Creating your own text class

• Define a storage mechanism.
• Override the streaming operators and default constructor.
• Implement all TText pure virtual functions. These include functions for:
  • Accessing and copying character and style data, separately or simultaneously
  • Applying or modifying style information for ranges of characters
  • Comparing text, character, and style data
  • Inserting, deleting, and replacing characters

Note that you should not override the TText Insert, Delete, or Replace functions. Instead, you implement protected functions that are broken down to handle the operations on character and style data separately, as shown in this figure:

The HandleInsertCharacterGap and HandleInsertStylesGap functions should be implemented to manipulate storage as necessary so that character or style data can be copied into the text object.

The TText Insert, Delete, and Replace functions are implemented to call the protected functions as follows:

Insert makes the following calls:

1. HandleInsertCharacterGap
   
2. HandleCopyCharacters
   
3. HandleInsertStylesGap
   
4. HandleCopyStyles--when the text to insert is a text object and not a UniChar array
   

1. HandleDeleteStyles
   
2. HandleDeleteCharacters
   

1. HandleDeleteStyles
   
2. HandleInsertCharacterGap--when the text to insert is longer than the text being replaced; or
   HandleDeleteCharacters--when the text to insert is shorter than the text being replaced
   
3. HandleCopyCharacters
   
4. HandleInsertStylesGap
   
5. HandleCopyStyles-- when the replacement text is a text object and not a UniChar array