26 lines
937 B
Plaintext
26 lines
937 B
Plaintext
[This file and the accompanying source code were derived from
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Oleg's code for Gambit available from
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http://okmij.org/ftp/Scheme/index.html#binio
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]
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(make-bit-reader byte-reader) -> bit-reader
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Given a BYTE-READER (a thunk), construct and return a function
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(bit-reader N) -> integer
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that reads N bits from a byte-stream represented by the BYTE-READER.
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The BYTE-READER is a function that takes no arguments and returns
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the current byte as an exact integer [0-255]. The byte reader
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should return #f on EOF.
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The bit reader returns N bits as an exact unsigned integer,
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0 -... (no limit). N must be a positive integer, otherwise the bit reader
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returns #f. There is no upper limit on N -- other than the size of the
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input stream itself and the amount of (virtual) memory an OS is willing
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to give to your process. If you want to read 1M of _bits_, go ahead.
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It is assumed that the bit order is the most-significant bit first.
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