merge revision(s) 58453,58454: [Backport #13499]

	Fix space flag when Inf/NaN and width==3

	* sprintf.c (rb_str_format): while `"% 2f"` and `"% 4f"` result in
	  `" Inf"` and `" Inf"` respectively, `"% 3f"` results in
	  `"Inf"` (no space).
	Refactor "%f" % Inf/NaN

	* sprintf.c (rb_str_format): as for non-finite float, calculate
	  the exact needed size with the space flag.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_4@58625 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 17 insertions, 20 deletions

diff --git a/sprintf.c b/sprintf.c
index 4342904bdc..bb83d842fc 100644
--- a/sprintf.c
+++ b/sprintf.c
@@ -1135,6 +1135,8 @@ rb_str_format(int argc, const VALUE *argv, VALUE fmt)
 		fval = RFLOAT_VALUE(rb_Float(val));
 		if (isnan(fval) || isinf(fval)) {
 		    const char *expr;
+		    int elen;
+		    char sign = '\0';
 
 		    if (isnan(fval)) {
 			expr = "NaN";
@@ -1143,33 +1145,28 @@ rb_str_format(int argc, const VALUE *argv, VALUE fmt)
 			expr = "Inf";
 		    }
 		    need = (int)strlen(expr);
-		    if ((!isnan(fval) && fval < 0.0) || (flags & FPLUS))
-			need++;
+		    elen = need;
+		    i = 0;
+		    if (!isnan(fval) && fval < 0.0)
+			sign = '-';
+		    else if (flags & (FPLUS|FSPACE))
+			sign = (flags & FPLUS) ? '+' : ' ';
+		    if (sign)
+			++need;
 		    if ((flags & FWIDTH) && need < width)
 			need = width;
 
-		    CHECK(need + 1);
-		    snprintf(&buf[blen], need + 1, "%*s", need, "");
+		    FILL(' ', need);
 		    if (flags & FMINUS) {
-			if (!isnan(fval) && fval < 0.0)
-			    buf[blen++] = '-';
-			else if (flags & FPLUS)
-			    buf[blen++] = '+';
-			else if (flags & FSPACE)
-			    blen++;
-			memcpy(&buf[blen], expr, strlen(expr));
+			if (sign)
+			    buf[blen - need--] = sign;
+			memcpy(&buf[blen - need], expr, elen);
 		    }
 		    else {
-			if (!isnan(fval) && fval < 0.0)
-			    buf[blen + need - strlen(expr) - 1] = '-';
-			else if (flags & FPLUS)
-			    buf[blen + need - strlen(expr) - 1] = '+';
-			else if ((flags & FSPACE) && need > width)
-			    blen++;
-			memcpy(&buf[blen + need - strlen(expr)], expr,
-			       strlen(expr));
+			if (sign)
+			    buf[blen - elen - 1] = sign;
+			memcpy(&buf[blen - elen], expr, elen);
 		    }
-		    blen += strlen(&buf[blen]);
 		    break;
 		}