1 # The software in this package is distributed under the GNU General
2 # Public License version 2 (with a special exception described below).
4 # A copy of GNU General Public License (GPL) is included in this distribution,
5 # in the file COPYING.GPL.
7 # As a special exception, if other files instantiate templates or use macros
8 # or inline functions from this file, or you compile this file and link it
9 # with other works to produce a work based on this file, this file
10 # does not by itself cause the resulting work to be covered
11 # by the GNU General Public License.
13 # However the source code for this file must still be made available
14 # in accordance with section (3) of the GNU General Public License.
16 # This exception does not invalidate any other reasons why a work based
17 # on this file might be covered by the GNU General Public License.
19 # Copyright (c) 2016-2018 Intra2net AG <info@intra2net.com>
22 Functions for improving textual output.
24 Copyright: 2015 Intra2net AG
26 This module has two parts. Part 1 includes:
27 - head_and_tail: shows the first few and last few elements of an iterable that
28 could potentially be pretty long
29 - size_str: textual representation of data size
31 Part2 contains functions for coloring text, a poor-man's version of other
32 modules like :py:mod:`colorclass` (which is now also available on Intra2net
35 Functions might cause trouble when combined, e.g.::
37 bold('this is bold and ' + red('red') + ' and ' + green('green'))
39 will show the text "and green" not in bold. May have to try using specific
40 end-of-color or end-of-style escape sequences instead of 0 (reset-everything).
43 .. seealso:: http://stackoverflow.com/questions/287871/print-in-terminal-with-colors-using-python
44 .. seealso:: https://en.wikipedia.org/wiki/ANSI_escape_code
45 .. seealso:: :py:mod:`textwrap`
48 from builtins import print as _builtin_print
50 from functools import partial
51 from itertools import islice
53 from .type_helpers import isstr
54 from sys import stdout
57 def head_and_tail(iterable, n_head=20, n_tail=20, n_elems=None,
58 skip_elem="...(skipping {n_skipped} elements)..."):
60 Convenient way to shorten a possibly very long iterable before printing.
62 Will not modify short iterables, but for longer lists/tuples/... will only
63 yield first few, then a message how many were skipped and the last few
65 The iterable does not even have to have a `len(..)` method if argument
66 `n_elems` is given. Only needs a `next(..)` method. However, for very long
67 iterables this will be faster if random element access is provided via []
69 :param iterable: an iterable
70 :type iterable: anything that can be iterated over
71 :param int n_head: number of starting elements to yield (optional)
72 :param int n_tail: number of ending elements to yield (optional)
73 :param int n_elems: number of elements in iterable; give this to avoid a
74 call to `len(iterable)` (optional)
75 :param skip_elem: element to replace bulge of skipped elements; yielded
76 once at most; None to not yield a skip replacement; if str
77 then it will be formatted; optional, defaults to string
78 with number of skipped elems
79 :type skip_elem: anything you like
80 :yields: `n_head+n_tail` elements from iterable plus the `skip_elem` (or
81 less if iterable is shorter than this).
83 .. seealso:: :py:func:`slice`, :py:func:`itertools.islice`, :py:func:`textwrap.shorten`
87 n_elems = len(iterable)
89 # yield first n_head elems
98 if n_elems > n_head + n_tail:
99 if skip_elem is not None:
101 yield skip_elem.format(n_skipped=n_elems-n_head-n_tail)
104 elif n_elems <= n_head:
109 # try to access end directly
110 for elem in iterable[n_elems-n_tail:]:
113 # if this did not work, then need to iterate through whole thing
114 # do this as in itertool recipe for consume():
115 n_skip = n_elems - n_head - n_tail - 1
116 next(islice(iterable, n_skip, n_skip), None)
117 for elem in iterable:
121 def size_str(byte_number, is_diff=False):
123 Create a human-readable text representation of a file size.
125 Rounds and shortens size to something easily human-readable like '1.5 GB'.
127 :param float byte_number: Number of bytes to express as text
128 :param bool is_diff: Set to True to include a '+' or '-' in output;
130 :returns: textual representation of data
134 units = '', 'k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'
136 thresh_add_comma = 10. # below this, return 1.2G, above this return 12G
145 curr_num = abs(float(byte_number))
149 if curr_num > factor:
152 elif curr_num < thresh_add_comma and unit != 'B': # e.g. 1.2G
153 return '{2}{0:.1f} {1}B'.format(curr_num, unit, sign_str)
154 else: # e.g. 12G or 1B
155 return '{2}{0:d} {1}B'.format(int(round(curr_num)), unit, sign_str)
157 # have an impossible amount of data. (>1024**4 GB)
158 # undo last "/factor" and show thousand-separator
159 return f'{sign_str}{int(round(curr_num*factor)):,d} {units[-1]}B'
162 ###############################################################################
163 # TEXT FORMATTING/COLORING
164 ###############################################################################
166 COLOR_BLACK = 'black'
168 COLOR_GREEN = 'green'
169 COLOR_YELLOW = 'yellow'
171 COLOR_MAGENTA = 'magenta'
173 COLOR_WHITE = 'white'
182 _COLOR_TO_CODE = dict(zip([COLOR_BLACK, COLOR_RED, COLOR_GREEN, COLOR_YELLOW,
183 COLOR_BLUE, COLOR_MAGENTA, COLOR_CYAN, COLOR_WHITE],
186 _ANSI_ESCAPE_SURROUND = '\x1b[{}m{}\x1b[0m'
188 # only color output if we are writing output to a terminal (not a file or so)
190 _STDOUT_IS_TTY = stdout.isatty()
192 # stdout might be some wrapper around the real thing to capture output
193 _STDOUT_IS_TTY = False
196 def colored(text, foreground=None, background=None, style=None):
197 """ return text with given foreground/background ANSI color escape sequence
199 :param str text: text to color
200 :param str style: one of the style constants above
201 :param str foreground: one of the color constants to use for text color
202 or None to leave as-is
203 :param str background: one of the color constants to use for background
204 or None to leave as-is
205 :param style: single STYLE constant or iterable of those
206 or None to leave as-is
207 :returns: text surrounded in ansi escape sequences
210 if foreground is None and background is None and style is None:
215 prefixes.append(str(30 + _COLOR_TO_CODE[foreground]))
217 prefixes.append(str(40 + _COLOR_TO_CODE[background]))
220 elif isinstance(style, int):
221 prefixes.append(str(style))
222 else: # assume iterable of ints
223 prefixes.extend(str(style_item) for style_item in style)
225 return _ANSI_ESCAPE_SURROUND.format(';'.join(prefixes), text)
228 def print(text, *args, **kwargs): # pylint: disable=redefined-builtin
229 """ like the builtin print function but also accepts color args
231 If any arg of :py:func:`colored` is given in `kwargs`, will run text with
232 color-args through that function. Runs built-in :py:func:`print`
233 function with result and other args.
235 ...todo:: color all args, not just first
241 # remove color info from kwargs
243 foreground = kwargs['foreground']
244 del kwargs['foreground']
249 background = kwargs['background']
250 del kwargs['background']
255 style = kwargs['style']
261 text_c = colored(text, foreground, background, style)
265 _builtin_print(text_c, *args, **kwargs)
268 black = partial(print, foreground=COLOR_BLACK)
269 red = partial(print, foreground=COLOR_RED)
270 green = partial(print, foreground=COLOR_GREEN)
271 yellow = partial(print, foreground=COLOR_YELLOW)
272 blue = partial(print, foreground=COLOR_BLUE)
273 magenta = partial(print, foreground=COLOR_MAGENTA)
274 cyan = partial(print, foreground=COLOR_CYAN)
275 white = partial(print, foreground=COLOR_WHITE)
277 normal = partial(print, style=STYLE_NORMAL)
278 bold = partial(print, style=STYLE_BOLD)
279 underline = partial(print, style=STYLE_UNDERLINE)
280 blink = partial(print, style=STYLE_BLINK)
281 reverse = partial(print, style=STYLE_REVERSE)