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Amiga Format CD 43
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Amiga Format CD43 (1999)(Future Publishing)(GB)(Track 1 of 2)[!][issue 1999-09].iso
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python-1.52
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python1.5
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amigapath.py
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# Module 'amigapath' -- common operations on Amiga pathnames.
# Irmen de Jong, april 1st, 1996 (no joke)
# (adapted from `posixpath.py')
#
# 26-mar-96: fixed split, islink. Improved expanduser.
# 1-apr-96: fixed expanduser (works 100% now)
# 25-dec-96: slight changes to comments and expanduser.
# 27-jan-98: adapted to Python1.5
# 26-apr-99: adapted to Python1.5.2
#
"""Common pathname manipulations, Amiga version.
Instead of importing this module
directly, import os and refer to this module as os.path.
"""
import os
import stat
import string
import amiga
# Normalize the case of a pathname.
normcase=string.lower
# Return wheter a path is absolute.
def isabs(s):
"""Test whether a path is absolute"""
return ':' in s
# Join two pathnames.
# Ignore the previous parts if a part is absolute.
# Insert a '/' unless the first part is empty or already ends in '/' or ':'.
def join(a, *p):
"""Join two or more pathname components, inserting '/' as needed"""
path = a
for b in p:
if ':' in b:
path = b
elif path == '' or path[-1:] == '/':
path = path + b
else:
if path[-1:]==':':
path = path+b
else:
path = path + '/' + b
return path
# Split a path in head (everything up to the last '/') and tail (the
# rest). If the path ends in '/' or ':', tail will be empty. If there is no
# '/' or ':' in the path, head will be empty.
# Trailing '/'es are stripped from head unless it is the root.
# DIFFERENCE WITH posixpath: only ONE trailing '/' will be stripped from head!
# (on the Amiga a double slash means "parent dir"! ) This means that if
# head ends in a '/', you MUST add a '/' to it when reconstructing the path,
# or you will lose the "parent dir" slash.
# Functions that depend on this function are also affected!
# (basename, dirname)
#
# Suggested by Kent Polk, kent@eaenki.nde.swri.edu
def split(p):
"""Split a pathname. Returns tuple "(head, tail)" where "tail" is
everything after the final slash. Either part may be empty"""
i = string.rfind(p, '/')
j = string.rfind(p, ':')
if (i>j) and p[-1]=='/':
p=p[:-1]
i = string.rfind(p, '/')
if (j>i) or ((j>=0) and (i<0)): i=j
head, tail = p[:i+1], p[i+1:]
if head:
if head[-1]=='/': head=head[:-1]
return head, tail
# Split a path in root and extension.
# The extension is everything starting at the last dot in the last
# pathname component; the root is everything before that.
# It is always true that root + ext == p.
def splitext(p):
"""Split the extension from a pathname. Extension is everything from the
last dot to the end. Returns "(root, ext)", either part may be empty"""
root, ext = '', ''
for c in p:
if c == '/':
root, ext = root + ext + c, ''
elif c == '.':
if ext:
root, ext = root + ext, c
else:
ext = c
elif ext:
ext = ext + c
else:
root = root + c
return root, ext
# Split a pathname into a drive specification and the rest of the
# path.
def splitdrive(p):
"""Split a pathname into drive and path. On Posix, drive is always
empty"""
i = string.rfind(p,':') + 1
if i<=0: return '', p
return p[:i],p[i:]
# Return the tail (basename) part of a path.
def basename(p):
"""Returns the final component of a pathname"""
return split(p)[1]
# Return the head (dirname) part of a path.
def dirname(p):
"""Returns the directory component of a pathname"""
return split(p)[0]
# Return the longest prefix of all list elements.
def commonprefix(m):
"Given a list of pathnames, returns the longest common leading component"
if not m: return ''
prefix = m[0]
for item in m:
for i in range(len(prefix)):
if prefix[:i+1] <> item[:i+1]:
prefix = prefix[:i]
if i == 0: return ''
break
return prefix
# Get size, mtime, atime of files.
def getsize(filename):
"""Return the size of a file, reported by os.stat()."""
st = os.stat(filename)
return st[stat.ST_SIZE]
def getmtime(filename):
"""Return the last modification time of a file, reported by os.stat()."""
st = os.stat(filename)
return st[stat.ST_MTIME]
def getatime(filename):
"""Return the last access time of a file, reported by os.stat()."""
st = os.stat(filename)
return st[stat.ST_MTIME]
# Get the full pathname of a file/directory (i.e. expand assigns).
fullpath = amiga.fullpath
# Is a path a symbolic link?
# This will always return false on systems where os.lstat doesn't exist.
# (or where S_ISLNK isn't defined)
def islink(path):
"""Test whether a path is a symbolic link"""
try:
st = os.lstat(path)
return stat.S_ISLNK(st[stat.ST_MODE])
except (os.error, AttributeError):
return 0
# Does a path exist?
# This is false for dangling symbolic links.
def exists(path):
"""Test whether a path exists. Returns false for broken symbolic links"""
try:
st = os.stat(path)
except os.error:
return 0
return 1
# Is a path a directory?
# This follows symbolic links, so both islink() and isdir() can be true
# for the same path.
def isdir(path):
"""Test whether a path is a directory"""
try:
st = os.stat(path)
except os.error:
return 0
return stat.S_ISDIR(st[stat.ST_MODE])
# Is a path a regular file?
# This follows symbolic links, so both islink() and isfile() can be true
# for the same path.
def isfile(path):
"""Test whether a path is a regular file"""
try:
st = os.stat(path)
except os.error:
return 0
return stat.S_ISREG(st[stat.ST_MODE])
# Are two filenames really pointing to the same file?
def samefile(f1, f2):
"""Test whether two pathnames reference the same actual file"""
s1 = os.stat(f1)
s2 = os.stat(f2)
return samestat(s1, s2)
# Are two open files really referencing the same file?
# (Not necessarily the same file descriptor!)
def sameopenfile(fp1, fp2):
"""Test whether two open file objects reference the same file"""
s1 = os.fstat(fp1)
s2 = os.fstat(fp2)
return samestat(s1, s2)
# Are two stat buffers (obtained from stat, fstat or lstat)
# describing the same file?
def samestat(s1, s2):
"""Test whether two stat buffers reference the same file"""
return s1[stat.ST_INO] == s2[stat.ST_INO] and \
s1[stat.ST_DEV] == s2[stat.ST_DEV]
# Is a path a mount point? Amiga: Is it a device name?
def ismount(path):
"""Test whether a path is a mount point (Amiga: a device name)"""
drive,rest = splitdrive(path)
if rest=='':
return 1
else:
return 0
# Directory tree walk.
# For each directory under top (including top itself, but excluding
# '.' and '..'), func(arg, dirname, filenames) is called, where
# dirname is the name of the directory and filenames is the list
# of files (and subdirectories etc.) in the directory.
# The func may modify the filenames list, to implement a filter,
# or to impose a different order of visiting.
def walk(top, func, arg):
"""walk(top,func,args) calls func(arg, d, files) for each directory "d"
in the tree rooted at "top" (including "top" itself). "files" is a list
of all the files and subdirs in directory "d".
"""
try:
names = os.listdir(top)
except os.error:
return
func(arg, top, names)
for name in names:
name = join(top, name)
if isdir(name) and not islink(name):
walk(name, func, arg)
# Expand paths beginning with '~' or '~user'.
# '~' means $HOME; '~user' means that user's home directory.
# If the path doesn't begin with '~', or if the user or $HOME is unknown,
# the path is returned unchanged (leaving error reporting to whatever
# function is called with the expanded path as argument).
# See also module 'glob' for expansion of *, ? and [...] in pathnames.
# (A function should also be defined to do full *sh-style environment
# variable expansion.)
def expanduser(path):
"""Expand ~ and ~user constructions. If user or $HOME is unknown,
do nothing"""
if path[:1] <> '~':
return path
i, n = 1, len(path)
while i < n and path[i] <> '/':
i = i+1
if i == 1:
if not os.environ.has_key('HOME'):
return path
userhome = os.environ['HOME']
else:
try:
import pwd
pwent = pwd.getpwnam(path[1:i])
except (KeyError,ImportError,SystemError):
return path # ~user only works if pwd module works
userhome = pwent[5]
if userhome[-1:] == '/': i = i+1
return userhome + path[i:]
# Expand paths containing shell variable substitutions.
# This expands the forms $variable and ${variable} only.
# Non-existant variables are left unchanged.
_varprog = None
def expandvars(path):
"""Expand shell variables of form $var and ${var}. Unknown variables
are left unchanged"""
global _varprog
if '$' not in path:
return path
if not _varprog:
import re
_varprog = re.compile(r'\$(\w+|\{[^}]*\})')
i = 0
while 1:
m = _varprog.search(path, i)
if not m:
break
i, j = m.span(0)
name = m.group(1)
if name[:1] == '{' and name[-1:] == '}':
name = name[1:-1]
if os.environ.has_key(name):
tail = path[j:]
path = path[:i] + os.environ[name]
i = len(path)
path = path + tail
else:
i = j
return path
# Normalize a path, e.g. A//B, A/./B and A/foo/../B all become A/B.
# It should be understood that this may change the meaning of the path
# if it contains symbolic links!
# Note: does nothing on Amiga because x/y//z is different than x/y/z.
def normpath(path):
"""Normalize path, eliminating double slashes, etc. (Not on Amiga)"""
return path;
# Return an absolute path.
def abspath(path):
if not isabs(path):
path = join(os.getcwd(), path)
return normpath(path)