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merge with algo and add brython files that were missing
Commit Description:
merge with algo and add brython files that were missing
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lib/assets/Lib/_csv.py | 594 lines | 21.8 KiB | text/x-python | PythonLexer |
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"""CSV parsing and writing.
[Copied from PyPy
https://bitbucket-assetroot.s3.amazonaws.com/pypy/pypy/1400171824.19/641/_csv.py?Signature=cc%2Bc8m06cBMbsxt2e15XXXUDACk%3D&Expires=1404136251&AWSAccessKeyId=0EMWEFSGA12Z1HF1TZ82
and adapted to Python 3 syntax for Brython]
This module provides classes that assist in the reading and writing
of Comma Separated Value (CSV) files, and implements the interface
described by PEP 305. Although many CSV files are simple to parse,
the format is not formally defined by a stable specification and
is subtle enough that parsing lines of a CSV file with something
like line.split(\",\") is bound to fail. The module supports three
basic APIs: reading, writing, and registration of dialects.
DIALECT REGISTRATION:
Readers and writers support a dialect argument, which is a convenient
handle on a group of settings. When the dialect argument is a string,
it identifies one of the dialects previously registered with the module.
If it is a class or instance, the attributes of the argument are used as
the settings for the reader or writer:
class excel:
delimiter = ','
quotechar = '\"'
escapechar = None
doublequote = True
skipinitialspace = False
lineterminator = '\\r\\n'
quoting = QUOTE_MINIMAL
SETTINGS:
* quotechar - specifies a one-character string to use as the
quoting character. It defaults to '\"'.
* delimiter - specifies a one-character string to use as the
field separator. It defaults to ','.
* skipinitialspace - specifies how to interpret whitespace which
immediately follows a delimiter. It defaults to False, which
means that whitespace immediately following a delimiter is part
of the following field.
* lineterminator - specifies the character sequence which should
terminate rows.
* quoting - controls when quotes should be generated by the writer.
It can take on any of the following module constants:
csv.QUOTE_MINIMAL means only when required, for example, when a
field contains either the quotechar or the delimiter
csv.QUOTE_ALL means that quotes are always placed around fields.
csv.QUOTE_NONNUMERIC means that quotes are always placed around
fields which do not parse as integers or floating point
numbers.
csv.QUOTE_NONE means that quotes are never placed around fields.
* escapechar - specifies a one-character string used to escape
the delimiter when quoting is set to QUOTE_NONE.
* doublequote - controls the handling of quotes inside fields. When
True, two consecutive quotes are interpreted as one during read,
and when writing, each quote character embedded in the data is
written as two quotes.
"""
__version__ = "1.0"
QUOTE_MINIMAL, QUOTE_ALL, QUOTE_NONNUMERIC, QUOTE_NONE = range(4)
_dialects = {}
_field_limit = 128 * 1024 # max parsed field size
class Error(Exception):
pass
class Dialect(object):
"""CSV dialect
The Dialect type records CSV parsing and generation options."""
__slots__ = ["_delimiter", "_doublequote", "_escapechar",
"_lineterminator", "_quotechar", "_quoting",
"_skipinitialspace", "_strict"]
def __new__(cls, dialect, **kwargs):
for name in kwargs:
if '_' + name not in Dialect.__slots__:
raise TypeError("unexpected keyword argument '%s'" %
(name,))
if dialect is not None:
if isinstance(dialect, str):
dialect = get_dialect(dialect)
# Can we reuse this instance?
if (isinstance(dialect, Dialect)
and all(value is None for value in kwargs.values())):
return dialect
self = object.__new__(cls)
def set_char(x):
if x is None:
return None
if isinstance(x, str) and len(x) <= 1:
return x
raise TypeError("%r must be a 1-character string" % (name,))
def set_str(x):
if isinstance(x, str):
return x
raise TypeError("%r must be a string" % (name,))
def set_quoting(x):
if x in range(4):
return x
raise TypeError("bad 'quoting' value")
attributes = {"delimiter": (',', set_char),
"doublequote": (True, bool),
"escapechar": (None, set_char),
"lineterminator": ("\r\n", set_str),
"quotechar": ('"', set_char),
"quoting": (QUOTE_MINIMAL, set_quoting),
"skipinitialspace": (False, bool),
"strict": (False, bool),
}
# Copy attributes
notset = object()
for name in Dialect.__slots__:
name = name[1:]
value = notset
if name in kwargs:
value = kwargs[name]
elif dialect is not None:
value = getattr(dialect, name, notset)
# mapping by name: (default, converter)
if value is notset:
value = attributes[name][0]
if name == 'quoting' and not self.quotechar:
value = QUOTE_NONE
else:
converter = attributes[name][1]
if converter:
value = converter(value)
setattr(self, '_' + name, value)
if not self.delimiter:
raise TypeError("delimiter must be set")
if self.quoting != QUOTE_NONE and not self.quotechar:
raise TypeError("quotechar must be set if quoting enabled")
if not self.lineterminator:
raise TypeError("lineterminator must be set")
return self
delimiter = property(lambda self: self._delimiter)
doublequote = property(lambda self: self._doublequote)
escapechar = property(lambda self: self._escapechar)
lineterminator = property(lambda self: self._lineterminator)
quotechar = property(lambda self: self._quotechar)
quoting = property(lambda self: self._quoting)
skipinitialspace = property(lambda self: self._skipinitialspace)
strict = property(lambda self: self._strict)
def _call_dialect(dialect_inst, kwargs):
return Dialect(dialect_inst, **kwargs)
def register_dialect(name, dialect=None, **kwargs):
"""Create a mapping from a string name to a dialect class.
dialect = csv.register_dialect(name, dialect)"""
if not isinstance(name, str):
raise TypeError("dialect name must be a string or unicode")
dialect = _call_dialect(dialect, kwargs)
_dialects[name] = dialect
def unregister_dialect(name):
"""Delete the name/dialect mapping associated with a string name.\n
csv.unregister_dialect(name)"""
try:
del _dialects[name]
except KeyError:
raise Error("unknown dialect")
def get_dialect(name):
"""Return the dialect instance associated with name.
dialect = csv.get_dialect(name)"""
try:
return _dialects[name]
except KeyError:
raise Error("unknown dialect")
def list_dialects():
"""Return a list of all know dialect names
names = csv.list_dialects()"""
return list(_dialects)
class Reader(object):
"""CSV reader
Reader objects are responsible for reading and parsing tabular data
in CSV format."""
(START_RECORD, START_FIELD, ESCAPED_CHAR, IN_FIELD,
IN_QUOTED_FIELD, ESCAPE_IN_QUOTED_FIELD, QUOTE_IN_QUOTED_FIELD,
EAT_CRNL) = range(8)
def __init__(self, iterator, dialect=None, **kwargs):
self.dialect = _call_dialect(dialect, kwargs)
# null characters are not allowed to be in the string so we can use
# it as a fall back
self._delimiter = self.dialect.delimiter if self.dialect.delimiter else '\0'
self._quotechar = self.dialect.quotechar if self.dialect.quotechar else '\0'
self._escapechar = self.dialect.escapechar if self.dialect.escapechar else '\0'
self._doublequote = self.dialect.doublequote
self._quoting = self.dialect.quoting
self._skipinitialspace = self.dialect.skipinitialspace
self._strict = self.dialect.strict
self.input_iter = iter(iterator)
self.line_num = 0
self._parse_reset()
def _parse_reset(self):
self.field = ''
self.fields = []
self.state = self.START_RECORD
self.numeric_field = False
def __iter__(self):
return self
def __next__(self):
self._parse_reset()
while True:
try:
line = next(self.input_iter)
except StopIteration:
# End of input OR exception
if len(self.field) > 0:
raise Error("newline inside string")
raise
self.line_num += 1
if '\0' in line:
raise Error("line contains NULL byte")
self._parse_process_char(line)
self._parse_eol()
if self.state == self.START_RECORD:
break
fields = self.fields
self.fields = []
return fields
def _parse_process_char(self, line):
pos = 0
while pos < len(line):
if self.state == self.IN_FIELD:
# in unquoted field and have already found one character when starting the field
pos2 = pos
while pos2 < len(line):
if line[pos2] == '\n' or line[pos2] == '\r':
# end of line - return [fields]
if pos2 > pos:
self._parse_add_str(line[pos:pos2])
pos = pos2
self._parse_save_field()
self.state = self.EAT_CRNL
break
elif line[pos2] == self._escapechar[0]:
# possible escaped character
if pos2 > pos:
self._parse_add_str(line[pos:pos2])
pos = pos2
self.state = self.ESCAPED_CHAR
break
elif line[pos2] == self._delimiter[0]:
# save field - wait for new field
if pos2 > pos:
self._parse_add_str(line[pos:pos2])
pos = pos2
self._parse_save_field()
self.state = self.START_FIELD
break
# normal character - save in field
pos2 += 1
else:
if pos2 > pos:
self._parse_add_str(line[pos:pos2])
pos = pos2
continue
elif self.state == self.START_RECORD:
if line[pos] == '\n' or line[pos] == '\r':
self.state = self.EAT_CRNL
else:
self.state = self.START_FIELD
# restart process
continue
elif self.state == self.START_FIELD:
if line[pos] == '\n' or line[pos] == '\r':
# save empty field - return [fields]
self._parse_save_field()
self.state = self.EAT_CRNL
elif (line[pos] == self._quotechar[0]
and self._quoting != QUOTE_NONE):
# start quoted field
self.state = self.IN_QUOTED_FIELD
elif line[pos] == self._escapechar[0]:
# possible escaped character
self.state = self.ESCAPED_CHAR
elif self._skipinitialspace and line[pos] == ' ':
# ignore space at start of field
pass
elif line[pos] == self._delimiter[0]:
# save empty field
self._parse_save_field()
else:
# begin new unquoted field
if self._quoting == QUOTE_NONNUMERIC:
self.numeric_field = True
self.state = self.IN_FIELD
continue
elif self.state == self.ESCAPED_CHAR:
self._parse_add_char(line[pos])
self.state = self.IN_FIELD
elif self.state == self.IN_QUOTED_FIELD:
if line[pos] == self._escapechar:
# possible escape character
self.state = self.ESCAPE_IN_QUOTED_FIELD
elif (line[pos] == self._quotechar
and self._quoting != QUOTE_NONE):
if self._doublequote:
# doublequote; " represented by ""
self.state = self.QUOTE_IN_QUOTED_FIELD
else:
#end of quote part of field
self.state = self.IN_FIELD
else:
# normal character - save in field
self._parse_add_char(line[pos])
elif self.state == self.ESCAPE_IN_QUOTED_FIELD:
self._parse_add_char(line[pos])
self.state = self.IN_QUOTED_FIELD
elif self.state == self.QUOTE_IN_QUOTED_FIELD:
# doublequote - seen a quote in a quoted field
if (line[pos] == self._quotechar
and self._quoting != QUOTE_NONE):
# save "" as "
self._parse_add_char(line[pos])
self.state = self.IN_QUOTED_FIELD
elif line[pos] == self._delimiter[0]:
# save field - wait for new field
self._parse_save_field()
self.state = self.START_FIELD
elif line[pos] == '\r' or line[pos] == '\n':
# end of line - return [fields]
self._parse_save_field()
self.state = self.EAT_CRNL
elif not self._strict:
self._parse_add_char(line[pos])
self.state = self.IN_FIELD
else:
raise Error("'%c' expected after '%c'" %
(self._delimiter, self._quotechar))
elif self.state == self.EAT_CRNL:
if line[pos] == '\r' or line[pos] == '\n':
pass
else:
raise Error("new-line character seen in unquoted field - "
"do you need to open the file "
"in universal-newline mode?")
else:
raise RuntimeError("unknown state: %r" % (self.state,))
pos += 1
def _parse_eol(self):
if self.state == self.EAT_CRNL:
self.state = self.START_RECORD
elif self.state == self.START_RECORD:
# empty line - return []
pass
elif self.state == self.IN_FIELD:
# in unquoted field
# end of line - return [fields]
self._parse_save_field()
self.state = self.START_RECORD
elif self.state == self.START_FIELD:
# save empty field - return [fields]
self._parse_save_field()
self.state = self.START_RECORD
elif self.state == self.ESCAPED_CHAR:
self._parse_add_char('\n')
self.state = self.IN_FIELD
elif self.state == self.IN_QUOTED_FIELD:
pass
elif self.state == self.ESCAPE_IN_QUOTED_FIELD:
self._parse_add_char('\n')
self.state = self.IN_QUOTED_FIELD
elif self.state == self.QUOTE_IN_QUOTED_FIELD:
# end of line - return [fields]
self._parse_save_field()
self.state = self.START_RECORD
else:
raise RuntimeError("unknown state: %r" % (self.state,))
def _parse_save_field(self):
field, self.field = self.field, ''
if self.numeric_field:
self.numeric_field = False
field = float(field)
self.fields.append(field)
def _parse_add_char(self, c):
if len(self.field) + 1 > _field_limit:
raise Error("field larget than field limit (%d)" % (_field_limit))
self.field += c
def _parse_add_str(self, s):
if len(self.field) + len(s) > _field_limit:
raise Error("field larget than field limit (%d)" % (_field_limit))
self.field += s
class Writer(object):
"""CSV writer
Writer objects are responsible for generating tabular data
in CSV format from sequence input."""
def __init__(self, file, dialect=None, **kwargs):
if not (hasattr(file, 'write') and callable(file.write)):
raise TypeError("argument 1 must have a 'write' method")
self.writeline = file.write
self.dialect = _call_dialect(dialect, kwargs)
def _join_reset(self):
self.rec = []
self.num_fields = 0
def _join_append(self, field, quoted, quote_empty):
dialect = self.dialect
# If this is not the first field we need a field separator
if self.num_fields > 0:
self.rec.append(dialect.delimiter)
if dialect.quoting == QUOTE_NONE:
need_escape = tuple(dialect.lineterminator) + (
dialect.escapechar, # escapechar always first
dialect.delimiter, dialect.quotechar)
else:
for c in tuple(dialect.lineterminator) + (
dialect.delimiter, dialect.escapechar):
if c and c in field:
quoted = True
need_escape = ()
if dialect.quotechar in field:
if dialect.doublequote:
field = field.replace(dialect.quotechar,
dialect.quotechar * 2)
quoted = True
else:
need_escape = (dialect.quotechar,)
for c in need_escape:
if c and c in field:
if not dialect.escapechar:
raise Error("need to escape, but no escapechar set")
field = field.replace(c, dialect.escapechar + c)
# If field is empty check if it needs to be quoted
if field == '' and quote_empty:
if dialect.quoting == QUOTE_NONE:
raise Error("single empty field record must be quoted")
quoted = 1
if quoted:
field = dialect.quotechar + field + dialect.quotechar
self.rec.append(field)
self.num_fields += 1
def writerow(self, row):
dialect = self.dialect
try:
rowlen = len(row)
except TypeError:
raise Error("sequence expected")
# join all fields in internal buffer
self._join_reset()
for field in row:
quoted = False
if dialect.quoting == QUOTE_NONNUMERIC:
try:
float(field)
except:
quoted = True
# This changed since 2.5:
# quoted = not isinstance(field, (int, long, float))
elif dialect.quoting == QUOTE_ALL:
quoted = True
if field is None:
self._join_append("", quoted, rowlen == 1)
else:
self._join_append(str(field), quoted, rowlen == 1)
# add line terminator
self.rec.append(dialect.lineterminator)
self.writeline(''.join(self.rec))
def writerows(self, rows):
for row in rows:
self.writerow(row)
def reader(*args, **kwargs):
"""
csv_reader = reader(iterable [, dialect='excel']
[optional keyword args])
for row in csv_reader:
process(row)
The "iterable" argument can be any object that returns a line
of input for each iteration, such as a file object or a list. The
optional \"dialect\" parameter is discussed below. The function
also accepts optional keyword arguments which override settings
provided by the dialect.
The returned object is an iterator. Each iteration returns a row
of the CSV file (which can span multiple input lines)"""
return Reader(*args, **kwargs)
def writer(*args, **kwargs):
"""
csv_writer = csv.writer(fileobj [, dialect='excel']
[optional keyword args])
for row in sequence:
csv_writer.writerow(row)
[or]
csv_writer = csv.writer(fileobj [, dialect='excel']
[optional keyword args])
csv_writer.writerows(rows)
The \"fileobj\" argument can be any object that supports the file API."""
return Writer(*args, **kwargs)
undefined = object()
def field_size_limit(limit=undefined):
"""Sets an upper limit on parsed fields.
csv.field_size_limit([limit])
Returns old limit. If limit is not given, no new limit is set and
the old limit is returned"""
global _field_limit
old_limit = _field_limit
if limit is not undefined:
if not isinstance(limit, (int, long)):
raise TypeError("int expected, got %s" %
(limit.__class__.__name__,))
_field_limit = limit
return old_limit