bcp.py

#!/usr/bin/env python
import sys
import csv


def convert(bcpdata, lineterminator='*@@*', delimiter='@**@', quote='"', newdelimiter=',', escapechar='\\', newline='\n'):
    """
    returns data from a string of BCP data. Default is to present as CSV data.
    """
    bcpdata = bcpdata.replace(escapechar, escapechar + escapechar)
    bcpdata = bcpdata.replace(quote, escapechar + quote)
    bcpdata = bcpdata.replace(delimiter, quote + newdelimiter + quote)
    bcpdata = bcpdata.replace(lineterminator, quote + newline + quote)
    bcpdata = quote + bcpdata + quote
    return bcpdata


def stream(file, lineterminator='*@@*', delimiter='@**@', encoding='utf-8'):
    """
    Returns a generator for parsing a BCP file. The input is a file object, and
    the output is a list for each row in the data.

    Usage:

    with open("bcp_file.bcp", 'rb') as bcpfile:
        for bcpfields in bcp_stream(bcpfile):
            print(bcpfields)

    More pythonic, but slower than using the `convert()` function above and then
    parsing the CSV file, as the python CSV utilities are written in pure C.
    """

    buffer = ''
    fields = []

    while True:
        byte = file.read(1)
        try:
            byte = byte.decode(encoding)
        except AttributeError:
            pass

        buffer += byte

        if not byte:
            break

        # check if we've seen a field delimiter
        if(buffer[-len(delimiter):] == delimiter):
            fields.append(buffer[:-len(delimiter)])
            buffer = ''

        # check if we've seen a line delimiter
        if(buffer[-len(lineterminator):] == lineterminator):
            fields.append(buffer[:-len(lineterminator)])
            buffer = ''
            yield fields
            fields = []

    yield fields


def main():

    # get arguments
    bcp_filename = sys.argv[1]
    try:
        csv_filename = sys.argv[2]
    except IndexError:
        csv_filename = bcp_filename.replace('.bcp', '.csv')

    # have to check system version annoyingly
    # for python 3 >
    if sys.version_info >= (3, 0):

        with open(bcp_filename, 'r') as bcpfile:
            with open(csv_filename, 'w', newline='') as csvfile:
                writer = csv.writer(csvfile)
                for bcpfields in stream(bcpfile):
                    writer.writerow(bcpfields)

    # for python 2
    else:
        with open(bcp_filename, 'rb') as bcpfile:
            with open(csv_filename, 'wb') as csvfile:
                writer = csv.writer(csvfile)
                for bcpfields in stream(bcpfile):
                    writer.writerow(bcpfields)

if __name__ == '__main__':
    main()