ref: fea0707d208c05f55b4d23392d261695ce22fa25
parent: 4792d16f17b15a1eca3c2a9c856dc13fda1d23c5
author: Tor Andersson <tor.andersson@artifex.com>
date: Thu Jun 29 10:10:11 EDT 2017
Support 'radix' argument for Number.prototype.toString. The conversion is not very accurate, but should work well enough for most purposes.
--- a/jsnumber.c
+++ b/jsnumber.c
@@ -2,6 +2,12 @@
#include "jsvalue.h"
#include "jsbuiltin.h"
+#ifdef _MSC_VER
+typedef unsigned __int64 uint64_t;
+#else
+#include <stdint.h>
+#endif
+
static void jsB_new_Number(js_State *J)
{js_newnumber(J, js_gettop(J) > 1 ? js_tonumber(J, 1) : 0);
@@ -24,12 +30,86 @@
char buf[32];
js_Object *self = js_toobject(J, 0);
int radix = js_isundefined(J, 1) ? 10 : js_tointeger(J, 1);
- if (self->type != JS_CNUMBER) js_typeerror(J, "not a number");
+ if (self->type != JS_CNUMBER)
+ js_typeerror(J, "not a number");
+ if (radix == 10) {+ js_pushstring(J, jsV_numbertostring(J, buf, self->u.number));
+ return;
+ }
if (radix < 2 || radix > 36)
js_rangeerror(J, "invalid radix");
- if (radix != 10)
- js_rangeerror(J, "invalid radix");
- js_pushstring(J, jsV_numbertostring(J, buf, self->u.number));
+
+ /* lame number to string conversion for any radix from 2 to 36 */
+ {+ static const char digits[36] = "0123456789abcdefghijklmnopqrstuvwxyz";
+ char buf[100];
+ double number = self->u.number;
+ int sign = self->u.number < 0;
+ js_Buffer *sb = NULL;
+ uint64_t u, limit = ((uint64_t)1<<52);
+
+ int ndigits, exp, point;
+
+ if (number == 0) { js_pushstring(J, "0"); return; }+ if (isnan(number)) { js_pushstring(J, "NaN"); return; }+ if (isinf(number)) { js_pushstring(J, sign ? "-Infinity" : "Infinity"); return; }+
+ if (sign)
+ number = -number;
+
+ /* fit as many digits as we want in an int */
+ exp = 0;
+ while (number * pow(radix, exp) > limit)
+ --exp;
+ while (number * pow(radix, exp+1) < limit)
+ ++exp;
+ u = number * pow(radix, exp) + 0.5;
+
+ /* trim trailing zeros */
+ while (u > 0 && (u % radix) == 0) {+ u /= radix;
+ --exp;
+ }
+
+ /* serialize digits */
+ ndigits = 0;
+ while (u > 0) {+ buf[ndigits++] = digits[u % radix];
+ u /= radix;
+ }
+ point = ndigits - exp;
+
+ if (js_try(J)) {+ js_free(J, sb);
+ js_throw(J);
+ }
+
+ if (sign)
+ js_putc(J, &sb, '-');
+
+ if (point <= 0) {+ js_putc(J, &sb, '0');
+ js_putc(J, &sb, '.');
+ while (point++ < 0)
+ js_putc(J, &sb, '0');
+ while (ndigits-- > 0)
+ js_putc(J, &sb, buf[ndigits]);
+ } else {+ while (ndigits-- > 0) {+ js_putc(J, &sb, buf[ndigits]);
+ if (--point == 0 && ndigits > 0)
+ js_putc(J, &sb, '.');
+ }
+ while (point-- > 0)
+ js_putc(J, &sb, '0');
+ }
+
+ js_putc(J, &sb, 0);
+ js_pushstring(J, sb->s);
+
+ js_endtry(J);
+ js_free(J, sb);
+ }
}
/* Customized ToString() on a number */