Padding, Truncation, ...

• Padding

  The padding character, usually blank, should be an SBCS character for the character data type and a DBCS character for the DBCS data type.

• Truncation

  Truncation may be required within programs by any operation that is associated with a data move operation. Special processing is necessary to maintain the validity of the resulting string; i.e. a character string should not be truncated between the first byte and the second byte of a DBCS character.

  The following figures are examples of the adjustment for the character data type

  SOURCE DATA             RIGHT SIDE ADJUSTMENT RESULTS
           TRUNCATED HERE              |
            |                          |
            V                          V
    eDiDjDke                   eDiDjDke
     eDiDjDke                   eDiDjDk
      eDiDjDke                   eDiDjp
       eDiDjDke                   eDiDj
        eDiDjDke                   eDip
         eDiDjDke                   eDi
          eDiDjDke                   ep
  
                             Note: The character 'p'
                                   depicts the padding
                                   character.
  Example of Truncation - RIGHT SIDE ADJUSTMENT
  

  SOURCE DATA             LEFT SIDE ADJUSTMENT RESULTS
          TRUNCATED HERE    |
          |                 |
          V                 V
    eDiDjDke                 e
     eDiDjDke                pe
      eDiDjDke               Dke
       eDiDjDke              pDke
        eDiDjDke             DjDke
         eDiDjDke            pDjDke
          eDiDjDke           DiDjDke
  
                             Note: The character 'p'
                                   depicts the padding
                                   character.
  
  Example of Truncation - LEFT SIDE ADJUSTMENT
  

  As for the DBCS data type, any truncation that results in an odd byte length string should be either prohibited or adjusted to result an even byte length string (usually discarding the fragment byte).

• Substring

  A substring operation can be considered as a combination of two truncation operations, left side and right side.See Truncation part, too.

• Assignment

  In an assignment operation, truncation or padding may be required. See Truncation and Padding part.