2024-10-16 19:37:45 -04:00

347 lines
13 KiB
Python

import copy
import numbers
import struct
from ._common import *
from ._exif import *
TIFF_HEADER_LENGTH = 8
def dump(exif_dict_original):
"""
py:function:: piexif.load(data)
Return exif as bytes.
:param dict exif: Exif data({"0th":dict, "Exif":dict, "GPS":dict, "Interop":dict, "1st":dict, "thumbnail":bytes})
:return: Exif
:rtype: bytes
"""
exif_dict = copy.deepcopy(exif_dict_original)
header = b"Exif\x00\x00\x4d\x4d\x00\x2a\x00\x00\x00\x08"
exif_is = False
gps_is = False
interop_is = False
first_is = False
if "0th" in exif_dict:
zeroth_ifd = exif_dict["0th"]
else:
zeroth_ifd = {}
if (("Exif" in exif_dict) and len(exif_dict["Exif"]) or
("Interop" in exif_dict) and len(exif_dict["Interop"]) ):
zeroth_ifd[ImageIFD.ExifTag] = 1
exif_is = True
exif_ifd = exif_dict["Exif"]
if ("Interop" in exif_dict) and len(exif_dict["Interop"]):
exif_ifd[ExifIFD. InteroperabilityTag] = 1
interop_is = True
interop_ifd = exif_dict["Interop"]
elif ExifIFD. InteroperabilityTag in exif_ifd:
exif_ifd.pop(ExifIFD.InteroperabilityTag)
elif ImageIFD.ExifTag in zeroth_ifd:
zeroth_ifd.pop(ImageIFD.ExifTag)
if ("GPS" in exif_dict) and len(exif_dict["GPS"]):
zeroth_ifd[ImageIFD.GPSTag] = 1
gps_is = True
gps_ifd = exif_dict["GPS"]
elif ImageIFD.GPSTag in zeroth_ifd:
zeroth_ifd.pop(ImageIFD.GPSTag)
if (("1st" in exif_dict) and
("thumbnail" in exif_dict) and
(exif_dict["thumbnail"] is not None)):
first_is = True
exif_dict["1st"][ImageIFD.JPEGInterchangeFormat] = 1
exif_dict["1st"][ImageIFD.JPEGInterchangeFormatLength] = 1
first_ifd = exif_dict["1st"]
zeroth_set = _dict_to_bytes(zeroth_ifd, "0th", 0)
zeroth_length = (len(zeroth_set[0]) + exif_is * 12 + gps_is * 12 + 4 +
len(zeroth_set[1]))
if exif_is:
exif_set = _dict_to_bytes(exif_ifd, "Exif", zeroth_length)
exif_length = len(exif_set[0]) + interop_is * 12 + len(exif_set[1])
else:
exif_bytes = b""
exif_length = 0
if gps_is:
gps_set = _dict_to_bytes(gps_ifd, "GPS", zeroth_length + exif_length)
gps_bytes = b"".join(gps_set)
gps_length = len(gps_bytes)
else:
gps_bytes = b""
gps_length = 0
if interop_is:
offset = zeroth_length + exif_length + gps_length
interop_set = _dict_to_bytes(interop_ifd, "Interop", offset)
interop_bytes = b"".join(interop_set)
interop_length = len(interop_bytes)
else:
interop_bytes = b""
interop_length = 0
if first_is:
offset = zeroth_length + exif_length + gps_length + interop_length
first_set = _dict_to_bytes(first_ifd, "1st", offset)
thumbnail = _get_thumbnail(exif_dict["thumbnail"])
thumbnail_max_size = 64000
if len(thumbnail) > thumbnail_max_size:
raise ValueError("Given thumbnail is too large. max 64kB")
else:
first_bytes = b""
if exif_is:
pointer_value = TIFF_HEADER_LENGTH + zeroth_length
pointer_str = struct.pack(">I", pointer_value)
key = ImageIFD.ExifTag
key_str = struct.pack(">H", key)
type_str = struct.pack(">H", TYPES.Long)
length_str = struct.pack(">I", 1)
exif_pointer = key_str + type_str + length_str + pointer_str
else:
exif_pointer = b""
if gps_is:
pointer_value = TIFF_HEADER_LENGTH + zeroth_length + exif_length
pointer_str = struct.pack(">I", pointer_value)
key = ImageIFD.GPSTag
key_str = struct.pack(">H", key)
type_str = struct.pack(">H", TYPES.Long)
length_str = struct.pack(">I", 1)
gps_pointer = key_str + type_str + length_str + pointer_str
else:
gps_pointer = b""
if interop_is:
pointer_value = (TIFF_HEADER_LENGTH +
zeroth_length + exif_length + gps_length)
pointer_str = struct.pack(">I", pointer_value)
key = ExifIFD.InteroperabilityTag
key_str = struct.pack(">H", key)
type_str = struct.pack(">H", TYPES.Long)
length_str = struct.pack(">I", 1)
interop_pointer = key_str + type_str + length_str + pointer_str
else:
interop_pointer = b""
if first_is:
pointer_value = (TIFF_HEADER_LENGTH + zeroth_length +
exif_length + gps_length + interop_length)
first_ifd_pointer = struct.pack(">L", pointer_value)
thumbnail_pointer = (pointer_value + len(first_set[0]) + 24 +
4 + len(first_set[1]))
thumbnail_p_bytes = (b"\x02\x01\x00\x04\x00\x00\x00\x01" +
struct.pack(">L", thumbnail_pointer))
thumbnail_length_bytes = (b"\x02\x02\x00\x04\x00\x00\x00\x01" +
struct.pack(">L", len(thumbnail)))
first_bytes = (first_set[0] + thumbnail_p_bytes +
thumbnail_length_bytes + b"\x00\x00\x00\x00" +
first_set[1] + thumbnail)
else:
first_ifd_pointer = b"\x00\x00\x00\x00"
zeroth_bytes = (zeroth_set[0] + exif_pointer + gps_pointer +
first_ifd_pointer + zeroth_set[1])
if exif_is:
exif_bytes = exif_set[0] + interop_pointer + exif_set[1]
return (header + zeroth_bytes + exif_bytes + gps_bytes +
interop_bytes + first_bytes)
def _get_thumbnail(jpeg):
segments = split_into_segments(jpeg)
while (b"\xff\xe0" <= segments[1][0:2] <= b"\xff\xef"):
segments.pop(1)
thumbnail = b"".join(segments)
return thumbnail
def _pack_byte(*args):
return struct.pack("B" * len(args), *args)
def _pack_signed_byte(*args):
return struct.pack("b" * len(args), *args)
def _pack_short(*args):
return struct.pack(">" + "H" * len(args), *args)
def _pack_signed_short(*args):
return struct.pack(">" + "h" * len(args), *args)
def _pack_long(*args):
return struct.pack(">" + "L" * len(args), *args)
def _pack_slong(*args):
return struct.pack(">" + "l" * len(args), *args)
def _pack_float(*args):
return struct.pack(">" + "f" * len(args), *args)
def _pack_double(*args):
return struct.pack(">" + "d" * len(args), *args)
def _value_to_bytes(raw_value, value_type, offset):
four_bytes_over = b""
value_str = b""
if value_type == TYPES.Byte:
length = len(raw_value)
if length <= 4:
value_str = (_pack_byte(*raw_value) +
b"\x00" * (4 - length))
else:
value_str = struct.pack(">I", offset)
four_bytes_over = _pack_byte(*raw_value)
elif value_type == TYPES.Short:
length = len(raw_value)
if length <= 2:
value_str = (_pack_short(*raw_value) +
b"\x00\x00" * (2 - length))
else:
value_str = struct.pack(">I", offset)
four_bytes_over = _pack_short(*raw_value)
elif value_type == TYPES.Long:
length = len(raw_value)
if length <= 1:
value_str = _pack_long(*raw_value)
else:
value_str = struct.pack(">I", offset)
four_bytes_over = _pack_long(*raw_value)
elif value_type == TYPES.SLong:
length = len(raw_value)
if length <= 1:
value_str = _pack_slong(*raw_value)
else:
value_str = struct.pack(">I", offset)
four_bytes_over = _pack_slong(*raw_value)
elif value_type == TYPES.Ascii:
try:
new_value = raw_value.encode("latin1") + b"\x00"
except:
try:
new_value = raw_value + b"\x00"
except TypeError:
raise ValueError("Got invalid type to convert.")
length = len(new_value)
if length > 4:
value_str = struct.pack(">I", offset)
four_bytes_over = new_value
else:
value_str = new_value + b"\x00" * (4 - length)
elif value_type == TYPES.Rational:
if isinstance(raw_value[0], numbers.Integral):
length = 1
num, den = raw_value
new_value = struct.pack(">L", num) + struct.pack(">L", den)
elif isinstance(raw_value[0], tuple):
length = len(raw_value)
new_value = b""
for n, val in enumerate(raw_value):
num, den = val
new_value += (struct.pack(">L", num) +
struct.pack(">L", den))
value_str = struct.pack(">I", offset)
four_bytes_over = new_value
elif value_type == TYPES.SRational:
if isinstance(raw_value[0], numbers.Integral):
length = 1
num, den = raw_value
new_value = struct.pack(">l", num) + struct.pack(">l", den)
elif isinstance(raw_value[0], tuple):
length = len(raw_value)
new_value = b""
for n, val in enumerate(raw_value):
num, den = val
new_value += (struct.pack(">l", num) +
struct.pack(">l", den))
value_str = struct.pack(">I", offset)
four_bytes_over = new_value
elif value_type == TYPES.Undefined:
length = len(raw_value)
if length > 4:
value_str = struct.pack(">I", offset)
try:
four_bytes_over = b"" + raw_value
except TypeError:
raise ValueError("Got invalid type to convert.")
else:
try:
value_str = raw_value + b"\x00" * (4 - length)
except TypeError:
raise ValueError("Got invalid type to convert.")
elif value_type == TYPES.SByte: # Signed Byte
length = len(raw_value)
if length <= 4:
value_str = (_pack_signed_byte(*raw_value) +
b"\x00" * (4 - length))
else:
value_str = struct.pack(">I", offset)
four_bytes_over = _pack_signed_byte(*raw_value)
elif value_type == TYPES.SShort: # Signed Short
length = len(raw_value)
if length <= 2:
value_str = (_pack_signed_short(*raw_value) +
b"\x00\x00" * (2 - length))
else:
value_str = struct.pack(">I", offset)
four_bytes_over = _pack_signed_short(*raw_value)
elif value_type == TYPES.Float:
length = len(raw_value)
if length <= 1:
value_str = _pack_float(*raw_value)
else:
value_str = struct.pack(">I", offset)
four_bytes_over = _pack_float(*raw_value)
elif value_type == TYPES.DFloat: # Double
length = len(raw_value)
value_str = struct.pack(">I", offset)
four_bytes_over = _pack_double(*raw_value)
length_str = struct.pack(">I", length)
return length_str, value_str, four_bytes_over
def _dict_to_bytes(ifd_dict, ifd, ifd_offset):
tag_count = len(ifd_dict)
entry_header = struct.pack(">H", tag_count)
if ifd in ("0th", "1st"):
entries_length = 2 + tag_count * 12 + 4
else:
entries_length = 2 + tag_count * 12
entries = b""
values = b""
for n, key in enumerate(sorted(ifd_dict)):
if (ifd == "0th") and (key in (ImageIFD.ExifTag, ImageIFD.GPSTag)):
continue
elif (ifd == "Exif") and (key == ExifIFD.InteroperabilityTag):
continue
elif (ifd == "1st") and (key in (ImageIFD.JPEGInterchangeFormat, ImageIFD.JPEGInterchangeFormatLength)):
continue
raw_value = ifd_dict[key]
key_str = struct.pack(">H", key)
value_type = TAGS[ifd][key]["type"]
type_str = struct.pack(">H", value_type)
four_bytes_over = b""
if isinstance(raw_value, numbers.Integral) or isinstance(raw_value, float):
raw_value = (raw_value,)
offset = TIFF_HEADER_LENGTH + entries_length + ifd_offset + len(values)
try:
length_str, value_str, four_bytes_over = _value_to_bytes(raw_value,
value_type,
offset)
except ValueError:
raise ValueError(
'"dump" got wrong type of exif value.\n' +
'{} in {} IFD. Got as {}.'.format(key, ifd, type(ifd_dict[key]))
)
entries += key_str + type_str + length_str + value_str
values += four_bytes_over
return (entry_header + entries, values)