nibbles

nibbles is a library for accessing multibyte integers from octet arrays and streams. While such accessors are straightforward to write, nibbles aims to centralize such facilities and also provide optimizations for them when appropriate.

Installation

nibbles can be downloaded at http://www.method-combination.net/lisp/files/nibbles.tar.gz. The latest version is 0.9.

It comes with an ASDF system definition, so (ASDF:OOS 'ASDF:LOAD-OP :NIBBLES) should be all that you need to get started.

License

nibbles is released under a MIT-like license; you can do pretty much anything you want to with the code except claim that you wrote it.

Integer array accessors

ub16ref/le vector index => value
ub32ref/le vector index => value
ub64ref/le vector index => value

This family of functions accesses an unsigned 16-bit, 32-bit or 64-bit value stored in little-endian order starting at index in vector. vector must be a (VECTOR (UNSIGNED-BYTE 8)). These functions are SETFable. For instance:

CL-USER> (nibbles:ub16ref/le (coerce #(42 53) '(vector (unsigned-byte 8))) 0)
13610
CL-USER> (format nil "~X" *)
"352A"

ub16ref/be vector index => value
ub32ref/be vector index => value
ub64ref/be vector index => value

As the above, only the value is accessed in big-endian order. For instance:

CL-USER> (nibbles:ub16ref/be (coerce #(42 53) '(vector (unsigned-byte 8))) 0)
10805
CL-USER> (format nil "~X" *)
"2A35"

sb16ref/le vector index => value
sb32ref/le vector index => value
sb64ref/le vector index => value

sb16ref/be vector index => value
sb32ref/be vector index => value
sb64ref/be vector index => value

As the above, only the value accessed is a signed value. For instance:

CL-USER> (nibbles:sb16ref/be (coerce #(81 92) '(vector (unsigned-byte 8))) 0)
20828
CL-USER> (nibbles:sb16ref/be (coerce #(129 135) '(vector (unsigned-byte 8))) 0)
-32377
CL-USER> (format nil "~X ~X" ** *)
"515C -7E79"
CL-USER> (nibbles:sb16ref/le (coerce #(81 92) '(vector (unsigned-byte 8))) 0)
23633
CL-USER> (nibbles:sb16ref/le (coerce #(129 135) '(vector (unsigned-byte 8))) 0)
-30847
CL-USER> (format nil "~X ~X" ** *)
"5C51 -787F"

Stream readers

read-ub16/le stream => value
read-ub32/le stream => value
read-ub64/le stream => value

This family of functions reads an unsigned 16-bit, 32-bit, or 64-bit value from stream in little-endian order. stream must have an element-type of (UNSIGNED-BYTE 8).

read-ub16/be stream => value
read-ub32/be stream => value
read-ub64/be stream => value

As the above, only the value is read in big-endian order.

read-sb16/le stream => value
read-sb32/le stream => value
read-sb64/le stream => value

read-sb16/be stream => value
read-sb32/be stream => value
read-sb64/be stream => value

As the above, only the value is signed, rather than unsigned.

Stream writers

write-ub16/le integer stream => value
write-ub32/le integer stream => value
write-ub64/le integer stream => value

This family of functions writes an unsigned 16-bit, 32-bit, or 64-bit integer to stream in little-endian order. stream must have an element-type of (UNSIGNED-BYTE 8). The value written is returned.

write-ub16/be integer stream => value
write-ub32/be integer stream => value
write-ub64/be integer stream => value

As the above, only the value is read in big-endian order.

write-sb16/le integer stream => value
write-sb32/le integer stream => value
write-sb64/le integer stream => value

write-sb16/be integer stream => value
write-sb32/be integer stream => value
write-sb64/be integer stream => value

As the above, only the value is signed, rather than unsigned.