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>
24 ------------------------------------------------------
25 Functions for improving textual output.
27 Copyright: 2015 Intra2net AG
31 ------------------------------------------------------
32 This module has two parts. Part 1 includes:
34 - head_and_tail: shows the first few and last few elements of an iterable that
35 could potentially be pretty long
36 - size_str: textual representation of data size
38 Part2 contains functions for coloring text, a poor-man's version of other
39 modules like :py:mod:`colorclass` (which is now also available on Intra2net
42 Functions might cause trouble when combined, e.g.::
44 bold('this is bold and ' + red('red') + ' and ' + green('green'))
46 will show the text "and green" not in bold. May have to try using specific
47 end-of-color or end-of-style escape sequences instead of 0 (reset-everything).
50 .. seealso:: http://stackoverflow.com/questions/287871/print-in-terminal-with-colors-using-python
51 .. seealso:: https://en.wikipedia.org/wiki/ANSI_escape_code
52 .. seealso:: :py:mod:`textwrap`
56 ------------------------------------------------------
60 from builtins import print as _builtin_print
61 except ImportError: # different name in py2
62 from __builtin__ import print as _builtin_print
64 from functools import partial
65 from itertools import islice
67 from .type_helpers import isstr
68 from sys import stdout
71 def head_and_tail(iterable, n_head=20, n_tail=20, n_elems=None,
72 skip_elem="...(skipping {n_skipped} elements)..."):
74 Convenient way to shorten a possibly very long iterable before printing.
76 Will not modify short iterables, but for longer lists/tuples/... will only
77 yield first few, then a message how many were skipped and the last few
79 The iterable does not even have to have a `len(..)` method if argument
80 `n_elems` is given. Only needs a `next(..)` method. However, for very long
81 iterables this will be faster if random element access is provided via []
83 :param iterable: an iterable
84 :type iterable: anything that can be iterated over
85 :param int n_head: number of starting elements to yield (optional)
86 :param int n_tail: number of ending elements to yield (optional)
87 :param int n_elems: number of elements in iterable; give this to avoid a
88 call to `len(iterable)` (optional)
89 :param skip_elem: element to replace bulge of skipped elements; yielded
90 once at most; None to not yield a skip replacement; if str
91 then it will be formatted; optional, defaults to string
92 with number of skipped elems
93 :type skip_elem: anything you like
94 :yields: `n_head+n_tail` elements from iterable plus the `skip_elem` (or
95 less if iterable is shorter than this).
97 .. seealso:: :py:func:`slice`, :py:func:`itertools.islice`, :py:func:`textwrap.shorten`
101 n_elems = len(iterable)
103 # yield first n_head elems
105 for elem in iterable:
112 if n_elems > n_head + n_tail:
113 if skip_elem is not None:
115 yield skip_elem.format(n_skipped=n_elems-n_head-n_tail)
118 elif n_elems <= n_head:
123 # try to access end directly
124 for elem in iterable[n_elems-n_tail:]:
127 # if this did not work, then need to iterate through whole thing
128 # do this as in itertool recipe for consume():
129 n_skip = n_elems - n_head - n_tail - 1
130 next(islice(iterable, n_skip, n_skip), None)
131 for elem in iterable:
135 def size_str(byte_number, is_diff=False):
137 Create a human-readable text representation of a file size.
139 Rounds and shortens size to something easily human-readable like '1.5 GB'.
141 :param int byte_number: Number of bytes to express as text
142 :param bool is_diff: Set to True to include a '+' or '-' in output;
144 :returns: textual representation of data
148 units = '', 'k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'
150 thresh_add_comma = 10. # below this, return 1.2G, above this return 12G
159 curr_num = abs(float(byte_number))
163 if curr_num > factor:
166 elif curr_num < thresh_add_comma and unit != 'B': # e.g. 1.2G
167 return '{2}{0:.1f} {1}B'.format(curr_num, unit, sign_str)
168 else: # e.g. 12G or 1B
169 return '{2}{0:d} {1}B'.format(int(round(curr_num)), unit, sign_str)
171 # have an impossible amount of data. (>1024**4 GB)
172 # undo last "/factor" and show thousand-separator
173 return '{2}{0:,d} {1}B'.format(int(round(curr_num*factor)), units[-1],
177 ###############################################################################
178 # TEXT FORMATTING/COLORING
179 ###############################################################################
181 COLOR_BLACK = 'black'
183 COLOR_GREEN = 'green'
184 COLOR_YELLOW = 'yellow'
186 COLOR_MAGENTA = 'magenta'
188 COLOR_WHITE = 'white'
197 _COLOR_TO_CODE = dict(zip([COLOR_BLACK, COLOR_RED, COLOR_GREEN, COLOR_YELLOW, \
198 COLOR_BLUE, COLOR_MAGENTA, COLOR_CYAN, COLOR_WHITE],
201 _ANSI_ESCAPE_SURROUND = '\x1b[{}m{}\x1b[0m'
203 # only color output if we are writing output to a terminal (not a file or so)
205 _STDOUT_IS_TTY = stdout.isatty()
207 # stdout might be some wrapper around the real thing to capture output
208 _STDOUT_IS_TTY = False
211 def colored(text, foreground=None, background=None, style=None):
212 """ return text with given foreground/background ANSI color escape seqence
214 :param str text: text to color
215 :param str style: one of the style constants above
216 :param str foreground: one of the color constants to use for text color
217 or None to leave as-is
218 :param str foreground: one of the color constants to use for background
219 or None to leave as-is
220 :param style: single STYLE constant or iterable of those
221 or None to leave as-is
222 :returns: text surrounded in ansi escape sequences
225 if foreground is None and background is None and style is None:
230 prefixes.append(str(30 + _COLOR_TO_CODE[foreground]))
232 prefixes.append(str(40 + _COLOR_TO_CODE[background]))
235 elif isinstance(style, int):
236 prefixes.append(str(style))
237 else: # assume iterable of ints
238 prefixes.extend(str(style_item) for style_item in style)
240 return _ANSI_ESCAPE_SURROUND.format(';'.join(prefixes), text)
243 def print(text, *args, **kwargs): # pylint: disable=redefined-builtin
244 """ like the builtin print function but also accepts color args
246 If any arg of :py:func:`colored` is given in `kwargs`, will run text with
247 color-args through that function. Runs built-in :py:func:`print`
248 function with result and other args.
250 ...todo:: color all args, not just first
256 # remove color info from kwargs
258 foreground = kwargs['foreground']
259 del kwargs['foreground']
264 background = kwargs['background']
265 del kwargs['background']
270 style = kwargs['style']
276 text_c = colored(text, foreground, background, style)
280 _builtin_print(text_c, *args, **kwargs)
283 black = partial(print, foreground=COLOR_BLACK)
284 red = partial(print, foreground=COLOR_RED)
285 green = partial(print, foreground=COLOR_GREEN)
286 yellow = partial(print, foreground=COLOR_YELLOW)
287 blue = partial(print, foreground=COLOR_BLUE)
288 magenta = partial(print, foreground=COLOR_MAGENTA)
289 cyan = partial(print, foreground=COLOR_CYAN)
290 white = partial(print, foreground=COLOR_WHITE)
292 normal = partial(print, style=STYLE_NORMAL)
293 bold = partial(print, style=STYLE_BOLD)
294 underline = partial(print, style=STYLE_UNDERLINE)
295 blink = partial(print, style=STYLE_BLINK)
296 reverse = partial(print, style=STYLE_REVERSE)