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* numbers.c (scm_mkbig): Add cast, and note that signed/unsigned

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comparison is okay here.
* numbers.c (scm_istr2int): Add cast; len is known to be positive.
* numbers.c (scm_bigcomp): Clarify logic, and avoid relying on the
(true, but confusing) fact that -1 == ((unsigned) 0 - 1).
* numbers.c (scm_adjbig): Make nsiz an scm_sizet, to avoid mixing
signed/unsigned.
This commit is contained in:
Jim Blandy 1998-09-06 18:15:59 +00:00
parent c7023c693a
commit 2bf746cc9f
1 changed files with 43 additions and 14 deletions
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47
libguile/numbers.c
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@ -712,7 +712,8 @@ scm_mkbig(nlen, sign)
int sign;
{
SCM v = nlen;
if (((v << 16) >> 16) != nlen)
/* Cast to SCM to avoid signed/unsigned comparison warnings. */
if (((v << 16) >> 16) != (SCM) nlen)
scm_wta(SCM_MAKINUM(nlen), (char *)SCM_NALLOC, s_bignum);
SCM_NEWCELL(v);
SCM_DEFER_INTS;
@ -746,13 +747,21 @@ scm_adjbig(b, nlen)
SCM b;
scm_sizet nlen;
{
long nsiz = nlen;
if (((nsiz << 16) >> 16) != nlen) scm_wta(SCM_MAKINUM(nsiz), (char *)SCM_NALLOC, s_adjbig);
scm_sizet nsiz = nlen;
if (((nsiz << 16) >> 16) != nlen)
scm_wta (scm_ulong2num (nsiz), (char *)SCM_NALLOC, s_adjbig);
SCM_DEFER_INTS;
SCM_SETCHARS(b, (SCM_BIGDIG *)scm_must_realloc((char *)SCM_CHARS(b),
{
SCM_BIGDIG *digits
= ((SCM_BIGDIG *)
scm_must_realloc((char *)SCM_CHARS(b),
(long)(SCM_NUMDIGS(b)*sizeof(SCM_BIGDIG)),
(long)(nsiz*sizeof(SCM_BIGDIG)), s_adjbig));
SCM_SETCHARS (b, digits);
SCM_SETNUMDIGS (b, nsiz, SCM_TYP16(b));
}
SCM_ALLOW_INTS;
return b;
}
@ -903,16 +912,34 @@ scm_bigcomp(x, y)
int xsign = SCM_BIGSIGN(x);
int ysign = SCM_BIGSIGN(y);
scm_sizet xlen, ylen;
/* Look at the signs, first. */
if (ysign < xsign) return 1;
if (ysign > xsign) return -1;
if ((ylen = SCM_NUMDIGS(y)) > (xlen = SCM_NUMDIGS(x))) return (xsign) ? -1 : 1;
/* They're the same sign, so see which one has more digits. Note
that, if they are negative, the longer number is the lesser. */
ylen = SCM_NUMDIGS(y);
xlen = SCM_NUMDIGS(x);
if (ylen > xlen)
return (xsign) ? -1 : 1;
if (ylen < xlen) return (xsign) ? 1 : -1;
while(xlen-- && (SCM_BDIGITS(y)[xlen]==SCM_BDIGITS(x)[xlen]));
if (-1==xlen) return 0;
/* They have the same number of digits, so find the most significant
digit where they differ. */
while (xlen)
{
--xlen;
if (SCM_BDIGITS (y)[xlen] != SCM_BDIGITS (x)[xlen])
/* Make the discrimination based on the digit that differs. */
return (SCM_BDIGITS(y)[xlen] > SCM_BDIGITS(x)[xlen]) ?
(xsign ? -1 : 1) : (xsign ? 1 : -1);
}
/* The numbers are identical. */
return 0;
}
#ifndef SCM_DIGSTOOBIG
@ -1550,7 +1577,9 @@ scm_istr2int(str, len, radix)
else j = 1+(len*sizeof(char))/(SCM_BITSPERDIG);
switch (str[0]) { /* leading sign */
case '-':
case '+': if (++i==len) return SCM_BOOL_F; /* bad if lone `+' or `-' */
case '+':
if (++i==(unsigned) len)
return SCM_BOOL_F; /* bad if lone `+' or `-' */
}
res = scm_mkbig(j, '-'==str[0]);
ds = SCM_BDIGITS(res);
@ -1583,7 +1612,7 @@ scm_istr2int(str, len, radix)
default:
return SCM_BOOL_F; /* not a digit */
}
} while (i < len);
} while (i < (unsigned) len);
if (blen * SCM_BITSPERDIG/SCM_CHAR_BIT <= sizeof(SCM))
if SCM_INUMP(res = scm_big2inum(res, blen)) return res;
if (j==blen) return res;