Class: ByteString
Description
This method extracts a portion of a ByteString based on a specified first and last byte position to extract.
Because both the first and the last position are expressed as byte offsets, the resulting substring may no longer represent a valid character String, even if the source did represent a valid String (e.g. as obtained by String.toByteString()). Either the first or the last character of the source may have been "cut in halves".
Use ByteString.extract() if you want a sequence of bytes with exactly to-from +1 bytes (assuming from>0 and to'>byteString.length(). If you want to be sure that substrings are character aligned consider using String.extract() or String.byteLimitSubstring().
Syntax
ByteString.extract(Number from,Number to)
Parameters
|
from |
The first byte in the string to extract. The default is 1. |
|
to |
The last byte in the string to extract. The default is the value in the from parameter. |
Returns
A ByteString that is a substring of the source ByteString.
When Became Available
Profile V7.0
Example #1
type RecordCIFSIG cifsig = Db.getRecord("CIFSIG","ACN=:ACN")
type ByteString SIG = cifsig.sig.toByteString()
type ByteString CHUNK = SIG.extract(1,450)
*ACN must be defined prior to the getRecord statement
Example #2
type String STR = "Knäckebröd"
type ByteString BST = STR.toByteString()
//
// get first three byres (cuts the ä in halves)
type ByteString XTR = BST.extract(1,3)
type String ERROR = {String}XTR // may throw runtime exception !!