old_line -= 1

                new_line -= 1

                context = len(gr) == 5

                old_end += old_line

                new_end += new_line

                if context:

                    # skip context only if it's first line

                    if int(gr[0]) > 1:

                        lines.append({

                            'old_lineno': '...',

                            'new_lineno': '...',

                            'action':     'context',

                            'line':       line,

                        })

                line = diff.next()

                while old_line < old_end or new_line < new_end:

                    if not line:

                        raise Exception('error parsing diff - empty line at -%s+%s' % (old_line, new_line))

                    affects_old = affects_new = False

                    command = line[0]

                    if command == '+':

                        affects_new = True

                        action = 'add'

                        stats[0] += 1

                    elif command == '-':

                        affects_old = True

                        action = 'del'

                        stats[1] += 1

                    elif command == ' ':

                        affects_old = affects_new = True

                        action = 'unmod'

                    else:

                        raise Exception('error parsing diff - unknown command in line %r at -%s+%s' % (line, old_line, new_line))

                    if not self._newline_marker.match(line):

                        old_line += affects_old

                        new_line += affects_new

                        lines.append({

                            'old_lineno':   affects_old and old_line or '',

                            'new_lineno':   affects_new and new_line or '',

                            'action':       action,

                            'line':         self._clean_line(line, command)

                        })

                    line = diff.next()

                    if self._newline_marker.match(line):

                        # we need to append to lines, since this is not

                        # counted in the line specs of diff

                        lines.append({

                            'old_lineno':   '...',

                            'new_lineno':   '...',

                            'action':       'context',

                            'line':         self._clean_line(line, command)

                        })

                        line = diff.next()

                if old_line > old_end:

                        raise Exception('error parsing diff - more than %s "-" lines at -%s+%s' % (old_end, old_line, new_line))

                if new_line > new_end:

                        raise Exception('error parsing diff - more than %s "+" lines at -%s+%s' % (new_end, old_line, new_line))

        except StopIteration:

            pass

        if old_line != old_end or new_line != new_end:

            raise Exception('diff processing broken when old %s<>%s or new %s<>%s line %r' % (old_line, old_end, new_line, new_end, line))

        return chunks, stats

    def _safe_id(self, idstring):

        """Make a string safe for including in an id attribute.

        The HTML spec says that id attributes 'must begin with

        a letter ([A-Za-z]) and may be followed by any number

        of letters, digits ([0-9]), hyphens ("-"), underscores

        ("_"), colons (":"), and periods (".")'. These regexps

        are slightly over-zealous, in that they remove colons

        and periods unnecessarily.

        Whitespace is transformed into underscores, and then

        anything which is not a hyphen or a character that

        matches \w (alphanumerics and underscore) is removed.

        """

        # Transform all whitespace to underscore

        idstring = re.sub(r'\s', "_", idstring)

        # Remove everything that is not a hyphen or a member of \w

        idstring = re.sub(r'(?!-)\W', "", idstring).lower()

        return idstring

    def prepare(self, inline_diff=True):

        """

        of dicts with diff information

        """

        parsed = self._parser(inline_diff=inline_diff)

        self.parsed = True

        self.parsed_diff = parsed

        return parsed

    def as_raw(self, diff_lines=None):

        """

        Returns raw string diff

        """

        return self._diff

        #return u''.join(imap(self._line_counter, self._diff.splitlines(1)))

    def as_html(self, table_class='code-difftable', line_class='line',

                old_lineno_class='lineno old', new_lineno_class='lineno new',

                no_lineno_class='lineno',

                code_class='code', enable_comments=False, parsed_lines=None):

        """

        Return given diff as html table with customized css classes

        """

        def _link_to_if(condition, label, url):

            """

            Generates a link if condition is meet or just the label if not.

            """

            if condition:

                return '''<a href="%(url)s">%(label)s</a>''' % {

                    'url': url,

                    'label': label

                }

            else:

                return label

        if not self.parsed:

            self.prepare()

        diff_lines = self.parsed_diff

        if parsed_lines:

            diff_lines = parsed_lines

        _html_empty = True

        _html = []

        _html.append('''<table class="%(table_class)s">\n''' % {

            'table_class': table_class

        })

        for diff in diff_lines:

            for line in diff['chunks']:

                _html_empty = False

                for change in line:

                    _html.append('''<tr class="%(lc)s %(action)s">\n''' % {

                        'lc': line_class,

                        'action': change['action']

                    })

                    anchor_old_id = ''

                    anchor_new_id = ''

                    anchor_old = "%(filename)s_o%(oldline_no)s" % {

                        'filename': self._safe_id(diff['filename']),

                        'oldline_no': change['old_lineno']

                    }

                    anchor_new = "%(filename)s_n%(oldline_no)s" % {

                        'filename': self._safe_id(diff['filename']),

                        'oldline_no': change['new_lineno']

                    }

                    cond_old = (change['old_lineno'] != '...' and

                                change['old_lineno'])

                    cond_new = (change['new_lineno'] != '...' and

                                change['new_lineno'])

                    no_lineno = (change['old_lineno'] == '...' and

                                 change['new_lineno'] == '...')

                    if cond_old:

                        anchor_old_id = 'id="%s"' % anchor_old

                    if cond_new:

                        anchor_new_id = 'id="%s"' % anchor_new

                    ###########################################################

                    # OLD LINE NUMBER

                    ###########################################################

                    _html.append('''\t<td %(a_id)s class="%(olc)s" %(colspan)s>''' % {

                        'a_id': anchor_old_id,

                        'olc': no_lineno_class if no_lineno else old_lineno_class,

                        'colspan': 'colspan="2"' if no_lineno else ''

                    })

                    _html.append('''%(link)s''' % {

                        'link': _link_to_if(True, change['old_lineno'],

                                            '#%s' % anchor_old)

                    })

                    _html.append('''</td>\n''')

                    ###########################################################

                    # NEW LINE NUMBER

                    ###########################################################

                    if not no_lineno:

                        _html.append('''\t<td %(a_id)s class="%(nlc)s">''' % {

                            'a_id': anchor_new_id,

                            'nlc': new_lineno_class

                    line = lineiter.next()

                    continue

                chunks = []

                filename, old_rev, new_rev = \

                    self._extract_rev(line, lineiter.next())

                files.append({

                    'filename':         filename,

                    'old_revision':     old_rev,

                    'new_revision':     new_rev,

                    'chunks':           chunks

                })

                line = lineiter.next()

                while line:

                    match = self._chunk_re.match(line)

                    if not match:

                        break

                    lines = []

                    chunks.append(lines)

                    old_line, old_end, new_line, new_end = \

                        [int(x or 1) for x in match.groups()[:-1]]

                    old_line -= 1

                    new_line -= 1

                    context = len(match.groups()) == 5

                    old_end += old_line

                    new_end += new_line

                    if context:

                        if not skipfirst:

                            lines.append({

                                'old_lineno': '...',

                                'new_lineno': '...',

                                'action': 'context',

                                'line': line,

                            })

                        else:

                            skipfirst = False

                    line = lineiter.next()

                    while old_line < old_end or new_line < new_end:

                        if line:

                            command, line = line[0], line[1:]

                        else:

                            command = ' '

                        affects_old = affects_new = False

                        # ignore those if we don't expect them

                        if command in '#@':

                            continue

                        elif command == '+':

                            affects_new = True

                            action = 'add'

                        elif command == '-':

                            affects_old = True

                            action = 'del'

                        else:

                            affects_old = affects_new = True

                            action = 'unmod'

                        old_line += affects_old

                        new_line += affects_new

                        lines.append({

                            'old_lineno':   affects_old and old_line or '',

                            'new_lineno':   affects_new and new_line or '',

                            'action':       action,

                            'line':         line

                        })

                        line = lineiter.next()

        except StopIteration:

            pass

        # highlight inline changes

        for file in files:

            for chunk in chunks:

                lineiter = iter(chunk)

                #first = True

                try:

                    while 1:

                        line = lineiter.next()

                        if line['action'] != 'unmod':

                            nextline = lineiter.next()

                            if nextline['action'] == 'unmod' or \

                               nextline['action'] == line['action']:

                                continue

                            self.differ(line, nextline)

                except StopIteration:

                    pass

        return files

    def prepare(self):

        """

        of dicts

        """

        return self._parse_udiff()

    def _safe_id(self, idstring):

        """Make a string safe for including in an id attribute.

        The HTML spec says that id attributes 'must begin with

        a letter ([A-Za-z]) and may be followed by any number

        of letters, digits ([0-9]), hyphens ("-"), underscores

        ("_"), colons (":"), and periods (".")'. These regexps

        are slightly over-zealous, in that they remove colons

        and periods unnecessarily.

        Whitespace is transformed into underscores, and then

        anything which is not a hyphen or a character that

        matches \w (alphanumerics and underscore) is removed.

        """

        # Transform all whitespace to underscore

        idstring = re.sub(r'\s', "_", idstring)

        # Remove everything that is not a hyphen or a member of \w

        idstring = re.sub(r'(?!-)\W', "", idstring).lower()

        return idstring

    def raw_diff(self):

        """

        Returns raw string as udiff

        """

        udiff_copy = self.copy_iterator()

        if self.__format == 'gitdiff':

            udiff_copy = self._parse_gitdiff(udiff_copy)

        return u''.join(udiff_copy)

    def as_html(self, table_class='code-difftable', line_class='line',

                new_lineno_class='lineno old', old_lineno_class='lineno new',

                code_class='code'):

        """

        Return udiff as html table with customized css classes

        """

        def _link_to_if(condition, label, url):

            """

            Generates a link if condition is meet or just the label if not.

            """

            if condition:

                return '''<a href="%(url)s">%(label)s</a>''' % {'url': url,

                                                                'label': label}

            else:

                return label

        diff_lines = self.prepare()

        _html_empty = True

        _html = []

        _html.append('''<table class="%(table_class)s">\n'''

                     % {'table_class': table_class})

        for diff in diff_lines:

            for line in diff['chunks']:

                _html_empty = False

                for change in line:

                    _html.append('''<tr class="%(line_class)s %(action)s">\n'''

                                 % {'line_class': line_class,

                                    'action': change['action']})

                    anchor_old_id = ''

                    anchor_new_id = ''

                    anchor_old = "%(filename)s_o%(oldline_no)s" % \

                                {'filename': self._safe_id(diff['filename']),

                                 'oldline_no': change['old_lineno']}

                    anchor_new = "%(filename)s_n%(oldline_no)s" % \

                                {'filename': self._safe_id(diff['filename']),

                                 'oldline_no': change['new_lineno']}

                    cond_old = change['old_lineno'] != '...' and \

                                                        change['old_lineno']

                    cond_new = change['new_lineno'] != '...' and \

                                                        change['new_lineno']

                    if cond_old:

                        anchor_old_id = 'id="%s"' % anchor_old

                    if cond_new:

                        anchor_new_id = 'id="%s"' % anchor_new

                    ###########################################################

                    # OLD LINE NUMBER

                    ###########################################################

                    _html.append('''\t<td %(a_id)s class="%(old_lineno_cls)s">'''

                                  % {'a_id': anchor_old_id,

                                     'old_lineno_cls': old_lineno_class})

                    _html.append('''<pre>%(link)s</pre>'''

                                 % {'link':

                                    _link_to_if(cond_old, change['old_lineno'], '#%s' % anchor_old)})

                    _html.append('''</td>\n''')

                    ###########################################################

                    # NEW LINE NUMBER

                    ###########################################################

                    _html.append('''\t<td %(a_id)s class="%(new_lineno_cls)s">'''

                                  % {'a_id': anchor_new_id,

                                     'new_lineno_cls': new_lineno_class})