1 #!/usr/bin/env python 2 3 """ 4 Stream objects. 5 6 Copyright (C) 2015, 2016, 2017 Paul Boddie <paul@boddie.org.uk> 7 8 This program is free software; you can redistribute it and/or modify it under 9 the terms of the GNU General Public License as published by the Free Software 10 Foundation; either version 3 of the License, or (at your option) any later 11 version. 12 13 This program is distributed in the hope that it will be useful, but WITHOUT 14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 15 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more 16 details. 17 18 You should have received a copy of the GNU General Public License along with 19 this program. If not, see <http://www.gnu.org/licenses/>. 20 """ 21 22 from __builtins__.types import check_int, check_string 23 from native import isinstance as _isinstance, fclose, fflush, fread, fwrite 24 25 class filestream: 26 27 "Generic file-oriented stream functionality." 28 29 def __init__(self, encoding=None, bufsize=1024): 30 31 "Initialise the stream with the given 'encoding' and 'bufsize'." 32 33 self.encoding = encoding 34 self.bufsize = bufsize 35 36 # Internal stream details. 37 38 self.__data__ = None 39 40 def _convert(self, bytes): 41 42 "Convert 'bytes' to text if necessary." 43 44 if self.encoding: 45 return unicode(bytes, self.encoding) 46 else: 47 return bytes 48 49 def flush(self): 50 51 "Flush the stream." 52 53 fflush(self.__data__) 54 55 def read(self, n=0): 56 57 "Read 'n' bytes from the stream." 58 59 check_int(n) 60 61 # Read any indicated number of bytes. 62 63 if n > 0: 64 s = fread(self.__data__, n) 65 66 # Read all remaining bytes. 67 68 else: 69 l = [] 70 71 # Read until end-of-file. 72 73 try: 74 while True: 75 self._read_data(l) 76 77 # Handle end-of-file reads. 78 79 except EOFError: 80 pass 81 82 s = "".join(l) 83 84 return self._convert(s) 85 86 def readline(self, n=0): 87 88 """ 89 Read until an end-of-line indicator is encountered or at most 'n' bytes, 90 if indicated. 91 """ 92 93 check_int(n) 94 95 # Read any indicated number of bytes. 96 97 if n > 0: 98 s = fread(self.__data__, n) 99 100 # Read until an end-of-line indicator. 101 102 else: 103 l = [] 104 105 # Read until end-of-line or end-of-file. 106 107 try: 108 while not self._read_until_newline(l): 109 pass 110 111 # Handle end-of-file reads. 112 113 except EOFError: 114 pass 115 116 s = "".join(l) 117 118 return self._convert(s) 119 120 def _read_data(self, l): 121 122 "Read data into 'l'." 123 124 l.append(fread(self.__data__, self.bufsize)) 125 126 def _read_until_newline(self, l): 127 128 "Read data into 'l', returning whether a newline has been read." 129 130 # NOTE: Only POSIX newlines are supported currently. 131 132 s = fread(self.__data__, 1) 133 l.append(s) 134 return s == "\n" 135 136 def readlines(self, n=None): pass 137 138 def write(self, s): 139 140 "Write string 's' to the stream." 141 142 check_string(s) 143 144 # Encode text as bytes if necessary. When the encoding is not set, any 145 # original encoding of the text will be applied. 146 147 if _isinstance(s, unicode): 148 s = s.encode(self.encoding) 149 150 fwrite(self.__data__, s) 151 152 def close(self): 153 154 "Close the stream." 155 156 fclose(self.__data__) 157 158 # vim: tabstop=4 expandtab shiftwidth=4
