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|
"""passlib.utils._blowfish._gen_files - meta script that generates unrolled.py"""
#==========================================================================
# imports
#==========================================================================
# core
import os
import textwrap
# pkg
from passlib.utils.compat import irange
# local
#==========================================================================
# helpers
#==========================================================================
def varlist(name, count):
return ", ".join(name + str(x) for x in irange(count))
def indent_block(block, padding):
"ident block of text"
lines = block.split("\n")
return "\n".join(
padding + line if line else ""
for line in lines
)
BFSTR = """\
((((S0[l >> 24] + S1[(l >> 16) & 0xff]) ^ S2[(l >> 8) & 0xff]) +
S3[l & 0xff]) & 0xffffffff)
""".strip()
def render_encipher(write, indent=0):
for i in irange(0, 15, 2):
write(indent, """\
# Feistel substitution on left word (round %(i)d)
r ^= %(left)s ^ p%(i1)d
# Feistel substitution on right word (round %(i1)d)
l ^= %(right)s ^ p%(i2)d
""", i=i, i1=i+1, i2=i+2,
left=BFSTR, right=BFSTR.replace("l","r"),
)
def write_encipher_function(write, indent=0):
write(indent, """\
def encipher(self, l, r):
\"""blowfish encipher a single 64-bit block encoded as two 32-bit ints\"""
(p0, p1, p2, p3, p4, p5, p6, p7, p8, p9,
p10, p11, p12, p13, p14, p15, p16, p17) = self.P
S0, S1, S2, S3 = self.S
l ^= p0
""")
render_encipher(write, indent+1)
write(indent+1, """\
return r ^ p17, l
""")
def write_expand_function(write, indent=0):
write(indent, """\
def expand(self, key_words):
\"""unrolled version of blowfish key expansion\"""
#assert len(key_words) >= 18, "size of key_words must be >= 18"
P, S = self.P, self.S
S0, S1, S2, S3 = S
#=============================================================
# integrate key
#=============================================================
""")
for i in irange(18):
write(indent+1, """\
p%(i)d = P[%(i)d] ^ key_words[%(i)d]
""", i=i)
write(indent+1, """\
#=============================================================
# update P
#=============================================================
#------------------------------------------------
# update P[0] and P[1]
#------------------------------------------------
l, r = p0, 0
""")
render_encipher(write, indent+1)
write(indent+1, """\
p0, p1 = l, r = r ^ p17, l
""")
for i in irange(2, 18, 2):
write(indent+1, """\
#------------------------------------------------
# update P[%(i)d] and P[%(i1)d]
#------------------------------------------------
l ^= p0
""", i=i, i1=i+1)
render_encipher(write, indent+1)
write(indent+1, """\
p%(i)d, p%(i1)d = l, r = r ^ p17, l
""", i=i, i1=i+1)
write(indent+1, """\
#------------------------------------------------
# save changes to original P array
#------------------------------------------------
P[:] = (p0, p1, p2, p3, p4, p5, p6, p7, p8, p9,
p10, p11, p12, p13, p14, p15, p16, p17)
#=============================================================
# update S
#=============================================================
for box in S:
j = 0
while j < 256:
l ^= p0
""")
render_encipher(write, indent+3)
write(indent+3, """\
box[j], box[j+1] = l, r = r ^ p17, l
j += 2
""")
#==========================================================================
# main
#==========================================================================
def main():
target = os.path.join(os.path.dirname(__file__), "unrolled.py")
fh = file(target, "w")
def write(indent, msg, **kwds):
literal = kwds.pop("literal", False)
if kwds:
msg %= kwds
if not literal:
msg = textwrap.dedent(msg.rstrip(" "))
if indent:
msg = indent_block(msg, " " * (indent*4))
fh.write(msg)
write(0, """\
\"""passlib.utils._blowfish.unrolled - unrolled loop implementation of bcrypt,
autogenerated by _gen_files.py
currently this override the encipher() and expand() methods
with optimized versions, and leaves the other base.py methods alone.
\"""
#=================================================================
# imports
#=================================================================
# pkg
from passlib.utils._blowfish.base import BlowfishEngine as _BlowfishEngine
# local
__all__ = [
"BlowfishEngine",
]
#=================================================================
#
#=================================================================
class BlowfishEngine(_BlowfishEngine):
""")
write_encipher_function(write, indent=1)
write_expand_function(write, indent=1)
write(0, """\
#=================================================================
# eoc
#=================================================================
#=================================================================
# eof
#=================================================================
""")
if __name__ == "__main__":
main()
#==========================================================================
# eof
#==========================================================================
|
