I humbly submit this question, but these two hold great confusion for me. Especially when mixed with fileIO and implicit conversions.

Given, I have 'slurped' this (hex dumped) data into a scalar:

00000000  d0 cf 11 e0 a1 b1 1a e1  00 00 00 00 00 00 00 00  |.........
+.......|
00000010  00 00 00 00 00 00 00 00  3e 00 03 00 fe ff 09 00  |........>
+.......|
00000020  06 00 00 00 00 00 00 00  00 00 00 00 01 00 00 00  |.........
+.......|
00000030  38 00 00 00 00 00 00 00  00 10 00 00 3a 00 00 00  |8........
+...:...|
00000040  01 00 00 00 fe ff ff ff  00 00 00 00 37 00 00 00  |.........
+...7...|
00000050  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |.........
+.......|

[download]
I wish to repeatedly extract 4 bytes, and interpret them as a signed (little-endian) integer; stopping when I find a value of -1.

I have attempted using a 'substr' in a loop indexed +4 for extraction; then packing the restult as an 'i'. But I don't seem to find an operation that results in 3759263696 for the first 4 bytes.

--UPDATE I got some results; not what I had expected, but not necessarily wrong, with: 

@r = unpack "i30" , $doc;
print join (",",@r);
----
-535703600,-518344287,0,0,0,0,196670,655358,6,0,0,1,56,0,4096,58,1,-2,
+0,55,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1

[download]
Upon reflection, this is probably correct, and just what I needed.

In reply to To 'pack' or 'unpack' that is the question by Wiggins

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