def v4_int_to_packed(address):
"""Represent an address as 4 packed bytes in network (big-endian) order.
Args:
address: An integer representation of an IPv4 IP address.
Returns:
The integer address packed as 4 bytes in network (big-endian) order.
Raises:
ValueError: If the integer is negative or too large to be an
IPv4 IP address.
"""
try:
return _compat_to_bytes(address, 4, 'big')
except (struct.error, OverflowError):
raise ValueError("Address negative or too large for IPv4")
python类error()的实例源码
def _parse_hextet(cls, hextet_str):
"""Convert an IPv6 hextet string into an integer.
Args:
hextet_str: A string, the number to parse.
Returns:
The hextet as an integer.
Raises:
ValueError: if the input isn't strictly a hex number from
[0..FFFF].
"""
# Whitelist the characters, since int() allows a lot of bizarre stuff.
if not cls._HEX_DIGITS.issuperset(hextet_str):
raise ValueError("Only hex digits permitted in %r" % hextet_str)
# We do the length check second, since the invalid character error
# is likely to be more informative for the user
if len(hextet_str) > 4:
msg = "At most 4 characters permitted in %r"
raise ValueError(msg % hextet_str)
# Length check means we can skip checking the integer value
return int(hextet_str, 16)
def v4_int_to_packed(address):
"""Represent an address as 4 packed bytes in network (big-endian) order.
Args:
address: An integer representation of an IPv4 IP address.
Returns:
The integer address packed as 4 bytes in network (big-endian) order.
Raises:
ValueError: If the integer is negative or too large to be an
IPv4 IP address.
"""
try:
return _compat_to_bytes(address, 4, 'big')
except (struct.error, OverflowError):
raise ValueError("Address negative or too large for IPv4")
def _parse_hextet(cls, hextet_str):
"""Convert an IPv6 hextet string into an integer.
Args:
hextet_str: A string, the number to parse.
Returns:
The hextet as an integer.
Raises:
ValueError: if the input isn't strictly a hex number from
[0..FFFF].
"""
# Whitelist the characters, since int() allows a lot of bizarre stuff.
if not cls._HEX_DIGITS.issuperset(hextet_str):
raise ValueError("Only hex digits permitted in %r" % hextet_str)
# We do the length check second, since the invalid character error
# is likely to be more informative for the user
if len(hextet_str) > 4:
msg = "At most 4 characters permitted in %r"
raise ValueError(msg % hextet_str)
# Length check means we can skip checking the integer value
return int(hextet_str, 16)
def crc(self, cid, data):
"Read and verify checksum"
# Skip CRC checks for ancillary chunks if allowed to load truncated images
# 5th byte of first char is 1 [specs, section 5.4]
if ImageFile.LOAD_TRUNCATED_IMAGES and (i8(cid[0]) >> 5 & 1):
self.crc_skip(cid, data)
return
try:
crc1 = Image.core.crc32(data, Image.core.crc32(cid))
crc2 = i16(self.fp.read(2)), i16(self.fp.read(2))
if crc1 != crc2:
raise SyntaxError("broken PNG file (bad header checksum in %r)"
% cid)
except struct.error:
raise SyntaxError("broken PNG file (incomplete checksum in %r)"
% cid)
def close(self):
"""
Closes the file pointer, if possible.
This operation will destroy the image core and release its memory.
The image data will be unusable afterward.
This function is only required to close images that have not
had their file read and closed by the
:py:meth:`~PIL.Image.Image.load` method.
"""
try:
self.fp.close()
self.fp = None
except Exception as msg:
logger.debug("Error closing: %s", msg)
if getattr(self, 'map', None):
self.map = None
# Instead of simply setting to None, we're setting up a
# deferred error that will better explain that the core image
# object is gone.
self.im = deferred_error(ValueError("Operation on closed image"))
def _process_tRNS(self, data):
# http://www.w3.org/TR/PNG/#11tRNS
self.trns = data
if self.colormap:
if not self.plte:
warnings.warn("PLTE chunk is required before tRNS chunk.")
else:
if len(data) > len(self.plte)/3:
# Was warning, but promoted to Error as it
# would otherwise cause pain later on.
raise FormatError("tRNS chunk is too long.")
else:
if self.alpha:
raise FormatError(
"tRNS chunk is not valid with colour type %d." %
self.color_type)
try:
self.transparent = \
struct.unpack("!%dH" % self.color_planes, data)
except struct.error:
raise FormatError("tRNS chunk has incorrect length.")
def v4_int_to_packed(address):
"""Represent an address as 4 packed bytes in network (big-endian) order.
Args:
address: An integer representation of an IPv4 IP address.
Returns:
The integer address packed as 4 bytes in network (big-endian) order.
Raises:
ValueError: If the integer is negative or too large to be an
IPv4 IP address.
"""
try:
return _compat_to_bytes(address, 4, 'big')
except (struct.error, OverflowError):
raise ValueError("Address negative or too large for IPv4")
def _parse_hextet(cls, hextet_str):
"""Convert an IPv6 hextet string into an integer.
Args:
hextet_str: A string, the number to parse.
Returns:
The hextet as an integer.
Raises:
ValueError: if the input isn't strictly a hex number from
[0..FFFF].
"""
# Whitelist the characters, since int() allows a lot of bizarre stuff.
if not cls._HEX_DIGITS.issuperset(hextet_str):
raise ValueError("Only hex digits permitted in %r" % hextet_str)
# We do the length check second, since the invalid character error
# is likely to be more informative for the user
if len(hextet_str) > 4:
msg = "At most 4 characters permitted in %r"
raise ValueError(msg % hextet_str)
# Length check means we can skip checking the integer value
return int(hextet_str, 16)
def v4_int_to_packed(address):
"""Represent an address as 4 packed bytes in network (big-endian) order.
Args:
address: An integer representation of an IPv4 IP address.
Returns:
The integer address packed as 4 bytes in network (big-endian) order.
Raises:
ValueError: If the integer is negative or too large to be an
IPv4 IP address.
"""
try:
return _compat_to_bytes(address, 4, 'big')
except (struct.error, OverflowError):
raise ValueError("Address negative or too large for IPv4")
def __init__(self, address):
"""
Args:
address: A string or integer representing the IP
'192.168.1.1'
Additionally, an integer can be passed, so
IPv4Address('192.168.1.1') == IPv4Address(3232235777).
or, more generally
IPv4Address(int(IPv4Address('192.168.1.1'))) ==
IPv4Address('192.168.1.1')
Raises:
AddressValueError: If ipaddr isn't a valid IPv4 address.
"""
_BaseV4.__init__(self, address)
# Efficient constructor from integer.
if isinstance(address, (int, long)):
self._ip = address
if address < 0 or address > self._ALL_ONES:
raise AddressValueError(address)
return
# Constructing from a packed address
if isinstance(address, Bytes):
try:
self._ip, = struct.unpack('!I', address)
except struct.error:
raise AddressValueError(address) # Wrong length.
return
# Assume input argument to be string or any object representation
# which converts into a formatted IP string.
addr_str = str(address)
self._ip = self._ip_int_from_string(addr_str)
def _compat_to_bytes(intval, length, endianess):
assert isinstance(intval, _compat_int_types)
assert endianess == 'big'
if length == 4:
if intval < 0 or intval >= 2 ** 32:
raise struct.error("integer out of range for 'I' format code")
return struct.pack(b'!I', intval)
elif length == 16:
if intval < 0 or intval >= 2 ** 128:
raise struct.error("integer out of range for 'QQ' format code")
return struct.pack(b'!QQ', intval >> 64, intval & 0xffffffffffffffff)
else:
raise NotImplementedError()
def v6_int_to_packed(address):
"""Represent an address as 16 packed bytes in network (big-endian) order.
Args:
address: An integer representation of an IPv6 IP address.
Returns:
The integer address packed as 16 bytes in network (big-endian) order.
"""
try:
return _compat_to_bytes(address, 16, 'big')
except (struct.error, OverflowError):
raise ValueError("Address negative or too large for IPv6")
def _parse_octet(cls, octet_str):
"""Convert a decimal octet into an integer.
Args:
octet_str: A string, the number to parse.
Returns:
The octet as an integer.
Raises:
ValueError: if the octet isn't strictly a decimal from [0..255].
"""
if not octet_str:
raise ValueError("Empty octet not permitted")
# Whitelist the characters, since int() allows a lot of bizarre stuff.
if not cls._DECIMAL_DIGITS.issuperset(octet_str):
msg = "Only decimal digits permitted in %r"
raise ValueError(msg % octet_str)
# We do the length check second, since the invalid character error
# is likely to be more informative for the user
if len(octet_str) > 3:
msg = "At most 3 characters permitted in %r"
raise ValueError(msg % octet_str)
# Convert to integer (we know digits are legal)
octet_int = int(octet_str, 10)
# Any octets that look like they *might* be written in octal,
# and which don't look exactly the same in both octal and
# decimal are rejected as ambiguous
if octet_int > 7 and octet_str[0] == '0':
msg = "Ambiguous (octal/decimal) value in %r not permitted"
raise ValueError(msg % octet_str)
if octet_int > 255:
raise ValueError("Octet %d (> 255) not permitted" % octet_int)
return octet_int
def iterstraight(self, raw):
"""Iterator that undoes the effect of filtering, and yields
each row in serialised format (as a sequence of bytes).
Assumes input is straightlaced. `raw` should be an iterable
that yields the raw bytes in chunks of arbitrary size.
"""
# length of row, in bytes
rb = self.row_bytes
a = array('B')
# The previous (reconstructed) scanline. None indicates first
# line of image.
recon = None
for some in raw:
a.extend(some)
while len(a) >= rb + 1:
filter_type = a[0]
scanline = a[1:rb+1]
del a[:rb+1]
recon = self.undo_filter(filter_type, scanline, recon)
yield recon
if len(a) != 0:
# :file:format We get here with a file format error:
# when the available bytes (after decompressing) do not
# pack into exact rows.
raise FormatError(
'Wrong size for decompressed IDAT chunk.')
assert len(a) == 0
def _process_bKGD(self, data):
try:
if self.colormap:
if not self.plte:
warnings.warn(
"PLTE chunk is required before bKGD chunk.")
self.background = struct.unpack('B', data)
else:
self.background = struct.unpack("!%dH" % self.color_planes,
data)
except struct.error:
raise FormatError("bKGD chunk has incorrect length.")
def _process_gAMA(self, data):
try:
self.gamma = struct.unpack("!L", data)[0] / 100000.0
except struct.error:
raise FormatError("gAMA chunk has incorrect length.")
def __unpack__(self, type_, buf, _size=None):
fmt = self.endian + type_
size = struct.calcsize(fmt) if _size is None else _size
try:
unpacked = struct.unpack(fmt, buf[:size]), buf[size:]
except struct.error as exc:
raise_from(UnpackError("Unable to unpack structure"), exc)
else:
return unpacked
def _compat_to_bytes(intval, length, endianess):
assert isinstance(intval, _compat_int_types)
assert endianess == 'big'
if length == 4:
if intval < 0 or intval >= 2 ** 32:
raise struct.error("integer out of range for 'I' format code")
return struct.pack(b'!I', intval)
elif length == 16:
if intval < 0 or intval >= 2 ** 128:
raise struct.error("integer out of range for 'QQ' format code")
return struct.pack(b'!QQ', intval >> 64, intval & 0xffffffffffffffff)
else:
raise NotImplementedError()
def v6_int_to_packed(address):
"""Represent an address as 16 packed bytes in network (big-endian) order.
Args:
address: An integer representation of an IPv6 IP address.
Returns:
The integer address packed as 16 bytes in network (big-endian) order.
"""
try:
return _compat_to_bytes(address, 16, 'big')
except (struct.error, OverflowError):
raise ValueError("Address negative or too large for IPv6")
