Overview

python-libguess 1.1

python-libguess is a Python wrapper for libguess.

libguess enables finding out in what encoding some text is for given language. This library is especially useful for short text strings that themselves don't carry reliable encoding information, like ID3 tags in MP3 files. For example we can encode the same Japanese string in 3 different encodings (UTF-8, SHIFT-JIS, EUC-JP) and libguess will hopefully guess the encoding correctly just by looking at the first few bytes of the given string.

You can also use this as a regular command line program by giving region as the first parameter and possible target files after that:

Usage: python -m guess REGION [INPUT_FILE]

If input file name is not given, this program reads from the standard input.

Functions

determine_encoding(in_string, region)

Determines encoding of a string for the given language region.

Arguments:
in_string -- a raw byte string for which encoding needs to be guessed.
region -- one of the REGION_* constants for which encoding is guessed.
Returns:
String value indicating the guessed encoding of in_string argument for given region or None if error happened.

As an usage example we might see what happens when given Japanese text in 2 different encodings:

>>> import guess
>>> guess.determine_encoding(u'\u3042'.encode('euc-jp'), guess.REGION_JP)
'EUC-JP'
>>> guess.determine_encoding(u'\u3042'.encode('utf-8'), guess.REGION_JP)
'UTF-8'

The output string of this function can be given directly to iconv_open() C function and the resulting names should be compatible with the encoding string of str.decode() function:

>>> encoded_value = u'\u3042'.encode('shift-jis')
>>> encoding = guess.determine_encoding(encoded_value, guess.REGION_JP)
>>> encoding
'SJIS'
>>> encoded_value.decode(encoding)
u'\u3042'

In case the given region name is invalid or the underlying libguess_determine_encoding() call fails for any other reason, None value is returned:

>>> encoding = guess.determine_encoding("asdf", "UNKNOWN")
>>> encoding is None
True

Use REGION_* constants for region names.

validate_utf8(in_string)

Checks if the given string is a valid UTF-8 byte sequence.

Arguments:
in_string -- a raw byte string to be inspected for UTF-8 validity.
Return value:
True if given string is a valid UTF-8 byte sequence, False otherwise.

This function is included here for the completeness with libguess interface. It gives more precise results for UTF-8 validity than for example functions in glib.

>>> import guess
>>> guess.validate_utf8(u'\u3042'.encode('EUC-JP'))
False
>>> guess.validate_utf8(u'\u3042'.encode('UTF-8'))
True

Region names

REGION_AR = 'arabic'
REGION_BL = 'baltic'
REGION_CN = 'chinese'
REGION_GR = 'greek'
REGION_HW = 'hebrew'
REGION_JP = 'japanese'
REGION_KR = 'korean'
REGION_PL = 'polish'
REGION_RU = 'russian'
REGION_TR = 'turkish'
REGION_TW = 'taiwanese'