* marshal.c (w_float): use minimal representation.

* numeric.c (ruby_dbl2cstr): split from rb_float_new.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@27774 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 43 insertions, 41 deletions

diff --git a/numeric.c b/numeric.c
index 00d670b70f..31b3756d25 100644
--- a/numeric.c
+++ b/numeric.c
@@ -545,6 +545,8 @@ rb_float_new(double d)
     return (VALUE)flt;
 }
 
+int ruby_dbl2cstr(double value, char *buf, int size);
+
 /*
  *  call-seq:
  *     flt.to_s  ->  string
@@ -558,70 +560,70 @@ rb_float_new(double d)
 static VALUE
 flo_to_s(VALUE flt)
 {
-    char *ruby_dtoa(double d_, int mode, int ndigits, int *decpt, int *sign, char **rve);
     enum {decimal_mant = DBL_MANT_DIG-DBL_DIG};
     enum {float_dig = DBL_DIG+1};
     char buf[float_dig + (decimal_mant + CHAR_BIT - 1) / CHAR_BIT + 10];
     double value = RFLOAT_VALUE(flt);
-    VALUE s;
-    char *p, *e;
-    int sign, decpt, digs;
 
     if (isinf(value))
 	return rb_usascii_str_new2(value < 0 ? "-Infinity" : "Infinity");
     else if (isnan(value))
 	return rb_usascii_str_new2("NaN");
+    return rb_usascii_str_new(buf, ruby_dbl2cstr(value, buf, (int)sizeof(buf)));
+}
+
+int
+ruby_dbl2cstr(double value, char *buf, int size)
+{
+    char *ruby_dtoa(double d_, int mode, int ndigits, int *decpt, int *sign, char **rve);
+    char *p, *e;
+    int sign, decpt, digs;
 
+    if (size <= 0) return 0;
     p = ruby_dtoa(value, 0, 0, &decpt, &sign, &e);
-    s = sign ? rb_usascii_str_new_cstr("-") : rb_usascii_str_new(0, 0);
-    if ((digs = (int)(e - p)) >= (int)sizeof(buf)) digs = (int)sizeof(buf) - 1;
-    memcpy(buf, p, digs);
-    xfree(p);
-    if (decpt > 0) {
-	if (decpt < digs) {
-	    memmove(buf + decpt + 1, buf + decpt, digs - decpt);
-	    buf[decpt] = '.';
-	    rb_str_cat(s, buf, digs + 1);
-	}
-	else if (decpt - digs < float_dig) {
-	    long len;
-	    char *ptr;
-	    rb_str_cat(s, buf, digs);
-	    rb_str_resize(s, (len = RSTRING_LEN(s)) + decpt - digs + 2);
-	    ptr = RSTRING_PTR(s) + len;
-	    if (decpt > digs) {
-		memset(ptr, '0', decpt - digs);
-		ptr += decpt - digs;
+    if (sign) *buf++ = '-', --size;
+    if ((digs = (int)(e - p)) >= size) digs = size - 1;
+    if (decpt > -4 && (decpt < digs || decpt - digs < DBL_DIG+1)) {
+	int i = 0, j = 0, n;
+	if (decpt > 0) {
+	    memcpy(buf + j, p + i, (n = decpt > digs ? digs : decpt));
+	    i += n, j += n;
+	    if ((n = decpt - n) > 0) {
+		memset(buf + j, '0', n);
+		j += n;
 	    }
-	    memcpy(ptr, ".0", 2);
 	}
 	else {
-	    goto exp;
+	    buf[j++] = '0';
 	}
-    }
-    else if (decpt > -4) {
-	long len;
-	char *ptr;
-	rb_str_cat(s, "0.", 2);
-	rb_str_resize(s, (len = RSTRING_LEN(s)) - decpt + digs);
-	ptr = RSTRING_PTR(s);
-	memset(ptr += len, '0', -decpt);
-	memcpy(ptr -= decpt, buf, digs);
+	buf[j++] = '.';
+	if (decpt < 0) {
+	    memset(buf + j, '0', -decpt);
+	    j -= decpt, decpt = 0;
+	}
+	if (decpt < digs) {
+	    memcpy(buf + j, p + i, (n = digs - decpt));
+	    j += n;
+	}
+	else {
+	    buf[j++] = '0';
+	}
+	digs = j;
     }
     else {
-      exp:
+	buf[0] = p[0];
+	buf[1] = '.';
 	if (digs > 1) {
-	    memmove(buf + 2, buf + 1, digs - 1);
+	    memcpy(buf + 2, p + 1, digs++ - 1);
 	}
 	else {
 	    buf[2] = '0';
-	    digs++;
+	    digs = 3;
 	}
-	buf[1] = '.';
-	rb_str_cat(s, buf, digs + 1);
-	rb_str_catf(s, "e%+03d", decpt - 1);
+	digs += snprintf(buf + digs, size - digs, "e%+03d", decpt - 1);
     }
-    return s;
+    xfree(p);
+    return digs + sign;
 }
 
 /*