On a related note, I found something else in kernel/FileDescr.st:
copyFrom: from to: to
"Answer the contents of the file between the two given positions"
| offset fromPos toPos savePos |
from > to ifTrue: [
from = to + 1 ifTrue: [ ^self species new ].
^SystemExceptions.ArgumentOutOfRange signalOn: from mustBeBetween: 1
and: to + 1
].
savePos := self fileOp: 5.
^[
self position: fromPos.
self next: toPos - fromPos + 1
] ensure: [
self position: savePos
]
How do offset, fromPos, and toPos get set in this method?