Reviewers: Lasse Reichstein, Description: Make better use of the %_FastAsciiArrayJoin function.
Please review this at http://codereview.chromium.org/6100005/ SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/ Affected files: M src/array.js Index: src/array.js =================================================================== --- src/array.js (revision 6227) +++ src/array.js (working copy) @@ -125,12 +125,11 @@ } // Construct an array for the elements. - var elements; + var elements = new $Array(length); var elements_length = 0; // We pull the empty separator check outside the loop for speed! if (separator.length == 0) { - elements = new $Array(length); for (var i = 0; i < length; i++) { var e = array[i]; if (!IS_UNDEFINED(e) || (i in array)) { @@ -138,21 +137,32 @@ elements[elements_length++] = e; } } - } else { - elements = new $Array(length << 1); - for (var i = 0; i < length; i++) { - var e = array[i]; - if (i != 0) elements[elements_length++] = separator; - if (!IS_UNDEFINED(e) || (i in array)) { - if (!IS_STRING(e)) e = convert(e); - elements[elements_length++] = e; - } + elements.length = elements_length; + var result = %_FastAsciiArrayJoin(elements, ''); + if (!IS_UNDEFINED(result)) return result; + return %StringBuilderConcat(elements, elements_length, ''); + } + // Non-empty separator. + for (var i = 0; i < length; i++) { + var e = array[i]; + if (!IS_UNDEFINED(e) || (i in array)) { + if (!IS_STRING(e)) e = convert(e); + elements[i] = e; + } else { + elements[i] = ''; } } - elements.length = elements_length; - var result = %_FastAsciiArrayJoin(elements, ""); - if (!IS_UNDEFINED(result)) return result; - return %StringBuilderConcat(elements, elements_length, ''); + var result = %_FastAsciiArrayJoin(elements, separator); + if (!IS_UNDEFINED(result)) return result; + + var length2 = (length << 1) - 1; + var elements2 = new $Array(length2); + elements2[0] = elements[0]; + for (var i = 1, j = 1; i < length; i++) { + elements2[j++] = separator; + elements2[j++] = elements[i]; + } + return %StringBuilderConcat(elements2, length2, ''); } finally { // Make sure to pop the visited array no matter what happens. if (is_array) visited_arrays.pop(); -- v8-dev mailing list v8-dev@googlegroups.com http://groups.google.com/group/v8-dev