zlib.crc32 and zlib.adler32 now return an unsigned value as any sane person

gpshead · gpshead · commit ab0d8a1f59aa · 2008-03-17T20:24:09.000Z
would expect.

Fixes issues1202.
diff --git a/Doc/library/zlib.rst b/Doc/library/zlib.rst
@@ -42,6 +42,8 @@ The available exception and functions in this module are:
    the algorithm is designed for use as a checksum algorithm, it is not suitable
    for use as a general hash algorithm.
 
+   Always returns an unsigned 32-bit integer.
+
 
 .. function:: compress(string[, level])
 
@@ -74,6 +76,8 @@ The available exception and functions in this module are:
    the algorithm is designed for use as a checksum algorithm, it is not suitable
    for use as a general hash algorithm.
 
+   Always returns an unsigned 32-bit integer.
+
 
 .. function:: decompress(string[, wbits[, bufsize]])
 
diff --git a/Lib/test/test_zlib.py b/Lib/test/test_zlib.py
@@ -38,6 +38,14 @@ def test_penguins(self):
         self.assertEqual(zlib.crc32(b"penguin"), zlib.crc32(b"penguin", 0))
         self.assertEqual(zlib.adler32(b"penguin"),zlib.adler32(b"penguin",1))
 
+    def test_crc32_adler32_unsigned(self):
+        foo = 'abcdefghijklmnop'
+        # explicitly test signed behavior
+        self.assertEqual(zlib.crc32(foo), 2486878355)
+        self.assertEqual(zlib.crc32('spam'), 1138425661)
+        self.assertEqual(zlib.adler32(foo+foo), 3573550353)
+        self.assertEqual(zlib.adler32('spam'), 72286642)
+
 
 
 class ExceptionTestCase(unittest.TestCase):
diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c
@@ -922,7 +922,7 @@ PyZlib_adler32(PyObject *self, PyObject *args)
     if (!PyArg_ParseTuple(args, "s#|k:adler32", &buf, &len, &adler32val))
 	return NULL;
     adler32val = adler32(adler32val, buf, len);
-    return PyLong_FromLong(adler32val);
+    return PyLong_FromUnsignedLong(adler32val & 0xffffffff);
 }
 
 PyDoc_STRVAR(crc32__doc__,
@@ -940,7 +940,7 @@ PyZlib_crc32(PyObject *self, PyObject *args)
     if (!PyArg_ParseTuple(args, "s#|k:crc32", &buf, &len, &crc32val))
 	return NULL;
     crc32val = crc32(crc32val, buf, len);
-    return PyLong_FromLong(crc32val);
+    return PyLong_FromUnsignedLong(crc32val & 0xffffffff);
 }
 
 

Original file line number	Diff line number	Diff line change
`@@ -922,7 +922,7 @@ PyZlib_adler32(PyObject self, PyObject args)`
`922`	`922`	`if (!PyArg_ParseTuple(args, "s#\|k:adler32", &buf, &len, &adler32val))`
`923`	`923`	`return NULL;`
`924`	`924`	`adler32val = adler32(adler32val, buf, len);`
`925`		`- return PyLong_FromLong(adler32val);`
	`925`	`+ return PyLong_FromUnsignedLong(adler32val & 0xffffffff);`
`926`	`926`	`}`
`927`	`927`
`928`	`928`	`PyDoc_STRVAR(crc32__doc__,`
`@@ -940,7 +940,7 @@ PyZlib_crc32(PyObject self, PyObject args)`
`940`	`940`	`if (!PyArg_ParseTuple(args, "s#\|k:crc32", &buf, &len, &crc32val))`
`941`	`941`	`return NULL;`
`942`	`942`	`crc32val = crc32(crc32val, buf, len);`
`943`		`- return PyLong_FromLong(crc32val);`
	`943`	`+ return PyLong_FromUnsignedLong(crc32val & 0xffffffff);`
`944`	`944`	`}`
`945`	`945`
`946`	`946`