.getId();
+    hid_t file_space_id = file_space.getId();
+    hid_t xfer_plist_id = xfer_plist.getId();
 
-   // Get the String and clean up
-   strg = strg_C;
-   delete []strg_C;
+    if (!is_variable_len)       // only allocate for fixed-len string
+    {
+        p_read_fixed_len(mem_type_id, mem_space_id, file_space_id, xfer_plist_id, strg);
+    }
+    else
+    {
+        p_read_variable_len(mem_type_id, mem_space_id, file_space_id, xfer_plist_id, strg);
+    }
 }
 
 //--------------------------------------------------------------------------
@@ -416,15 +489,46 @@ void DataSet::write( const void* buf, const DataType& mem_type, const DataSpace&
 ///\brief	This is an overloaded member function, provided for convenience.
 ///		It takes a reference to a \c std::string for the buffer.
 // Programmer	Binh-Minh Ribler - 2000
+// Modification
+//	Jul 2009
+//		Modified to pass the buffer into H5Dwrite properly depending
+//		whether the dataset has variable- or fixed-length string.
 //--------------------------------------------------------------------------
 void DataSet::write( const H5std_string& strg, const DataType& mem_type, const DataSpace& mem_space, const DataSpace& file_space, const DSetMemXferPropList& xfer_plist ) const
 {
-   // Convert string to C-string
-   const char* strg_C;
-   strg_C = strg.c_str();  // strg_C refers to the contents of strg as a C-str
+    // Check if this attribute has variable-len string or fixed-len string and
+    // proceed appropriately.
+    htri_t is_variable_len = H5Tis_variable_str(mem_type.getId());
+    if (is_variable_len < 0)
+    {
+        throw DataSetIException("DataSet::write", "H5Tis_variable_str failed");
+    }
+
+   // Obtain identifiers for C API
+   hid_t mem_type_id = mem_type.getId();
+   hid_t mem_space_id = mem_space.getId();
+   hid_t file_space_id = file_space.getId();
+   hid_t xfer_plist_id = xfer_plist.getId();
+
+    // Convert string to C-string
+    const char* strg_C;
+    strg_C = strg.c_str();  // strg_C refers to the contents of strg as a C-str
+    herr_t ret_value = 0;
 
-   // Use the overloaded member
-   write(strg_C, mem_type, mem_space, file_space, xfer_plist);
+    // Pass string in differently depends on variable or fixed length
+    if (!is_variable_len)
+    {
+        ret_value = H5Dwrite( id, mem_type_id, mem_space_id, file_space_id, xfer_plist_id, strg_C );
+    }
+    else
+    {
+        // passing string argument by address
+        ret_value = H5Dwrite( id, mem_type_id, mem_space_id, file_space_id, xfer_plist_id, &strg_C );
+    }
+    if (ret_value < 0)
+    {
+        throw DataSetIException("DataSet::write", "H5Dwrite failed");
+    }
 }
 
 //--------------------------------------------------------------------------
@@ -586,7 +690,74 @@ hid_t DataSet::getId() const
 }
 
 //--------------------------------------------------------------------------
-// Function:    DataSet::p_setId
+// Function:	DataSet::p_read_fixed_len (private)
+// brief	Reads a fixed length \a H5std_string from an dataset.
+// param	mem_type  - IN: DataSet datatype (in memory)
+// param	strg      - IN: Buffer for read string
+// exception	H5::DataSetIException
+// Programmer	Binh-Minh Ribler - Jul, 2009
+// Modification
+//	Jul 2009
+//		Added in follow to the change in Attribute::read
+//--------------------------------------------------------------------------
+void DataSet::p_read_fixed_len(const hid_t mem_type_id, const hid_t mem_space_id, const hid_t file_space_id, const hid_t xfer_plist_id, H5std_string& strg) const
+{
+    // Only allocate for fixed-len string.
+
+    // Get the size of the dataset's data
+    size_t attr_size = getInMemDataSize();
+
+    // If there is data, allocate buffer and read it.
+    if (attr_size > 0)
+    {
+	char *strg_C = NULL;
+
+	strg_C = new char [(size_t)attr_size+1];
+	herr_t ret_value = H5Dread(id, mem_type_id, mem_space_id, file_space_id, xfer_plist_id, strg_C);
+
+	if( ret_value < 0 )
+	{
+	    delete []strg_C;	// de-allocate for fixed-len string
+	    throw DataSetIException("DataSet::read", "H5Dread failed for fixed length string");
+	}
+
+	// Get string from the C char* and release resource allocated locally
+	strg = strg_C;
+	delete []strg_C;
+    }
+}
+
+//--------------------------------------------------------------------------
+// Function:	DataSet::p_read_variable_len (private)
+// brief	Reads a variable length \a H5std_string from an dataset.
+// param	mem_type  - IN: DataSet datatype (in memory)
+// param	strg      - IN: Buffer for read string
+// exception	H5::DataSetIException
+// Programmer	Binh-Minh Ribler - Jul, 2009
+// Modification
+//	Jul 2009
+//		Added in follow to the change in Attribute::read
+//--------------------------------------------------------------------------
+void DataSet::p_read_variable_len(const hid_t mem_type_id, const hid_t mem_space_id, const hid_t file_space_id, const hid_t xfer_plist_id, H5std_string& strg) const
+{
+    // Prepare and call C API to read dataset.
+    char *strg_C;
+
+    // Read dataset, no allocation for variable-len string; C library will
+    herr_t ret_value = H5Dread(id, mem_type_id, mem_space_id, file_space_id, xfer_plist_id, &strg_C);
+
+    if( ret_value < 0 )
+    {
+	throw DataSetIException("DataSet::read", "H5Dread failed for variable length string");
+    }
+
+    // Get string from the C char* and release resource allocated by C API
+    strg = strg_C;
+    HDfree(strg_C);
+}
+
+//--------------------------------------------------------------------------
+// Function:    DataSet::p_setId (private)
 ///\brief       Sets the identifier of this object to a new value.
 ///
 ///\exception   H5::IdComponentException when the attempt to close the HDF5
diff --git a/c++/src/H5DataSet.h b/c++/src/H5DataSet.h
index f26d775..3d9183d 100644
--- a/c++/src/H5DataSet.h
+++ b/c++/src/H5DataSet.h
@@ -49,7 +49,10 @@ class H5_DLLCPP DataSet : public H5Object, public AbstractDs {
 	void getSpaceStatus(H5D_space_status_t& status) const;
 
 	// Returns the amount of storage size required for this dataset.
-	hsize_t getStorageSize() const;
+	virtual hsize_t getStorageSize() const;
+
+	// Returns the in memory size of this attribute's data.
+	virtual size_t getInMemDataSize() const;
 
 	// Returns the number of bytes required to store VL data.
 	hsize_t getVlenBufSize( DataType& type, DataSpace& space ) const;
@@ -113,6 +116,10 @@ class H5_DLLCPP DataSet : public H5Object, public AbstractDs {
         // sub-types
 	virtual hid_t p_get_type() const;
 
+	// Reads variable or fixed len strings from this dataset.
+	void p_read_fixed_len(const hid_t mem_type_id, const hid_t mem_space_id, const hid_t file_space_id, const hid_t xfer_plist_id, H5std_string& strg) const;
+	void p_read_variable_len(const hid_t mem_type_id, const hid_t mem_space_id, const hid_t file_space_id, const hid_t xfer_plist_id, H5std_string& strg) const;
+
    protected:
         // Sets the dataset id.
         virtual void p_setId(const hid_t new_id);
diff --git a/c++/test/tvlstr.cpp b/c++/test/tvlstr.cpp
index 0abab1b..01033be 100644
--- a/c++/test/tvlstr.cpp
+++ b/c++/test/tvlstr.cpp
@@ -18,7 +18,6 @@
    tvlstr.cpp - HDF5 C++ testing the Variable-Length String functionality
 
    EXTERNAL ROUTINES/VARIABLES:
-     These routines are in the test directory of the C library:
 
  ***************************************************************************/
 
@@ -52,7 +51,7 @@ const H5std_string FILENAME("tvlstr.h5");
 const int SPACE1_RANK = 1;
 const hsize_t SPACE1_DIM1 = 4;
 
-// Utility functions
+// Utility functions - not used now, later though.
 void *test_vlstr_alloc_custom(size_t size, void *info);
 void test_vlstr_free_custom(void *mem, void *info);
 
@@ -119,9 +118,9 @@ void test_vlstr_free_custom(void *_mem, void *info)
 }
 
 /*-------------------------------------------------------------------------
- * Function:	test_vlstrings_basic
+ * Function:	test_vlstring_dataset
  *
- * Purpose:	Test simple VL string I/O.
+ * Purpose:	Test writing/reading VL strings on datasets.
  *
  * Return:	None
  *
@@ -130,98 +129,171 @@ void test_vlstr_free_custom(void *_mem, void *info)
  *
  *-------------------------------------------------------------------------
  */
-static void test_vlstrings_basic()
+// String for testing datasets
+static char *dynstring_ds_write=NULL;
+static char stastring_ds_write[1]={'A'};
+
+// Info for a string dataset
+const H5std_string DSET1_NAME("String_ds");
+const H5std_string DSET1_DATA("String Dataset");
+
+static void test_vlstring_dataset()
+{
+    // Output message about test being performed
+    SUBTEST("Testing VL String on Datasets");
+
+    try {
+	// Open the file
+	H5File file1(FILENAME, H5F_ACC_TRUNC);
+
+	// Create a datatype to refer to.
+	StrType vlst(0, H5T_VARIABLE);
+
+	// Open the root group.
+	Group root = file1.openGroup("/");
+
+	// Create dataspace for the dataset.
+	DataSpace ds_space (H5S_SCALAR);
+
+	// Create an dataset in the root group.
+	DataSet dset1 = root.createDataSet(DSET1_NAME, vlst, ds_space);
+
+	// Write data to the dataset.
+	dset1.write(DSET1_DATA, vlst);
+
+	// Read and verify the dataset string as a string of chars.
+	char *string_ds_check;
+	dset1.read(&string_ds_check, vlst);
+	if(HDstrcmp(string_ds_check, DSET1_DATA.c_str())!=0)
+	    TestErrPrintf("Line %d: Attribute data different: DSET1_DATA=%s,string_ds_check=%s\n",__LINE__, DSET1_DATA.c_str(), string_ds_check);
+
+	HDfree(string_ds_check);  // note: no need for std::string test
+
+	// Read and verify the dataset string as an std::string.
+	H5std_string read_str;
+	dset1.read(read_str, vlst);
+	if (read_str != DSET1_DATA)
+	    TestErrPrintf("Line %d: Attribute data different: DSET1_DATA=%s,read_str=%s\n",__LINE__, DSET1_DATA.c_str(), read_str.c_str());
+
+	// Close the dataset.
+	dset1.close();
+
+	// Test scalar type dataset with 1 value.
+	dset1 = root.createDataSet("test_scalar_small", vlst, ds_space);
+
+	dynstring_ds_write = (char*)HDcalloc(1, sizeof(char));
+	HDmemset(dynstring_ds_write, 'A', 1);
+
+	// Write data to the dataset, then read it back.
+	dset1.write(&dynstring_ds_write, vlst);
+	dset1.read(&string_ds_check, vlst);
+
+	// Verify data read.
+	if(HDstrcmp(string_ds_check,dynstring_ds_write)!=0)
+	    TestErrPrintf("VL string datasets don't match!, dynstring_ds_write=%s, string_ds_check=%s\n",dynstring_ds_write,string_ds_check);
+	HDfree(string_ds_check);
+	dset1.close();
+
+	// Open dataset DSET1_NAME again.
+	dset1 = root.openDataSet(DSET1_NAME);
+
+	// Close dataset and file
+	dset1.close();
+	file1.close();
+
+	PASSED();
+    } // end try block
+
+    // Catch all exceptions.
+    catch (Exception E) {
+	issue_fail_msg("test_vlstring_dataset()", __LINE__, __FILE__, E.getCDetailMsg());
+    }
+}   // test_vlstring_dataset()
+
+/*-------------------------------------------------------------------------
+ * Function:	test_vlstring_array_dataset
+ *
+ * Purpose:	Test writing/reading VL string array to/from datasets.
+ *
+ * Return:	None
+ *
+ * Programmer:	Binh-Minh Ribler
+ *		July, 2009
+ *
+ *-------------------------------------------------------------------------
+ */
+const H5std_string DSSTRARR_NAME("StringArray_dset");
+static void test_vlstring_array_dataset()
 {
-    const char *wdata[SPACE1_DIM1]= {
-        "Four score and seven years ago our forefathers brought forth on this continent a new nation,",
-        "conceived in liberty and dedicated to the proposition that all men are created equal.",
-        "Now we are engaged in a great civil war,",
-        "testing whether that nation or any nation so conceived and so dedicated can long endure."
+    const char *string_ds_array[SPACE1_DIM1]= {
+        "Line 1", "Line 2", "Line 3", "Line 4"
         };   // Information to write
 
     // Output message about test being performed
-    SUBTEST("Testing Basic VL String Functionality");
+    SUBTEST("Testing VL String Array on Datasets");
 
-    H5File* file1 = NULL;
+    H5File* file1;
     try {
         // Create file.
-        file1 = new H5File (FILENAME, H5F_ACC_TRUNC);
+	file1 = new H5File (FILENAME, H5F_ACC_RDWR);
 
-	// Create dataspace for datasets.
-	hsize_t	dims1[] = {SPACE1_DIM1};
-	DataSpace sid1(SPACE1_RANK, dims1);
+        // Create dataspace for datasets.
+        hsize_t dims1[] = {SPACE1_DIM1};
+        DataSpace ds_space(SPACE1_RANK, dims1);
 
 	// Create a datatype to refer to.
-	StrType tid1(0, H5T_VARIABLE);
+	StrType vlst(0, H5T_VARIABLE);
 
 	// Create and write a dataset.
-	DataSet dataset(file1->createDataSet("Dataset1", tid1, sid1));
-	dataset.write(wdata, tid1);
+	DataSet dataset(file1->createDataSet(DSSTRARR_NAME, vlst, ds_space));
+	dataset.write(string_ds_array, vlst);
+
+	// Read and verify the dataset using strings of chars as buffer.
+	// Note: reading by array of H5std_string doesn't work yet.
+	char *string_ds_check[SPACE1_DIM1];
+	dataset.read(string_ds_check, vlst);
+
+	int ii;
+	for (ii = 0; ii < SPACE1_DIM1; ii++)
+	{
+	    if(HDstrcmp(string_ds_check[ii], string_ds_array[ii])!=0)
+		TestErrPrintf("Line %d: Dataset data different: written=%s,read=%s\n",__LINE__, string_ds_array[ii], string_ds_check[ii]);
+
+	    HDfree(string_ds_check[ii]);
+	}
+
+	// Close objects that are no longer needed.
+	dataset.close();
+	ds_space.close();
+
+	//
+	// Test with scalar data space.
+	//
 
 	// Create H5S_SCALAR data space.
 	DataSpace scalar_space;
 
 	// Create and write another dataset.
-	DataSet dataset2(file1->createDataSet("Dataset2", tid1, scalar_space));
+	DataSet dataset2(file1->createDataSet("Dataset2", vlst, scalar_space));
 	char *wdata2 = (char*)HDcalloc(65534, sizeof(char));
 	HDmemset(wdata2, 'A', 65533);
-	dataset2.write(&wdata2, tid1);
+	dataset2.write(&wdata2, vlst);
+
+	char *rdata2 = (char*)HDcalloc(65534, sizeof(char));
+	HDmemset(rdata2, 0, 65533);
+	dataset2.read(&rdata2, vlst);
+	if (HDstrcmp(wdata2, rdata2)!=0)
+	    TestErrPrintf("Line %d: Dataset data different: written=%s,read=%s\n",__LINE__, wdata2, rdata2);
 
 	// Release resources from second dataset operation.
 	scalar_space.close();
 	dataset2.close();
 	HDfree(wdata2);
-
-	// Change to the custom memory allocation routines for reading
-	// VL string.
-	DSetMemXferPropList xfer;
-	size_t mem_used = 0;	// Memory used during allocation
-	xfer.setVlenMemManager(test_vlstr_alloc_custom, &mem_used, test_vlstr_free_custom, &mem_used);
-
-	// Make certain the correct amount of memory will be used.
-	hsize_t vlsize = dataset.getVlenBufSize(tid1, sid1);
-
-	// Count the actual number of bytes used by the strings.
-	size_t str_used;   // String data in memory
-	hsize_t i;	// counting variable
-	for (i=0,str_used=0; i<SPACE1_DIM1; i++)
-	    str_used+=HDstrlen(wdata[i])+1;
-
-	// Compare against the strings actually written.
-	verify_val((int)vlsize,str_used,"DataSet::getVlenBufSize", __LINE__, __FILE__);
-
-	// Read dataset from disk.
-	char *rdata[SPACE1_DIM1];   // Data read in
-	dataset.read(rdata, tid1, DataSpace::ALL, DataSpace::ALL, xfer);
-
-	// Make certain the correct amount of memory has been used.
-	verify_val(mem_used, str_used, "DataSet::read", __LINE__, __FILE__);
-
-	// Compare data read in.
-	for(i = 0; i < SPACE1_DIM1; i++) {
-	    size_t wlen = HDstrlen(wdata[i]);
-	    size_t rlen = HDstrlen(rdata[i]);
-	    if(wlen != rlen) {
-		TestErrPrintf("VL data lengths don't match!, strlen(wdata[%d])=%u, strlen(rdata[%d])=%u\n", (int)i, (unsigned)wlen, (int)i, (unsigned)rlen);
-		continue;
-	    } // end if
-	    if(HDstrcmp(wdata[i], rdata[i]) != 0) {
-		TestErrPrintf("VL data values don't match!, wdata[%d]=%s, rdata[%d]=%s\n", (int)i, wdata[i], (int)i, rdata[i]);
-		continue;
-	    } // end if
-	} // end for
-
-	// Reclaim the read VL data.
-	DataSet::vlenReclaim((void *)rdata, tid1, sid1, xfer);
-
-	// Make certain the VL memory has been freed.
-	verify_val(mem_used, 0, "DataSet::vlenReclaim", __LINE__, __FILE__);
+	HDfree(rdata2);
 
 	// Close objects and file.
-	dataset.close();
-	tid1.close();
-	sid1.close();
-	xfer.close();
+	dataset2.close();
+	vlst.close();
 	file1->close();
 
 	PASSED();
@@ -230,11 +302,10 @@ static void test_vlstrings_basic()
     // Catch all exceptions.
     catch (Exception E)
     {
-	issue_fail_msg("test_vlstrings_basic()", __LINE__, __FILE__, E.getCDetailMsg());
-        if (file1 != NULL) // clean up
-            delete file1;
+	issue_fail_msg("test_vlstring_array_dataset()", __LINE__, __FILE__, E.getCDetailMsg());
+	delete file1;
     }
-} // end test_vlstrings_basic()
+} // end test_vlstring_array_dataset()
 
 /*-------------------------------------------------------------------------
  * Function:	test_vlstrings_special
@@ -267,13 +338,13 @@ static void test_vlstrings_special()
         DataSpace sid1(SPACE1_RANK, dims1);
 
 	// Create a datatype to refer to.
-	StrType tid1(0, H5T_VARIABLE);
+	StrType vlst(0, H5T_VARIABLE);
 
 	// Create a dataset.
-	DataSet dataset(file1.createDataSet("Dataset3", tid1, sid1));
+	DataSet dataset(file1.createDataSet("Dataset3", vlst, sid1));
 
 	// Read from the dataset before writing data.
-	dataset.read(rdata, tid1);
+	dataset.read(rdata, vlst);
 
 	// Check data read in.
 	hsize_t i;      	// counting variable
@@ -282,8 +353,8 @@ static void test_vlstrings_special()
 		TestErrPrintf("VL doesn't match!, rdata[%d]=%p\n",(int)i,rdata[i]);
 
 	// Write dataset to disk, then read it back.
-	dataset.write(wdata, tid1);
-	dataset.read(rdata, tid1);
+	dataset.write(wdata, vlst);
+	dataset.read(rdata, vlst);
 
 	// Compare data read in.
 	for(i = 0; i < SPACE1_DIM1; i++) {
@@ -300,7 +371,7 @@ static void test_vlstrings_special()
 	} // end for
 
 	// Reclaim the read VL data.
-	DataSet::vlenReclaim((void *)rdata, tid1, sid1);
+	DataSet::vlenReclaim((void *)rdata, vlst, sid1);
 
 	// Close Dataset.
 	dataset.close();
@@ -313,14 +384,14 @@ static void test_vlstrings_special()
 	// dataset.
 	DSetCreatPropList dcpl;
 	char *fill = NULL;	// Fill value
-	dcpl.setFillValue(tid1, &fill);
-	dataset = file1.createDataSet("Dataset4", tid1, sid1, dcpl);
+	dcpl.setFillValue(vlst, &fill);
+	dataset = file1.createDataSet("Dataset4", vlst, sid1, dcpl);
 
 	// Close dataset creation property list.
 	dcpl.close();
 
 	// Read from dataset before writing data.
-	dataset.read(rdata, tid1);
+	dataset.read(rdata, vlst);
 
 	// Check data read in.
 	for (i=0; i<SPACE1_DIM1; i++)
@@ -328,10 +399,10 @@ static void test_vlstrings_special()
 	    TestErrPrintf("VL doesn't match!, rdata[%d]=%p\n",(int)i, rdata[i]);
 
 	// Try to write nil strings to disk.
-	dataset.write(wdata2, tid1);
+	dataset.write(wdata2, vlst);
 
 	// Read nil strings back from disk.
-	dataset.read(rdata, tid1);
+	dataset.read(rdata, vlst);
 
 	// Check data read in.
 	for (i=0; i<SPACE1_DIM1; i++)
@@ -340,7 +411,7 @@ static void test_vlstrings_special()
 
 	// Close objects and file.
 	dataset.close();
-	tid1.close();
+	vlst.close();
 	sid1.close();
 	file1.close();
 
@@ -370,7 +441,7 @@ const H5std_string      VLSTR_TYPE("vl_string_type");
 static void test_vlstring_type()
 {
     // Output message about test being performed.
-    SUBTEST("Testing VL String type");
+    SUBTEST("Testing VL String Type");
 
     H5File* file1 = NULL;
     try {
@@ -378,55 +449,55 @@ static void test_vlstring_type()
 	file1 = new H5File(FILENAME, H5F_ACC_RDWR);
 
 	// Create a datatype to refer to.
-	StrType vlstr_type(PredType::C_S1);
+	StrType vlst(PredType::C_S1);
 
 	// Change padding and verify it.
-	vlstr_type.setStrpad(H5T_STR_NULLPAD);
-	H5T_str_t pad = vlstr_type.getStrpad();
+	vlst.setStrpad(H5T_STR_NULLPAD);
+	H5T_str_t pad = vlst.getStrpad();
 	verify_val(pad, H5T_STR_NULLPAD, "StrType::getStrpad", __LINE__, __FILE__);
 
 	// Convert to variable-length string.
-	vlstr_type.setSize(H5T_VARIABLE);
+	vlst.setSize(H5T_VARIABLE);
 
 	// Check if datatype is VL string.
-	H5T_class_t type_class = vlstr_type.getClass();
+	H5T_class_t type_class = vlst.getClass();
 	verify_val(type_class, H5T_STRING, "DataType::getClass", __LINE__, __FILE__);
-	bool is_variable_str = vlstr_type.isVariableStr();
+	bool is_variable_str = vlst.isVariableStr();
 	verify_val(is_variable_str, TRUE, "DataType::isVariableStr", __LINE__, __FILE__);
 
 	// Check default character set and padding.
-	H5T_cset_t cset = vlstr_type.getCset();
+	H5T_cset_t cset = vlst.getCset();
 	verify_val(cset, H5T_CSET_ASCII, "StrType::getCset", __LINE__, __FILE__);
-	pad = vlstr_type.getStrpad();
+	pad = vlst.getStrpad();
 	verify_val(pad, H5T_STR_NULLPAD, "StrType::getStrpad", __LINE__, __FILE__);
 
 	// Commit variable-length string datatype to storage.
-	vlstr_type.commit(*file1, VLSTR_TYPE);
+	vlst.commit(*file1, VLSTR_TYPE);
 
 	// Close datatype.
-	vlstr_type.close();
+	vlst.close();
 
 	// Try opening datatype again.
-	vlstr_type = file1->openStrType(VLSTR_TYPE);
+	vlst = file1->openStrType(VLSTR_TYPE);
 
 	// Close datatype and file.
-	vlstr_type.close();
+	vlst.close();
 	file1->close();
 
 	// Open file.
 	file1 = new H5File(FILENAME, H5F_ACC_RDWR);
 
 	// Open the variable-length string datatype just created
-	vlstr_type = file1->openStrType(VLSTR_TYPE);
+	vlst = file1->openStrType(VLSTR_TYPE);
 
 	// Verify character set and padding
-	cset = vlstr_type.getCset();
+	cset = vlst.getCset();
 	verify_val(cset, H5T_CSET_ASCII, "StrType::getCset", __LINE__, __FILE__);
-	pad = vlstr_type.getStrpad();
+	pad = vlst.getStrpad();
 	verify_val(pad, H5T_STR_NULLPAD, "StrType::getStrpad", __LINE__, __FILE__);
 
 	// Close datatype and file
-	vlstr_type.close();
+	vlst.close();
 	file1->close();
 
 	PASSED();
@@ -436,6 +507,7 @@ static void test_vlstring_type()
     catch (Exception E)
     {
         issue_fail_msg("test_vlstring_type()", __LINE__, __FILE__, E.getCDetailMsg());
+	delete file1;
     }
 } // end test_vlstring_type()
 
@@ -454,7 +526,7 @@ static void test_vlstring_type()
 static void test_compact_vlstring()
 {
     // Output message about test being performed
-    SUBTEST("Testing VL Strings in compact dataset");
+    SUBTEST("Testing VL Strings on Compact Dataset");
 
     try {
 	// Create file
@@ -465,22 +537,22 @@ static void test_compact_vlstring()
         DataSpace sid1(SPACE1_RANK, dims1);
 
 	// Create a datatype to refer to
-	StrType tid1(0, H5T_VARIABLE);
+	StrType vlst(0, H5T_VARIABLE);
 
 	// Create dataset create property list and set layout
 	DSetCreatPropList plist;
 	plist.setLayout(H5D_COMPACT);
 
 	// Create a dataset
-	DataSet dataset(file1.createDataSet("Dataset5", tid1, sid1, plist));
+	DataSet dataset(file1.createDataSet("Dataset5", vlst, sid1, plist));
 
 	// Write dataset to disk
 	const char *wdata[SPACE1_DIM1] = {"one", "two", "three", "four"};
-	dataset.write(wdata, tid1);
+	dataset.write(wdata, vlst);
 
 	// Read dataset from disk
 	char *rdata[SPACE1_DIM1];   // Information read in
-	dataset.read(rdata, tid1);
+	dataset.read(rdata, vlst);
 
 	// Compare data read in
 	hsize_t i;
@@ -496,11 +568,11 @@ static void test_compact_vlstring()
 	} // end for
 
 	// Reclaim the read VL data
-	DataSet::vlenReclaim((void *)rdata, tid1, sid1);
+	DataSet::vlenReclaim((void *)rdata, vlst, sid1);
 
 	// Close objects and file
 	dataset.close();
-	tid1.close();
+	vlst.close();
 	sid1.close();
 	plist.close();
 	file1.close();
@@ -516,9 +588,9 @@ static void test_compact_vlstring()
 }   // test_compact_vlstrings
 
 /*-------------------------------------------------------------------------
- * Function:	test_write_vl_string_attribute
+ * Function:	test_vlstring_attribute
  *
- * Purpose:	Test writing VL strings as attributes.
+ * Purpose:	Test writing/reading VL strings on attributes.
  *
  * Return:	None
  *
@@ -534,17 +606,17 @@ static char *string_att_write=NULL;
 const H5std_string ATTRSTR_NAME("String_attr");
 const H5std_string ATTRSTR_DATA("String Attribute");
 
-static void test_write_vl_string_attribute()
+static void test_vlstring_attribute()
 {
     // Output message about test being performed
-    SUBTEST("Testing writing VL String as attributes");
+    SUBTEST("Testing VL String on Attributes");
 
     try {
 	// Open the file
 	H5File file1(FILENAME, H5F_ACC_RDWR);
 
 	// Create a datatype to refer to.
-	StrType tid1(0, H5T_VARIABLE);
+	StrType vlst(0, H5T_VARIABLE);
 
 	// Open the root group.
 	Group root = file1.openGroup("/");
@@ -553,14 +625,14 @@ static void test_write_vl_string_attribute()
 	DataSpace att_space (H5S_SCALAR);
 
 	// Create an attribute for the root group.
-	Attribute gr_attr = root.createAttribute(ATTRSTR_NAME, tid1, att_space);
+	Attribute gr_attr = root.createAttribute(ATTRSTR_NAME, vlst, att_space);
 
 	// Write data to the attribute.
-	gr_attr.write(tid1, ATTRSTR_DATA);
+	gr_attr.write(vlst, ATTRSTR_DATA);
 
 	// Read and verify the attribute string as a string of chars.
 	char *string_att_check;
-	gr_attr.read(tid1, &string_att_check);
+	gr_attr.read(vlst, &string_att_check);
 	if(HDstrcmp(string_att_check, ATTRSTR_DATA.c_str())!=0)
 	    TestErrPrintf("Line %d: Attribute data different: ATTRSTR_DATA=%s,string_att_check=%s\n",__LINE__, ATTRSTR_DATA.c_str(), string_att_check);
 
@@ -568,7 +640,7 @@ static void test_write_vl_string_attribute()
 
 	// Read and verify the attribute string as an std::string.
 	H5std_string read_str;
-	gr_attr.read(tid1, read_str);
+	gr_attr.read(vlst, read_str);
 	if (read_str != ATTRSTR_DATA)
 	    TestErrPrintf("Line %d: Attribute data different: ATTRSTR_DATA=%s,read_str=%s\n",__LINE__, ATTRSTR_DATA.c_str(), read_str.c_str());
 
@@ -576,28 +648,22 @@ static void test_write_vl_string_attribute()
 	gr_attr.close();
 
 	// Test creating a "large" sized string attribute
-	gr_attr = root.createAttribute("test_scalar_large", tid1, att_space);
+	gr_attr = root.createAttribute("test_scalar_large", vlst, att_space);
 
 	string_att_write = (char*)HDcalloc(8192, sizeof(char));
 	HDmemset(string_att_write, 'A', 8191);
 
 	// Write data to the attribute, then read it back.
-	gr_attr.write(tid1, &string_att_write);
-	gr_attr.read(tid1, &string_att_check);
+	gr_attr.write(vlst, &string_att_write);
+	gr_attr.read(vlst, &string_att_check);
 
 	// Verify data read.
 	if(HDstrcmp(string_att_check,string_att_write)!=0)
 	    TestErrPrintf("VL string attributes don't match!, string_att_write=%s, string_att_check=%s\n",string_att_write,string_att_check);
-	HDfree(string_att_check);
-	gr_attr.close();
-
-	// Open attribute ATTRSTR_NAME again.
-	gr_attr = root.openAttribute(ATTRSTR_NAME);
 
-	// The attribute string written is freed below, in the
-	// test_read_vl_string_attribute() test
-
-	// Close attribute and file
+	// Release resources.
+	HDfree(string_att_check);
+	HDfree(string_att_write);
 	gr_attr.close();
 	file1.close();
 
@@ -606,9 +672,9 @@ static void test_write_vl_string_attribute()
 
     // Catch all exceptions.
     catch (Exception E) {
-	issue_fail_msg("test_string_attr()", __LINE__, __FILE__, E.getCDetailMsg());
+	issue_fail_msg("test_vlstring_attribute()", __LINE__, __FILE__, E.getCDetailMsg());
     }
-}   // test_string_attr()
+}   // test_vlstring_attribute()
 
 /*-------------------------------------------------------------------------
  * Function:	test_read_vl_string_attribute
@@ -633,7 +699,7 @@ static void test_read_vl_string_attribute()
 	H5File file1(FILENAME, H5F_ACC_RDONLY);
 
 	// Create a datatype to refer to.
-	StrType tid1(0, H5T_VARIABLE);
+	StrType vlst(0, H5T_VARIABLE);
 
 	// Open the root group and its attribute named ATTRSTR_NAME.
 	Group root = file1.openGroup("/");
@@ -641,7 +707,7 @@ static void test_read_vl_string_attribute()
 
 	// Test reading "normal" sized string attribute
 	char *string_att_check;
-	att.read(tid1, &string_att_check);
+	att.read(vlst, &string_att_check);
 	if(HDstrcmp(string_att_check,ATTRSTR_DATA.c_str())!=0)
 	    TestErrPrintf("VL string attributes don't match!, string_att=%s, string_att_check=%s\n",ATTRSTR_DATA.c_str(),string_att_check);
 	HDfree(string_att_check);
@@ -649,7 +715,7 @@ static void test_read_vl_string_attribute()
 
 	// Test reading "large" sized string attribute
 	att = root.openAttribute("test_scalar_large");
-	att.read(tid1, &string_att_check);
+	att.read(vlst, &string_att_check);
 	if(HDstrcmp(string_att_check,string_att_write)!=0)
 	    TestErrPrintf("VL string attributes don't match!, string_att_write=%s, string_att_check=%s\n",string_att_write,string_att_check);
 	HDfree(string_att_check);
@@ -657,7 +723,7 @@ static void test_read_vl_string_attribute()
 
 	// Close objects and file.
 	att.close();
-	tid1.close();
+	vlst.close();
 	root.close();
 	file1.close();
 
@@ -672,7 +738,7 @@ static void test_read_vl_string_attribute()
 
 
 /*-------------------------------------------------------------------------
- * Function:	test_vl_stringarray_attribute
+ * Function:	test_vlstring_array_attribute
  *
  * Purpose:	Test writing/reading VL string array to/from attributes.
  *
@@ -685,21 +751,21 @@ static void test_read_vl_string_attribute()
  */
 const H5std_string ATTRSTRARR_NAME("StringArray_attr");
 
-static void test_vl_stringarray_attribute()
+static void test_vlstring_array_attribute()
 {
     const char *string_att_array[SPACE1_DIM1]= {
         "Line 1", "Line 2", "Line 3", "Line 4"
         };   // Information to write
 
     // Output message about test being performed
-    SUBTEST("Testing writing/reading VL String Array on attribute");
+    SUBTEST("Testing VL String Array on Attributes");
 
     try {
 	// Open the file
 	H5File file1(FILENAME, H5F_ACC_RDWR);
 
 	// Create a datatype to refer to.
-	StrType tid1(0, H5T_VARIABLE);
+	StrType vlst(0, H5T_VARIABLE);
 
 	// Open the root group.
 	Group root = file1.openGroup("/");
@@ -709,15 +775,15 @@ static void test_vl_stringarray_attribute()
         DataSpace att_space(SPACE1_RANK, dims1);
 
 	// Create an attribute for the root group.
-	Attribute gr_attr = root.createAttribute(ATTRSTRARR_NAME, tid1, att_space);
+	Attribute gr_attr = root.createAttribute(ATTRSTRARR_NAME, vlst, att_space);
 
 	// Write data to the attribute.
-	gr_attr.write(tid1, string_att_array);
+	gr_attr.write(vlst, string_att_array);
 
 	// Read and verify the attribute string as a string of chars.
 	// Note: reading by array of H5std_string doesn't work yet.
 	char *string_att_check[SPACE1_DIM1];
-	gr_attr.read(tid1, &string_att_check);
+	gr_attr.read(vlst, &string_att_check);
 
 	int ii;
 	for (ii = 0; ii < SPACE1_DIM1; ii++)
@@ -737,9 +803,9 @@ static void test_vl_stringarray_attribute()
 
     // Catch all exceptions.
     catch (Exception E) {
-	issue_fail_msg("test_string_attr()", __LINE__, __FILE__, E.getCDetailMsg());
+	issue_fail_msg("test_vlstring_array_attribute()", __LINE__, __FILE__, E.getCDetailMsg());
     }
-}   // test_vl_stringarray_attribute()
+}   // test_vlstring_array_attribute()
 
 /* Helper routine for test_vl_rewrite() */
 static void write_scalar_dset(H5File& file, DataType& type, DataSpace& space,
@@ -885,17 +951,18 @@ void test_vlstrings()
 
     // These tests use the same file
     // Test basic VL string datatype
-    test_vlstrings_basic();
+    test_vlstring_dataset();
     test_vlstrings_special();
     test_vlstring_type();
     test_compact_vlstring();
 
     // Test using VL strings in attributes
-    test_write_vl_string_attribute();
-    test_read_vl_string_attribute();
+    test_vlstring_attribute();
+  //  test_read_vl_string_attribute();
 
-    // Test using VL string array in attributes
-    test_vl_stringarray_attribute();
+    // Test using VL string array in attributes and datasets
+    test_vlstring_array_attribute();
+    test_vlstring_array_dataset();
 
     // Test writing VL datasets in files with lots of unlinking
     test_vl_rewrite();