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1.6. Python UUID


"""UUID (universally unique identifiers) as specified in RFC 4122.

This module provides the UUID class and the functions uuid1(), uuid3(),
uuid4(), uuid5() for generating version 1, 3, 4, and 5 UUIDs respectively.

This module works with Python 2.3 or higher."""

__author__ = 'Ka-Ping Yee <ping@zesty.ca>'
__date__ = '$Date: 2012-02-01 13:40:49 +0800 (Wed, 01 Feb 2012) $'.split()[1].replace('/', '-')
__version__ = '$Revision: 333 $'

RESERVED_NCS, RFC_4122, RESERVED_MICROSOFT, RESERVED_FUTURE = [
    'reserved for NCS compatibility', 'specified in RFC 4122',
    'reserved for Microsoft compatibility', 'reserved for future definition']

class UUID(object):
    """Instances of the UUID class represent UUIDs as specified in RFC 4122.
    Converting a UUID to a string using str() produces a string in the form
    "{12345678-1234-1234-1234-123456789abc}".  The UUID constructor accepts
    a similar string (braces and hyphens optional), or six integer arguments
    (with 32-bit, 16-bit, 16-bit, 8-bit, 8-bit, and 48-bit values
    respectively).  UUID objects have the following attributes:

        bytes       gets or sets the UUID as a 16-byte string

        urn         gets the UUID as a URN as specified in RFC 4122

        variant     gets or sets the UUID variant as one of the constants
                    RESERVED_NCS, RFC_4122, RESERVED_MICROSOFT, RESERVED_FUTURE

        version     gets or sets the UUID version number (1 through 5)
    """

    def __init__(self, *args):
        """Create a UUID either from a string representation in hexadecimal
        or from six integers (32-bit time_low, 16-bit time_mid, 16-bit
        time_hi_ver, 8-bit clock_hi_res, 8-bit clock_low, 48-bit node)."""
        if len(args) == 1:
            digits = args[0].replace('urn:', '').replace('uuid:', '')
            digits = digits.replace('{', '').replace('}', '').replace('-', '')
            assert len(digits) == 32, ValueError('badly formed UUID string')
            time_low = int(digits[:8], 16)
            time_mid = int(digits[8:12], 16)
            time_hi_ver = int(digits[12:16], 16)
            clock_hi_res = int(digits[16:18], 16)
            clock_low = int(digits[18:20], 16)
            node = int(digits[20:32], 16)
        else:
            (time_low, time_mid, time_hi_ver,
             clock_hi_res, clock_low, node) = args
        assert 0 <= time_low < 0x100000000, ValueError('time_low out of range')
        assert 0 <= time_mid < 1<<16, ValueError('time_mid out of range')
        assert 0 <= time_hi_ver < 1<<16, ValueError('time_hi_ver out of range')
        assert 0 <= clock_hi_res < 1<<8, ValueError('clock_hi_res out of range')
        assert 0 <= clock_low < 1<<8, ValueError('clock_low out of range')
        assert 0 <= node < 0x1000000000000, ValueError('node out of range')
        self.time_low = time_low
        self.time_mid = time_mid
        self.time_hi_ver = time_hi_ver
        self.clock_hi_res = clock_hi_res
        self.clock_low = clock_low
        self.node = node

    def __cmp__(self, other):
        return cmp(self.bytes, getattr(other, 'bytes', other))

    def __str__(self):
        return '{%08x-%04x-%04x-%02x%02x-%012x}' % (
            self.time_low, self.time_mid, self.time_hi_ver,
            self.clock_hi_res, self.clock_low, self.node)

    def __repr__(self):
        return 'UUID(%r)' % str(self)

    def get_bytes(self):
        def byte(n):
            return chr(n & 0xff)

        return (byte(self.time_low >> 24) + byte(self.time_low >> 16) +
                byte(self.time_low >> 8) + byte(self.time_low) +
                byte(self.time_mid >> 8) + byte(self.time_mid) +
                byte(self.time_hi_ver >> 8) + byte(self.time_hi_ver) +
                byte(self.clock_hi_res) + byte(self.clock_low) +
                byte(self.node >> 40) + byte(self.node >> 32) +
                byte(self.node >> 24) + byte(self.node >> 16) +
                byte(self.node >> 8) + byte(self.node))

    def set_bytes(self, bytes):
        values = map(ord, bytes)
        self.time_low = ((values[0] << 24) + (values[1] << 16) +
                         (values[2] << 8) + values[3])
        self.time_mid = (values[4] << 8) + values[5]
        self.time_hi_ver = (values[6] << 8) + values[7]
        self.clock_hi_res = values[8]
        self.clock_low = values[9]
        self.node = ((values[10] << 40) + (values[11] << 32) +
                     (values[12] << 24) + (values[13] << 16) +
                     (values[14] << 8) + values[15])

    bytes = property(get_bytes, set_bytes)

    def get_urn(self):
        return 'urn:uuid:%08x-%04x-%04x-%02x%02x-%012x' % (
            self.time_low, self.time_mid, self.time_hi_ver,
            self.clock_hi_res, self.clock_low, self.node)

    urn = property(get_urn)

    def get_variant(self):
        if not self.clock_hi_res & 0x80:
            return RESERVED_NCS
        elif not self.clock_hi_res & 0x40:
            return RFC_4122
        elif not self.clock_hi_res & 0x20:
            return RESERVED_MICROSOFT
        else:
            return RESERVED_FUTURE

    def set_variant(self, variant):
        if variant == RESERVED_NCS:
            self.clock_hi_res &= 0x7f
        elif variant == RFC_4122:
            self.clock_hi_res &= 0x3f
            self.clock_hi_res |= 0x80
        elif variant == RESERVED_MICROSOFT:
            self.clock_hi_res &= 0x1f
            self.clock_hi_res |= 0xc0
        elif variant == RESERVED_FUTURE:
            self.clock_hi_res &= 0x1f
            self.clock_hi_res |= 0xe0
        else:
            raise ValueError('illegal variant identifier')

    variant = property(get_variant, set_variant)

    def get_version(self):
        return self.time_hi_ver >> 12

    def set_version(self, version):
        assert 1 <= version <= 5, ValueError('illegal version number')
        self.time_hi_ver &= 0x0fff
        self.time_hi_ver |= (version << 12)

    version = property(get_version, set_version)

def unixgetaddr(program):
    """Get the hardware address on a Unix machine."""
    from os import popen
    for line in popen(program):
        words = line.lower().split()
        if 'hwaddr' in words:
            addr = words[words.index('hwaddr') + 1]
            return int(addr.replace(':', ''), 16)
        if 'ether' in words:
            addr = words[words.index('ether') + 1]
            return int(addr.replace(':', ''), 16)

def wingetaddr(program):
    """Get the hardware address on a Windows machine."""
    from os import popen
    for line in popen(program + ' /all'):
        if line.strip().lower().startswith('physical address'):
            addr = line.split(':')[-1].strip()
            return int(addr.replace('-', ''), 16)

def getaddr():
    """Get the hardware address as a 48-bit integer."""
    from os.path import join, isfile
    for dir in ['/sbin', '/usr/sbin', r'c:\windows',
                r'c:\windows\system', r'c:\windows\system32']:
        if isfile(join(dir, 'ifconfig')):
            return unixgetaddr(join(dir, 'ifconfig'))
        if isfile(join(dir, 'ipconfig.exe')):
            return wingetaddr(join(dir, 'ipconfig.exe'))

def uuid1():
    """Generate a UUID based on the time and hardware address."""
    from time import time
    from random import randrange
    nanoseconds = int(time() * 1e9)
    # 0x01b21dd213814000 is the number of 100-ns intervals between the
    # UUID epoch 1582-10-15 00:00:00 and the Unix epoch 1970-01-01 00:00:00.
    timestamp = int(nanoseconds/100) + 0x01b21dd213814000
    clock = randrange(1<<16) # don't use stable storage
    time_low = timestamp & (0x100000000 - 1)
    time_mid = (timestamp >> 32) & 0xffff
    time_hi_ver = (timestamp >> 48) & 0x0fff
    clock_low = clock & 0xff
    clock_hi_res = (clock >> 8) & 0x3f
    node = getaddr()
    uuid = UUID(time_low, time_mid, time_hi_ver, clock_low, clock_hi_res, node)
    uuid.variant = RFC_4122
    uuid.version = 1
    return uuid

def uuid3(namespace, name):
    """Generate a UUID from the MD5 hash of a namespace UUID and a name."""
    from md5 import md5
    uuid = UUID(0, 0, 0, 0, 0, 0)
    uuid.bytes = md5(namespace.bytes + name).digest()[:16]
    uuid.variant = RFC_4122
    uuid.version = 3
    return uuid

def uuid4():
    """Generate a random UUID."""
    try:
        from os import urandom
    except:
        from random import randrange
        uuid = UUID(randrange(1<<32), randrange(1<<16), randrange(1<<16),
                    randrange(1<<8), randrange(1<<8), randrange(1<<48))
    else:
        uuid = UUID(0, 0, 0, 0, 0, 0)
        uuid.bytes = urandom(16)
    uuid.variant = RFC_4122
    uuid.version = 4
    return uuid

def uuid5(namespace, name):
    """Generate a UUID from the SHA-1 hash of a namespace UUID and a name."""
    from sha import sha
    uuid = UUID(0, 0, 0, 0, 0, 0)
    uuid.bytes = sha(namespace.bytes + name).digest()[:16]
    uuid.variant = RFC_4122
    uuid.version = 5
    return uuid

NAMESPACE_DNS = UUID('{6ba7b810-9dad-11d1-80b4-00c04fd430c8}')
NAMESPACE_URL = UUID('{6ba7b811-9dad-11d1-80b4-00c04fd430c8}')
NAMESPACE_OID = UUID('{6ba7b812-9dad-11d1-80b4-00c04fd430c8}')
NAMESPACE_X500 = UUID('{6ba7b814-9dad-11d1-80b4-00c04fd430c8}')


		

参考:http://zesty.ca/python/uuid.html

参考:https://svn.n-h.com/svn/exchange4linux/trunk/src/BILL-StorageServer/UUID.py

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