193 lines
5.9 KiB
Python
193 lines
5.9 KiB
Python
"""
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pyexcel_io.readers.csv_sheet
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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csv file reader
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:copyright: (c) 2014-2022 by Onni Software Ltd.
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:license: New BSD License, see LICENSE for more details
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"""
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import csv
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import pyexcel_io.service as service
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import pyexcel_io._compact as compact
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import pyexcel_io.constants as constants
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from pyexcel_io.plugin_api import ISheet
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DEFAULT_SEPARATOR = "__"
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DEFAULT_SHEET_SEPARATOR_FORMATTER = "---%s---" % constants.DEFAULT_NAME + "%s"
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SEPARATOR_MATCHER = "---%s:(.*)---" % constants.DEFAULT_NAME
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DEFAULT_CSV_STREAM_FILE_FORMATTER = (
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"---%s:" % constants.DEFAULT_NAME + "%s---%s"
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)
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DEFAULT_NEWLINE = "\r\n"
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BOM_LITTLE_ENDIAN = b"\xff\xfe"
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BOM_BIG_ENDIAN = b"\xfe\ff"
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LITTLE_ENDIAN = 0
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BIG_ENDIAN = 1
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class CSVMemoryMapIterator(object):
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"""
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Wrapper class for mmap object
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mmap object does not handle encoding at all. This class
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provide the necessary transcoding for utf-8, utf-16 and utf-32
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"""
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def __init__(self, mmap_obj, encoding):
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self.__mmap_obj = mmap_obj
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self.__encoding = encoding
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self.__count = 0
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self.__endian = LITTLE_ENDIAN
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if encoding == "utf-8":
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# ..\r\x00\n
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# \x00\x..
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self.__zeros_left_in_2_row = 0
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elif encoding == "utf-16":
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# ..\r\x00\n
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# \x00\x..
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self.__zeros_left_in_2_row = 1
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elif encoding == "utf-32":
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# \r\x00\x00\x00\n
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# \x00\x00\x00\x..
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self.__zeros_left_in_2_row = 3
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elif encoding in ["utf-32-be", "utf-16-be"]:
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self.__zeros_left_in_2_row = 0
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self.__endian = BIG_ENDIAN
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elif encoding == "utf-32-le":
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self.__zeros_left_in_2_row = 3
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self.__endian = LITTLE_ENDIAN
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elif encoding == "utf-16-le":
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self.__zeros_left_in_2_row = 1
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self.__endian = LITTLE_ENDIAN
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else:
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raise Exception("Encoding %s is not supported" % encoding)
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def __iter__(self):
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return self
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def __next__(self):
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line = self.__mmap_obj.readline()
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if self.__count == 0:
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utf_16_32 = (
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self.__encoding == "utf-16" or self.__encoding == "utf-32"
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)
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if utf_16_32:
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bom_header = line[:2]
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if bom_header == BOM_BIG_ENDIAN:
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self.__endian = BIG_ENDIAN
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elif self.__endian == LITTLE_ENDIAN:
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line = line[self.__zeros_left_in_2_row :] # noqa: E203
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if self.__endian == LITTLE_ENDIAN:
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line = line.rstrip()
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line = line.decode(self.__encoding)
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self.__count += 1
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if line == "":
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raise StopIteration
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return line
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def close(self):
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pass
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class CSVSheetReader(ISheet):
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"""generic csv file reader"""
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def __init__(
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self,
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sheet,
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encoding="utf-8",
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auto_detect_float=True,
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ignore_infinity=True,
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auto_detect_int=True,
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auto_detect_datetime=True,
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pep_0515_off=True,
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ignore_nan_text=False,
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default_float_nan=None,
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**keywords
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):
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self._native_sheet = sheet
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self._encoding = encoding
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self.__auto_detect_int = auto_detect_int
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self.__auto_detect_float = auto_detect_float
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self.__ignore_infinity = ignore_infinity
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self.__auto_detect_datetime = auto_detect_datetime
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self.__file_handle = None
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self.__pep_0515_off = pep_0515_off
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self.__ignore_nan_text = ignore_nan_text
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self.__default_float_nan = default_float_nan
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self._keywords = keywords
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def get_file_handle(self):
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"""return me unicde reader for csv"""
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raise NotImplementedError("Please implement get_file_handle()")
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def row_iterator(self):
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self.__file_handle = self.get_file_handle()
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return csv.reader(self.__file_handle, **self._keywords)
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def column_iterator(self, row):
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for element in row:
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if element is not None and element != "":
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element = self.__convert_cell(element)
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yield element
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def __convert_cell(self, csv_cell_text):
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ret = None
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if self.__auto_detect_int:
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ret = service.detect_int_value(csv_cell_text, self.__pep_0515_off)
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if ret is None and self.__auto_detect_float:
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ret = service.detect_float_value(
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csv_cell_text,
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self.__pep_0515_off,
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ignore_nan_text=self.__ignore_nan_text,
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default_float_nan=self.__default_float_nan,
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)
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shall_we_ignore_the_conversion = (
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ret in [float("inf"), float("-inf")]
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) and self.__ignore_infinity
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if shall_we_ignore_the_conversion:
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ret = None
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if ret is None and self.__auto_detect_datetime:
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ret = service.detect_date_value(csv_cell_text)
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if ret is None:
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ret = csv_cell_text
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return ret
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def close(self):
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if self.__file_handle:
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self.__file_handle.close()
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# else: means the generator has been run
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# yes, no run, no file open.
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class CSVFileReader(CSVSheetReader):
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"""read csv from phyical file"""
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def get_file_handle(self):
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unicode_reader = open(
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self._native_sheet.payload, "r", encoding=self._encoding
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)
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return unicode_reader
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class CSVinMemoryReader(CSVSheetReader):
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"""read csv file from memory"""
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def get_file_handle(self):
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if isinstance(self._native_sheet.payload, compact.BytesIO):
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# please note that
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# if the end developer feed us bytesio in python3
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# we will do the conversion to StriongIO but that
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# comes at a cost.
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content = self._native_sheet.payload.read()
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unicode_reader = compact.StringIO(content.decode(self._encoding))
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else:
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unicode_reader = self._native_sheet.payload
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return unicode_reader
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