At Tue, 6 Mar 2012 17:12:02 +0000,
Stuart Henderson wrote:
>
> On 2012/03/07 01:00, AIDA Shinra wrote:
> > Hi,
> >
> > I found the e() and l() in the bc(1) math library are not
> > precise. Their scaling algorithms are wrong.
> >
> > In addition, BSD bc evaluates length(0.000) to 1 instead of 3.
> > Such a behaviour will surprise people who expect that
> > length(x) >= scale(x). While POSIX is silent, the GNU bc returns 3.
> >
> > The attached patches fix them. They also enable the editline in the
> > intaractive "bc -d".
> >
> > See also:
> > http://www.FreeBSD.org/cgi/query-pr.cgi?pr=bin/159227
> >
> > Regards,
> > shinra
> >
> > [demime 1.01d removed an attachment of type application/octet-stream]
> >
> > [demime 1.01d removed an attachment of type application/octet-stream]
> >
>
> Please send your diffs inline in the email body (diff -u format).
> Thanks!
Sorry, the patches follow:
Index: bc.library
===================================================================
RCS file: /cvs/src/usr.bin/bc/bc.library,v
retrieving revision 1.3
diff -u -r1.3 bc.library
--- bc.library 3 Feb 2007 21:15:06 -0000 1.3
+++ bc.library 6 Mar 2012 14:20:40 -0000
@@ -45,7 +45,9 @@
r = ibase
ibase = A
t = scale
- scale = t + .434*x + 1
+ scale = 0
+ if (x > 0) scale = (0.435*x)/1
+ scale = scale + t + 1
w = 0
if (x < 0) {
@@ -94,26 +96,33 @@
t = scale
f = 1
- scale = scale + scale(x) - length(x) + 1
- s = scale
+ if (x < 1) {
+ s = scale(x)
+ } else {
+ s = length(x)-scale(x)
+ }
+ scale = 0
+ a = (2.31*s)/1 /* estimated integer part of the answer */
+ s = t + length(a) + 2 /* estimated length of the answer */
while (x > 2) {
- s = s + (length(x) - scale(x))/2 + 1
- if (s > 0) scale = s
+ scale=0
+ scale = (length(x) + scale(x))/2 + 1
+ if (scale < s) scale = s
x = sqrt(x)
f = f*2
}
while (x < .5) {
- s = s + (length(x) - scale(x))/2 + 1
- if (s > 0) scale = s
+ scale = 0
+ scale = scale(x)/2 + 1
+ if (scale < s) scale = s
x = sqrt(x)
f = f*2
}
- scale = t + length(f) - scale(f) + 1
+ scale = t + length(f) + length(t + length(f)) + 1
u = (x - 1)/(x + 1)
-
- scale = scale + 1.1*length(t) - 1.1*scale(t)
s = u*u
+ scale = t + 2
b = 2*f
c = b
d = 1
Index: bc.y
===================================================================
RCS file: /cvs/src/usr.bin/bc/bc.y,v
retrieving revision 1.40
diff -u -r1.40 bc.y
--- bc.y 6 Oct 2011 14:37:56 -0000 1.40
+++ bc.y 6 Mar 2012 14:20:40 -0000
@@ -45,6 +45,7 @@
#include <string.h>
#include <termios.h>
#include <unistd.h>
+#include <stdlib.h>
#include "extern.h"
#include "pathnames.h"
@@ -1144,19 +1145,6 @@
dup(p[1]);
close(p[0]);
close(p[1]);
- if (interactive) {
- gettty(&ttysaved);
- el = el_init("bc", stdin, stderr, stderr);
- hist = history_init();
- history(hist, &he, H_SETSIZE, 100);
- el_set(el, EL_HIST, history, hist);
- el_set(el, EL_EDITOR, "emacs");
- el_set(el, EL_SIGNAL, 0);
- el_set(el, EL_PROMPT, dummy_prompt);
- el_set(el, EL_ADDFN, "bc_eof", "", bc_eof);
- el_set(el, EL_BIND, "^D", "bc_eof", NULL);
- el_source(el, NULL);
- }
} else {
close(STDIN_FILENO);
dup(p[0]);
@@ -1165,6 +1153,19 @@
execl(_PATH_DC, "dc", "-x", (char *)NULL);
err(1, "cannot find dc");
}
+ }
+ if (interactive) {
+ gettty(&ttysaved);
+ el = el_init("bc", stdin, stderr, stderr);
+ hist = history_init();
+ history(hist, &he, H_SETSIZE, 100);
+ el_set(el, EL_HIST, history, hist);
+ el_set(el, EL_EDITOR, "emacs");
+ el_set(el, EL_SIGNAL, 0);
+ el_set(el, EL_PROMPT, dummy_prompt);
+ el_set(el, EL_ADDFN, "bc_eof", "", bc_eof);
+ el_set(el, EL_BIND, "^D", "bc_eof", NULL);
+ el_source(el, NULL);
}
yywrap();
return yyparse();
Index: bcode.c
===================================================================
RCS file: /cvs/src/usr.bin/dc/bcode.c,v
retrieving revision 1.41
diff -u -r1.41 bcode.c
--- bcode.c 15 May 2010 10:59:29 -0000 1.41
+++ bcode.c 6 Mar 2012 14:25:38 -0000
@@ -682,7 +682,7 @@
u_int i;
if (BN_is_zero(n->number))
- return 1;
+ return n->scale ? n->scale : 1;
int_part = new_number();
fract_part = new_number();
