"""

Script utile per:

- copiare un file a chunks a partire da una data stringa

- fare una replace su delle stringe in un chunk

- printare a partire da una certa stringa

Usage:

::

python read_replace.py --function "replace" -i "file_input.txt" -o "file_output.txt" -f "Buongiorno" -r "Buonasera"

python read_replace.py --function "copy" -i "file_input.txt" -o "file_output.txt" -f "Buongiorno"

python read_replace.py --function "printer" --find "Buongiorno" -i "file_input.txt"

"""

__author__ = 'davide.cacciavillani@energee3.com'

__reviewer__ = 'alessandro.cucci@energee3.com'

import argparse

def read_in_chunks(file_object, chunk_size=1024):

"""Lazy function (generator) to read a file piece by piece.

Default chunk size: 1k."""

while True:

data = file_object.read(chunk_size)

if not data:

break

yield data

def readfile(f, string_to_find):

already_found = False

for line in f:

if string_to_find in line or already_found:

already_found = True

print line

raw_input('avanti')

def find_and_replace(file_input, file_output, string_to_find, string_to_replace):

print file_input, file_output, string_to_find, string_to_replace

with open(file_input, 'r') as file_in, open(file_output, 'w') as file_out:

for chunk in read_in_chunks(file_in, 102400):

chunk = chunk.replace(string_to_find, string_to_replace)

file_out.write(chunk)

def find_and_print(file_input, string_to_find):

with open(file_input, 'r') as file_in:

readfile(file_in, string_to_find)

def find_and_copy(file_input, file_output, string_to_find):

print file_input, file_output, string_to_find

start_copy = False

with open(file_input, 'r') as file_in, open(file_output, 'w') as file_out:

for chunk in read_in_chunks(file_in):

if start_copy:

file_out.write(chunk)

if string_to_find in chunk:

start_copy = True

file_out.write(chunk)

if __name__ == "__main__":

parser = argparse.ArgumentParser()

parser.add_argument('--function', help='Must be one of "printer", "copy" or "replace"')

parser.add_argument('--find', '-f', help='string to find')

parser.add_argument('--replace', '-r', help='string to replace')

parser.add_argument('--file_input', '-i', help='Input file')

parser.add_argument('--file_output', '-o', help='Output file')

args = parser.parse_args()

if args.function not in ("replace", "printer", "copy"):

raise ValueError("function not recognised")

if args.function == "replace":

find_and_replace(args.file_input, args.file_output, args.find, args.replace)

elif args.function == "printer":

find_and_print(args.file_input, args.find)

elif args.function == "copy":

find_and_copy(args.file_input, args.file_output, args.find)