Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 1 | """ codecs -- Python Codec Registry, API and helpers. |
| 2 | |
| 3 | |
| 4 | Written by Marc-Andre Lemburg (mal@lemburg.com). |
| 5 | |
| 6 | (c) Copyright CNRI, All Rights Reserved. NO WARRANTY. |
| 7 | |
| 8 | """#" |
| 9 | |
Marc-André Lemburg | b28de0d | 2002-12-12 17:37:50 +0000 | [diff] [blame] | 10 | import __builtin__, sys |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 11 | |
| 12 | ### Registry and builtin stateless codec functions |
| 13 | |
Guido van Rossum | b95de4f | 2000-03-31 17:25:23 +0000 | [diff] [blame] | 14 | try: |
| 15 | from _codecs import * |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 16 | except ImportError, why: |
Guido van Rossum | b95de4f | 2000-03-31 17:25:23 +0000 | [diff] [blame] | 17 | raise SystemError,\ |
| 18 | 'Failed to load the builtin codecs: %s' % why |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 19 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 20 | __all__ = ["register", "lookup", "open", "EncodedFile", "BOM", "BOM_BE", |
Walter Dörwald | 474458d | 2002-06-04 15:16:29 +0000 | [diff] [blame] | 21 | "BOM_LE", "BOM32_BE", "BOM32_LE", "BOM64_BE", "BOM64_LE", |
| 22 | "BOM_UTF8", "BOM_UTF16", "BOM_UTF16_LE", "BOM_UTF16_BE", |
Walter Dörwald | 3aeb632 | 2002-09-02 13:14:32 +0000 | [diff] [blame] | 23 | "BOM_UTF32", "BOM_UTF32_LE", "BOM_UTF32_BE", |
| 24 | "strict_errors", "ignore_errors", "replace_errors", |
| 25 | "xmlcharrefreplace_errors", |
| 26 | "register_error", "lookup_error"] |
Skip Montanaro | e99d5ea | 2001-01-20 19:54:20 +0000 | [diff] [blame] | 27 | |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 28 | ### Constants |
| 29 | |
| 30 | # |
Walter Dörwald | 474458d | 2002-06-04 15:16:29 +0000 | [diff] [blame] | 31 | # Byte Order Mark (BOM = ZERO WIDTH NO-BREAK SPACE = U+FEFF) |
| 32 | # and its possible byte string values |
| 33 | # for UTF8/UTF16/UTF32 output and little/big endian machines |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 34 | # |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 35 | |
Walter Dörwald | 474458d | 2002-06-04 15:16:29 +0000 | [diff] [blame] | 36 | # UTF-8 |
| 37 | BOM_UTF8 = '\xef\xbb\xbf' |
| 38 | |
| 39 | # UTF-16, little endian |
| 40 | BOM_LE = BOM_UTF16_LE = '\xff\xfe' |
| 41 | |
| 42 | # UTF-16, big endian |
| 43 | BOM_BE = BOM_UTF16_BE = '\xfe\xff' |
| 44 | |
| 45 | # UTF-32, little endian |
| 46 | BOM_UTF32_LE = '\xff\xfe\x00\x00' |
| 47 | |
| 48 | # UTF-32, big endian |
| 49 | BOM_UTF32_BE = '\x00\x00\xfe\xff' |
| 50 | |
Marc-André Lemburg | b28de0d | 2002-12-12 17:37:50 +0000 | [diff] [blame] | 51 | if sys.byteorder == 'little': |
Walter Dörwald | 474458d | 2002-06-04 15:16:29 +0000 | [diff] [blame] | 52 | |
Marc-André Lemburg | b28de0d | 2002-12-12 17:37:50 +0000 | [diff] [blame] | 53 | # UTF-16, native endianness |
| 54 | BOM = BOM_UTF16 = BOM_UTF16_LE |
| 55 | |
| 56 | # UTF-32, native endianness |
| 57 | BOM_UTF32 = BOM_UTF32_LE |
| 58 | |
| 59 | else: |
| 60 | |
| 61 | # UTF-16, native endianness |
| 62 | BOM = BOM_UTF16 = BOM_UTF16_BE |
| 63 | |
| 64 | # UTF-32, native endianness |
| 65 | BOM_UTF32 = BOM_UTF32_BE |
Walter Dörwald | 474458d | 2002-06-04 15:16:29 +0000 | [diff] [blame] | 66 | |
| 67 | # Old broken names (don't use in new code) |
| 68 | BOM32_LE = BOM_UTF16_LE |
| 69 | BOM32_BE = BOM_UTF16_BE |
| 70 | BOM64_LE = BOM_UTF32_LE |
| 71 | BOM64_BE = BOM_UTF32_BE |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 72 | |
| 73 | |
| 74 | ### Codec base classes (defining the API) |
| 75 | |
| 76 | class Codec: |
| 77 | |
| 78 | """ Defines the interface for stateless encoders/decoders. |
| 79 | |
Walter Dörwald | 7f82f79 | 2002-11-19 21:42:53 +0000 | [diff] [blame] | 80 | The .encode()/.decode() methods may use different error |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 81 | handling schemes by providing the errors argument. These |
Walter Dörwald | 7f82f79 | 2002-11-19 21:42:53 +0000 | [diff] [blame] | 82 | string values are predefined: |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 83 | |
Guido van Rossum | d8855fd | 2000-03-24 22:14:19 +0000 | [diff] [blame] | 84 | 'strict' - raise a ValueError error (or a subclass) |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 85 | 'ignore' - ignore the character and continue with the next |
| 86 | 'replace' - replace with a suitable replacement character; |
| 87 | Python will use the official U+FFFD REPLACEMENT |
Walter Dörwald | 7f82f79 | 2002-11-19 21:42:53 +0000 | [diff] [blame] | 88 | CHARACTER for the builtin Unicode codecs on |
| 89 | decoding and '?' on encoding. |
| 90 | 'xmlcharrefreplace' - Replace with the appropriate XML |
| 91 | character reference (only for encoding). |
| 92 | 'backslashreplace' - Replace with backslashed escape sequences |
| 93 | (only for encoding). |
| 94 | |
| 95 | The set of allowed values can be extended via register_error. |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 96 | |
| 97 | """ |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 98 | def encode(self, input, errors='strict'): |
Guido van Rossum | 1c89b0e | 2000-04-11 15:41:38 +0000 | [diff] [blame] | 99 | |
Fred Drake | 3e74c0d | 2000-03-17 15:40:35 +0000 | [diff] [blame] | 100 | """ Encodes the object input and returns a tuple (output |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 101 | object, length consumed). |
| 102 | |
| 103 | errors defines the error handling to apply. It defaults to |
| 104 | 'strict' handling. |
| 105 | |
| 106 | The method may not store state in the Codec instance. Use |
| 107 | StreamCodec for codecs which have to keep state in order to |
| 108 | make encoding/decoding efficient. |
| 109 | |
| 110 | The encoder must be able to handle zero length input and |
| 111 | return an empty object of the output object type in this |
| 112 | situation. |
| 113 | |
| 114 | """ |
| 115 | raise NotImplementedError |
| 116 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 117 | def decode(self, input, errors='strict'): |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 118 | |
| 119 | """ Decodes the object input and returns a tuple (output |
| 120 | object, length consumed). |
| 121 | |
| 122 | input must be an object which provides the bf_getreadbuf |
| 123 | buffer slot. Python strings, buffer objects and memory |
| 124 | mapped files are examples of objects providing this slot. |
Guido van Rossum | 1c89b0e | 2000-04-11 15:41:38 +0000 | [diff] [blame] | 125 | |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 126 | errors defines the error handling to apply. It defaults to |
| 127 | 'strict' handling. |
| 128 | |
| 129 | The method may not store state in the Codec instance. Use |
| 130 | StreamCodec for codecs which have to keep state in order to |
| 131 | make encoding/decoding efficient. |
| 132 | |
| 133 | The decoder must be able to handle zero length input and |
| 134 | return an empty object of the output object type in this |
| 135 | situation. |
| 136 | |
Guido van Rossum | 1c89b0e | 2000-04-11 15:41:38 +0000 | [diff] [blame] | 137 | """ |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 138 | raise NotImplementedError |
| 139 | |
| 140 | # |
| 141 | # The StreamWriter and StreamReader class provide generic working |
Andrew M. Kuchling | 97c5635 | 2001-09-18 20:29:48 +0000 | [diff] [blame] | 142 | # interfaces which can be used to implement new encoding submodules |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 143 | # very easily. See encodings/utf_8.py for an example on how this is |
| 144 | # done. |
Guido van Rossum | 1c89b0e | 2000-04-11 15:41:38 +0000 | [diff] [blame] | 145 | # |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 146 | |
| 147 | class StreamWriter(Codec): |
| 148 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 149 | def __init__(self, stream, errors='strict'): |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 150 | |
| 151 | """ Creates a StreamWriter instance. |
| 152 | |
| 153 | stream must be a file-like object open for writing |
| 154 | (binary) data. |
| 155 | |
Walter Dörwald | 7f82f79 | 2002-11-19 21:42:53 +0000 | [diff] [blame] | 156 | The StreamWriter may use different error handling |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 157 | schemes by providing the errors keyword argument. These |
Walter Dörwald | 7f82f79 | 2002-11-19 21:42:53 +0000 | [diff] [blame] | 158 | parameters are predefined: |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 159 | |
| 160 | 'strict' - raise a ValueError (or a subclass) |
| 161 | 'ignore' - ignore the character and continue with the next |
| 162 | 'replace'- replace with a suitable replacement character |
Walter Dörwald | 7f82f79 | 2002-11-19 21:42:53 +0000 | [diff] [blame] | 163 | 'xmlcharrefreplace' - Replace with the appropriate XML |
| 164 | character reference. |
| 165 | 'backslashreplace' - Replace with backslashed escape |
| 166 | sequences (only for encoding). |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 167 | |
Walter Dörwald | 7f82f79 | 2002-11-19 21:42:53 +0000 | [diff] [blame] | 168 | The set of allowed parameter values can be extended via |
| 169 | register_error. |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 170 | """ |
| 171 | self.stream = stream |
| 172 | self.errors = errors |
| 173 | |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 174 | def write(self, object): |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 175 | |
| 176 | """ Writes the object's contents encoded to self.stream. |
| 177 | """ |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 178 | data, consumed = self.encode(object, self.errors) |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 179 | self.stream.write(data) |
| 180 | |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 181 | def writelines(self, list): |
| 182 | |
| 183 | """ Writes the concatenated list of strings to the stream |
| 184 | using .write(). |
| 185 | """ |
| 186 | self.write(''.join(list)) |
Guido van Rossum | 1c89b0e | 2000-04-11 15:41:38 +0000 | [diff] [blame] | 187 | |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 188 | def reset(self): |
| 189 | |
| 190 | """ Flushes and resets the codec buffers used for keeping state. |
| 191 | |
| 192 | Calling this method should ensure that the data on the |
| 193 | output is put into a clean state, that allows appending |
| 194 | of new fresh data without having to rescan the whole |
| 195 | stream to recover state. |
| 196 | |
| 197 | """ |
| 198 | pass |
| 199 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 200 | def __getattr__(self, name, |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 201 | getattr=getattr): |
| 202 | |
| 203 | """ Inherit all other methods from the underlying stream. |
| 204 | """ |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 205 | return getattr(self.stream, name) |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 206 | |
| 207 | ### |
| 208 | |
| 209 | class StreamReader(Codec): |
| 210 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 211 | def __init__(self, stream, errors='strict'): |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 212 | |
| 213 | """ Creates a StreamReader instance. |
| 214 | |
| 215 | stream must be a file-like object open for reading |
| 216 | (binary) data. |
| 217 | |
Walter Dörwald | 7f82f79 | 2002-11-19 21:42:53 +0000 | [diff] [blame] | 218 | The StreamReader may use different error handling |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 219 | schemes by providing the errors keyword argument. These |
Walter Dörwald | 7f82f79 | 2002-11-19 21:42:53 +0000 | [diff] [blame] | 220 | parameters are predefined: |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 221 | |
| 222 | 'strict' - raise a ValueError (or a subclass) |
| 223 | 'ignore' - ignore the character and continue with the next |
| 224 | 'replace'- replace with a suitable replacement character; |
| 225 | |
Walter Dörwald | 7f82f79 | 2002-11-19 21:42:53 +0000 | [diff] [blame] | 226 | The set of allowed parameter values can be extended via |
| 227 | register_error. |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 228 | """ |
| 229 | self.stream = stream |
| 230 | self.errors = errors |
| 231 | |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 232 | def read(self, size=-1): |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 233 | |
| 234 | """ Decodes data from the stream self.stream and returns the |
| 235 | resulting object. |
| 236 | |
| 237 | size indicates the approximate maximum number of bytes to |
| 238 | read from the stream for decoding purposes. The decoder |
| 239 | can modify this setting as appropriate. The default value |
| 240 | -1 indicates to read and decode as much as possible. size |
| 241 | is intended to prevent having to decode huge files in one |
| 242 | step. |
| 243 | |
| 244 | The method should use a greedy read strategy meaning that |
| 245 | it should read as much data as is allowed within the |
| 246 | definition of the encoding and the given size, e.g. if |
| 247 | optional encoding endings or state markers are available |
| 248 | on the stream, these should be read too. |
| 249 | |
| 250 | """ |
| 251 | # Unsliced reading: |
| 252 | if size < 0: |
Andrew M. Kuchling | c6c2838 | 2000-12-10 15:12:14 +0000 | [diff] [blame] | 253 | return self.decode(self.stream.read(), self.errors)[0] |
Guido van Rossum | 1c89b0e | 2000-04-11 15:41:38 +0000 | [diff] [blame] | 254 | |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 255 | # Sliced reading: |
| 256 | read = self.stream.read |
| 257 | decode = self.decode |
| 258 | data = read(size) |
| 259 | i = 0 |
| 260 | while 1: |
| 261 | try: |
Andrew M. Kuchling | c6c2838 | 2000-12-10 15:12:14 +0000 | [diff] [blame] | 262 | object, decodedbytes = decode(data, self.errors) |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 263 | except ValueError, why: |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 264 | # This method is slow but should work under pretty much |
| 265 | # all conditions; at most 10 tries are made |
| 266 | i = i + 1 |
| 267 | newdata = read(1) |
| 268 | if not newdata or i > 10: |
| 269 | raise |
| 270 | data = data + newdata |
| 271 | else: |
| 272 | return object |
| 273 | |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 274 | def readline(self, size=None): |
| 275 | |
| 276 | """ Read one line from the input stream and return the |
| 277 | decoded data. |
| 278 | |
Fred Drake | 49fd107 | 2000-04-13 14:11:21 +0000 | [diff] [blame] | 279 | Note: Unlike the .readlines() method, this method inherits |
| 280 | the line breaking knowledge from the underlying stream's |
| 281 | .readline() method -- there is currently no support for |
| 282 | line breaking using the codec decoder due to lack of line |
Walter Dörwald | 7f3ed74 | 2003-02-02 23:08:27 +0000 | [diff] [blame] | 283 | buffering. Subclasses should however, if possible, try to |
Fred Drake | 49fd107 | 2000-04-13 14:11:21 +0000 | [diff] [blame] | 284 | implement this method using their own knowledge of line |
| 285 | breaking. |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 286 | |
| 287 | size, if given, is passed as size argument to the stream's |
| 288 | .readline() method. |
Guido van Rossum | 1c89b0e | 2000-04-11 15:41:38 +0000 | [diff] [blame] | 289 | |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 290 | """ |
| 291 | if size is None: |
| 292 | line = self.stream.readline() |
| 293 | else: |
| 294 | line = self.stream.readline(size) |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 295 | return self.decode(line, self.errors)[0] |
Guido van Rossum | 1c89b0e | 2000-04-11 15:41:38 +0000 | [diff] [blame] | 296 | |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 297 | |
Martin v. Löwis | b786e61 | 2002-03-05 15:46:38 +0000 | [diff] [blame] | 298 | def readlines(self, sizehint=None): |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 299 | |
| 300 | """ Read all lines available on the input stream |
| 301 | and return them as list of lines. |
| 302 | |
| 303 | Line breaks are implemented using the codec's decoder |
| 304 | method and are included in the list entries. |
Guido van Rossum | 1c89b0e | 2000-04-11 15:41:38 +0000 | [diff] [blame] | 305 | |
Marc-André Lemburg | d594849 | 2004-02-26 15:22:17 +0000 | [diff] [blame] | 306 | sizehint, if given, is ignored since there is no efficient |
| 307 | way to finding the true end-of-line. |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 308 | |
| 309 | """ |
Marc-André Lemburg | d594849 | 2004-02-26 15:22:17 +0000 | [diff] [blame] | 310 | data = self.stream.read() |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 311 | return self.decode(data, self.errors)[0].splitlines(1) |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 312 | |
| 313 | def reset(self): |
| 314 | |
| 315 | """ Resets the codec buffers used for keeping state. |
| 316 | |
| 317 | Note that no stream repositioning should take place. |
Thomas Wouters | 7e47402 | 2000-07-16 12:04:32 +0000 | [diff] [blame] | 318 | This method is primarily intended to be able to recover |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 319 | from decoding errors. |
| 320 | |
| 321 | """ |
| 322 | pass |
| 323 | |
Walter Dörwald | 4dbf192 | 2002-11-06 16:53:44 +0000 | [diff] [blame] | 324 | def next(self): |
| 325 | |
| 326 | """ Return the next decoded line from the input stream.""" |
| 327 | line = self.readline() |
| 328 | if line: |
| 329 | return line |
| 330 | raise StopIteration |
| 331 | |
| 332 | def __iter__(self): |
| 333 | return self |
| 334 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 335 | def __getattr__(self, name, |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 336 | getattr=getattr): |
| 337 | |
| 338 | """ Inherit all other methods from the underlying stream. |
| 339 | """ |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 340 | return getattr(self.stream, name) |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 341 | |
| 342 | ### |
| 343 | |
| 344 | class StreamReaderWriter: |
| 345 | |
Fred Drake | 49fd107 | 2000-04-13 14:11:21 +0000 | [diff] [blame] | 346 | """ StreamReaderWriter instances allow wrapping streams which |
| 347 | work in both read and write modes. |
| 348 | |
| 349 | The design is such that one can use the factory functions |
Thomas Wouters | 7e47402 | 2000-07-16 12:04:32 +0000 | [diff] [blame] | 350 | returned by the codec.lookup() function to construct the |
Fred Drake | 49fd107 | 2000-04-13 14:11:21 +0000 | [diff] [blame] | 351 | instance. |
| 352 | |
| 353 | """ |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 354 | # Optional attributes set by the file wrappers below |
| 355 | encoding = 'unknown' |
| 356 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 357 | def __init__(self, stream, Reader, Writer, errors='strict'): |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 358 | |
| 359 | """ Creates a StreamReaderWriter instance. |
| 360 | |
| 361 | stream must be a Stream-like object. |
| 362 | |
| 363 | Reader, Writer must be factory functions or classes |
| 364 | providing the StreamReader, StreamWriter interface resp. |
| 365 | |
| 366 | Error handling is done in the same way as defined for the |
| 367 | StreamWriter/Readers. |
| 368 | |
| 369 | """ |
| 370 | self.stream = stream |
| 371 | self.reader = Reader(stream, errors) |
| 372 | self.writer = Writer(stream, errors) |
| 373 | self.errors = errors |
| 374 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 375 | def read(self, size=-1): |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 376 | |
| 377 | return self.reader.read(size) |
| 378 | |
Guido van Rossum | d58c26f | 2000-05-01 16:17:32 +0000 | [diff] [blame] | 379 | def readline(self, size=None): |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 380 | |
| 381 | return self.reader.readline(size) |
| 382 | |
Guido van Rossum | d58c26f | 2000-05-01 16:17:32 +0000 | [diff] [blame] | 383 | def readlines(self, sizehint=None): |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 384 | |
| 385 | return self.reader.readlines(sizehint) |
| 386 | |
Walter Dörwald | 4dbf192 | 2002-11-06 16:53:44 +0000 | [diff] [blame] | 387 | def next(self): |
| 388 | |
| 389 | """ Return the next decoded line from the input stream.""" |
| 390 | return self.reader.next() |
| 391 | |
| 392 | def __iter__(self): |
| 393 | return self |
| 394 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 395 | def write(self, data): |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 396 | |
| 397 | return self.writer.write(data) |
| 398 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 399 | def writelines(self, list): |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 400 | |
| 401 | return self.writer.writelines(list) |
| 402 | |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 403 | def reset(self): |
| 404 | |
| 405 | self.reader.reset() |
| 406 | self.writer.reset() |
| 407 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 408 | def __getattr__(self, name, |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 409 | getattr=getattr): |
| 410 | |
| 411 | """ Inherit all other methods from the underlying stream. |
| 412 | """ |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 413 | return getattr(self.stream, name) |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 414 | |
| 415 | ### |
| 416 | |
| 417 | class StreamRecoder: |
| 418 | |
Fred Drake | 49fd107 | 2000-04-13 14:11:21 +0000 | [diff] [blame] | 419 | """ StreamRecoder instances provide a frontend - backend |
| 420 | view of encoding data. |
| 421 | |
| 422 | They use the complete set of APIs returned by the |
| 423 | codecs.lookup() function to implement their task. |
| 424 | |
| 425 | Data written to the stream is first decoded into an |
| 426 | intermediate format (which is dependent on the given codec |
| 427 | combination) and then written to the stream using an instance |
| 428 | of the provided Writer class. |
| 429 | |
| 430 | In the other direction, data is read from the stream using a |
| 431 | Reader instance and then return encoded data to the caller. |
| 432 | |
| 433 | """ |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 434 | # Optional attributes set by the file wrappers below |
| 435 | data_encoding = 'unknown' |
| 436 | file_encoding = 'unknown' |
| 437 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 438 | def __init__(self, stream, encode, decode, Reader, Writer, |
| 439 | errors='strict'): |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 440 | |
| 441 | """ Creates a StreamRecoder instance which implements a two-way |
| 442 | conversion: encode and decode work on the frontend (the |
Guido van Rossum | 1c89b0e | 2000-04-11 15:41:38 +0000 | [diff] [blame] | 443 | input to .read() and output of .write()) while |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 444 | Reader and Writer work on the backend (reading and |
Fred Drake | 908670c | 2000-03-17 15:42:11 +0000 | [diff] [blame] | 445 | writing to the stream). |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 446 | |
| 447 | You can use these objects to do transparent direct |
| 448 | recodings from e.g. latin-1 to utf-8 and back. |
| 449 | |
| 450 | stream must be a file-like object. |
| 451 | |
| 452 | encode, decode must adhere to the Codec interface, Reader, |
| 453 | Writer must be factory functions or classes providing the |
| 454 | StreamReader, StreamWriter interface resp. |
| 455 | |
| 456 | encode and decode are needed for the frontend translation, |
| 457 | Reader and Writer for the backend translation. Unicode is |
| 458 | used as intermediate encoding. |
| 459 | |
| 460 | Error handling is done in the same way as defined for the |
| 461 | StreamWriter/Readers. |
| 462 | |
| 463 | """ |
| 464 | self.stream = stream |
| 465 | self.encode = encode |
| 466 | self.decode = decode |
| 467 | self.reader = Reader(stream, errors) |
| 468 | self.writer = Writer(stream, errors) |
| 469 | self.errors = errors |
| 470 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 471 | def read(self, size=-1): |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 472 | |
| 473 | data = self.reader.read(size) |
| 474 | data, bytesencoded = self.encode(data, self.errors) |
| 475 | return data |
| 476 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 477 | def readline(self, size=None): |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 478 | |
| 479 | if size is None: |
| 480 | data = self.reader.readline() |
| 481 | else: |
| 482 | data = self.reader.readline(size) |
| 483 | data, bytesencoded = self.encode(data, self.errors) |
| 484 | return data |
| 485 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 486 | def readlines(self, sizehint=None): |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 487 | |
Marc-André Lemburg | d594849 | 2004-02-26 15:22:17 +0000 | [diff] [blame] | 488 | data = self.reader.read() |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 489 | data, bytesencoded = self.encode(data, self.errors) |
| 490 | return data.splitlines(1) |
| 491 | |
Walter Dörwald | 4dbf192 | 2002-11-06 16:53:44 +0000 | [diff] [blame] | 492 | def next(self): |
| 493 | |
| 494 | """ Return the next decoded line from the input stream.""" |
| 495 | return self.reader.next() |
| 496 | |
| 497 | def __iter__(self): |
| 498 | return self |
| 499 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 500 | def write(self, data): |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 501 | |
| 502 | data, bytesdecoded = self.decode(data, self.errors) |
| 503 | return self.writer.write(data) |
| 504 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 505 | def writelines(self, list): |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 506 | |
| 507 | data = ''.join(list) |
| 508 | data, bytesdecoded = self.decode(data, self.errors) |
| 509 | return self.writer.write(data) |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 510 | |
| 511 | def reset(self): |
| 512 | |
| 513 | self.reader.reset() |
| 514 | self.writer.reset() |
| 515 | |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 516 | def __getattr__(self, name, |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 517 | getattr=getattr): |
| 518 | |
| 519 | """ Inherit all other methods from the underlying stream. |
| 520 | """ |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 521 | return getattr(self.stream, name) |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 522 | |
| 523 | ### Shortcuts |
| 524 | |
Marc-André Lemburg | 349a3d3 | 2000-06-21 21:21:04 +0000 | [diff] [blame] | 525 | def open(filename, mode='rb', encoding=None, errors='strict', buffering=1): |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 526 | |
| 527 | """ Open an encoded file using the given mode and return |
| 528 | a wrapped version providing transparent encoding/decoding. |
| 529 | |
| 530 | Note: The wrapped version will only accept the object format |
| 531 | defined by the codecs, i.e. Unicode objects for most builtin |
| 532 | codecs. Output is also codec dependent and will usually by |
| 533 | Unicode as well. |
| 534 | |
Marc-André Lemburg | 349a3d3 | 2000-06-21 21:21:04 +0000 | [diff] [blame] | 535 | Files are always opened in binary mode, even if no binary mode |
Walter Dörwald | 7f3ed74 | 2003-02-02 23:08:27 +0000 | [diff] [blame] | 536 | was specified. This is done to avoid data loss due to encodings |
Marc-André Lemburg | 349a3d3 | 2000-06-21 21:21:04 +0000 | [diff] [blame] | 537 | using 8-bit values. The default file mode is 'rb' meaning to |
| 538 | open the file in binary read mode. |
| 539 | |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 540 | encoding specifies the encoding which is to be used for the |
Walter Dörwald | 7f3ed74 | 2003-02-02 23:08:27 +0000 | [diff] [blame] | 541 | file. |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 542 | |
| 543 | errors may be given to define the error handling. It defaults |
| 544 | to 'strict' which causes ValueErrors to be raised in case an |
| 545 | encoding error occurs. |
| 546 | |
| 547 | buffering has the same meaning as for the builtin open() API. |
| 548 | It defaults to line buffered. |
| 549 | |
Fred Drake | 49fd107 | 2000-04-13 14:11:21 +0000 | [diff] [blame] | 550 | The returned wrapped file object provides an extra attribute |
| 551 | .encoding which allows querying the used encoding. This |
| 552 | attribute is only available if an encoding was specified as |
| 553 | parameter. |
| 554 | |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 555 | """ |
| 556 | if encoding is not None and \ |
| 557 | 'b' not in mode: |
| 558 | # Force opening of the file in binary mode |
| 559 | mode = mode + 'b' |
| 560 | file = __builtin__.open(filename, mode, buffering) |
| 561 | if encoding is None: |
| 562 | return file |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 563 | (e, d, sr, sw) = lookup(encoding) |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 564 | srw = StreamReaderWriter(file, sr, sw, errors) |
| 565 | # Add attributes to simplify introspection |
| 566 | srw.encoding = encoding |
| 567 | return srw |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 568 | |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 569 | def EncodedFile(file, data_encoding, file_encoding=None, errors='strict'): |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 570 | |
| 571 | """ Return a wrapped version of file which provides transparent |
| 572 | encoding translation. |
| 573 | |
| 574 | Strings written to the wrapped file are interpreted according |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 575 | to the given data_encoding and then written to the original |
| 576 | file as string using file_encoding. The intermediate encoding |
| 577 | will usually be Unicode but depends on the specified codecs. |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 578 | |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 579 | Strings are read from the file using file_encoding and then |
| 580 | passed back to the caller as string using data_encoding. |
| 581 | |
| 582 | If file_encoding is not given, it defaults to data_encoding. |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 583 | |
| 584 | errors may be given to define the error handling. It defaults |
| 585 | to 'strict' which causes ValueErrors to be raised in case an |
| 586 | encoding error occurs. |
| 587 | |
Fred Drake | 49fd107 | 2000-04-13 14:11:21 +0000 | [diff] [blame] | 588 | The returned wrapped file object provides two extra attributes |
| 589 | .data_encoding and .file_encoding which reflect the given |
| 590 | parameters of the same name. The attributes can be used for |
| 591 | introspection by Python programs. |
| 592 | |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 593 | """ |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 594 | if file_encoding is None: |
| 595 | file_encoding = data_encoding |
| 596 | encode, decode = lookup(data_encoding)[:2] |
| 597 | Reader, Writer = lookup(file_encoding)[2:] |
| 598 | sr = StreamRecoder(file, |
Tim Peters | 30324a7 | 2001-05-15 17:19:16 +0000 | [diff] [blame] | 599 | encode, decode, Reader, Writer, |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 600 | errors) |
| 601 | # Add attributes to simplify introspection |
| 602 | sr.data_encoding = data_encoding |
| 603 | sr.file_encoding = file_encoding |
| 604 | return sr |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 605 | |
Marc-André Lemburg | aa32c5a | 2001-09-19 11:24:48 +0000 | [diff] [blame] | 606 | ### Helpers for codec lookup |
| 607 | |
| 608 | def getencoder(encoding): |
| 609 | |
| 610 | """ Lookup up the codec for the given encoding and return |
| 611 | its encoder function. |
| 612 | |
| 613 | Raises a LookupError in case the encoding cannot be found. |
| 614 | |
| 615 | """ |
| 616 | return lookup(encoding)[0] |
| 617 | |
| 618 | def getdecoder(encoding): |
| 619 | |
| 620 | """ Lookup up the codec for the given encoding and return |
| 621 | its decoder function. |
| 622 | |
| 623 | Raises a LookupError in case the encoding cannot be found. |
| 624 | |
| 625 | """ |
| 626 | return lookup(encoding)[1] |
| 627 | |
| 628 | def getreader(encoding): |
| 629 | |
| 630 | """ Lookup up the codec for the given encoding and return |
| 631 | its StreamReader class or factory function. |
| 632 | |
| 633 | Raises a LookupError in case the encoding cannot be found. |
| 634 | |
| 635 | """ |
| 636 | return lookup(encoding)[2] |
| 637 | |
| 638 | def getwriter(encoding): |
| 639 | |
| 640 | """ Lookup up the codec for the given encoding and return |
| 641 | its StreamWriter class or factory function. |
| 642 | |
| 643 | Raises a LookupError in case the encoding cannot be found. |
| 644 | |
| 645 | """ |
| 646 | return lookup(encoding)[3] |
| 647 | |
Marc-André Lemburg | a866df8 | 2001-01-03 21:29:14 +0000 | [diff] [blame] | 648 | ### Helpers for charmap-based codecs |
| 649 | |
| 650 | def make_identity_dict(rng): |
| 651 | |
| 652 | """ make_identity_dict(rng) -> dict |
| 653 | |
| 654 | Return a dictionary where elements of the rng sequence are |
| 655 | mapped to themselves. |
Tim Peters | 88869f9 | 2001-01-14 23:36:06 +0000 | [diff] [blame] | 656 | |
Marc-André Lemburg | a866df8 | 2001-01-03 21:29:14 +0000 | [diff] [blame] | 657 | """ |
| 658 | res = {} |
| 659 | for i in rng: |
| 660 | res[i]=i |
| 661 | return res |
| 662 | |
Marc-André Lemburg | 716cf91 | 2001-05-16 09:41:45 +0000 | [diff] [blame] | 663 | def make_encoding_map(decoding_map): |
| 664 | |
| 665 | """ Creates an encoding map from a decoding map. |
| 666 | |
Walter Dörwald | 7f3ed74 | 2003-02-02 23:08:27 +0000 | [diff] [blame] | 667 | If a target mapping in the decoding map occurs multiple |
Marc-André Lemburg | 716cf91 | 2001-05-16 09:41:45 +0000 | [diff] [blame] | 668 | times, then that target is mapped to None (undefined mapping), |
| 669 | causing an exception when encountered by the charmap codec |
| 670 | during translation. |
| 671 | |
| 672 | One example where this happens is cp875.py which decodes |
| 673 | multiple character to \u001a. |
| 674 | |
| 675 | """ |
| 676 | m = {} |
| 677 | for k,v in decoding_map.items(): |
Raymond Hettinger | 54f0222 | 2002-06-01 14:18:47 +0000 | [diff] [blame] | 678 | if not v in m: |
Marc-André Lemburg | 716cf91 | 2001-05-16 09:41:45 +0000 | [diff] [blame] | 679 | m[v] = k |
| 680 | else: |
| 681 | m[v] = None |
| 682 | return m |
Tim Peters | 3a2ab1a | 2001-05-29 06:06:54 +0000 | [diff] [blame] | 683 | |
Walter Dörwald | 3aeb632 | 2002-09-02 13:14:32 +0000 | [diff] [blame] | 684 | ### error handlers |
| 685 | |
| 686 | strict_errors = lookup_error("strict") |
| 687 | ignore_errors = lookup_error("ignore") |
| 688 | replace_errors = lookup_error("replace") |
| 689 | xmlcharrefreplace_errors = lookup_error("xmlcharrefreplace") |
| 690 | backslashreplace_errors = lookup_error("backslashreplace") |
| 691 | |
Martin v. Löwis | 6cd441d | 2001-07-31 08:54:55 +0000 | [diff] [blame] | 692 | # Tell modulefinder that using codecs probably needs the encodings |
| 693 | # package |
| 694 | _false = 0 |
| 695 | if _false: |
| 696 | import encodings |
| 697 | |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 698 | ### Tests |
Guido van Rossum | 1c89b0e | 2000-04-11 15:41:38 +0000 | [diff] [blame] | 699 | |
Guido van Rossum | 0612d84 | 2000-03-10 23:20:43 +0000 | [diff] [blame] | 700 | if __name__ == '__main__': |
| 701 | |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 702 | # Make stdout translate Latin-1 output into UTF-8 output |
| 703 | sys.stdout = EncodedFile(sys.stdout, 'latin-1', 'utf-8') |
Guido van Rossum | 1c89b0e | 2000-04-11 15:41:38 +0000 | [diff] [blame] | 704 | |
Guido van Rossum | a327713 | 2000-04-11 15:37:43 +0000 | [diff] [blame] | 705 | # Have stdin translate Latin-1 input into UTF-8 input |
| 706 | sys.stdin = EncodedFile(sys.stdin, 'utf-8', 'latin-1') |