Doing things 4 bytes at a time. Leaner and somewhat faster.
The improvement is greatest if the file size is a multiple of 4.
read =: 1!:1
write =: 1!:2
scramble =: verb define
((128 (23 b.) a. i. read <y) { a. ) write <y,'.scrambled'
)
mask=: {. _2 (3!:4) 4$128{a.
scramble1=: 3 : 0
if. 4|#t=. read <y do.
((#t) {. mask&(23 b.)&.(_2&(3!:4)) t,(4|-#t)$'a') write <y,'.scrambled'
else.
( mask&(23 b.)&.(_2&(3!:4)) t ) write <y,'.scrambled'
end.
)
t=: read <'\j601\j.dll'
#t
1314816
t write <'\junk\foo'
(t,x) write <'\junk\foox'
ts=: 6!:2 , 7!:[EMAIL PROTECTED]
ts 'scramble ''\junk\foo'''
0.0657209 2.0975e7
ts 'scramble1 ''\junk\foo'''
0.0439592 6.2953e6
ts 'scramble ''\junk\foox'''
0.0669867 2.09751e7
ts 'scramble1 ''\junk\foox'''
0.0500449 8.39341e6
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