aboutsummaryrefslogtreecommitdiff
path: root/frozen_deps/Crypto/Random/OSRNG/rng_base.py
diff options
context:
space:
mode:
Diffstat (limited to 'frozen_deps/Crypto/Random/OSRNG/rng_base.py')
-rw-r--r--frozen_deps/Crypto/Random/OSRNG/rng_base.py88
1 files changed, 88 insertions, 0 deletions
diff --git a/frozen_deps/Crypto/Random/OSRNG/rng_base.py b/frozen_deps/Crypto/Random/OSRNG/rng_base.py
new file mode 100644
index 0000000..546f2e9
--- /dev/null
+++ b/frozen_deps/Crypto/Random/OSRNG/rng_base.py
@@ -0,0 +1,88 @@
+#
+# Random/OSRNG/rng_base.py : Base class for OSRNG
+#
+# Written in 2008 by Dwayne C. Litzenberger <dlitz@dlitz.net>
+#
+# ===================================================================
+# The contents of this file are dedicated to the public domain. To
+# the extent that dedication to the public domain is not available,
+# everyone is granted a worldwide, perpetual, royalty-free,
+# non-exclusive license to exercise all rights associated with the
+# contents of this file for any purpose whatsoever.
+# No rights are reserved.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+# ===================================================================
+
+__revision__ = "$Id$"
+
+import sys
+if sys.version_info[0] == 2 and sys.version_info[1] == 1:
+ from Crypto.Util.py21compat import *
+
+class BaseRNG(object):
+
+ def __init__(self):
+ self.closed = False
+ self._selftest()
+
+ def __del__(self):
+ self.close()
+
+ def _selftest(self):
+ # Test that urandom can return data
+ data = self.read(16)
+ if len(data) != 16:
+ raise AssertionError("read truncated")
+
+ # Test that we get different data every time (if we don't, the RNG is
+ # probably malfunctioning)
+ data2 = self.read(16)
+ if data == data2:
+ raise AssertionError("OS RNG returned duplicate data")
+
+ # PEP 343: Support for the "with" statement
+ def __enter__(self):
+ pass
+ def __exit__(self):
+ """PEP 343 support"""
+ self.close()
+
+ def close(self):
+ if not self.closed:
+ self._close()
+ self.closed = True
+
+ def flush(self):
+ pass
+
+ def read(self, N=-1):
+ """Return N bytes from the RNG."""
+ if self.closed:
+ raise ValueError("I/O operation on closed file")
+ if not isinstance(N, int):
+ raise TypeError("an integer is required")
+ if N < 0:
+ raise ValueError("cannot read to end of infinite stream")
+ elif N == 0:
+ return ""
+ data = self._read(N)
+ if len(data) != N:
+ raise AssertionError("%s produced truncated output (requested %d, got %d)" % (self.name, N, len(data)))
+ return data
+
+ def _close(self):
+ raise NotImplementedError("child class must implement this")
+
+ def _read(self, N):
+ raise NotImplementedError("child class must implement this")
+
+
+# vim:set ts=4 sw=4 sts=4 expandtab: