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diff lisp/subr.el @ 4329:d9eb5ea14f65

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Provide %b in #'format; use it for converting between ints and bit vectors. lisp/ChangeLog addition: 2007-12-17 Aidan Kehoe <kehoea@parhasard.net> * subr.el (integer-to-bit-vector): New. * subr.el (bit-vector-to-integer): New. Provide naive implementations using the Lisp reader for these. src/ChangeLog addition: 2007-12-17 Aidan Kehoe <kehoea@parhasard.net> * doprnt.c (emacs_doprnt_1): Add support for formatted printing of both longs and bignums as base 2. * editfns.c (Fformat): Document the new %b escape for #'format. * lisp.h: Make ulong_to_bit_string available beside long_to_string. * lread.c: Fix a bug where the integer base was being ignored in certain contexts; thank you Sebastian Freundt. This is necessary for correct behaviour of #'integer-to-bit-vector and #'bit-vector-to-integer, just added to subr.el * print.c (ulong_to_bit_string): New. Analagous to long_to_string, but used all the time when %b is encountered, since we can't pass that to sprintf. man/ChangeLog addition: 2007-12-17 Aidan Kehoe <kehoea@parhasard.net> * lispref/strings.texi (Formatting Strings): Document %b for binary output.
author Aidan Kehoe <kehoea@parhasard.net>
date Mon, 17 Dec 2007 08:44:14 +0100
parents 66e2714696bd
children ef9eb714f0e4
line wrap: on
line diff
--- a/lisp/subr.el	Fri Dec 14 14:25:04 2007 +0100
+++ b/lisp/subr.el	Mon Dec 17 08:44:14 2007 +0100
@@ -913,6 +913,26 @@
 (define-function 'char-int 'char-to-int)
 (define-function 'int-char 'int-to-char)
 
+;; XEmacs addition.
+(defun integer-to-bit-vector (integer &optional minlength)
+  "Return INTEGER converted to a bit vector.
+Optional argument MINLENGTH gives a minimum length for the returned vector.
+If MINLENGTH is not given, zero high-order bits will be ignored."
+  (check-argument-type #'integerp integer)
+  (setq minlength (or minlength 0))
+  (check-nonnegative-number minlength)
+  (read (format (format "#*%%0%db" minlength) integer)))
+
+;; XEmacs addition.
+(defun bit-vector-to-integer (bit-vector)
+  "Return BIT-VECTOR converted to an integer.
+If bignum support is available, BIT-VECTOR's length is unlimited.
+Otherwise the limit is the number of value bits in an Lisp integer. "
+  (check-argument-type #'bit-vector-p bit-vector)
+  (setq bit-vector (prin1-to-string bit-vector))
+  (aset bit-vector 1 ?b)
+  (read bit-vector))
+
 (defun string-width (string)
   "Return number of columns STRING occupies when displayed.
 With international (Mule) support, uses the charset-columns attribute of