362 lines
12 KiB
Python
362 lines
12 KiB
Python
"""
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EXIF metadata parser (can be found in a JPEG picture for example)
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Author: Victor Stinner
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"""
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from lib.hachoir_core.field import (FieldSet, ParserError,
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UInt8, UInt16, UInt32,
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Int32, Enum, String,
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Bytes, SubFile,
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NullBytes, createPaddingField)
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from lib.hachoir_core.endian import LITTLE_ENDIAN, BIG_ENDIAN, NETWORK_ENDIAN
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from lib.hachoir_core.text_handler import textHandler, hexadecimal
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from lib.hachoir_core.tools import createDict
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MAX_COUNT = 1000
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def rationalFactory(class_name, size, field_class):
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class Rational(FieldSet):
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static_size = size
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def createFields(self):
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yield field_class(self, "numerator")
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yield field_class(self, "denominator")
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def createValue(self):
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return float(self["numerator"].value) / self["denominator"].value
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cls = Rational
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cls.__name__ = class_name
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return cls
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RationalInt32 = rationalFactory("RationalInt32", 64, Int32)
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RationalUInt32 = rationalFactory("RationalUInt32", 64, UInt32)
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class BasicIFDEntry(FieldSet):
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TYPE_BYTE = 0
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TYPE_UNDEFINED = 7
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TYPE_RATIONAL = 5
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TYPE_SIGNED_RATIONAL = 10
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TYPE_INFO = {
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1: (UInt8, "BYTE (8 bits)"),
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2: (String, "ASCII (8 bits)"),
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3: (UInt16, "SHORT (16 bits)"),
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4: (UInt32, "LONG (32 bits)"),
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5: (RationalUInt32, "RATIONAL (2x LONG, 64 bits)"),
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7: (Bytes, "UNDEFINED (8 bits)"),
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9: (Int32, "SIGNED LONG (32 bits)"),
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10: (RationalInt32, "SRATIONAL (2x SIGNED LONGs, 64 bits)"),
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}
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ENTRY_FORMAT = createDict(TYPE_INFO, 0)
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TYPE_NAME = createDict(TYPE_INFO, 1)
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def createFields(self):
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yield Enum(textHandler(UInt16(self, "tag", "Tag"), hexadecimal), self.TAG_NAME)
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yield Enum(textHandler(UInt16(self, "type", "Type"), hexadecimal), self.TYPE_NAME)
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yield UInt32(self, "count", "Count")
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if self["type"].value not in (self.TYPE_BYTE, self.TYPE_UNDEFINED) \
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and MAX_COUNT < self["count"].value:
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raise ParserError("EXIF: Invalid count value (%s)" % self["count"].value)
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value_size, array_size = self.getSizes()
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# Get offset/value
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if not value_size:
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yield NullBytes(self, "padding", 4)
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elif value_size <= 32:
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if 1 < array_size:
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name = "value[]"
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else:
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name = "value"
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kw = {}
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cls = self.value_cls
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if cls is String:
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args = (self, name, value_size/8, "Value")
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kw["strip"] = " \0"
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kw["charset"] = "ISO-8859-1"
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elif cls is Bytes:
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args = (self, name, value_size/8, "Value")
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else:
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args = (self, name, "Value")
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for index in xrange(array_size):
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yield cls(*args, **kw)
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size = array_size * value_size
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if size < 32:
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yield NullBytes(self, "padding", (32-size)//8)
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else:
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yield UInt32(self, "offset", "Value offset")
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def getSizes(self):
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"""
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Returns (value_size, array_size): value_size in bits and
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array_size in number of items.
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"""
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# Create format
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self.value_cls = self.ENTRY_FORMAT.get(self["type"].value, Bytes)
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# Set size
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count = self["count"].value
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if self.value_cls in (String, Bytes):
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return 8 * count, 1
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else:
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return self.value_cls.static_size * count, count
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class ExifEntry(BasicIFDEntry):
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OFFSET_JPEG_SOI = 0x0201
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EXIF_IFD_POINTER = 0x8769
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TAG_WIDTH = 0xA002
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TAG_HEIGHT = 0xA003
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TAG_GPS_LATITUDE_REF = 0x0001
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TAG_GPS_LATITUDE = 0x0002
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TAG_GPS_LONGITUDE_REF = 0x0003
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TAG_GPS_LONGITUDE = 0x0004
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TAG_GPS_ALTITUDE_REF = 0x0005
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TAG_GPS_ALTITUDE = 0x0006
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TAG_GPS_TIMESTAMP = 0x0007
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TAG_GPS_DATESTAMP = 0x001d
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TAG_IMG_TITLE = 0x010e
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TAG_FILE_TIMESTAMP = 0x0132
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TAG_SOFTWARE = 0x0131
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TAG_CAMERA_MODEL = 0x0110
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TAG_CAMERA_MANUFACTURER = 0x010f
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TAG_ORIENTATION = 0x0112
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TAG_EXPOSURE = 0x829A
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TAG_FOCAL = 0x829D
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TAG_BRIGHTNESS = 0x9203
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TAG_APERTURE = 0x9205
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TAG_USER_COMMENT = 0x9286
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TAG_NAME = {
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# GPS
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0x0000: "GPS version ID",
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0x0001: "GPS latitude ref",
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0x0002: "GPS latitude",
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0x0003: "GPS longitude ref",
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0x0004: "GPS longitude",
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0x0005: "GPS altitude ref",
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0x0006: "GPS altitude",
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0x0007: "GPS timestamp",
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0x0008: "GPS satellites",
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0x0009: "GPS status",
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0x000a: "GPS measure mode",
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0x000b: "GPS DOP",
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0x000c: "GPS speed ref",
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0x000d: "GPS speed",
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0x000e: "GPS track ref",
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0x000f: "GPS track",
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0x0010: "GPS img direction ref",
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0x0011: "GPS img direction",
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0x0012: "GPS map datum",
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0x0013: "GPS dest latitude ref",
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0x0014: "GPS dest latitude",
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0x0015: "GPS dest longitude ref",
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0x0016: "GPS dest longitude",
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0x0017: "GPS dest bearing ref",
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0x0018: "GPS dest bearing",
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0x0019: "GPS dest distance ref",
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0x001a: "GPS dest distance",
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0x001b: "GPS processing method",
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0x001c: "GPS area information",
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0x001d: "GPS datestamp",
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0x001e: "GPS differential",
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0x0100: "Image width",
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0x0101: "Image height",
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0x0102: "Number of bits per component",
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0x0103: "Compression scheme",
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0x0106: "Pixel composition",
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TAG_ORIENTATION: "Orientation of image",
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0x0115: "Number of components",
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0x011C: "Image data arrangement",
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0x0212: "Subsampling ratio Y to C",
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0x0213: "Y and C positioning",
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0x011A: "Image resolution width direction",
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0x011B: "Image resolution in height direction",
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0x0128: "Unit of X and Y resolution",
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0x0111: "Image data location",
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0x0116: "Number of rows per strip",
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0x0117: "Bytes per compressed strip",
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0x0201: "Offset to JPEG SOI",
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0x0202: "Bytes of JPEG data",
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0x012D: "Transfer function",
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0x013E: "White point chromaticity",
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0x013F: "Chromaticities of primaries",
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0x0211: "Color space transformation matrix coefficients",
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0x0214: "Pair of blank and white reference values",
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TAG_FILE_TIMESTAMP: "File change date and time",
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TAG_IMG_TITLE: "Image title",
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TAG_CAMERA_MANUFACTURER: "Camera (Image input equipment) manufacturer",
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TAG_CAMERA_MODEL: "Camera (Input input equipment) model",
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TAG_SOFTWARE: "Software",
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0x013B: "File change date and time",
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0x8298: "Copyright holder",
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0x8769: "Exif IFD Pointer",
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TAG_EXPOSURE: "Exposure time",
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TAG_FOCAL: "F number",
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0x8822: "Exposure program",
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0x8824: "Spectral sensitivity",
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0x8827: "ISO speed rating",
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0x8828: "Optoelectric conversion factor OECF",
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0x9201: "Shutter speed",
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0x9202: "Aperture",
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TAG_BRIGHTNESS: "Brightness",
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0x9204: "Exposure bias",
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TAG_APERTURE: "Maximum lens aperture",
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0x9206: "Subject distance",
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0x9207: "Metering mode",
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0x9208: "Light source",
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0x9209: "Flash",
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0x920A: "Lens focal length",
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0x9214: "Subject area",
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0xA20B: "Flash energy",
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0xA20C: "Spatial frequency response",
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0xA20E: "Focal plane X resolution",
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0xA20F: "Focal plane Y resolution",
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0xA210: "Focal plane resolution unit",
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0xA214: "Subject location",
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0xA215: "Exposure index",
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0xA217: "Sensing method",
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0xA300: "File source",
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0xA301: "Scene type",
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0xA302: "CFA pattern",
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0xA401: "Custom image processing",
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0xA402: "Exposure mode",
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0xA403: "White balance",
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0xA404: "Digital zoom ratio",
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0xA405: "Focal length in 35 mm film",
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0xA406: "Scene capture type",
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0xA407: "Gain control",
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0xA408: "Contrast",
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0x9000: "Exif version",
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0xA000: "Supported Flashpix version",
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0xA001: "Color space information",
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0x9101: "Meaning of each component",
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0x9102: "Image compression mode",
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TAG_WIDTH: "Valid image width",
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TAG_HEIGHT: "Valid image height",
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0x927C: "Manufacturer notes",
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TAG_USER_COMMENT: "User comments",
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0xA004: "Related audio file",
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0x9003: "Date and time of original data generation",
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0x9004: "Date and time of digital data generation",
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0x9290: "DateTime subseconds",
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0x9291: "DateTimeOriginal subseconds",
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0x9292: "DateTimeDigitized subseconds",
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0xA420: "Unique image ID",
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0xA005: "Interoperability IFD Pointer"
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}
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def createDescription(self):
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return "Entry: %s" % self["tag"].display
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def sortExifEntry(a,b):
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return int( a["offset"].value - b["offset"].value )
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class ExifIFD(FieldSet):
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def seek(self, offset):
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"""
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Seek to byte address relative to parent address.
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"""
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padding = offset - (self.address + self.current_size)/8
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if 0 < padding:
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return createPaddingField(self, padding*8)
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else:
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return None
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def createFields(self):
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offset_diff = 6
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yield UInt16(self, "count", "Number of entries")
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entries = []
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next_chunk_offset = None
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count = self["count"].value
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if not count:
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return
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while count:
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addr = self.absolute_address + self.current_size
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next = self.stream.readBits(addr, 32, NETWORK_ENDIAN)
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if next in (0, 0xF0000000):
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break
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entry = ExifEntry(self, "entry[]")
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yield entry
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if entry["tag"].value in (ExifEntry.EXIF_IFD_POINTER, ExifEntry.OFFSET_JPEG_SOI):
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next_chunk_offset = entry["value"].value + offset_diff
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if 32 < entry.getSizes()[0]:
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entries.append(entry)
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count -= 1
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yield UInt32(self, "next", "Next IFD offset")
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try:
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entries.sort( sortExifEntry )
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except TypeError:
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raise ParserError("Unable to sort entries!")
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value_index = 0
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for entry in entries:
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padding = self.seek(entry["offset"].value + offset_diff)
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if padding is not None:
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yield padding
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value_size, array_size = entry.getSizes()
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if not array_size:
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continue
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cls = entry.value_cls
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if 1 < array_size:
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name = "value_%s[]" % entry.name
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else:
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name = "value_%s" % entry.name
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desc = "Value of \"%s\"" % entry["tag"].display
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if cls is String:
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for index in xrange(array_size):
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yield cls(self, name, value_size/8, desc, strip=" \0", charset="ISO-8859-1")
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elif cls is Bytes:
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for index in xrange(array_size):
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yield cls(self, name, value_size/8, desc)
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else:
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for index in xrange(array_size):
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yield cls(self, name, desc)
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value_index += 1
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if next_chunk_offset is not None:
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padding = self.seek(next_chunk_offset)
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if padding is not None:
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yield padding
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def createDescription(self):
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return "Exif IFD (id %s)" % self["id"].value
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class Exif(FieldSet):
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def createFields(self):
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# Headers
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yield String(self, "header", 6, "Header (Exif\\0\\0)", charset="ASCII")
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if self["header"].value != "Exif\0\0":
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raise ParserError("Invalid EXIF signature!")
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yield String(self, "byte_order", 2, "Byte order", charset="ASCII")
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if self["byte_order"].value not in ("II", "MM"):
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raise ParserError("Invalid endian!")
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if self["byte_order"].value == "II":
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self.endian = LITTLE_ENDIAN
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else:
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self.endian = BIG_ENDIAN
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yield UInt16(self, "version", "TIFF version number")
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yield UInt32(self, "img_dir_ofs", "Next image directory offset")
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while not self.eof:
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addr = self.absolute_address + self.current_size
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tag = self.stream.readBits(addr, 16, NETWORK_ENDIAN)
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if tag == 0xFFD8:
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size = (self._size - self.current_size) // 8
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yield SubFile(self, "thumbnail", size, "Thumbnail (JPEG file)", mime_type="image/jpeg")
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break
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elif tag == 0xFFFF:
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break
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yield ExifIFD(self, "ifd[]", "IFD")
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padding = self.seekBit(self._size)
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if padding is not None:
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yield padding
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