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authorshigek <shigek@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2003-08-08 15:31:27 +0000
committershigek <shigek@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2003-08-08 15:31:27 +0000
commit606c473683f53af6be614bec8fdb5c7a7d0e974d (patch)
tree0cba50faca21fbf04a9951aa7a4218b00447bdc5
parent0a0c87bb1204096c0fa28627340771fe88ca0d3b (diff)
F style output(like 1234.56789) implemented to to_s method.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@4356 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
-rw-r--r--ext/bigdecimal/bigdecimal.c297
-rw-r--r--ext/bigdecimal/bigdecimal.h5
-rw-r--r--ext/bigdecimal/bigdecimal_en.html36
-rw-r--r--ext/bigdecimal/bigdecimal_ja.html37
4 files changed, 267 insertions, 108 deletions
diff --git a/ext/bigdecimal/bigdecimal.c b/ext/bigdecimal/bigdecimal.c
index 8f0ab8bd67..e850fbd047 100644
--- a/ext/bigdecimal/bigdecimal.c
+++ b/ext/bigdecimal/bigdecimal.c
@@ -197,7 +197,7 @@ BigDecimal_dump(int argc, VALUE *argv, VALUE self)
rb_scan_args(argc, argv, "01", &dummy);
GUARD_OBJ(vp,GetVpValue(self,1));
sprintf(sz,"%lu:",VpMaxPrec(vp)*VpBaseFig());
- psz = ALLOCA_N(char,(unsigned int)VpNumOfChars(vp)+strlen(sz));
+ psz = ALLOCA_N(char,(unsigned int)VpNumOfChars(vp,"E")+strlen(sz));
sprintf(psz,"%s",sz);
VpToString(vp, psz+strlen(psz), 0);
return rb_str_new2(psz);
@@ -233,13 +233,17 @@ BigDecimal_mode(VALUE self, VALUE which, VALUE val)
{
unsigned long f,fo;
- if(TYPE(which)!=T_FIXNUM) return Qnil;
+ Check_Type(which, T_FIXNUM);
f = (unsigned long)FIX2INT(which);
- if(f&VP_EXCEPTION_ALL) {
+ if(f&VP_EXCEPTION_ALL) {
/* Exception mode setting */
fo = VpGetException();
- if(val!=Qfalse && val!=Qtrue) return Qnil;
+ if(val==Qnil) return INT2FIX(fo);
+ if(val!=Qfalse && val!=Qtrue) {
+ rb_raise(rb_eTypeError, "The second argument must be true or false.");
+ return Qnil; /* Not reached */
+ }
if(f&VP_EXCEPTION_INFINITY) {
VpSetException((unsigned short)((val==Qtrue)?(fo|VP_EXCEPTION_INFINITY):
(fo&(~VP_EXCEPTION_INFINITY))));
@@ -248,14 +252,22 @@ BigDecimal_mode(VALUE self, VALUE which, VALUE val)
VpSetException((unsigned short)((val==Qtrue)?(fo|VP_EXCEPTION_NaN):
(fo&(~VP_EXCEPTION_NaN))));
}
+ fo = VpGetException();
return INT2FIX(fo);
}
if(VP_ROUND_MODE==f) {
/* Rounding mode setting */
- if(TYPE(val)!=T_FIXNUM) return Qnil;
+ fo = VpGetRoundMode();
+ if(val==Qnil) return INT2FIX(fo);
+ Check_Type(val, T_FIXNUM);
+ if(!VpIsRoundMode(FIX2INT(val))) {
+ rb_raise(rb_eTypeError, "Invalid rounding mode.");
+ return Qnil;
+ }
fo = VpSetRoundMode((unsigned long)FIX2INT(val));
return INT2FIX(fo);
}
+ rb_raise(rb_eTypeError, "The first argument for BigDecimal#mode is invalid.");
return Qnil;
}
@@ -919,13 +931,14 @@ BigDecimal_round(int argc, VALUE *argv, VALUE self)
Check_Type(vLoc, T_FIXNUM);
iLoc = FIX2INT(vLoc);
break;
- case 2:{
- int sws = sw;
+ case 2:
Check_Type(vLoc, T_FIXNUM);
iLoc = FIX2INT(vLoc);
Check_Type(vRound, T_FIXNUM);
- sw = VpSetRoundMode(FIX2INT(vRound));
- VpSetRoundMode(sws);
+ sw = FIX2INT(vRound);
+ if(!VpIsRoundMode(sw)) {
+ rb_raise(rb_eTypeError, "Invalid rounding mode.");
+ return Qnil;
}
break;
}
@@ -1024,20 +1037,45 @@ static VALUE
BigDecimal_to_s(int argc, VALUE *argv, VALUE self)
{
ENTER(5);
- Real *vp;
- char *psz;
+ int fmt=0; /* 0:E format */
+ Real *vp;
+ char *psz;
+ char ch;
U_LONG nc;
- S_INT mc = 0;
- VALUE f;
+ S_INT mc = 0;
+ VALUE f;
GUARD_OBJ(vp,GetVpValue(self,1));
- nc = VpNumOfChars(vp)+1;
+
if(rb_scan_args(argc,argv,"01",&f)==1) {
- mc = GetPositiveInt(f);
- nc += (nc + mc - 1) / mc + 1;
+ if(TYPE(f)==T_STRING) {
+ SafeStringValue(f);
+ psz = RSTRING(f)->ptr;
+ while(ch=*psz++) {
+ if(!ISDIGIT(ch)) {
+ if(ch=='F' || ch=='f') fmt = 1; /* F format */
+ break;
+ }
+ mc = mc * 10 + ch - '0';
+ }
+ } else {
+ mc = GetPositiveInt(f);
+ }
+ if(fmt) {
+ nc = VpNumOfChars(vp,"F");
+ } else {
+ nc = VpNumOfChars(vp,"E");
+ }
+ if(mc>0) nc += (nc + mc - 1) / mc + 1;
}
+
psz = ALLOCA_N(char,(unsigned int)nc);
- VpToString(vp, psz, mc);
+
+ if(fmt) {
+ VpToFString(vp, psz, mc);
+ } else {
+ VpToString (vp, psz, mc);
+ }
return rb_str_new2(psz);
}
@@ -1052,7 +1090,7 @@ BigDecimal_split(VALUE self)
char *psz1;
GUARD_OBJ(vp,GetVpValue(self,1));
- psz1 = ALLOCA_N(char,(unsigned int)VpNumOfChars(vp));
+ psz1 = ALLOCA_N(char,(unsigned int)VpNumOfChars(vp,"E"));
VpSzMantissa(vp,psz1);
s = 1;
if(psz1[0]=='-') {
@@ -1087,7 +1125,7 @@ BigDecimal_inspect(VALUE self)
char *pszAll;
GUARD_OBJ(vp,GetVpValue(self,1));
- nc = VpNumOfChars(vp);
+ nc = VpNumOfChars(vp,"E");
nc +=(nc + 9) / 10;
psz1 = ALLOCA_N(char,nc);
@@ -1298,7 +1336,7 @@ Init_bigdecimal(void)
rb_define_const(rb_cBigDecimal, "SIGN_NEGATIVE_INFINITE",INT2FIX(VP_SIGN_NEGATIVE_INFINITE));
/* instance methods */
- rb_define_method(rb_cBigDecimal, "prec", BigDecimal_prec, 0);
+ rb_define_method(rb_cBigDecimal, "precs", BigDecimal_prec, 0);
rb_define_method(rb_cBigDecimal, "add", BigDecimal_add2, 2);
rb_define_method(rb_cBigDecimal, "sub", BigDecimal_sub2, 2);
rb_define_method(rb_cBigDecimal, "mult", BigDecimal_mult2, 2);
@@ -1478,14 +1516,21 @@ VpGetRoundMode(void)
return gfRoundMode;
}
-VP_EXPORT unsigned long
-VpSetRoundMode(unsigned long n)
+VP_EXPORT int
+VpIsRoundMode(unsigned long n)
{
if(n==VP_ROUND_UP || n!=VP_ROUND_DOWN ||
n==VP_ROUND_HALF_UP || n!=VP_ROUND_HALF_DOWN ||
n==VP_ROUND_CEIL || n!=VP_ROUND_FLOOR ||
n==VP_ROUND_HALF_EVEN
- ) gfRoundMode = n;
+ ) return 1;
+ return 0;
+}
+
+VP_EXPORT unsigned long
+VpSetRoundMode(unsigned long n)
+{
+ if(VpIsRoundMode(n)) gfRoundMode = n;
return gfRoundMode;
}
@@ -1630,13 +1675,13 @@ raise:
static int
VpIsDefOP(Real *c,Real *a,Real *b,int sw)
{
- if(VpIsNaN(a) || VpIsNaN(b)) {
+ if(VpIsNaN(a) || VpIsNaN(b)) {
/* at least a or b is NaN */
VpSetNaN(c);
goto NaN;
- }
+ }
- if(VpIsInf(a)) {
+ if(VpIsInf(a)) {
if(VpIsInf(b)) {
switch(sw)
{
@@ -1686,7 +1731,7 @@ VpIsDefOP(Real *c,Real *a,Real *b,int sw)
VpSetInf(c,VpGetSign(a)*VpGetSign(b));
}
goto Inf;
- }
+ }
if(VpIsInf(b)) {
switch(sw)
@@ -1722,14 +1767,35 @@ NaN:
*/
/*
- * returns number of chars needed to represent vp.
+ * returns number of chars needed to represent vp in specified format.
*/
VP_EXPORT U_LONG
-VpNumOfChars(Real *vp)
+VpNumOfChars(Real *vp,char *pszFmt)
{
+ S_INT ex;
+ U_LONG nc;
+
if(vp == NULL) return BASE_FIG*2+6;
if(!VpIsDef(vp)) return 32; /* not sure,may be OK */
- return BASE_FIG *(vp->Prec + 2)+6; /* 3: sign + exponent chars */
+
+ switch(*pszFmt)
+ {
+ case 'F':
+ nc = BASE_FIG*(vp->Prec + 1)+2;
+ ex = vp->exponent;
+ if(ex<0) {
+ nc += BASE_FIG*(-ex);
+ } else {
+ if(ex > (S_INT)vp->Prec) {
+ nc += BASE_FIG*(ex - (S_INT)vp->Prec);
+ }
+ }
+ break;
+ case 'E':
+ default:
+ nc = BASE_FIG*(vp->Prec + 2)+6; /* 3: sign + exponent chars */
+ }
+ return nc;
}
/*
@@ -2110,10 +2176,10 @@ end_if:
isw = VpGetSign(a) + sw *VpGetSign(b);
/*
* isw = 0 ...( 1)+(-1),( 1)-( 1),(-1)+(1),(-1)-(-1)
- * = 2 ...( 1)+( 1),( 1)-(-1)
- * =-2 ...(-1)+(-1),(-1)-( 1)
+ * = 2 ...( 1)+( 1),( 1)-(-1)
+ * =-2 ...(-1)+(-1),(-1)-( 1)
* If isw==0, then c =(Sign a_ptr)(|a_ptr|-|b_ptr|)
- * else c =(Sign of isw)(|a_ptr|+|b_ptr|)
+ * else c =(Sign ofisw)(|a_ptr|+|b_ptr|)
*/
if(isw) { /* addition */
VpSetSign(c,(S_INT)1);
@@ -2363,12 +2429,12 @@ Exit:
* a = xxxxxxxxxxx
* b = xxxxxxxxxx
* c =xxxxxxxxxxxxxxx
- * word_shift = | |
- * right_word = | | (Total digits in RHSV)
- * left_word = | | (Total digits in LHSV)
- * a_pos = |
- * b_pos = |
- * c_pos = |
+ * word_shift = | |
+ * right_word = | | (Total digits in RHSV)
+ * left_word = | | (Total digits in LHSV)
+ * a_pos = |
+ * b_pos = |
+ * c_pos = |
*/
static U_LONG
VpSetPTR(Real *a, Real *b, Real *c, U_LONG *a_pos, U_LONG *b_pos, U_LONG *c_pos, U_LONG *av, U_LONG *bv)
@@ -2381,17 +2447,17 @@ VpSetPTR(Real *a, Real *b, Real *c, U_LONG *a_pos, U_LONG *b_pos, U_LONG *c_pos,
right_word = Max((a->Prec),left_word);
left_word =(c->MaxPrec) - 1; /* -1 ... prepare for round up */
/*
- * check if 'round off' is needed.
+ * check if 'round' is needed.
*/
- if(right_word > left_word) { /* round off ? */
+ if(right_word > left_word) { /* round ? */
/*---------------------------------
* Actual size of a = xxxxxxAxx
* Actual size of b = xxxBxxxxx
* Max. size of c = xxxxxx
- * Round off = |-----|
- * c_pos = |
- * right_word = |
- * a_pos = |
+ * Round off = |-----|
+ * c_pos = |
+ * right_word = |
+ * a_pos = |
*/
*c_pos = right_word = left_word + 1; /* Set resulting precision */
/* be equal to that of c */
@@ -3036,7 +3102,8 @@ VpFormatSt(char *psz,S_INT fFmt)
U_LONG i;
S_INT nf = 0;
char ch;
- int fDot = 0;
+
+ if(fFmt<=0) return;
ie = strlen(psz);
for(i = 0; i < ie; ++i) {
@@ -3044,10 +3111,8 @@ VpFormatSt(char *psz,S_INT fFmt)
if(!ch) break;
if(ch == '.') {
nf = 0;
- fDot = 1;
continue;
}
- if(!fDot) continue;
if(ch == 'E') break;
nf++;
if(nf > fFmt) {
@@ -3123,60 +3188,118 @@ VpSzMantissa(Real *a,char *psz)
}
}
-VP_EXPORT void
-VpToString(Real *a,char *psz,int fFmt)
+VP_EXPORT int
+VpToSpecialString(Real *a,char *psz)
{
- U_LONG i, ZeroSup;
- U_LONG n, m, e, nn;
- char *pszSav = psz;
- S_LONG ex;
-
if(VpIsNaN(a)) {
sprintf(psz,SZ_NaN);
- return;
+ return 1;
}
if(VpIsPosInf(a)) {
sprintf(psz,SZ_INF);
- return;
+ return 1;
}
if(VpIsNegInf(a)) {
sprintf(psz,SZ_NINF);
- return;
+ return 1;
}
+ if(VpIsZero(a)) {
+ if(VpIsPosZero(a)) sprintf(psz, "0.0");
+ else sprintf(psz, "-0.0");
+ return 1;
+ }
+ return 0;
+}
+
+VP_EXPORT void
+VpToString(Real *a,char *psz,int fFmt)
+{
+ U_LONG i, ZeroSup;
+ U_LONG n, m, e, nn;
+ char *pszSav = psz;
+ S_LONG ex;
+
+ if(VpToSpecialString(a,psz)) return;
ZeroSup = 1; /* Flag not to print the leading zeros as 0.00xxxxEnn */
- if(!VpIsZero(a)) {
- if(VpGetSign(a) < 0) *psz++ = '-';
- *psz++ = '0';
- *psz++ = '.';
- n = a->Prec;
- for(i=0;i < n;++i) {
- m = BASE1;
- e = a->frac[i];
- while(m) {
- nn = e / m;
- if((!ZeroSup) || nn) {
- sprintf(psz, "%lu", nn); /* The reading zero(s) */
- psz += strlen(psz);
- /* as 0.00xx will be ignored. */
- ZeroSup = 0; /* Set to print succeeding zeros */
- }
- e = e - nn * m;
- m /= 10;
+
+ if(VpGetSign(a) < 0) *psz++ = '-';
+ *psz++ = '0';
+ *psz++ = '.';
+ n = a->Prec;
+ for(i=0;i < n;++i) {
+ m = BASE1;
+ e = a->frac[i];
+ while(m) {
+ nn = e / m;
+ if((!ZeroSup) || nn) {
+ sprintf(psz, "%lu", nn); /* The reading zero(s) */
+ psz += strlen(psz);
+ /* as 0.00xx will be ignored. */
+ ZeroSup = 0; /* Set to print succeeding zeros */
}
+ e = e - nn * m;
+ m /= 10;
}
- ex =(a->exponent) * BASE_FIG;
- n = BASE1;
- while((a->frac[0] / n) == 0) {
- --ex;
- n /= 10;
- }
- while(psz[-1]=='0') *(--psz) = 0;
- sprintf(psz, "E%ld", ex);
- } else {
- if(VpIsPosZero(a)) sprintf(psz, "0.0");
- else sprintf(psz, "-0.0");
}
+ ex =(a->exponent) * BASE_FIG;
+ n = BASE1;
+ while((a->frac[0] / n) == 0) {
+ --ex;
+ n /= 10;
+ }
+ while(psz[-1]=='0') *(--psz) = 0;
+ sprintf(psz, "E%ld", ex);
+ if(fFmt) VpFormatSt(pszSav, fFmt);
+}
+
+VP_EXPORT void
+VpToFString(Real *a,char *psz,int fFmt)
+{
+ U_LONG i;
+ U_LONG n, m, e, nn;
+ char *pszSav = psz;
+ S_LONG ex;
+
+ if(VpToSpecialString(a,psz)) return;
+
+ if(VpGetSign(a) < 0) *psz++ = '-';
+ n = a->Prec;
+ ex = a->exponent;
+ if(ex<=0) {
+ *psz++ = '0';*psz++ = '.';
+ while(ex<0) {
+ for(i=0;i<BASE_FIG;++i) *psz++ = '0';
+ ++ex;
+ }
+ ex = -1;
+ }
+
+ for(i=0;i < n;++i) {
+ --ex;
+ if(i==0 && ex >= 0) {
+ sprintf(psz, "%lu", a->frac[i]);
+ psz += strlen(psz);
+ } else {
+ m = BASE1;
+ e = a->frac[i];
+ while(m) {
+ nn = e / m;
+ *psz++ = nn + '0';
+ e = e - nn * m;
+ m /= 10;
+ }
+ }
+ if(ex == 0) *psz++ = '.';
+ }
+ while(--ex>=0) {
+ m = BASE;
+ while(m/=10) *psz++ = '0';
+ if(ex == 0) *psz++ = '.';
+ }
+ *psz = 0;
+ while(psz[-1]=='0') *(--psz) = 0;
+ if(psz[-1]=='.') sprintf(psz, "0");
if(fFmt) VpFormatSt(pszSav, fFmt);
}
diff --git a/ext/bigdecimal/bigdecimal.h b/ext/bigdecimal/bigdecimal.h
index 0af0b1dfc5..8230512e6a 100644
--- a/ext/bigdecimal/bigdecimal.h
+++ b/ext/bigdecimal/bigdecimal.h
@@ -122,12 +122,13 @@ VP_EXPORT U_LONG VpGetPrecLimit(void);
VP_EXPORT U_LONG VpSetPrecLimit(U_LONG n);
/* Round mode */
+VP_EXPORT int VpIsRoundMode(unsigned long n);
VP_EXPORT unsigned long VpGetRoundMode(void);
VP_EXPORT unsigned long VpSetRoundMode(unsigned long n);
VP_EXPORT int VpException(unsigned short f,char *str,int always);
VP_EXPORT int VpIsNegDoubleZero(double v);
-VP_EXPORT U_LONG VpNumOfChars(Real *vp);
+VP_EXPORT U_LONG VpNumOfChars(Real *vp,char *pszFmt);
VP_EXPORT U_LONG VpInit(U_LONG BaseVal);
VP_EXPORT void *VpMemAlloc(U_LONG mb);
VP_EXPORT void VpFree(Real *pv);
@@ -139,7 +140,9 @@ VP_EXPORT int VpDivd(Real *c,Real *r,Real *a,Real *b);
VP_EXPORT int VpComp(Real *a,Real *b);
VP_EXPORT S_LONG VpExponent10(Real *a);
VP_EXPORT void VpSzMantissa(Real *a,char *psz);
+VP_EXPORT int VpToSpecialString(Real *a,char *psz);
VP_EXPORT void VpToString(Real *a,char *psz,int fFmt);
+VP_EXPORT void VpToFString(Real *a,char *psz,int fFmt);
VP_EXPORT int VpCtoV(Real *a,char *int_chr,U_LONG ni,char *frac,U_LONG nf,char *exp_chr,U_LONG ne);
VP_EXPORT int VpVtoD(double *d,S_LONG *e,Real *m);
VP_EXPORT void VpDtoV(Real *m,double d);
diff --git a/ext/bigdecimal/bigdecimal_en.html b/ext/bigdecimal/bigdecimal_en.html
index a8ced21e01..c4ed6b4c01 100644
--- a/ext/bigdecimal/bigdecimal_en.html
+++ b/ext/bigdecimal/bigdecimal_en.html
@@ -148,8 +148,8 @@ EXCEPTION_ZERODIVIDE results to +Infinity or -Infinity<BR>
</BLOCKQUOTE>
EXCEPTION_INFINITY,EXCEPTION_OVERFLOW, and EXCEPTION_ZERODIVIDE are
currently the same.<BR>
-The return value of mode method is the previous value set.<BR>
-nil is returned if any argument is wrong.<BR>
+The return value of mode method is the value set.<BR>
+If nil is specified for the second argument,then current setting is returned.<BR>
Suppose the return value of the mode method is f,then
f &amp; BigDecimal::EXCEPTION_NaN !=0 means EXCEPTION_NaN is set to on.
<P>
@@ -169,8 +169,7 @@ where flag must be one of:
<TR><TD>ROUND_CEILING</TD><TD>round towards positive infinity(ceil).</TD></TR>
<TR><TD>ROUND_FLOOR</TD><TD>round towards negative infinity(floor).</TD></TR>
</TABLE>
-New rounding mode is returned,nil is returned if any argument is not an integer.
-Bad specification is ignored.<BR>
+New rounding mode is returned. If nil is specified for the second argument,then current setting is returned.<BR>
The digit location for rounding operation can not be specified by this mode method,
use truncate/round/ceil/floor/add/sub/mult/div mthods for each instance instead.
</BLOCKQUOTE>
@@ -359,10 +358,27 @@ If a is Infinity or NaN,then i becomes to nil.
</BLOCKQUOTE>
<LI><B>to_s[(n)]</B></LI><BLOCKQUOTE>
-converts to string(results look like "0.xxxxxEn").<BR>
-s = a.to_s<BR>
-If n is given,then a space is inserted after every n digits for readability.<BR>
-s = a.to_s(n)
+converts to string(default results look like "0.xxxxxEn").
+<CODE><PRE>
+BigDecimal("1.23456").to_s # ==> "0.123456E1"
+</PRE></CODE>
+If n(>0) is given,then a space is inserted to each of two parts divided by the decimal point
+after every n digits for readability.
+<CODE><PRE>
+BigDecimal("0.1234567890123456789").to_s(10) # ==> "0.1234567890 123456789E0"
+</PRE></CODE>
+n can be an string representing a positive integer number.
+<CODE><PRE>
+BigDecimal("0.1234567890123456789").to_s("10") # ==> "0.1234567890 123456789E0"
+</PRE></CODE>
+At the end of the string,'E'(or 'e') or 'F'(or 'f') can be specified to change
+number representation.
+<CODE><PRE>
+BigDecimal("1234567890.123456789").to_s("E") # ==> "0.1234567890123456789E10"
+BigDecimal("1234567890.123456789").to_s("F") # ==> "1234567890.123456789"
+BigDecimal("1234567890.123456789").to_s("5E") # ==> "0.12345 67890 12345 6789E10"
+BigDecimal("1234567890.123456789").to_s("5F") # ==> "12345 67890.12345 6789"
+</PRE></CODE>
</BLOCKQUOTE>
<LI><B>exponent</B></LI><BLOCKQUOTE>
@@ -371,8 +387,8 @@ n = a.exponent <BR>
means a = 0.xxxxxxx*10**n.
</BLOCKQUOTE>
-<LI><B>prec</B></LI><BLOCKQUOTE>
-n,m = a.prec <BR>
+<LI><B>precs</B></LI><BLOCKQUOTE>
+n,m = a.precs <BR>
prec returns number of significant digits (n) and maximum number of
significant digits (m) of a.
</BLOCKQUOTE>
diff --git a/ext/bigdecimal/bigdecimal_ja.html b/ext/bigdecimal/bigdecimal_ja.html
index 4fc3a4eb84..a59d61a838 100644
--- a/ext/bigdecimal/bigdecimal_ja.html
+++ b/ext/bigdecimal/bigdecimal_ja.html
@@ -157,10 +157,10 @@ EXCEPTION_ZERODIVIDE のとき、+Infinity か -Infinity<BR>
</BLOCKQUOTE>
EXCEPTION_INFINITY、EXCEPTION_OVERFLOW、EXCEPTION_ZERODIVIDE
は今のところ同じです。<BR>
-戻り値は、設定前の値です。「値」の意味は、例えば
+戻り値は、設定後の値です。「値」の意味は、例えば
BigDecimal::EXCEPTION_NaNと「値」の & が ゼロ以外ならば
EXCEPTION_NaNが設定されているという意味です。<BR>
-引数に正しくないものが指定された場合は nil が返ります。
+第2引数に nil を指定すると、現状の設定値が返ります。
<P>
<B>[丸め処理指定]</B><P>
@@ -181,8 +181,7 @@ f = BigDecimal::mode(BigDecimal::ROUND_MODE,flag)
</TABLE>
戻り値は指定後の flag の値です。
-引数に数値以外が指定された場合は nil が返ります。正しくない ROUND_MODE が指定されたときは
-無視され、現状の ROUND_MODE が返ります。<BR>
+第2引数に nil を指定すると、現状の設定値が返ります。
mode メソッドでは丸め操作の位置をユーザが指定することはできません。
丸め操作と位置を自分で制御したい場合は truncate/round/ceil/floor や
add/sub/mult/div といったインスタンスメソッドを使用して下さい。
@@ -375,10 +374,28 @@ Float オブジェクトに変換します。
ください。
</BLOCKQUOTE>
<LI><B>to_s[(n)]</B></LI><BLOCKQUOTE>
-文字列に変換します("0.xxxxxEn"の形になります)。<BR>
-s = a.to_s<BR>
-n が指定されたときは、仮数部分を n 桁毎に空白で区切ります。<BR>
-s = a.to_s(n)
+文字列に変換します(デフォルトは "0.xxxxxEn" の形になります)。
+<CODE><PRE>
+BigDecimal("1.23456").to_s # ==> "0.123456E1"
+</PRE></CODE>
+引数 n に正の整数が指定されたときは、少数点で分けられる左右部分を、それぞれ n 桁毎
+に空白で区切ります。
+<CODE><PRE>
+BigDecimal("0.1234567890123456789").to_s(10) # ==> "0.1234567890 123456789E0"
+</PRE></CODE>
+引数 n に正の整数を表す文字列を指定することもできます。
+<CODE><PRE>
+BigDecimal("0.1234567890123456789").to_s("10") # ==> "0.1234567890 123456789E0"
+</PRE></CODE>
+さらに文字列の最後に E(または e) か F(または f) を指定することで、以下のように
+表示形式を変更することができます。
+<CODE><PRE>
+BigDecimal("1234567890.123456789").to_s("E") # ==> "0.1234567890123456789E10"
+BigDecimal("1234567890.123456789").to_s("F") # ==> "1234567890.123456789"
+BigDecimal("1234567890.123456789").to_s("5E") # ==> "0.12345 67890 12345 6789E10"
+BigDecimal("1234567890.123456789").to_s("5F") # ==> "12345 67890.12345 6789"
+</PRE></CODE>
+
</BLOCKQUOTE>
<LI><B>exponent</B></LI><BLOCKQUOTE>
指数部を整数値で返します。
@@ -386,8 +403,8 @@ n = a.exponent <BR>
は a の値が 0.xxxxxxx*10**n を意味します。
</BLOCKQUOTE>
-<LI><B>prec</B></LI><BLOCKQUOTE>
-n,m = a.prec<BR>
+<LI><B>precs</B></LI><BLOCKQUOTE>
+n,m = a.precs<BR>
a の有効数字 (n) と最大有効数字 (m) の配列を返します。
</BLOCKQUOTE>