[gentoo-portage-dev] [PATCH 13/14] portage.checksum: Support pygost as fallback Streebog provider

[Michał Górny]

Support the pure Python implementation of Streebog in pygost as
a fallback algorithm. The code is horrible (it stores all the data
in memory before hashing), so it is really intended as last fallback.
---
 pym/portage/checksum.py | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/pym/portage/checksum.py b/pym/portage/checksum.py
index 3ee100c3f..df896533f 100644
--- a/pym/portage/checksum.py
+++ b/pym/portage/checksum.py
@@ -247,6 +247,21 @@ if 'RMD160' not in hashfunc_map or 'WHIRLPOOL' not in hashfunc_map:
 		pass
 
 
+# Support pygost as fallback streebog provider
+# It's mostly provided as a reference implementation; it's pure Python,
+# slow and reads all data to memory (i.e. doesn't hash on update()...)
+if 'STREEBOG256' not in hashfunc_map or 'STREEBOG512' not in hashfunc_map:
+	try:
+		import pygost.gost34112012
+
+		_generate_hash_function("STREEBOG256",
+			functools.partial(pygost.gost34112012.GOST34112012, digest_size=32), origin="pygost")
+		_generate_hash_function("STREEBOG512",
+			functools.partial(pygost.gost34112012.GOST34112012, digest_size=64), origin="pygost")
+	except ImportError:
+		pass
+
+
 _whirlpool_unaccelerated = False
 if "WHIRLPOOL" not in hashfunc_map:
 	# Bundled WHIRLPOOL implementation
-- 
2.12.0