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trim the length of unsized numbers.

This commit is contained in:
steve 2001-02-08 05:38:18 +00:00
parent d78c7392c2
commit 4b0e5bd173
1 changed files with 60 additions and 4 deletions
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64
verinum.cc
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@ -17,7 +17,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#if !defined(WINNT) && !defined(macintosh)
#ident "$Id: verinum.cc,v 1.24 2001/02/07 21:47:13 steve Exp $"
#ident "$Id: verinum.cc,v 1.25 2001/02/08 05:38:18 steve Exp $"
#endif
# include "verinum.h"
@ -269,6 +269,59 @@ bool verinum::is_defined() const
return true;
}
/*
* This function returns a version of the verinum that has only as
* many bits as are needed to accurately represent the value. It takes
* into account the signedness of the value.
*
* If the input value has a definite length, then that value is just
* returned as is.
*/
static verinum trim_vnum(const verinum&that)
{
unsigned tlen;
if (that.has_len())
return that;
if (that.len() < 2)
return that;
if (that.has_sign()) {
unsigned top = that.len()-1;
verinum::V sign = that.get(top);
while ((top > 0) && (that.get(top) == sign))
top -= 1;
/* top points to the first digit that is not the
sign. Set the length to include this and one proper
sign bit. */
if (that.get(top) != sign)
top += 1;
tlen = top+1;
} else {
/* If the result is unsigned and has an indefinite
length, then trim off leading zeros. */
tlen = 1;
for (unsigned idx = tlen ; idx < that.len() ; idx += 1)
if (that.get(idx) != verinum::V0)
tlen = idx;
}
verinum tmp (verinum::V0, tlen, false);
tmp.has_sign(that.has_sign());
for (unsigned idx = 0 ; idx < tmp.len() ; idx += 1)
tmp.set(idx, that.get(idx));
return tmp;
}
ostream& operator<< (ostream&o, verinum::V v)
{
switch (v) {
@ -537,6 +590,7 @@ verinum operator * (const verinum&left, const verinum&right)
}
verinum result(verinum::V0, left.len() + right.len(), has_len_flag);
result.has_sign(left.has_sign() || right.has_sign());
for (unsigned rdx = 0 ; rdx < right.len() ; rdx += 1) {
@ -551,8 +605,7 @@ verinum operator * (const verinum&left, const verinum&right)
}
}
result.has_sign(left.has_sign() || right.has_sign());
return result;
return trim_vnum(result);
}
/*
@ -609,7 +662,7 @@ verinum operator / (const verinum&left, const verinum&right)
}
}
return result;
return trim_vnum(result);
}
verinum operator % (const verinum&left, const verinum&right)
@ -690,6 +743,9 @@ verinum::V operator & (verinum::V l, verinum::V r)
/*
* $Log: verinum.cc,v $
* Revision 1.25 2001/02/08 05:38:18 steve
* trim the length of unsized numbers.
*
* Revision 1.24 2001/02/07 21:47:13 steve
* Fix expression widths for rvalues and parameters (PR#131,132)
*