24 lines
671 B
Scheme
24 lines
671 B
Scheme
(library
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(crc32)
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(export crc32)
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(import (chezscheme))
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(load-shared-object "libz.so")
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(define crc32
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(foreign-procedure "crc32" (unsigned-long u8* unsigned-int) unsigned-long))
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(define crc32-combine
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(foreign-procedure "crc32_combine" (unsigned-long unsigned-long unsigned-long) unsigned-long))
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;; FIXME: stop copying the bytevector. I'm not sure how to pass an offset
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;; into the bv.
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(define (crc32-region salt bv start end)
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(assert (< start end))
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(let ((len (- end start)))
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(let ((copy (make-bytevector len)))
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(bytevector-copy! bv start copy 0 len)
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(let ((crc (crc32 salt copy 0)))
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(crc32 crc copy len))))))
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