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from __future__ import print_function
from .lib import TestBase, FileCreator
from smmap.mman import (
SlidingWindowMapManager,
StaticWindowMapManager
)
from smmap.buf import SlidingWindowMapBuffer
from random import randint
from time import time
import sys
import os
man_optimal = SlidingWindowMapManager()
man_worst_case = SlidingWindowMapManager(
window_size=TestBase.k_window_test_size // 100,
max_memory_size=TestBase.k_window_test_size // 3,
max_open_handles=15)
static_man = StaticWindowMapManager()
class TestBuf(TestBase):
def test_basics(self):
with FileCreator(self.k_window_test_size, "buffer_test") as fc:
# invalid paths fail upon construction
c = man_optimal.make_cursor(fc.path)
self.assertRaises(ValueError, SlidingWindowMapBuffer, type(c)()) # invalid cursor
self.assertRaises(ValueError, SlidingWindowMapBuffer, c, fc.size) # offset too large
buf = SlidingWindowMapBuffer() # can create uninitailized buffers
assert buf.cursor() is None
# can call end access any time
buf.end_access()
buf.end_access()
assert len(buf) == 0
# begin access can revive it, if the offset is suitable
offset = 100
assert buf.begin_access(c, fc.size) == False
assert buf.begin_access(c, offset) == True
assert len(buf) == fc.size - offset
assert buf.cursor().is_valid()
# empty begin access keeps it valid on the same path, but alters the offset
assert buf.begin_access() == True
assert len(buf) == fc.size
assert buf.cursor().is_valid()
# simple access
with open(fc.path, 'rb') as fp:
data = fp.read()
assert data[offset] == buf[0]
assert data[offset:offset * 2] == buf[0:offset]
# negative indices, partial slices
assert buf[-1] == buf[len(buf) - 1]
assert buf[-10:] == buf[len(buf) - 10:len(buf)]
# end access makes its cursor invalid
buf.end_access()
assert not buf.cursor().is_valid()
assert buf.cursor().is_associated() # but it remains associated
# an empty begin access fixes it up again
assert buf.begin_access() == True and buf.cursor().is_valid()
del(buf) # ends access automatically
del(c)
assert man_optimal.num_file_handles() == 1
# PERFORMANCE
# blast away with random access and a full mapping - we don't want to
# exaggerate the manager's overhead, but measure the buffer overhead
# We do it once with an optimal setting, and with a worse manager which
# will produce small mappings only !
max_num_accesses = 100
fd = os.open(fc.path, os.O_RDONLY)
for item in (fc.path, fd):
for manager, man_id in ((man_optimal, 'optimal'),
(man_worst_case, 'worst case'),
(static_man, 'static optimal')):
buf = SlidingWindowMapBuffer(manager.make_cursor(item))
assert manager.num_file_handles() == 1
for access_mode in range(2): # single, multi
num_accesses_left = max_num_accesses
num_bytes = 0
fsize = fc.size
st = time()
buf.begin_access()
while num_accesses_left:
num_accesses_left -= 1
if access_mode: # multi
ofs_start = randint(0, fsize)
ofs_end = randint(ofs_start, fsize)
d = buf[ofs_start:ofs_end]
assert len(d) == ofs_end - ofs_start
assert d == data[ofs_start:ofs_end]
num_bytes += len(d)
del d
else:
pos = randint(0, fsize)
assert buf[pos] == data[pos]
num_bytes += 1
# END handle mode
# END handle num accesses
buf.end_access()
assert manager.num_file_handles()
assert manager.collect()
assert manager.num_file_handles() == 0
elapsed = max(time() - st, 0.001) # prevent zero division errors on windows
mb = float(1000 * 1000)
mode_str = (access_mode and "slice") or "single byte"
print("%s: Made %i random %s accesses to buffer created from %s reading a total of %f mb in %f s (%f mb/s)"
% (man_id, max_num_accesses, mode_str, type(item), num_bytes / mb, elapsed, (num_bytes / mb) / elapsed),
file=sys.stderr)
# END handle access mode
del buf
# END for each manager
# END for each input
os.close(fd)
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