94 lines
2.4 KiB
Python
94 lines
2.4 KiB
Python
import os
|
|
import string
|
|
import random
|
|
import mmap
|
|
import sys
|
|
|
|
DATATYPES = dict(
|
|
ascii_letters=string.ascii_letters.encode(),
|
|
ascii_lowercase=string.ascii_lowercase.encode(),
|
|
ascii_uppercase=string.ascii_uppercase.encode(),
|
|
digits=string.digits.encode(),
|
|
hexdigits=string.hexdigits.encode(),
|
|
octdigits=string.octdigits.encode(),
|
|
punctuation=string.punctuation.encode(),
|
|
whitespace=string.whitespace.encode(),
|
|
ascii=string.printable.encode(),
|
|
bytes=bytes(range(256))
|
|
)
|
|
|
|
|
|
class TransformGenerator:
|
|
|
|
"""
|
|
Perform a byte-by-byte transform another generator - that is, for each
|
|
input byte, the transformation must produce one output byte.
|
|
|
|
gen: A generator to wrap
|
|
transform: A function (offset, data) -> transformed
|
|
"""
|
|
|
|
def __init__(self, gen, transform):
|
|
self.gen = gen
|
|
self.transform = transform
|
|
|
|
def __len__(self):
|
|
return len(self.gen)
|
|
|
|
def __getitem__(self, x):
|
|
d = self.gen.__getitem__(x)
|
|
if isinstance(x, slice):
|
|
return self.transform(x.start, d)
|
|
return self.transform(x, d)
|
|
|
|
def __repr__(self):
|
|
return "'transform(%s)'" % self.gen
|
|
|
|
|
|
def rand_byte(chars):
|
|
"""
|
|
Return a random character as byte from a charset.
|
|
"""
|
|
# bytearray has consistent behaviour on both Python 2 and 3
|
|
# while bytes does not
|
|
return bytes([random.choice(chars)])
|
|
|
|
|
|
class RandomGenerator:
|
|
|
|
def __init__(self, dtype, length):
|
|
self.dtype = dtype
|
|
self.length = length
|
|
|
|
def __len__(self):
|
|
return self.length
|
|
|
|
def __getitem__(self, x):
|
|
chars = DATATYPES[self.dtype]
|
|
if isinstance(x, slice):
|
|
return b"".join(rand_byte(chars) for _ in range(*x.indices(min(self.length, sys.maxsize))))
|
|
return rand_byte(chars)
|
|
|
|
def __repr__(self):
|
|
return "%s random from %s" % (self.length, self.dtype)
|
|
|
|
|
|
class FileGenerator:
|
|
def __init__(self, path):
|
|
self.path = os.path.expanduser(path)
|
|
|
|
def __len__(self):
|
|
return os.path.getsize(self.path)
|
|
|
|
def __getitem__(self, x):
|
|
with open(self.path, mode="rb") as f:
|
|
if isinstance(x, slice):
|
|
with mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ) as mapped:
|
|
return mapped.__getitem__(x)
|
|
else:
|
|
f.seek(x)
|
|
return f.read(1)
|
|
|
|
def __repr__(self):
|
|
return "<%s" % self.path
|