127 lines
3.3 KiB
Python
Executable File
127 lines
3.3 KiB
Python
Executable File
"""
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vis.py
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======
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Ctypes based module to access libbsd's strvis & strunvis functions.
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The `vis` function is the equivalent of strvis.
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The `unvis` function is the equivalent of strunvis.
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All functions accept unicode string as input and return a unicode string.
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Constants:
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----------
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* to select alternate encoding format
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`VIS_OCTAL`: use octal \ddd format
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`VIS_CSTYLE`: use \[nrft0..] where appropiate
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* to alter set of characters encoded
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(default is to encode all non-graphic except space, tab, and newline).
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`VIS_SP`: also encode space
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`VIS_TAB`: also encode tab
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`VIS_NL`: also encode newline
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`VIS_WHITE`: same as (VIS_SP | VIS_TAB | VIS_NL)
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`VIS_SAFE`: only encode "unsafe" characters
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* other
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`VIS_NOSLASH`: inhibit printing '\'
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`VIS_HTTP1808`: http-style escape % hex hex
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`VIS_HTTPSTYLE`: http-style escape % hex hex
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`VIS_MIMESTYLE`: mime-style escape = HEX HEX
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`VIS_HTTP1866`: http-style &#num; or &string;
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`VIS_NOESCAPE`: don't decode `\'
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`VIS_GLOB`: encode glob(3) magic characters
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:Authors:
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- ju1ius (http://github.com/ju1ius)
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:Version: 1
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:Date: 2014-01-05
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"""
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from ctypes import CDLL, c_char_p, c_int
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from ctypes.util import find_library
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__all__ = [
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'vis', 'unvis',
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'VIS_OCTAL', 'VIS_CSTYLE',
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'VIS_SP', 'VIS_TAB', 'VIS_NL', 'VIS_WHITE', 'VIS_SAFE',
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'VIS_NOSLASH', 'VIS_HTTP1808', 'VIS_HTTPSTYLE', 'VIS_MIMESTYLE',
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'VIS_HTTP1866', 'VIS_NOESCAPE', 'VIS_GLOB'
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]
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#############################################################
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# Constants from bsd/vis.h
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#############################################################
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#to select alternate encoding format
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VIS_OCTAL = 0x0001
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VIS_CSTYLE = 0x0002
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# to alter set of characters encoded
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# (default is to encode all non-graphic except space, tab, and newline).
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VIS_SP = 0x0004
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VIS_TAB = 0x0008
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VIS_NL = 0x0010
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VIS_WHITE = VIS_SP | VIS_TAB | VIS_NL
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VIS_SAFE = 0x0020
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# other
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VIS_NOSLASH = 0x0040
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VIS_HTTP1808 = 0x0080
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VIS_HTTPSTYLE = 0x0080
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VIS_MIMESTYLE = 0x0100
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VIS_HTTP1866 = 0x0200
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VIS_NOESCAPE = 0x0400
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VIS_GLOB = 0x1000
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#############################################################
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# Import libbsd/vis functions
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#############################################################
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_libbsd = CDLL(find_library('bsd'))
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_strvis = _libbsd.strvis
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_strvis.argtypes = [c_char_p, c_char_p, c_int]
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_strvis.restype = c_int
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_strunvis = _libbsd.strunvis
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_strvis.argtypes = [c_char_p, c_char_p]
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_strvis.restype = c_int
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def vis(src, flags=VIS_WHITE):
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"""
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Encodes the string `src` into libbsd's vis encoding.
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`flags` must be one of the VIS_* constants
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C definition:
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int strvis(char *dst, char *src, int flags);
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"""
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src = bytes(src, 'utf-8')
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dst_p = c_char_p(bytes(len(src) * 4))
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src_p = c_char_p(src)
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flags = c_int(flags)
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bytes_written = _strvis(dst_p, src_p, flags)
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if -1 == bytes_written:
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raise RuntimeError('vis failed to encode string "{}"'.format(src))
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return dst_p.value.decode('utf-8')
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def unvis(src):
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"""
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Decodes a string encoded by vis.
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C definition:
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int strunvis(char *dst, char *src);
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"""
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src = bytes(src, 'utf-8')
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dst_p = c_char_p(bytes(len(src)))
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src_p = c_char_p(src)
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bytes_written = _strunvis(dst_p, src_p)
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if -1 == bytes_written:
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raise RuntimeError('unvis failed to decode string "{}"'.format(src))
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return dst_p.value.decode('utf-8')
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