Changes to allow pycrpyto to work on Python 3.x as well as 2.1 through 2.7

1 files changed, 73 insertions, 0 deletions

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+Py code:

+

+setup.py invokes 2to3 automatically. This handles int/long and print issues, among others.

+setup.py will touch nt.py on win32 after build and build again. This is necessary so 2to3 can do its magic on that file.

+

+There are still a lot of places in the code that need manual attention even with 2to3. They mostly have to do with string (2.x) vs. byte/unicode (3.x) representation

+

+Use "if sys.version_info[0] is 2:" where needed. Ideally, most of the conditional code can be in py3compat.

+

+Replace str(x) with bstr(x) if bytes were intended. Becomes str(x) in 2.x and bytes(x) in 3.x through py3compat module.

+Replace chr(x) with bchr(x) if bytes were intended. Becomes chr(x) in 2.x and bytes([x]) in 3.x through py3compat module.

+Replace ord(x) with bord(x) if bytes were intended. Becomes ord(x) in 2.x and x in 3.x through py3compat module.

+

+Comparing a string index to a string literal needs to be changed in 3.x, as b'string'[0] returns an integer, not b's'.

+The comparison can be fixed by indexing the right side, too: "if s[0]==b('\x30')[0]:" or "if self.typeTag!=self.typeTags['SEQUENCE'][0]:"

+

+String literals need to be bytes if bytes were intended. 

+Replace "x" with b("x") if bytes were intended. Becomes "x" in 2.x, and s.encode("x","latin-1") in 3.x through py3compat module.

+For example, '"".join' is replaced by 'b("").join', and 's = ""' becomes 's = b("")'.

+Search for \x to find literals that may have been intended as byte strings

+!! However, where a human-readable ASCII text string output was intended, such as in AllOrNothing.undigest(), leave as a string literal !!

+

+Only load python_compat.py "if sys.version_info[0] is 2 and sys.version_info[1] is 1:" . 

+The assignment to True, False generates syntax errors in 3.x, and >= 2.2 don't need the compatibility code.

+

+Where print is used with >> to redirect, use a separate function instead. See setup.py for an example

+

+The string module has been changed in 3.x. It lost join and split, maketrans now expects bytes, and so on. 

+Replace string.join(a,b) with b.join(a).

+Replace string.split(a) with a.split().

+Replace body of white-space-stripping functions with 'return "".join(s.split())'

+

+Integer division via the "/" operator can return a float in 3.x. This causes issues in Util.number.getStrongPrime. As 2.1 does not support

+the "//" operator, a helper function "floordiv()" is brought in via 'if sys.version_info' from floordiv.py or py21floordiv.py.

+

+

+C code:

+

+Extended "pycrypto_compat.h". It handles #define's for Python 3.x forward compatibility

+

+#include "pycrypto_compat.h"

+// All other local includes after this, so they can benefit from the definitions in pycrypto_compat.h

+

+The compat header #defines IS_PY3K if compiling on 3.x

+The compat header #defines PyBytes_*, PyUnicode_*, PyBytesObject to resolve to their PyString* counterparts if compiling on 2.x.

+PyLong_* can be dangerous depending on code construct (think an if that runs PyInt_* with else PyLong_*),

+therefore it is #defined in each individual module if needed and safe to do so.

+

+PyString_* has been replaced with PyBytes_* or PyUnicode_* depending on intent

+PyStringObject has been replaced with PyBytesObject or PyUnicodeObject depending on intent.

+PyInt_* has been replaced with PyLong_*, where safe to do (in all cases so far)

+

+The C code uses "#ifdef IS_PY3K" liberally.

+Code duplication has been avoided.

+

+Module initialization and module structure differ significantly in 3.x. Conditionals take care of it.

+

+myModuleType.ob_type assignment conditionally becomes PyTypeReady for 3.x.

+

+getattr cannot be used to check against custom attributes in 3.x. For 3.x, conditional code uses getattro

+and PyUnicode_CompareWithASCIIString instead of strcmp

+

+hexdigest() needed to be changed to return a Unicode object with 3.x

+

+

+TODO:

+- Check for type of string in functions and throw an error when it's not correct. While at it, ensure that functions observe the guidelines below re type. 

+  This is friendlier than just relying on Python's errors.

+- Document the expected types for functions. The cipher, the key and the input texts are byte-strings. Plaintext decodes are byte-strings currently, this needs review. 

+  In keeping with how Python 3.x's hash functions work, the input MODE is a text string. hexdigest() returns a text string, and digest() returns a byte-string.

+- Compile and test _fastmath.c

+- Go through test cases and see which modules are not covered

+- Look into exclusions in setup.py