8.12
2 Integers
| (require binaryio/integer) | package: binaryio-lib |
procedure
(integer->bytes val size signed? [ big-endian? dest start]) → bytes? val : exact-integer? size : exact-positive-integer? signed? : boolean? big-endian? : boolean? = #t dest : (and/c bytes? (not/c mutable?)) = (make-bytes size) start : exact-nonnegative-integer? = 0
Like integer->integer-bytes, except that arbitrary
size arguments are supported, and big-endian?
defaults to #t (network byte order) rather than the host byte
order.
Examples:
> (integer->bytes -1 3 #t) #"\377\377\377"
> (integer->bytes (expt 23 31) 18 #f) #"\22\305U2\375\302\332\26_\5\6\235q\30~\253\6\247"
procedure
(bytes->integer bstr signed? [ big-endian? start end]) → exact-integer? bstr : bytes? signed? : boolean? big-endian? : boolean? = #t start : exact-nonnegative-integer? = 0 end : exact-nonnegative-integer? = (bytes-length bstr)
Like integer-bytes->integer, except that arbitrary
sizes—
procedure
(integer-bytes-length val signed?) → exact-nonnegative-integer?
val : exact-integer? signed? : boolean?
Returns the number of bytes needed to encode val, including
the sign bit if signed? is true.
Examples:
> (integer-bytes-length 127 #t) 1
> (integer-bytes-length 128 #t) 2
procedure
(integer-bytes-length<=? val nbytes signed?) → boolean?
val : exact-integer? nbytes : exact-nonnegative-integer? signed? : boolean?
Equivalent to (<= (integer-bytes-length val signed?) nbytes),
but can be faster for small values of nbytes.
procedure
(write-integer val size signed? [ out big-endian?]) → void? val : exact-integer? size : exact-positive-integer? signed? : boolean? out : output-port? = (current-output-port) big-endian? : boolean? = #t
Writes the encoding of val to out.
Equivalent to (write-bytes (integer->bytes val size signed? big-endian?) out).
procedure
(read-integer size signed? [in big-endian?]) → exact-integer?
size : exact-positive-integer? signed? : boolean? in : input-port? = (current-input-port) big-endian? : boolean? = #t
Reads size bytes from in and decodes it as an
integer. If fewer than size bytes are available before the
end of input, an error is raised.
Equivalent to (bytes->integer (read-bytes* size in) signed? big-endian?).