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Adds speed tests for int2bytes and old_int2bytes.
* In the following tests, the first speed test for each version of Python checked is the new implementation and the second is the old implementation. $ ./speed.sh int2bytes speed test python2.5 1000 loops, best of 3: 315 usec per loop 100 loops, best of 3: 4.87 msec per loop python2.6 10000 loops, best of 3: 170 usec per loop 100 loops, best of 3: 3.34 msec per loop python2.7 10000 loops, best of 3: 169 usec per loop 100 loops, best of 3: 2.8 msec per loop python3.2 10000 loops, best of 3: 169 usec per loop 100 loops, best of 3: 3.16 msec per loop
1 parent c19a21b commit a4453c6

3 files changed

Lines changed: 89 additions & 7 deletions

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‎rsa/transform.py‎

Lines changed: 65 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -21,9 +21,11 @@
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from __future__ import absolute_import
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24+
import types
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import binascii
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from struct import pack
26-
from rsa._compat import is_integer, b
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from rsa import common
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from rsa._compat import is_integer, b, byte
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ZERO_BYTE = b('\x00')
2931

@@ -43,7 +45,7 @@ def bytes2int(raw_bytes):
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return int(binascii.hexlify(raw_bytes), 16)
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4547

46-
def int2bytes(number, block_size=None):
48+
def old_int2bytes(number, block_size=0):
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r'''Converts a number to a string of bytes.
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@param number: the number to convert
@@ -55,6 +57,65 @@ def int2bytes(number, block_size=None):
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bytes than fit into the block.
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5759
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>>> old_int2bytes(123456789)
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b'\x07[\xcd\x15'
62+
>>> bytes2int(int2bytes(123456789))
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123456789
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65+
>>> old_int2bytes(123456789, 6)
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b'\x00\x00\x07[\xcd\x15'
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>>> bytes2int(int2bytes(123456789, 128))
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123456789
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>>> old_int2bytes(123456789, 3)
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Traceback (most recent call last):
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...
73+
OverflowError: Needed 4 bytes for number, but block size is 3
74+
75+
'''
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77+
# Type checking
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if not is_integer(number):
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raise TypeError("You must pass an integer for 'number', not %s" %
80+
number.__class__)
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82+
if number < 0:
83+
raise ValueError('Negative numbers cannot be used: %i' % number)
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# Do some bounds checking
86+
needed_bytes = common.byte_size(number)
87+
if block_size > 0:
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if needed_bytes > block_size:
89+
raise OverflowError('Needed %i bytes for number, but block size '
90+
'is %i' % (needed_bytes, block_size))
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# Convert the number to bytes.
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raw_bytes = []
94+
while number > 0:
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raw_bytes.insert(0, byte(number & 0xFF))
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number >>= 8
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# Pad with zeroes to fill the block
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if block_size > 0:
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padding = (block_size - needed_bytes) * ZERO_BYTE
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else:
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padding = b('')
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return padding + b('').join(raw_bytes)
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def int2bytes(number, block_size=None):
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"""Converts a number to a string of bytes.
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@param number: the number to convert
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@param block_size: the number of bytes to output. If the number encoded to
112+
bytes is less than this, the block will be zero-padded. When not given,
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the returned block is not padded.
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@throws OverflowError when block_size is given and the number takes up more
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bytes than fit into the block.
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>>> int2bytes(123456789)
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'\x07[\xcd\x15'
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>>> bytes2int(int2bytes(123456789))
@@ -69,9 +130,7 @@ def int2bytes(number, block_size=None):
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Traceback (most recent call last):
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...
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OverflowError: Need 4 bytes for number, but block size is 3
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'''
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"""
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# Type checking
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if not is_integer(number):
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raise TypeError("You must pass an integer for 'number', not %s" %
@@ -95,7 +154,7 @@ def int2bytes(number, block_size=None):
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if x != ZERO_BYTE[0]:
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break
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if block_size > 0:
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if block_size is not None and block_size > 0:
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# Bounds checking. We're not doing this up-front because the
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# most common use case is not specifying a chunk size. In the worst
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# case, the number will already have been converted to bytes above.

‎speed.sh‎

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,15 @@
1+
#!/bin/sh
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echo "int2bytes speed test"
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echo "python2.5"
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python2.5 -mtimeit -s'from rsa.transform import int2bytes; n = 1<<4096' 'int2bytes(n)'
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python2.5 -mtimeit -s'from rsa.transform import old_int2bytes; n = 1<<4096' 'old_int2bytes(n)'
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echo "python2.6"
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python2.6 -mtimeit -s'from rsa.transform import int2bytes; n = 1<<4096' 'int2bytes(n)'
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python2.6 -mtimeit -s'from rsa.transform import old_int2bytes; n = 1<<4096' 'old_int2bytes(n)'
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echo "python2.7"
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python2.7 -mtimeit -s'from rsa.transform import int2bytes; n = 1<<4096' 'int2bytes(n)'
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python2.7 -mtimeit -s'from rsa.transform import old_int2bytes; n = 1<<4096' 'old_int2bytes(n)'
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echo "python3.2"
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python3 -mtimeit -s'from rsa.transform import int2bytes; n = 1<<4096' 'int2bytes(n)'
15+
python3 -mtimeit -s'from rsa.transform import old_int2bytes; n = 1<<4096' 'old_int2bytes(n)'

‎tests/test_transform.py‎

Lines changed: 9 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -3,7 +3,7 @@
33

44
import unittest2
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from rsa._compat import b
6-
from rsa.transform import int2bytes
6+
from rsa.transform import int2bytes, old_int2bytes
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88

99
class Test_integer_to_bytes(unittest2.TestCase):
@@ -12,13 +12,21 @@ def test_chunk_size(self):
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b('\x00\x00\x07[\xcd\x15'))
1313
self.assertEqual(int2bytes(123456789, 7),
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b('\x00\x00\x00\x07[\xcd\x15'))
15+
self.assertEqual(old_int2bytes(123456789, 6),
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b('\x00\x00\x07[\xcd\x15'))
17+
self.assertEqual(old_int2bytes(123456789, 7),
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b('\x00\x00\x00\x07[\xcd\x15'))
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1620
def test_raises_OverflowError_when_chunk_size_is_insufficient(self):
1721
self.assertRaises(OverflowError, int2bytes, 123456789, 3)
1822
self.assertRaises(OverflowError, int2bytes, 299999999999, 4)
23+
self.assertRaises(OverflowError, old_int2bytes, 123456789, 3)
24+
self.assertRaises(OverflowError, old_int2bytes, 299999999999, 4)
1925

2026
def test_raises_ValueError_when_negative_integer(self):
2127
self.assertRaises(ValueError, int2bytes, -1)
28+
self.assertRaises(ValueError, old_int2bytes, -1)
2229

2330
def test_raises_TypeError_when_not_integer(self):
2431
self.assertRaises(TypeError, int2bytes, None)
32+
self.assertRaises(TypeError, old_int2bytes, None)

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