glibc strverscmp called from python
vallor
vallor at cultnix.org
Thu Jun 20 18:13:51 EDT 2024
So there's been discussion in comp.lang.c and comp.unix.shell
about doing a "versionsort(3)" type sort on a list
of parameters. glibc offers strverscmp(3) for this type
of sort, and here I am posting a q&d python program to expose
that to its sort routine for commentary and future reference.
Caveat: I know just enough python to be dangerous -- wrote
this using ChatGPT. It is a learning experience, comments
very much appreciated.
- -%<- -
#!/usr/bin/python3
import ctypes
from ctypes import c_char_p, c_int
import os
import sys
# Load the C standard library (libc)
libc = ctypes.CDLL("libc.so.6")
# Define the prototype of strverscmp
# int strverscmp (const char *s1, const char *s2)
libc.strverscmp.argtypes = [c_char_p, c_char_p]
libc.strverscmp.restype = c_int
# Define a comparison function for Python sorting
def version_compare(x, y):
return libc.strverscmp(x.encode('utf-8'), y.encode('utf-8'))
# Define a key function for sorting
def version_key(s):
class K:
def __init__(self, s):
self.s = s
def __lt__(self, other):
return version_compare(self.s, other.s) < 0
def __gt__(self, other):
return version_compare(self.s, other.s) > 0
def __eq__(self, other):
return version_compare(self.s, other.s) == 0
def __le__(self, other):
return version_compare(self.s, other.s) <= 0
def __ge__(self, other):
return version_compare(self.s, other.s) >= 0
def __ne__(self, other):
return version_compare(self.s, other.s) != 0
return K(s)
# Function to escape special characters
def shell_escape(s):
return s.replace(" ", "\\ ").replace("\n", "\\n").replace("\t", "\\t")
# Parse command-line arguments
args = sys.argv[1:]
# Sort the list using the version key
sorted_args = sorted(args, key=version_key)
# Print each sorted, escaped value on a new line
for arg in sorted_args:
print(shell_escape(arg))
- -%<- -
--
-v
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