string.c: rb_str_cat_conv_enc_opts

* file.c (rb_file_expand_path_internal): concatenate converted
  string to the result instead of making converted string and
  append it.
* string.c (rb_str_cat_conv_enc_opts): from rb_str_conv_enc_opts,
  separate function to concatenate with transcoding.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52147 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 9 insertions, 7 deletions

diff --git a/file.c b/file.c
index 60975104f7..15ce4c1f4e 100644
--- a/file.c
+++ b/file.c
@@ -3604,14 +3604,16 @@ rb_file_expand_path_internal(VALUE fname, VALUE dname, int abs_mode, int long_na
 	    ++p;
 	    wlen = (int)len;
 	    len = WideCharToMultiByte(CP_UTF8, 0, wfd.cFileName, wlen, NULL, 0, NULL, NULL);
-	    BUFCHECK(bdiff + len >= buflen);
-	    WideCharToMultiByte(CP_UTF8, 0, wfd.cFileName, wlen, p, len + 1, NULL, NULL);
-	    if (tmp != result) {
-		rb_str_buf_cat(tmp, p, len);
-		tmp = rb_str_encode(tmp, rb_enc_from_encoding(enc), 0, Qnil);
-		len = RSTRING_LEN(tmp);
+	    if (tmp == result) {
 		BUFCHECK(bdiff + len >= buflen);
-		memcpy(p, RSTRING_PTR(tmp), len);
+		WideCharToMultiByte(CP_UTF8, 0, wfd.cFileName, wlen, p, len + 1, NULL, NULL);
+	    }
+	    else {
+		rb_str_modify_expand(tmp, len);
+		WideCharToMultiByte(CP_UTF8, 0, wfd.cFileName, wlen, RSTRING_PTR(tmp), len + 1, NULL, NULL);
+		rb_str_cat_conv_enc_opts(result, bdiff, RSTRING_PTR(tmp), len,
+					 rb_utf8_encoding(), 0, Qnil);
+		BUFINIT();
 		rb_str_resize(tmp, 0);
 	    }
 	    p += len;