Add a new junk generator.

It turns out to be about 150% faster than the previous
relevant candiate (sha1ofgetrandbits2). Also, almost 100%
faster than the previous faster candidate, but since that
produces repetition, it is no longer relevant.

1 files changed, 17 insertions, 0 deletions

diff --git a/binaryjunk.py b/binaryjunk.py
index 5dde88e..4df82ca 100644
--- a/binaryjunk.py
+++ b/binaryjunk.py
@@ -83,6 +83,22 @@ def sha1ofgetrandbits2(size):
     return "".join(chunks)
 
 
+def sha512ofgetrandbits(size):
+    """catenate successive SHA512 of random byte stream"""
+    chunks = []
+    sum = hashlib.sha512()
+    chunk_size = len(sum.digest())
+    for byte in [chr(random.getrandbits(8)) for i in xrange(size / chunk_size)]:
+        sum.update(byte)
+        chunk = sum.digest()
+        chunks.append(chunk)
+    if size % chunk_size > 0:
+        sum.update(chr(random.getrandbits(8)))
+        chunk = sum.digest()
+        chunks.append(chunk[:size % chunk_size])
+    return "".join(chunks)
+
+
 def md5ofrandomandstatic(size):
     """MD5 first of random byte stream, then constant"""
     chunks = []
@@ -166,6 +182,7 @@ funcs = [
     md5ofrandomandstatic,
     md5ofrandomandstatic2,
     sha1ofrandomandstatic2,
+    sha512ofgetrandbits, 
     ]