Added yield_fixedblock

2 files changed, 26 insertions, 0 deletions

diff --git a/rsa/blocks.py b/rsa/blocks.py
index c38c1f2..0250566 100644
--- a/rsa/blocks.py
+++ b/rsa/blocks.py
@@ -132,3 +132,22 @@ def yield_varblocks(infile):
         yield block
 
 
+def yield_fixedblocks(infile, blocksize):
+    '''Generator, yields each block of ``blocksize`` bytes in the input file.
+
+    :param infile: file to read and separate in blocks.
+    :returns: a generator that yields the contents of each block
+    '''
+
+    while True:
+        block = infile.read(blocksize)
+
+        read_bytes = len(block)
+        if read_bytes == 0:
+            break
+
+        yield block
+
+        if read_bytes < blocksize:
+            break
+
diff --git a/tests/test_blocks.py b/tests/test_blocks.py
index 8481c3c..ce5f03a 100644
--- a/tests/test_blocks.py
+++ b/tests/test_blocks.py
@@ -65,4 +65,11 @@ class VarblockTest(unittest.TestCase):
         varblocks = list(blocks.yield_varblocks(infile))
         self.assertEqual(['12345', 'Sybren'], varblocks)
 
+class FixedblockTest(unittest.TestCase):
 
+    def test_yield_fixedblock(self):
+
+        infile = StringIO('123456Sybren')
+
+        fixedblocks = list(blocks.yield_fixedblocks(infile, 6))
+        self.assertEqual(['123456', 'Sybren'], fixedblocks)