On Mon, Oct 08, 2018 at 01:25:31AM -0700, ToddAndMargo via perl6-users wrote: > Hi All! > > Question: I am using `read` to read the first 400 bytes of an unknown file > (could be a binary file). The 400 bytes go into a variable > of type "Buf". This is not a string. > > p6 'my $fh=open "/home/linuxutil/To", :r; my Buf $f = $fh.read( 400 ); > $fh.close;' > > Now in $f, I want to look at each byte one at a time for a > bitwise pattern using bitwise AND. > > How do I address each byte? > > `dd` seems to get me the information I need, but it prints it: > > $ p6 'my $fh=open "/home/linuxutil/To", :r; my Buf $f = $fh.read( 10 ); > $fh.close; dd $f;' > > Buf[uint8] $f = Buf[uint8].new(87,111,114,100,80,114,111,0,0,0) > > An array of bytes would be great.
Point a browser at https://docs.perl6.org/ and click on "Types" in the top ribbon. You will see a list of all the Perl 6 built-in types; "Buf" is there near the top. Click on "Buf". Now there are two clues as to what you want: one of them is that the table of contents on the left has a section "Routines supplied by role Positional", and the other one is that the very first example has a line saying "$b[1] = 42". So you can use a Buf object as an array of whatever it contains. G'luck, Peter -- Peter Pentchev roam@{ringlet.net,debian.org,FreeBSD.org} p...@storpool.com PGP key: http://people.FreeBSD.org/~roam/roam.key.asc Key fingerprint 2EE7 A7A5 17FC 124C F115 C354 651E EFB0 2527 DF13
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