38 lines
1.5 KiB
Racket
38 lines
1.5 KiB
Racket
(module windlldir mzscheme
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(require mzlib/port
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"winutf16.rkt")
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(provide update-dll-dir
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get-current-dll-dir)
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(define label (byte-regexp (bytes->utf-16-bytes #"dLl dIRECTORy:")))
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(define max-dir-len (* 512 2)) ; sizeof(wchar_t) is 2
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(define (update-dll-dir dest path)
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(let ([path-bytes (bytes->utf-16-bytes
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(cond [(eq? path #t) #"<system>"]
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[(path? path) (path->bytes path)]
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[else (string->bytes/locale path)]))])
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(unless ((bytes-length path-bytes) . <= . max-dir-len)
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(error 'update-dll-dir "path too long: ~e" path))
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(let ([m (with-input-from-file dest
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(lambda ()
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(regexp-match-positions label (current-input-port))))])
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(unless m
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(error 'update-ddl-dir "cannot find DLL path in file: ~e" dest))
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(with-output-to-file dest
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(lambda ()
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(file-position (current-output-port) (cdar m))
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(write-bytes path-bytes)
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(write-byte 0))
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'update))))
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(define (get-current-dll-dir dest)
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(with-input-from-file dest
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(lambda ()
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(unless (regexp-match label (current-input-port))
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(error 'get-current-dll-dir "cannot find DLL path in file: ~e" dest))
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(let ([p (make-limited-input-port (current-input-port) max-dir-len)])
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(let ([m (regexp-match #rx#"(?:[^\0].|.[^\0])*" p)])
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(bytes->path (utf-16-bytes->bytes (car m)))))))))
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