cpython/Lib/test/test_mmap.py

122 lines
3.2 KiB
Python

import mmap
import string, os, re, sys
PAGESIZE = mmap.PAGESIZE
def test_both():
"Test mmap module on Unix systems and Windows"
# Create an mmap'ed file
f = open('foo', 'w+')
# Write 2 pages worth of data to the file
f.write('\0'* PAGESIZE)
f.write('foo')
f.write('\0'* (PAGESIZE-3) )
m = mmap.mmap(f.fileno(), 2 * PAGESIZE)
f.close()
# Simple sanity checks
print ' Position of foo:', string.find(m, 'foo') / float(PAGESIZE), 'pages'
assert string.find(m, 'foo') == PAGESIZE
print ' Length of file:', len(m) / float(PAGESIZE), 'pages'
assert len(m) == 2*PAGESIZE
print ' Contents of byte 0:', repr(m[0])
assert m[0] == '\0'
print ' Contents of first 3 bytes:', repr(m[0:3])
assert m[0:3] == '\0\0\0'
# Modify the file's content
print "\n Modifying file's content..."
m[0] = '3'
m[PAGESIZE +3: PAGESIZE +3+3]='bar'
# Check that the modification worked
print ' Contents of byte 0:', repr(m[0])
assert m[0] == '3'
print ' Contents of first 3 bytes:', repr(m[0:3])
assert m[0:3] == '3\0\0'
print ' Contents of second page:', repr(m[PAGESIZE-1 : PAGESIZE + 7])
assert m[PAGESIZE-1 : PAGESIZE + 7] == '\0foobar\0'
m.flush()
# Test doing a regular expression match in an mmap'ed file
match=re.search('[A-Za-z]+', m)
if match == None:
print ' ERROR: regex match on mmap failed!'
else:
start, end = match.span(0)
length = end - start
print ' Regex match on mmap (page start, length of match):',
print start / float(PAGESIZE), length
assert start == PAGESIZE
assert end == PAGESIZE + 6
# test seeking around (try to overflow the seek implementation)
m.seek(0,0)
print ' Seek to zeroth byte'
assert m.tell() == 0
m.seek(42,1)
print ' Seek to 42nd byte'
assert m.tell() == 42
m.seek(0,2)
print ' Seek to last byte'
assert m.tell() == len(m)
print ' Try to seek to negative position...'
try:
m.seek(-1)
except ValueError:
pass
else:
assert 0, 'expected a ValueError but did not get it'
print ' Try to seek beyond end of mmap...'
try:
m.seek(1,2)
except ValueError:
pass
else:
assert 0, 'expected a ValueError but did not get it'
print ' Try to seek to negative position...'
try:
m.seek(-len(m)-1,2)
except ValueError:
pass
else:
assert 0, 'expected a ValueError but did not get it'
# Try resizing map
print ' Attempting resize()'
try:
m.resize( 512 )
except SystemError:
# resize() not supported
# No messages are printed, since the output of this test suite
# would then be different across platforms.
pass
else:
# resize() is supported
assert len(m) == 512, "len(m) is %d, but expecting 512" % (len(m),)
# Check that we can no longer seek beyond the new size.
try:
m.seek(513,0)
except ValueError:
pass
else:
assert 0, 'Could seek beyond the new size'
m.close()
os.unlink("foo")
print ' Test passed'
test_both()