mirror of
https://github.com/ccxvii/mujs.git
synced 2026-02-06 09:51:41 +08:00
Add and use dtoa function from plan9/libfmt.
This commit is contained in:
Tor Andersson
329
jsdtoa.c
Normal file
329
jsdtoa.c
Normal file
@@ -0,0 +1,329 @@
|
||||
/* The authors of this software are Rob Pike and Ken Thompson.
|
||||
* Copyright (c) 2002 by Lucent Technologies.
|
||||
* Permission to use, copy, modify, and distribute this software for any
|
||||
* purpose without fee is hereby granted, provided that this entire notice
|
||||
* is included in all copies of any software which is or includes a copy
|
||||
* or modification of this software and in all copies of the supporting
|
||||
* documentation for such software.
|
||||
* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
|
||||
* WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
|
||||
* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
|
||||
* OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
|
||||
*/
|
||||
|
||||
#include <stdio.h>
|
||||
#include <math.h>
|
||||
#include <float.h>
|
||||
#include <string.h>
|
||||
#include <stdlib.h>
|
||||
#include <errno.h>
|
||||
|
||||
enum { NSIGNIF = 17 };
|
||||
|
||||
/*
|
||||
* first few powers of 10, enough for about 1/2 of the
|
||||
* total space for doubles.
|
||||
*/
|
||||
static double pows10[] =
|
||||
{
|
||||
1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9,
|
||||
1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19,
|
||||
1e20, 1e21, 1e22, 1e23, 1e24, 1e25, 1e26, 1e27, 1e28, 1e29,
|
||||
1e30, 1e31, 1e32, 1e33, 1e34, 1e35, 1e36, 1e37, 1e38, 1e39,
|
||||
1e40, 1e41, 1e42, 1e43, 1e44, 1e45, 1e46, 1e47, 1e48, 1e49,
|
||||
1e50, 1e51, 1e52, 1e53, 1e54, 1e55, 1e56, 1e57, 1e58, 1e59,
|
||||
1e60, 1e61, 1e62, 1e63, 1e64, 1e65, 1e66, 1e67, 1e68, 1e69,
|
||||
1e70, 1e71, 1e72, 1e73, 1e74, 1e75, 1e76, 1e77, 1e78, 1e79,
|
||||
1e80, 1e81, 1e82, 1e83, 1e84, 1e85, 1e86, 1e87, 1e88, 1e89,
|
||||
1e90, 1e91, 1e92, 1e93, 1e94, 1e95, 1e96, 1e97, 1e98, 1e99,
|
||||
1e100, 1e101, 1e102, 1e103, 1e104, 1e105, 1e106, 1e107, 1e108, 1e109,
|
||||
1e110, 1e111, 1e112, 1e113, 1e114, 1e115, 1e116, 1e117, 1e118, 1e119,
|
||||
1e120, 1e121, 1e122, 1e123, 1e124, 1e125, 1e126, 1e127, 1e128, 1e129,
|
||||
1e130, 1e131, 1e132, 1e133, 1e134, 1e135, 1e136, 1e137, 1e138, 1e139,
|
||||
1e140, 1e141, 1e142, 1e143, 1e144, 1e145, 1e146, 1e147, 1e148, 1e149,
|
||||
1e150, 1e151, 1e152, 1e153, 1e154, 1e155, 1e156, 1e157, 1e158, 1e159,
|
||||
};
|
||||
#define npows10 ((int)(sizeof(pows10)/sizeof(pows10[0])))
|
||||
#define pow10(x) fmtpow10(x)
|
||||
|
||||
static double
|
||||
pow10(int n)
|
||||
{
|
||||
double d;
|
||||
int neg;
|
||||
|
||||
neg = 0;
|
||||
if(n < 0){
|
||||
neg = 1;
|
||||
n = -n;
|
||||
}
|
||||
|
||||
if(n < npows10)
|
||||
d = pows10[n];
|
||||
else{
|
||||
d = pows10[npows10-1];
|
||||
for(;;){
|
||||
n -= npows10 - 1;
|
||||
if(n < npows10){
|
||||
d *= pows10[n];
|
||||
break;
|
||||
}
|
||||
d *= pows10[npows10 - 1];
|
||||
}
|
||||
}
|
||||
if(neg)
|
||||
return 1./d;
|
||||
return d;
|
||||
}
|
||||
|
||||
/*
|
||||
* add 1 to the decimal integer string a of length n.
|
||||
* if 99999 overflows into 10000, return 1 to tell caller
|
||||
* to move the virtual decimal point.
|
||||
*/
|
||||
static int
|
||||
xadd1(char *a, int n)
|
||||
{
|
||||
char *b;
|
||||
int c;
|
||||
|
||||
if(n < 0 || n > NSIGNIF)
|
||||
return 0;
|
||||
for(b = a+n-1; b >= a; b--) {
|
||||
c = *b + 1;
|
||||
if(c <= '9') {
|
||||
*b = c;
|
||||
return 0;
|
||||
}
|
||||
*b = '0';
|
||||
}
|
||||
/*
|
||||
* need to overflow adding digit.
|
||||
* shift number down and insert 1 at beginning.
|
||||
* decimal is known to be 0s or we wouldn't
|
||||
* have gotten this far. (e.g., 99999+1 => 00000)
|
||||
*/
|
||||
a[0] = '1';
|
||||
return 1;
|
||||
}
|
||||
|
||||
/*
|
||||
* subtract 1 from the decimal integer string a.
|
||||
* if 10000 underflows into 09999, make it 99999
|
||||
* and return 1 to tell caller to move the virtual
|
||||
* decimal point. this way, xsub1 is inverse of xadd1.
|
||||
*/
|
||||
static int
|
||||
xsub1(char *a, int n)
|
||||
{
|
||||
char *b;
|
||||
int c;
|
||||
|
||||
if(n < 0 || n > NSIGNIF)
|
||||
return 0;
|
||||
for(b = a+n-1; b >= a; b--) {
|
||||
c = *b - 1;
|
||||
if(c >= '0') {
|
||||
if(c == '0' && b == a) {
|
||||
/*
|
||||
* just zeroed the top digit; shift everyone up.
|
||||
* decimal is known to be 9s or we wouldn't
|
||||
* have gotten this far. (e.g., 10000-1 => 09999)
|
||||
*/
|
||||
*b = '9';
|
||||
return 1;
|
||||
}
|
||||
*b = c;
|
||||
return 0;
|
||||
}
|
||||
*b = '9';
|
||||
}
|
||||
/*
|
||||
* can't get here. the number a is always normalized
|
||||
* so that it has a nonzero first digit.
|
||||
*/
|
||||
abort();
|
||||
}
|
||||
|
||||
/*
|
||||
* format exponent like sprintf(p, "e%+d", e)
|
||||
*/
|
||||
void
|
||||
jsV_fmtexp(char *p, int e)
|
||||
{
|
||||
char se[9];
|
||||
int i;
|
||||
|
||||
*p++ = 'e';
|
||||
if(e < 0) {
|
||||
*p++ = '-';
|
||||
e = -e;
|
||||
} else
|
||||
*p++ = '+';
|
||||
i = 0;
|
||||
while(e) {
|
||||
se[i++] = e % 10 + '0';
|
||||
e /= 10;
|
||||
}
|
||||
while(i < 1)
|
||||
se[i++] = '0';
|
||||
while(i > 0)
|
||||
*p++ = se[--i];
|
||||
*p++ = '\0';
|
||||
}
|
||||
|
||||
/*
|
||||
* compute decimal integer m, exp such that:
|
||||
* f = m*10^exp
|
||||
* m is as short as possible with losing exactness
|
||||
* assumes special cases (NaN, +Inf, -Inf) have been handled.
|
||||
*/
|
||||
void
|
||||
jsV_dtoa(double f, char *s, int *exp, int *neg, int *ns)
|
||||
{
|
||||
int c, d, e2, e, ee, i, ndigit, oerrno;
|
||||
char tmp[NSIGNIF+10];
|
||||
double g;
|
||||
|
||||
oerrno = errno; /* in case strtod smashes errno */
|
||||
|
||||
/*
|
||||
* make f non-negative.
|
||||
*/
|
||||
*neg = 0;
|
||||
if(f < 0) {
|
||||
f = -f;
|
||||
*neg = 1;
|
||||
}
|
||||
|
||||
/*
|
||||
* must handle zero specially.
|
||||
*/
|
||||
if(f == 0){
|
||||
*exp = 0;
|
||||
s[0] = '0';
|
||||
s[1] = '\0';
|
||||
*ns = 1;
|
||||
return;
|
||||
}
|
||||
|
||||
/*
|
||||
* find g,e such that f = g*10^e.
|
||||
* guess 10-exponent using 2-exponent, then fine tune.
|
||||
*/
|
||||
frexp(f, &e2);
|
||||
e = (int)(e2 * .301029995664);
|
||||
g = f * pow10(-e);
|
||||
while(g < 1) {
|
||||
e--;
|
||||
g = f * pow10(-e);
|
||||
}
|
||||
while(g >= 10) {
|
||||
e++;
|
||||
g = f * pow10(-e);
|
||||
}
|
||||
|
||||
/*
|
||||
* convert NSIGNIF digits as a first approximation.
|
||||
*/
|
||||
for(i=0; i<NSIGNIF; i++) {
|
||||
d = (int)g;
|
||||
s[i] = d+'0';
|
||||
g = (g-d) * 10;
|
||||
}
|
||||
s[i] = 0;
|
||||
|
||||
/*
|
||||
* adjust e because s is 314159... not 3.14159...
|
||||
*/
|
||||
e -= NSIGNIF-1;
|
||||
jsV_fmtexp(s+NSIGNIF, e);
|
||||
|
||||
/*
|
||||
* adjust conversion until strtod(s) == f exactly.
|
||||
*/
|
||||
for(i=0; i<10; i++) {
|
||||
g = strtod(s, NULL);
|
||||
if(f > g) {
|
||||
if(xadd1(s, NSIGNIF)) {
|
||||
/* gained a digit */
|
||||
e--;
|
||||
jsV_fmtexp(s+NSIGNIF, e);
|
||||
}
|
||||
continue;
|
||||
}
|
||||
if(f < g) {
|
||||
if(xsub1(s, NSIGNIF)) {
|
||||
/* lost a digit */
|
||||
e++;
|
||||
jsV_fmtexp(s+NSIGNIF, e);
|
||||
}
|
||||
continue;
|
||||
}
|
||||
break;
|
||||
}
|
||||
|
||||
/*
|
||||
* play with the decimal to try to simplify.
|
||||
*/
|
||||
|
||||
/*
|
||||
* bump last few digits up to 9 if we can
|
||||
*/
|
||||
for(i=NSIGNIF-1; i>=NSIGNIF-3; i--) {
|
||||
c = s[i];
|
||||
if(c != '9') {
|
||||
s[i] = '9';
|
||||
g = strtod(s, NULL);
|
||||
if(g != f) {
|
||||
s[i] = c;
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* add 1 in hopes of turning 9s to 0s
|
||||
*/
|
||||
if(s[NSIGNIF-1] == '9') {
|
||||
strcpy(tmp, s);
|
||||
ee = e;
|
||||
if(xadd1(tmp, NSIGNIF)) {
|
||||
ee--;
|
||||
jsV_fmtexp(tmp+NSIGNIF, ee);
|
||||
}
|
||||
g = strtod(tmp, NULL);
|
||||
if(g == f) {
|
||||
strcpy(s, tmp);
|
||||
e = ee;
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* bump last few digits down to 0 as we can.
|
||||
*/
|
||||
for(i=NSIGNIF-1; i>=NSIGNIF-3; i--) {
|
||||
c = s[i];
|
||||
if(c != '0') {
|
||||
s[i] = '0';
|
||||
g = strtod(s, NULL);
|
||||
if(g != f) {
|
||||
s[i] = c;
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* remove trailing zeros.
|
||||
*/
|
||||
ndigit = NSIGNIF;
|
||||
while(ndigit > 1 && s[ndigit-1] == '0'){
|
||||
e++;
|
||||
--ndigit;
|
||||
}
|
||||
s[ndigit] = 0;
|
||||
*exp = e;
|
||||
*ns = ndigit;
|
||||
errno = oerrno;
|
||||
}
|
||||
@@ -34,12 +34,19 @@ static void Np_toString(js_State *J)
|
||||
/* Customized ToString() on a number */
|
||||
void numtostr(js_State *J, const char *fmt, int w, double n)
|
||||
{
|
||||
char buf[40];
|
||||
char buf[32], *e;
|
||||
if (isnan(n)) js_pushliteral(J, "NaN");
|
||||
else if (isinf(n)) js_pushliteral(J, n < 0 ? "-Infinity" : "Infinity");
|
||||
else if (n == 0) js_pushliteral(J, "0");
|
||||
else {
|
||||
if (w < 1) w = 1;
|
||||
if (w > 17) w = 17;
|
||||
sprintf(buf, fmt, w, n);
|
||||
e = strchr(buf, 'e');
|
||||
if (e) {
|
||||
int exp = atoi(e+1);
|
||||
sprintf(e, "e%+d", exp);
|
||||
}
|
||||
js_pushstring(J, buf);
|
||||
}
|
||||
}
|
||||
|
||||
53
jsvalue.c
53
jsvalue.c
@@ -104,6 +104,7 @@ js_Value jsV_toprimitive(js_State *J, const js_Value *v, int preferred)
|
||||
return vv;
|
||||
}
|
||||
}
|
||||
|
||||
js_typeerror(J, "cannot convert object to primitive");
|
||||
}
|
||||
|
||||
@@ -187,13 +188,53 @@ double jsV_tointeger(js_State *J, const js_Value *v)
|
||||
}
|
||||
|
||||
/* ToString() on a number */
|
||||
const char *jsV_numbertostring(js_State *J, double n)
|
||||
const char *jsV_numbertostring(js_State *J, double f)
|
||||
{
|
||||
char buf[32];
|
||||
if (isnan(n)) return "NaN";
|
||||
if (isinf(n)) return n < 0 ? "-Infinity" : "Infinity";
|
||||
if (n == 0) return "0";
|
||||
sprintf(buf, "%.17g", n); /* DBL_DECIMAL_DIG == 17 */
|
||||
char buf[32], digits[32], *p = buf, *s = digits;
|
||||
int exp, neg, ndigits, point;
|
||||
|
||||
if (isnan(f)) return "NaN";
|
||||
if (isinf(f)) return f < 0 ? "-Infinity" : "Infinity";
|
||||
if (f == 0) return "0";
|
||||
|
||||
jsV_dtoa(f, digits, &exp, &neg, &ndigits);
|
||||
point = ndigits + exp;
|
||||
|
||||
if (neg)
|
||||
*p++ = '-';
|
||||
|
||||
if (point < -5 || point > 21) {
|
||||
*p++ = *s++;
|
||||
if (ndigits > 1) {
|
||||
int n = ndigits - 1;
|
||||
*p++ = '.';
|
||||
while (n--)
|
||||
*p++ = *s++;
|
||||
}
|
||||
jsV_fmtexp(p, point - 1);
|
||||
}
|
||||
|
||||
else if (point <= 0) {
|
||||
*p++ = '0';
|
||||
*p++ = '.';
|
||||
while (point++ < 0)
|
||||
*p++ = '0';
|
||||
while (ndigits-- > 0)
|
||||
*p++ = *s++;
|
||||
*p = 0;
|
||||
}
|
||||
|
||||
else {
|
||||
while (ndigits-- > 0) {
|
||||
*p++ = *s++;
|
||||
if (--point == 0 && ndigits > 0)
|
||||
*p++ = '.';
|
||||
}
|
||||
while (point-- > 0)
|
||||
*p++ = '0';
|
||||
*p = 0;
|
||||
}
|
||||
|
||||
return js_intern(J, buf);
|
||||
}
|
||||
|
||||
|
||||
@@ -132,6 +132,10 @@ unsigned short jsV_numbertouint16(double n);
|
||||
const char *jsV_numbertostring(js_State *J, double number);
|
||||
double jsV_stringtonumber(js_State *J, const char *string);
|
||||
|
||||
/* jsdtoa.c */
|
||||
void jsV_fmtexp(char *p, int e);
|
||||
void jsV_dtoa(double f, char *digits, int *exp, int *neg, int *ndigits);
|
||||
|
||||
/* jsproperty.c */
|
||||
js_Object *jsV_newobject(js_State *J, enum js_Class type, js_Object *prototype);
|
||||
js_Property *jsV_getownproperty(js_State *J, js_Object *obj, const char *name);
|
||||
|
||||
Reference in New Issue
Block a user