Issue #1023290: Added API for the conversion of longs to bytes and vice-versa.
diff --git a/Lib/test/test_long.py b/Lib/test/test_long.py
index 9974a5f..b4ab74f 100644
--- a/Lib/test/test_long.py
+++ b/Lib/test/test_long.py
@@ -4,6 +4,7 @@
import random
import math
+import array
# Used for lazy formatting of failure messages
class Frm(object):
@@ -900,6 +901,237 @@
for e in bad_exponents:
self.assertRaises(TypeError, round, 3, e)
+ def test_to_bytes(self):
+ def check(tests, byteorder, signed=False):
+ for test, expected in tests.items():
+ try:
+ self.assertEqual(
+ test.to_bytes(len(expected), byteorder, signed=signed),
+ expected)
+ except Exception as err:
+ raise AssertionError(
+ "failed to convert {0} with byteorder={1} and signed={2}"
+ .format(test, byteorder, signed)) from err
+
+ # Convert integers to signed big-endian byte arrays.
+ tests1 = {
+ 0: b'\x00',
+ 1: b'\x01',
+ -1: b'\xff',
+ -127: b'\x81',
+ -128: b'\x80',
+ -129: b'\xff\x7f',
+ 127: b'\x7f',
+ 129: b'\x00\x81',
+ -255: b'\xff\x01',
+ -256: b'\xff\x00',
+ 255: b'\x00\xff',
+ 256: b'\x01\x00',
+ 32767: b'\x7f\xff',
+ -32768: b'\xff\x80\x00',
+ 65535: b'\x00\xff\xff',
+ -65536: b'\xff\x00\x00',
+ -8388608: b'\x80\x00\x00'
+ }
+ check(tests1, 'big', signed=True)
+
+ # Convert integers to signed little-endian byte arrays.
+ tests2 = {
+ 0: b'\x00',
+ 1: b'\x01',
+ -1: b'\xff',
+ -127: b'\x81',
+ -128: b'\x80',
+ -129: b'\x7f\xff',
+ 127: b'\x7f',
+ 129: b'\x81\x00',
+ -255: b'\x01\xff',
+ -256: b'\x00\xff',
+ 255: b'\xff\x00',
+ 256: b'\x00\x01',
+ 32767: b'\xff\x7f',
+ -32768: b'\x00\x80',
+ 65535: b'\xff\xff\x00',
+ -65536: b'\x00\x00\xff',
+ -8388608: b'\x00\x00\x80'
+ }
+ check(tests2, 'little', signed=True)
+
+ # Convert integers to unsigned big-endian byte arrays.
+ tests3 = {
+ 0: b'\x00',
+ 1: b'\x01',
+ 127: b'\x7f',
+ 128: b'\x80',
+ 255: b'\xff',
+ 256: b'\x01\x00',
+ 32767: b'\x7f\xff',
+ 32768: b'\x80\x00',
+ 65535: b'\xff\xff',
+ 65536: b'\x01\x00\x00'
+ }
+ check(tests3, 'big', signed=False)
+
+ # Convert integers to unsigned little-endian byte arrays.
+ tests4 = {
+ 0: b'\x00',
+ 1: b'\x01',
+ 127: b'\x7f',
+ 128: b'\x80',
+ 255: b'\xff',
+ 256: b'\x00\x01',
+ 32767: b'\xff\x7f',
+ 32768: b'\x00\x80',
+ 65535: b'\xff\xff',
+ 65536: b'\x00\x00\x01'
+ }
+ check(tests4, 'little', signed=False)
+
+ self.assertRaises(OverflowError, (256).to_bytes, 1, 'big', signed=False)
+ self.assertRaises(OverflowError, (256).to_bytes, 1, 'big', signed=True)
+ self.assertRaises(OverflowError, (256).to_bytes, 1, 'little', signed=False)
+ self.assertRaises(OverflowError, (256).to_bytes, 1, 'little', signed=True)
+ self.assertRaises(OverflowError, (-1).to_bytes, 2, 'big', signed=False),
+ self.assertRaises(OverflowError, (-1).to_bytes, 2, 'little', signed=False)
+ self.assertEqual((0).to_bytes(0, 'big'), b'')
+ self.assertEqual((1).to_bytes(5, 'big'), b'\x00\x00\x00\x00\x01')
+ self.assertEqual((0).to_bytes(5, 'big'), b'\x00\x00\x00\x00\x00')
+ self.assertEqual((-1).to_bytes(5, 'big', signed=True),
+ b'\xff\xff\xff\xff\xff')
+ self.assertRaises(OverflowError, (1).to_bytes, 0, 'big')
+
+ def test_from_bytes(self):
+ def check(tests, byteorder, signed=False):
+ for test, expected in tests.items():
+ try:
+ self.assertEqual(
+ int.from_bytes(test, byteorder, signed=signed),
+ expected)
+ except Exception as err:
+ raise AssertionError(
+ "failed to convert {0} with byteorder={1!r} and signed={2}"
+ .format(test, byteorder, signed)) from err
+
+ # Convert signed big-endian byte arrays to integers.
+ tests1 = {
+ b'': 0,
+ b'\x00': 0,
+ b'\x00\x00': 0,
+ b'\x01': 1,
+ b'\x00\x01': 1,
+ b'\xff': -1,
+ b'\xff\xff': -1,
+ b'\x81': -127,
+ b'\x80': -128,
+ b'\xff\x7f': -129,
+ b'\x7f': 127,
+ b'\x00\x81': 129,
+ b'\xff\x01': -255,
+ b'\xff\x00': -256,
+ b'\x00\xff': 255,
+ b'\x01\x00': 256,
+ b'\x7f\xff': 32767,
+ b'\x80\x00': -32768,
+ b'\x00\xff\xff': 65535,
+ b'\xff\x00\x00': -65536,
+ b'\x80\x00\x00': -8388608
+ }
+ check(tests1, 'big', signed=True)
+
+ # Convert signed little-endian byte arrays to integers.
+ tests2 = {
+ b'': 0,
+ b'\x00': 0,
+ b'\x00\x00': 0,
+ b'\x01': 1,
+ b'\x00\x01': 256,
+ b'\xff': -1,
+ b'\xff\xff': -1,
+ b'\x81': -127,
+ b'\x80': -128,
+ b'\x7f\xff': -129,
+ b'\x7f': 127,
+ b'\x81\x00': 129,
+ b'\x01\xff': -255,
+ b'\x00\xff': -256,
+ b'\xff\x00': 255,
+ b'\x00\x01': 256,
+ b'\xff\x7f': 32767,
+ b'\x00\x80': -32768,
+ b'\xff\xff\x00': 65535,
+ b'\x00\x00\xff': -65536,
+ b'\x00\x00\x80': -8388608
+ }
+ check(tests2, 'little', signed=True)
+
+ # Convert unsigned big-endian byte arrays to integers.
+ tests3 = {
+ b'': 0,
+ b'\x00': 0,
+ b'\x01': 1,
+ b'\x7f': 127,
+ b'\x80': 128,
+ b'\xff': 255,
+ b'\x01\x00': 256,
+ b'\x7f\xff': 32767,
+ b'\x80\x00': 32768,
+ b'\xff\xff': 65535,
+ b'\x01\x00\x00': 65536,
+ }
+ check(tests3, 'big', signed=False)
+
+ # Convert integers to unsigned little-endian byte arrays.
+ tests4 = {
+ b'': 0,
+ b'\x00': 0,
+ b'\x01': 1,
+ b'\x7f': 127,
+ b'\x80': 128,
+ b'\xff': 255,
+ b'\x00\x01': 256,
+ b'\xff\x7f': 32767,
+ b'\x00\x80': 32768,
+ b'\xff\xff': 65535,
+ b'\x00\x00\x01': 65536,
+ }
+ check(tests4, 'little', signed=False)
+
+ class myint(int):
+ pass
+
+ self.assertTrue(type(myint.from_bytes(b'\x00', 'big')) is myint)
+ self.assertEqual(myint.from_bytes(b'\x01', 'big'), 1)
+ self.assertTrue(
+ type(myint.from_bytes(b'\x00', 'big', signed=False)) is myint)
+ self.assertEqual(myint.from_bytes(b'\x01', 'big', signed=False), 1)
+ self.assertTrue(type(myint.from_bytes(b'\x00', 'little')) is myint)
+ self.assertEqual(myint.from_bytes(b'\x01', 'little'), 1)
+ self.assertTrue(type(myint.from_bytes(
+ b'\x00', 'little', signed=False)) is myint)
+ self.assertEqual(myint.from_bytes(b'\x01', 'little', signed=False), 1)
+ self.assertEqual(
+ int.from_bytes([255, 0, 0], 'big', signed=True), -65536)
+ self.assertEqual(
+ int.from_bytes((255, 0, 0), 'big', signed=True), -65536)
+ self.assertEqual(int.from_bytes(
+ bytearray(b'\xff\x00\x00'), 'big', signed=True), -65536)
+ self.assertEqual(int.from_bytes(
+ bytearray(b'\xff\x00\x00'), 'big', signed=True), -65536)
+ self.assertEqual(int.from_bytes(
+ array.array('B', b'\xff\x00\x00'), 'big', signed=True), -65536)
+ self.assertEqual(int.from_bytes(
+ memoryview(b'\xff\x00\x00'), 'big', signed=True), -65536)
+ self.assertRaises(ValueError, int.from_bytes, [256], 'big')
+ self.assertRaises(ValueError, int.from_bytes, [0], 'big\x00')
+ self.assertRaises(ValueError, int.from_bytes, [0], 'little\x00')
+ self.assertRaises(TypeError, int.from_bytes, "", 'big')
+ self.assertRaises(TypeError, int.from_bytes, "\x00", 'big')
+ self.assertRaises(TypeError, int.from_bytes, 0, 'big')
+ self.assertRaises(TypeError, int.from_bytes, 0, 'big', True)
+ self.assertRaises(TypeError, myint.from_bytes, "", 'big')
+ self.assertRaises(TypeError, myint.from_bytes, "\x00", 'big')
+ self.assertRaises(TypeError, myint.from_bytes, 0, 'big')
+ self.assertRaises(TypeError, int.from_bytes, 0, 'big', True)
def test_main():