1 files changed, 185 insertions, 0 deletions
diff --git a/asciidoc/utils.py b/asciidoc/utils.py
new file mode 100644
index 0000000..fee2c00
--- /dev/null
+++ b/asciidoc/utils.py
@@ -0,0 +1,185 @@
+import locale
+import math
+import os
+import re
+import time
+from typing import Optional
+import unicodedata
+
+
+def userdir() -> Optional[str]:
+    """
+    Return user's home directory or None if it is not defined.
+    """
+    result = os.path.expanduser('~')
+    if result == '~':
+        result = None
+    return result
+
+
+def file_in(fname, directory) -> bool:
+    """Return True if file fname resides inside directory."""
+    assert os.path.isfile(fname)
+    # Empty directory (not to be confused with None) is the current directory.
+    if directory == '':
+        directory = os.getcwd()
+    else:
+        assert os.path.isdir(directory)
+        directory = os.path.realpath(directory)
+    fname = os.path.realpath(fname)
+    return os.path.commonprefix((directory, fname)) == directory
+
+
+def assign(dst, src):
+    """Assign all attributes from 'src' object to 'dst' object."""
+    for a, v in list(src.__dict__.items()):
+        setattr(dst, a, v)
+
+
+def strip_quotes(s):
+    """Trim white space and, if necessary, quote characters from s."""
+    s = s.strip()
+    # Strip quotation mark characters from quoted strings.
+    if len(s) >= 3 and s[0] == '"' and s[-1] == '"':
+        s = s[1:-1]
+    return s
+
+
+def is_re(s) -> bool:
+    """Return True if s is a valid regular expression else return False."""
+    try:
+        re.compile(s)
+        return True
+    except BaseException:
+        return False
+
+
+def re_join(relist):
+    """Join list of regular expressions re1,re2,... to single regular
+    expression (re1)|(re2)|..."""
+    if len(relist) == 0:
+        return None
+    result = []
+    # Delete named groups to avoid ambiguity.
+    for s in relist:
+        result.append(re.sub(r'\?P<\S+?>', '', s))
+    result = ')|('.join(result)
+    result = '(' + result + ')'
+    return result
+
+
+def lstrip_list(s):
+    """
+    Return list with empty items from start of list removed.
+    """
+    for i in range(len(s)):
+        if s[i]:
+            break
+    else:
+        return []
+    return s[i:]
+
+
+def rstrip_list(s):
+    """
+    Return list with empty items from end of list removed.
+    """
+    for i in range(len(s) - 1, -1, -1):
+        if s[i]:
+            break
+    else:
+        return []
+    return s[:i + 1]
+
+
+def strip_list(s):
+    """
+    Return list with empty items from start and end of list removed.
+    """
+    s = lstrip_list(s)
+    s = rstrip_list(s)
+    return s
+
+
+def is_array(obj) -> bool:
+    """
+    Return True if object is list or tuple type.
+    """
+    return isinstance(obj, list) or isinstance(obj, tuple)
+
+
+def dovetail(lines1, lines2):
+    """
+    Append list or tuple of strings 'lines2' to list 'lines1'.  Join the last
+    non-blank item in 'lines1' with the first non-blank item in 'lines2' into a
+    single string.
+    """
+    assert is_array(lines1)
+    assert is_array(lines2)
+    lines1 = strip_list(lines1)
+    lines2 = strip_list(lines2)
+    if not lines1 or not lines2:
+        return list(lines1) + list(lines2)
+    result = list(lines1[:-1])
+    result.append(lines1[-1] + lines2[0])
+    result += list(lines2[1:])
+    return result
+
+
+def dovetail_tags(stag, content, etag):
+    """Merge the end tag with the first content line and the last
+    content line with the end tag. This ensures verbatim elements don't
+    include extraneous opening and closing line breaks."""
+    return dovetail(dovetail(stag, content), etag)
+
+
+def py2round(n, d=0):
+    """Utility function to get python2 rounding in python3. Python3 changed it such that
+    given two equally close multiples, it'll round towards the even choice. For example,
+    round(42.5) == 42 instead of the expected round(42.5) == 43). This function gives us
+    back that functionality."""
+    p = 10 ** d
+    return float(math.floor((n * p) + math.copysign(0.5, n))) / p
+
+
+east_asian_widths = {
+    'W': 2,   # Wide
+    'F': 2,   # Full-width (wide)
+    'Na': 1,  # Narrow
+    'H': 1,   # Half-width (narrow)
+    'N': 1,   # Neutral (not East Asian, treated as narrow)
+    'A': 1,   # Ambiguous (s/b wide in East Asian context, narrow otherwise, but that
+              #   doesn't work)
+}
+"""Mapping of result codes from `unicodedata.east_asian_width()` to character
+column widths."""
+
+
+def column_width(s):
+    width = 0
+    for c in s:
+        width += east_asian_widths[unicodedata.east_asian_width(c)]
+    return width
+
+
+def date_time_str(t):
+    """Convert seconds since the Epoch to formatted local date and time strings."""
+    source_date_epoch = os.environ.get('SOURCE_DATE_EPOCH')
+    if source_date_epoch is not None:
+        t = time.gmtime(min(t, int(source_date_epoch)))
+    else:
+        t = time.localtime(t)
+    date_str = time.strftime('%Y-%m-%d', t)
+    time_str = time.strftime('%H:%M:%S', t)
+    if source_date_epoch is not None:
+        time_str += ' UTC'
+    elif time.daylight and t.tm_isdst == 1:
+        time_str += ' ' + time.tzname[1]
+    else:
+        time_str += ' ' + time.tzname[0]
+    # Attempt to convert the localtime to the output encoding.
+    try:
+        time_str = time_str.decode(locale.getdefaultlocale()[1])
+    except Exception:
+        pass
+    return date_str, time_str