[svn-r3602]

Purpose: Usability enhancement

Description:
	- Added more information about the failure to all the throw's,
	i.e, member function name and more detail about the failure, where
	appropriate.  Also, added exception throws for private functions,
	such as p_close to provide more specific details.

	- Added two api functions: Exception::getFuncName() and
	Exception::getCFuncName() to provide the name of the member
	function where failure occurs.

	- Fixed some typos, one of which caused segn. fault in some
	situations (resetIdComponent was accidentally called twice
	in a couple of places :)

Platforms:
	arabica (sparc-sun-solaris 2.7)

1 files changed, 31 insertions, 18 deletions

diff --git a/c++/src/H5CompType.cpp b/c++/src/H5CompType.cpp
index c4143df..0bfa220 100644
--- a/c++/src/H5CompType.cpp
+++ b/c++/src/H5CompType.cpp
@@ -11,6 +11,7 @@
 #include "H5DxferProp.h"
 #include "H5DataSpace.h"
 #include "H5DataSet.h"
+#include "H5private.h"
 
 #ifndef H5_NO_NAMESPACE
 namespace H5 {
@@ -37,7 +38,7 @@ CompType::CompType( const DataSet& dataset ) : DataType()
    // If the datatype id is invalid, throw exception
    if( id <= 0 )
    {
-      throw DataSetIException();
+      throw DataSetIException("CompType constructor", "H5Dget_type failed");
    }
 }
 
@@ -47,7 +48,8 @@ int CompType::getNmembers() const
    int num_members = H5Tget_nmembers( id );
    if( num_members < 0 )
    {
-      throw DataTypeIException();
+      throw DataTypeIException("CompType::getNmembers", 
+		"H5Tget_nmembers returns negative number of members");
    }
    return( num_members );
 }
@@ -55,13 +57,15 @@ int CompType::getNmembers() const
 // Retrieves the name of a member of this compound datatype. 
 string CompType::getMemberName( int member_num ) const
 {
-   char* member_name_C = H5Tget_member_name( id, member_num );
-   if( member_name_C == NULL )  // should this be returned also???
-   {
-      throw DataTypeIException();
-   }
-   string member_name = string( member_name_C );
-   return( member_name );
+    char* member_name_C = H5Tget_member_name( id, member_num );
+    if( member_name_C == NULL )  // NULL means failure
+    {
+	throw DataTypeIException("CompType::getMemberName", 
+		"H5Tget_member_name returns NULL for member name");
+    }
+    string member_name = string(member_name_C); // convert C string to string 
+    HDfree(member_name_C); // free the C string 
+    return( member_name ); // return the member name string
 }
 
 // Retrieves the offset of a member of a compound datatype. 
@@ -71,7 +75,8 @@ size_t CompType::getMemberOffset( int member_num ) const
    // Q. said: for now, 0 is not a failure
    //if( offset == 0 )
    //{
-      //throw DataTypeIException();
+      //throw DataTypeIException("CompType::getMemberOffset",
+		//"H5Tget_member_offset failed");
    //}
    return( offset );
 }
@@ -80,7 +85,8 @@ size_t CompType::getMemberOffset( int member_num ) const
 int CompType::getMemberDims( int member_num, size_t* dims, int* perm ) const
 {
    throw DataTypeIException( "Error: getMemberDims is no longer supported." );
-   return (-1);
+   return (-1); // unreachable statement; but without it, the compiler 
+		// will complain
 }
 
 // Gets the type class of the specified member.
@@ -90,29 +96,35 @@ H5T_class_t CompType::getMemberClass( int member_num ) const
    hid_t member_type_id = H5Tget_member_type( id, member_num );
    if( member_type_id <= 0 )
    {
-      throw DataTypeIException();
+      throw DataTypeIException("CompType::getMemberClass", 
+		"H5Tget_member_type failed");
    }
 
    // then get its class
    H5T_class_t member_class = H5Tget_class( member_type_id );
    if( member_class == H5T_NO_CLASS )
    {
-      throw DataTypeIException();
+      throw DataTypeIException("CompType::getMemberClass", 
+		"H5Tget_class returns H5T_NO_CLASS");
    }
    return( member_class );
 }
 
 // This private member function calls the C API to get the identifier 
-// of the specified member.  It is used by the getMemberXxxType
-// below for the sub-types.
+// of the specified member.  It provides the id to construct appropriate
+// sub-types in the functions getMemberXxxType below, where Xxx indicates
+// the sub-types.
 hid_t CompType::p_getMemberType( int member_num ) const
 {
+   // get the id of the specified member first
    hid_t member_type_id = H5Tget_member_type( id, member_num );
    if( member_type_id > 0 )
       return( member_type_id );
    else
    {
-      throw DataTypeIException();
+	// p_getMemberType is private, use caller's function name for api
+      throw DataTypeIException("CompType::getMemberDataType", 
+		"H5Tget_member_type failed");
    }
 }
 
@@ -155,6 +167,7 @@ StrType CompType::getMemberStrType( int member_num ) const
 
 /* old style of getMemberType - using overloads; new style above 
    returns the appropriate datatypes but has different named functions.
+   In the old style, a datatype must be passed into the function.
 // Returns the datatype of the specified member in this compound datatype. 
 // Several overloading of getMemberType are for different datatypes
 void CompType::getMemberType( int member_num, EnumType& enumtype ) const
@@ -197,7 +210,7 @@ void CompType::insertMember( const string name, size_t offset, const DataType& n
    herr_t ret_value = H5Tinsert( id, name_C, offset, new_member_id );
    if( ret_value < 0 )
    {
-      throw DataTypeIException();
+      throw DataTypeIException("CompType::insertMember", "H5Tinsert failed");
    }
 }
 
@@ -208,7 +221,7 @@ void CompType::pack() const
    herr_t ret_value = H5Tpack( id );
    if( ret_value < 0 )
    {
-      throw DataTypeIException();
+      throw DataTypeIException("CompType::pack", "H5Tpack failed");
    }
 }