CyberSoft CVDL Tutorial

by Rick Perry
16 September 2001

Table of Contents
1. Introduction 2. VDL Format 3. String and Logic Examples 4. XOR and NOT 5. Concatenation and Offsets 6. White space 7. Absolute Offsets 8. Phone Numbers 9. Digits 10.Only Digits 11.| (Low-level Or)	12.Byte Expressions 13.Fuzzy Expressions 14.Repetition Expressions 15.Defining VDL Macros 16.Using VDL Macros 17.VDL Macro Examples 18.File Type Restriction Directives 19.File Type Restriction Examples 20.VDL Version Reporting 21.VFind --vdlc= Option 22.CVDL Syntax Summary

5. Concatenation and Offsets

VDL pattern elements are concatenated into larger patterns by using a comma, for example:

  "abc", "def"

is the same as:

  "abcdef"

• In a VDL definition the comma means followed by.

You can specify an offset range for concatenation of strings and other VDL patterns using the @ operator, for example:

  "abc", @0-10, "def"

will match "abc" followed by "def" at an offset of anywhere from 0 to 10 bytes from the end of "abc". So this will match "abcdef", "abcXdef", ..., "abcXXXXXXXXXXdef", where X represents any byte.

Listen to the Audio (Quicktime required)

Previous | Next

Back