Fixed #6668 -- Optimized utils.text wrap function

def wrap(text, width):

    """

    A word-wrap function that preserves existing line breaks and most spaces in

    the text. Expects that existing line breaks are posix newlines.

    A word-wrap function that preserves existing line breaks. Expects that

    existing line breaks are posix newlines.

    All white space is preserved except added line breaks consume the space on

    which they break the line.

    Long words are not wrapped, so the output text may have lines longer than

    ``width``.

    """

    text = force_text(text)

    def _generator():

        it = iter(text.split(' '))

        word = next(it)

        yield word

        pos = len(word) - word.rfind('\n') - 1

        for word in it:

            if "\n" in word:

                lines = word.split('\n')

            else:

                lines = (word,)

            pos += len(lines[0]) + 1

            if pos > width:

                yield '\n'

                pos = len(lines[-1])

            else:

                yield ' '

                if len(lines) > 1:

                    pos = len(lines[-1])

            yield word

        for line in text.splitlines(True):  # True keeps trailing linebreaks

            max_width = min((line.endswith('\n') and width + 1 or width), width)

            while len(line) > max_width:

                space = line[:max_width + 1].rfind(' ') + 1

                if space == 0:

                    space = line.find(' ') + 1

                    if space == 0:

                        yield line

                        line = ''

                        break

                yield '%s\n' % line[:space - 1]

                line = line[space:]

                max_width = min((line.endswith('\n') and width + 1 or width), width)

            if line:

                yield line

    return ''.join(_generator())

wrap = allow_lazy(wrap, six.text_type)