| Flag | Value | Description |
| RegExpTypeANSI | 0x00000000 | Treat the given range as a stream of single-byte characters. May not be used with RegExpTypeUNICODE flag. |
| RegExpTypeUNICODE | 0x00000001 | Treat the given range as a stream of 16-bit unicode characters. May not be used with RegExpTypeANSI |
| RegExpIgnoreCase | 0x00000002 | True to ignore case and false to match case. |
Calculates file statistics for a given regular expression. See the Pattern Statistics section for more information. On method return, the pDataBuffer buffer is filled with calculated statistics values. Complexity: linear-time, depending on the file's size and regular expression complexity.
This method is obsole. Use the IFileDocument.PatternStatisticsRegExp2 instead.