--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mysite/photologue/utils/EXIF.py	Mon Apr 06 03:10:59 2009 +0000
@@ -0,0 +1,1568 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# Library to extract EXIF information from digital camera image files
+# http://sourceforge.net/projects/exif-py/
+#
+# VERSION 1.0.7
+#
+# To use this library call with:
+#    f = open(path_name, 'rb')
+#    tags = EXIF.process_file(f)
+#
+# To ignore makerNote tags, pass the -q or --quick
+# command line arguments, or as
+#    f = open(path_name, 'rb')
+#    tags = EXIF.process_file(f, details=False)
+#
+# To stop processing after a certain tag is retrieved,
+# pass the -t TAG or --stop-tag TAG argument, or as
+#    f = open(path_name, 'rb')
+#    tags = EXIF.process_file(f, stop_tag='TAG')
+#
+# where TAG is a valid tag name, ex 'DateTimeOriginal'
+#
+# These are useful when you are retrieving a large list of images
+#
+# Returned tags will be a dictionary mapping names of EXIF tags to their
+# values in the file named by path_name.  You can process the tags
+# as you wish.  In particular, you can iterate through all the tags with:
+#     for tag in tags.keys():
+#         if tag not in ('JPEGThumbnail', 'TIFFThumbnail', 'Filename',
+#                        'EXIF MakerNote'):
+#             print "Key: %s, value %s" % (tag, tags[tag])
+# (This code uses the if statement to avoid printing out a few of the
+# tags that tend to be long or boring.)
+#
+# The tags dictionary will include keys for all of the usual EXIF
+# tags, and will also include keys for Makernotes used by some
+# cameras, for which we have a good specification.
+#
+# Note that the dictionary keys are the IFD name followed by the
+# tag name. For example:
+# 'EXIF DateTimeOriginal', 'Image Orientation', 'MakerNote FocusMode'
+#
+# Copyright (c) 2002-2007 Gene Cash All rights reserved
+# Copyright (c) 2007 Ianaré Sévi All rights reserved
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+#  1. Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#
+#  2. Redistributions in binary form must reproduce the above
+#     copyright notice, this list of conditions and the following
+#     disclaimer in the documentation and/or other materials provided
+#     with the distribution.
+#
+#  3. Neither the name of the authors nor the names of its contributors
+#     may be used to endorse or promote products derived from this
+#     software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+#
+# ----- See 'changes.txt' file for all contributors and changes ----- #
+#
+
+
+# Don't throw an exception when given an out of range character.
+def make_string(seq):
+    str = ""
+    for c in seq:
+        # Screen out non-printing characters
+        if 32 <= c and c < 256:
+            str += chr(c)
+    # If no printing chars
+    if not str:
+        return seq
+    return str
+
+# Special version to deal with the code in the first 8 bytes of a user comment.
+def make_string_uc(seq):
+    code = seq[0:8]
+    seq = seq[8:]
+    # Of course, this is only correct if ASCII, and the standard explicitly
+    # allows JIS and Unicode.
+    return make_string(seq)
+
+# field type descriptions as (length, abbreviation, full name) tuples
+FIELD_TYPES = (
+    (0, 'X', 'Proprietary'), # no such type
+    (1, 'B', 'Byte'),
+    (1, 'A', 'ASCII'),
+    (2, 'S', 'Short'),
+    (4, 'L', 'Long'),
+    (8, 'R', 'Ratio'),
+    (1, 'SB', 'Signed Byte'),
+    (1, 'U', 'Undefined'),
+    (2, 'SS', 'Signed Short'),
+    (4, 'SL', 'Signed Long'),
+    (8, 'SR', 'Signed Ratio'),
+    )
+
+# dictionary of main EXIF tag names
+# first element of tuple is tag name, optional second element is
+# another dictionary giving names to values
+EXIF_TAGS = {
+    0x0100: ('ImageWidth', ),
+    0x0101: ('ImageLength', ),
+    0x0102: ('BitsPerSample', ),
+    0x0103: ('Compression',
+             {1: 'Uncompressed TIFF',
+              6: 'JPEG Compressed'}),
+    0x0106: ('PhotometricInterpretation', ),
+    0x010A: ('FillOrder', ),
+    0x010D: ('DocumentName', ),
+    0x010E: ('ImageDescription', ),
+    0x010F: ('Make', ),
+    0x0110: ('Model', ),
+    0x0111: ('StripOffsets', ),
+    0x0112: ('Orientation',
+             {1: 'Horizontal (normal)',
+              2: 'Mirrored horizontal',
+              3: 'Rotated 180',
+              4: 'Mirrored vertical',
+              5: 'Mirrored horizontal then rotated 90 CCW',
+              6: 'Rotated 90 CW',
+              7: 'Mirrored horizontal then rotated 90 CW',
+              8: 'Rotated 90 CCW'}),
+    0x0115: ('SamplesPerPixel', ),
+    0x0116: ('RowsPerStrip', ),
+    0x0117: ('StripByteCounts', ),
+    0x011A: ('XResolution', ),
+    0x011B: ('YResolution', ),
+    0x011C: ('PlanarConfiguration', ),
+    0x0128: ('ResolutionUnit',
+             {1: 'Not Absolute',
+              2: 'Pixels/Inch',
+              3: 'Pixels/Centimeter'}),
+    0x012D: ('TransferFunction', ),
+    0x0131: ('Software', ),
+    0x0132: ('DateTime', ),
+    0x013B: ('Artist', ),
+    0x013E: ('WhitePoint', ),
+    0x013F: ('PrimaryChromaticities', ),
+    0x0156: ('TransferRange', ),
+    0x0200: ('JPEGProc', ),
+    0x0201: ('JPEGInterchangeFormat', ),
+    0x0202: ('JPEGInterchangeFormatLength', ),
+    0x0211: ('YCbCrCoefficients', ),
+    0x0212: ('YCbCrSubSampling', ),
+    0x0213: ('YCbCrPositioning', ),
+    0x0214: ('ReferenceBlackWhite', ),
+    0x828D: ('CFARepeatPatternDim', ),
+    0x828E: ('CFAPattern', ),
+    0x828F: ('BatteryLevel', ),
+    0x8298: ('Copyright', ),
+    0x829A: ('ExposureTime', ),
+    0x829D: ('FNumber', ),
+    0x83BB: ('IPTC/NAA', ),
+    0x8769: ('ExifOffset', ),
+    0x8773: ('InterColorProfile', ),
+    0x8822: ('ExposureProgram',
+             {0: 'Unidentified',
+              1: 'Manual',
+              2: 'Program Normal',
+              3: 'Aperture Priority',
+              4: 'Shutter Priority',
+              5: 'Program Creative',
+              6: 'Program Action',
+              7: 'Portrait Mode',
+              8: 'Landscape Mode'}),
+    0x8824: ('SpectralSensitivity', ),
+    0x8825: ('GPSInfo', ),
+    0x8827: ('ISOSpeedRatings', ),
+    0x8828: ('OECF', ),
+    # print as string
+    0x9000: ('ExifVersion', make_string),
+    0x9003: ('DateTimeOriginal', ),
+    0x9004: ('DateTimeDigitized', ),
+    0x9101: ('ComponentsConfiguration',
+             {0: '',
+              1: 'Y',
+              2: 'Cb',
+              3: 'Cr',
+              4: 'Red',
+              5: 'Green',
+              6: 'Blue'}),
+    0x9102: ('CompressedBitsPerPixel', ),
+    0x9201: ('ShutterSpeedValue', ),
+    0x9202: ('ApertureValue', ),
+    0x9203: ('BrightnessValue', ),
+    0x9204: ('ExposureBiasValue', ),
+    0x9205: ('MaxApertureValue', ),
+    0x9206: ('SubjectDistance', ),
+    0x9207: ('MeteringMode',
+             {0: 'Unidentified',
+              1: 'Average',
+              2: 'CenterWeightedAverage',
+              3: 'Spot',
+              4: 'MultiSpot'}),
+    0x9208: ('LightSource',
+             {0: 'Unknown',
+              1: 'Daylight',
+              2: 'Fluorescent',
+              3: 'Tungsten',
+              10: 'Flash',
+              17: 'Standard Light A',
+              18: 'Standard Light B',
+              19: 'Standard Light C',
+              20: 'D55',
+              21: 'D65',
+              22: 'D75',
+              255: 'Other'}),
+    0x9209: ('Flash', {0: 'No',
+                       1: 'Fired',
+                       5: 'Fired (?)', # no return sensed
+                       7: 'Fired (!)', # return sensed
+                       9: 'Fill Fired',
+                       13: 'Fill Fired (?)',
+                       15: 'Fill Fired (!)',
+                       16: 'Off',
+                       24: 'Auto Off',
+                       25: 'Auto Fired',
+                       29: 'Auto Fired (?)',
+                       31: 'Auto Fired (!)',
+                       32: 'Not Available'}),
+    0x920A: ('FocalLength', ),
+    0x9214: ('SubjectArea', ),
+    0x927C: ('MakerNote', ),
+    # print as string
+    0x9286: ('UserComment', make_string_uc),  # First 8 bytes gives coding system e.g. ASCII vs. JIS vs Unicode
+    0x9290: ('SubSecTime', ),
+    0x9291: ('SubSecTimeOriginal', ),
+    0x9292: ('SubSecTimeDigitized', ),
+    # print as string
+    0xA000: ('FlashPixVersion', make_string),
+    0xA001: ('ColorSpace', ),
+    0xA002: ('ExifImageWidth', ),
+    0xA003: ('ExifImageLength', ),
+    0xA005: ('InteroperabilityOffset', ),
+    0xA20B: ('FlashEnergy', ),               # 0x920B in TIFF/EP
+    0xA20C: ('SpatialFrequencyResponse', ),  # 0x920C    -  -
+    0xA20E: ('FocalPlaneXResolution', ),     # 0x920E    -  -
+    0xA20F: ('FocalPlaneYResolution', ),     # 0x920F    -  -
+    0xA210: ('FocalPlaneResolutionUnit', ),  # 0x9210    -  -
+    0xA214: ('SubjectLocation', ),           # 0x9214    -  -
+    0xA215: ('ExposureIndex', ),             # 0x9215    -  -
+    0xA217: ('SensingMethod', ),             # 0x9217    -  -
+    0xA300: ('FileSource',
+             {3: 'Digital Camera'}),
+    0xA301: ('SceneType',
+             {1: 'Directly Photographed'}),
+    0xA302: ('CVAPattern', ),
+    0xA401: ('CustomRendered', ),
+    0xA402: ('ExposureMode',
+             {0: 'Auto Exposure',
+              1: 'Manual Exposure',
+              2: 'Auto Bracket'}),
+    0xA403: ('WhiteBalance',
+             {0: 'Auto',
+              1: 'Manual'}),
+    0xA404: ('DigitalZoomRatio', ),
+    0xA405: ('FocalLengthIn35mm', ),
+    0xA406: ('SceneCaptureType', ),
+    0xA407: ('GainControl', ),
+    0xA408: ('Contrast', ),
+    0xA409: ('Saturation', ),
+    0xA40A: ('Sharpness', ),
+    0xA40C: ('SubjectDistanceRange', ),
+    }
+
+# interoperability tags
+INTR_TAGS = {
+    0x0001: ('InteroperabilityIndex', ),
+    0x0002: ('InteroperabilityVersion', ),
+    0x1000: ('RelatedImageFileFormat', ),
+    0x1001: ('RelatedImageWidth', ),
+    0x1002: ('RelatedImageLength', ),
+    }
+
+# GPS tags (not used yet, haven't seen camera with GPS)
+GPS_TAGS = {
+    0x0000: ('GPSVersionID', ),
+    0x0001: ('GPSLatitudeRef', ),
+    0x0002: ('GPSLatitude', ),
+    0x0003: ('GPSLongitudeRef', ),
+    0x0004: ('GPSLongitude', ),
+    0x0005: ('GPSAltitudeRef', ),
+    0x0006: ('GPSAltitude', ),
+    0x0007: ('GPSTimeStamp', ),
+    0x0008: ('GPSSatellites', ),
+    0x0009: ('GPSStatus', ),
+    0x000A: ('GPSMeasureMode', ),
+    0x000B: ('GPSDOP', ),
+    0x000C: ('GPSSpeedRef', ),
+    0x000D: ('GPSSpeed', ),
+    0x000E: ('GPSTrackRef', ),
+    0x000F: ('GPSTrack', ),
+    0x0010: ('GPSImgDirectionRef', ),
+    0x0011: ('GPSImgDirection', ),
+    0x0012: ('GPSMapDatum', ),
+    0x0013: ('GPSDestLatitudeRef', ),
+    0x0014: ('GPSDestLatitude', ),
+    0x0015: ('GPSDestLongitudeRef', ),
+    0x0016: ('GPSDestLongitude', ),
+    0x0017: ('GPSDestBearingRef', ),
+    0x0018: ('GPSDestBearing', ),
+    0x0019: ('GPSDestDistanceRef', ),
+    0x001A: ('GPSDestDistance', ),
+    }
+
+# Ignore these tags when quick processing
+# 0x927C is MakerNote Tags
+# 0x9286 is user comment
+IGNORE_TAGS=(0x9286, 0x927C)
+
+# http://tomtia.plala.jp/DigitalCamera/MakerNote/index.asp
+def nikon_ev_bias(seq):
+    # First digit seems to be in steps of 1/6 EV.
+    # Does the third value mean the step size?  It is usually 6,
+    # but it is 12 for the ExposureDifference.
+    #
+    if seq == [252, 1, 6, 0]:
+        return "-2/3 EV"
+    if seq == [253, 1, 6, 0]:
+        return "-1/2 EV"
+    if seq == [254, 1, 6, 0]:
+        return "-1/3 EV"
+    if seq == [0, 1, 6, 0]:
+        return "0 EV"
+    if seq == [2, 1, 6, 0]:
+        return "+1/3 EV"
+    if seq == [3, 1, 6, 0]:
+        return "+1/2 EV"
+    if seq == [4, 1, 6, 0]:
+        return "+2/3 EV"
+    # Handle combinations not in the table.
+    a = seq[0]
+    # Causes headaches for the +/- logic, so special case it.
+    if a == 0:
+        return "0 EV"
+    if a > 127:
+        a = 256 - a
+        ret_str = "-"
+    else:
+        ret_str = "+"
+    b = seq[2]	# Assume third value means the step size
+    whole = a / b
+    a = a % b
+    if whole != 0:
+        ret_str = ret_str + str(whole) + " "
+    if a == 0:
+        ret_str = ret_str + "EV"
+    else:
+        r = Ratio(a, b)
+        ret_str = ret_str + r.__repr__() + " EV"
+    return ret_str
+
+# Nikon E99x MakerNote Tags
+MAKERNOTE_NIKON_NEWER_TAGS={
+    0x0001: ('MakernoteVersion', make_string),	# Sometimes binary
+    0x0002: ('ISOSetting', ),
+    0x0003: ('ColorMode', ),
+    0x0004: ('Quality', ),
+    0x0005: ('Whitebalance', ),
+    0x0006: ('ImageSharpening', ),
+    0x0007: ('FocusMode', ),
+    0x0008: ('FlashSetting', ),
+    0x0009: ('AutoFlashMode', ),
+    0x000B: ('WhiteBalanceBias', ),
+    0x000C: ('WhiteBalanceRBCoeff', ),
+    0x000D: ('ProgramShift', nikon_ev_bias),
+    # Nearly the same as the other EV vals, but step size is 1/12 EV (?)
+    0x000E: ('ExposureDifference', nikon_ev_bias),
+    0x000F: ('ISOSelection', ),
+    0x0011: ('NikonPreview', ),
+    0x0012: ('FlashCompensation', nikon_ev_bias),
+    0x0013: ('ISOSpeedRequested', ),
+    0x0016: ('PhotoCornerCoordinates', ),
+    # 0x0017: Unknown, but most likely an EV value
+    0x0018: ('FlashBracketCompensationApplied', nikon_ev_bias),
+    0x0019: ('AEBracketCompensationApplied', ),
+    0x001A: ('ImageProcessing', ),
+    0x0080: ('ImageAdjustment', ),
+    0x0081: ('ToneCompensation', ),
+    0x0082: ('AuxiliaryLens', ),
+    0x0083: ('LensType', ),
+    0x0084: ('LensMinMaxFocalMaxAperture', ),
+    0x0085: ('ManualFocusDistance', ),
+    0x0086: ('DigitalZoomFactor', ),
+    0x0087: ('FlashMode',
+             {0x00: 'Did Not Fire',
+              0x01: 'Fired, Manual',
+              0x07: 'Fired, External',
+              0x08: 'Fired, Commander Mode ',
+              0x09: 'Fired, TTL Mode'}),
+    0x0088: ('AFFocusPosition',
+             {0x0000: 'Center',
+              0x0100: 'Top',
+              0x0200: 'Bottom',
+              0x0300: 'Left',
+              0x0400: 'Right'}),
+    0x0089: ('BracketingMode',
+             {0x00: 'Single frame, no bracketing',
+              0x01: 'Continuous, no bracketing',
+              0x02: 'Timer, no bracketing',
+              0x10: 'Single frame, exposure bracketing',
+              0x11: 'Continuous, exposure bracketing',
+              0x12: 'Timer, exposure bracketing',
+              0x40: 'Single frame, white balance bracketing',
+              0x41: 'Continuous, white balance bracketing',
+              0x42: 'Timer, white balance bracketing'}),
+    0x008A: ('AutoBracketRelease', ),
+    0x008B: ('LensFStops', ),
+    0x008C: ('NEFCurve2', ),
+    0x008D: ('ColorMode', ),
+    0x008F: ('SceneMode', ),
+    0x0090: ('LightingType', ),
+    0x0091: ('ShotInfo', ),	# First 4 bytes are probably a version number in ASCII
+    0x0092: ('HueAdjustment', ),
+    # 0x0093: ('SaturationAdjustment', ),
+    0x0094: ('Saturation',	# Name conflict with 0x00AA !!
+             {-3: 'B&W',
+              -2: '-2',
+              -1: '-1',
+              0: '0',
+              1: '1',
+              2: '2'}),
+    0x0095: ('NoiseReduction', ),
+    0x0096: ('NEFCurve2', ),
+    0x0097: ('ColorBalance', ),
+    0x0098: ('LensData', ),	# First 4 bytes are a version number in ASCII
+    0x0099: ('RawImageCenter', ),
+    0x009A: ('SensorPixelSize', ),
+    0x009C: ('Scene Assist', ),
+    0x00A0: ('SerialNumber', ),
+    0x00A2: ('ImageDataSize', ),
+    # A4: In NEF, looks like a 4 byte ASCII version number
+    0x00A5: ('ImageCount', ),
+    0x00A6: ('DeletedImageCount', ),
+    0x00A7: ('TotalShutterReleases', ),
+    # A8: ExposureMode?  JPG: First 4 bytes are probably a version number in ASCII
+    # But in a sample NEF, its 8 zeros, then the string "NORMAL"
+    0x00A9: ('ImageOptimization', ),
+    0x00AA: ('Saturation', ),
+    0x00AB: ('DigitalVariProgram', ),
+    0x00AC: ('ImageStabilization', ),
+    0x00AD: ('Responsive AF', ),	# 'AFResponse'
+    0x0010: ('DataDump', ),
+    }
+
+MAKERNOTE_NIKON_OLDER_TAGS = {
+    0x0003: ('Quality',
+             {1: 'VGA Basic',
+              2: 'VGA Normal',
+              3: 'VGA Fine',
+              4: 'SXGA Basic',
+              5: 'SXGA Normal',
+              6: 'SXGA Fine'}),
+    0x0004: ('ColorMode',
+             {1: 'Color',
+              2: 'Monochrome'}),
+    0x0005: ('ImageAdjustment',
+             {0: 'Normal',
+              1: 'Bright+',
+              2: 'Bright-',
+              3: 'Contrast+',
+              4: 'Contrast-'}),
+    0x0006: ('CCDSpeed',
+             {0: 'ISO 80',
+              2: 'ISO 160',
+              4: 'ISO 320',
+              5: 'ISO 100'}),
+    0x0007: ('WhiteBalance',
+             {0: 'Auto',
+              1: 'Preset',
+              2: 'Daylight',
+              3: 'Incandescent',
+              4: 'Fluorescent',
+              5: 'Cloudy',
+              6: 'Speed Light'}),
+    }
+
+# decode Olympus SpecialMode tag in MakerNote
+def olympus_special_mode(v):
+    a={
+        0: 'Normal',
+        1: 'Unknown',
+        2: 'Fast',
+        3: 'Panorama'}
+    b={
+        0: 'Non-panoramic',
+        1: 'Left to right',
+        2: 'Right to left',
+        3: 'Bottom to top',
+        4: 'Top to bottom'}
+    if v[0] not in a or v[2] not in b:
+        return v
+    return '%s - sequence %d - %s' % (a[v[0]], v[1], b[v[2]])
+
+MAKERNOTE_OLYMPUS_TAGS={
+    # ah HAH! those sneeeeeaky bastids! this is how they get past the fact
+    # that a JPEG thumbnail is not allowed in an uncompressed TIFF file
+    0x0100: ('JPEGThumbnail', ),
+    0x0200: ('SpecialMode', olympus_special_mode),
+    0x0201: ('JPEGQual',
+             {1: 'SQ',
+              2: 'HQ',
+              3: 'SHQ'}),
+    0x0202: ('Macro',
+             {0: 'Normal',
+             1: 'Macro',
+             2: 'SuperMacro'}),
+    0x0203: ('BWMode',
+             {0: 'Off',
+             1: 'On'}),
+    0x0204: ('DigitalZoom', ),
+    0x0205: ('FocalPlaneDiagonal', ),
+    0x0206: ('LensDistortionParams', ),
+    0x0207: ('SoftwareRelease', ),
+    0x0208: ('PictureInfo', ),
+    0x0209: ('CameraID', make_string), # print as string
+    0x0F00: ('DataDump', ),
+    0x0300: ('PreCaptureFrames', ),
+    0x0404: ('SerialNumber', ),
+    0x1000: ('ShutterSpeedValue', ),
+    0x1001: ('ISOValue', ),
+    0x1002: ('ApertureValue', ),
+    0x1003: ('BrightnessValue', ),
+    0x1004: ('FlashMode', ),
+    0x1004: ('FlashMode',
+       {2: 'On',
+        3: 'Off'}),
+    0x1005: ('FlashDevice',
+       {0: 'None',
+        1: 'Internal',
+        4: 'External',
+        5: 'Internal + External'}),
+    0x1006: ('ExposureCompensation', ),
+    0x1007: ('SensorTemperature', ),
+    0x1008: ('LensTemperature', ),
+    0x100b: ('FocusMode',
+       {0: 'Auto',
+        1: 'Manual'}),
+    0x1017: ('RedBalance', ),
+    0x1018: ('BlueBalance', ),
+    0x101a: ('SerialNumber', ),
+    0x1023: ('FlashExposureComp', ),
+    0x1026: ('ExternalFlashBounce',
+       {0: 'No',
+        1: 'Yes'}),
+    0x1027: ('ExternalFlashZoom', ),
+    0x1028: ('ExternalFlashMode', ),
+    0x1029: ('Contrast 	int16u',
+       {0: 'High',
+        1: 'Normal',
+        2: 'Low'}),
+    0x102a: ('SharpnessFactor', ),
+    0x102b: ('ColorControl', ),
+    0x102c: ('ValidBits', ),
+    0x102d: ('CoringFilter', ),
+    0x102e: ('OlympusImageWidth', ),
+    0x102f: ('OlympusImageHeight', ),
+    0x1034: ('CompressionRatio', ),
+    0x1035: ('PreviewImageValid',
+       {0: 'No',
+        1: 'Yes'}),
+    0x1036: ('PreviewImageStart', ),
+    0x1037: ('PreviewImageLength', ),
+    0x1039: ('CCDScanMode',
+       {0: 'Interlaced',
+        1: 'Progressive'}),
+    0x103a: ('NoiseReduction',
+       {0: 'Off',
+        1: 'On'}),
+    0x103b: ('InfinityLensStep', ),
+    0x103c: ('NearLensStep', ),
+
+    # TODO - these need extra definitions
+    # http://search.cpan.org/src/EXIFTOOL/Image-ExifTool-6.90/html/TagNames/Olympus.html
+    0x2010: ('Equipment', ),
+    0x2020: ('CameraSettings', ),
+    0x2030: ('RawDevelopment', ),
+    0x2040: ('ImageProcessing', ),
+    0x2050: ('FocusInfo', ),
+    0x3000: ('RawInfo ', ),
+    }
+
+# 0x2020 CameraSettings
+MAKERNOTE_OLYMPUS_TAG_0x2020={
+    0x0100: ('PreviewImageValid',
+        {0: 'No',
+         1: 'Yes'}),
+    0x0101: ('PreviewImageStart', ),
+    0x0102: ('PreviewImageLength', ),
+    0x0200: ('ExposureMode', {
+        1: 'Manual',
+        2: 'Program',
+        3: 'Aperture-priority AE',
+        4: 'Shutter speed priority AE',
+        5: 'Program-shift'}),
+    0x0201: ('AELock',
+       {0: 'Off',
+        1: 'On'}),
+    0x0202: ('MeteringMode',
+       {2: 'Center Weighted',
+        3: 'Spot',
+        5: 'ESP',
+        261: 'Pattern+AF',
+        515: 'Spot+Highlight control',
+        1027: 'Spot+Shadow control'}),
+    0x0300: ('MacroMode',
+       {0: 'Off',
+        1: 'On'}),
+    0x0301: ('FocusMode',
+       {0: 'Single AF',
+        1: 'Sequential shooting AF',
+        2: 'Continuous AF',
+        3: 'Multi AF',
+        10: 'MF'}),
+    0x0302: ('FocusProcess',
+       {0: 'AF Not Used',
+        1: 'AF Used'}),
+    0x0303: ('AFSearch',
+       {0: 'Not Ready',
+        1: 'Ready'}),
+    0x0304: ('AFAreas', ),
+    0x0401: ('FlashExposureCompensation', ),
+    0x0500: ('WhiteBalance2',
+       {0: 'Auto',
+        16: '7500K (Fine Weather with Shade)',
+        17: '6000K (Cloudy)',
+        18: '5300K (Fine Weather)',
+        20: '3000K (Tungsten light)',
+        21: '3600K (Tungsten light-like)',
+        33: '6600K (Daylight fluorescent)',
+        34: '4500K (Neutral white fluorescent)',
+        35: '4000K (Cool white fluorescent)',
+        48: '3600K (Tungsten light-like)',
+        256: 'Custom WB 1',
+        257: 'Custom WB 2',
+        258: 'Custom WB 3',
+        259: 'Custom WB 4',
+        512: 'Custom WB 5400K',
+        513: 'Custom WB 2900K',
+        514: 'Custom WB 8000K', }),
+    0x0501: ('WhiteBalanceTemperature', ),
+    0x0502: ('WhiteBalanceBracket', ),
+    0x0503: ('CustomSaturation', ), # (3 numbers: 1. CS Value, 2. Min, 3. Max)
+    0x0504: ('ModifiedSaturation',
+       {0: 'Off',
+        1: 'CM1 (Red Enhance)',
+        2: 'CM2 (Green Enhance)',
+        3: 'CM3 (Blue Enhance)',
+        4: 'CM4 (Skin Tones)'}),
+    0x0505: ('ContrastSetting', ), # (3 numbers: 1. Contrast, 2. Min, 3. Max)
+    0x0506: ('SharpnessSetting', ), # (3 numbers: 1. Sharpness, 2. Min, 3. Max)
+    0x0507: ('ColorSpace',
+       {0: 'sRGB',
+        1: 'Adobe RGB',
+        2: 'Pro Photo RGB'}),
+    0x0509: ('SceneMode',
+       {0: 'Standard',
+        6: 'Auto',
+        7: 'Sport',
+        8: 'Portrait',
+        9: 'Landscape+Portrait',
+        10: 'Landscape',
+        11: 'Night scene',
+        13: 'Panorama',
+        16: 'Landscape+Portrait',
+        17: 'Night+Portrait',
+        19: 'Fireworks',
+        20: 'Sunset',
+        22: 'Macro',
+        25: 'Documents',
+        26: 'Museum',
+        28: 'Beach&Snow',
+        30: 'Candle',
+        35: 'Underwater Wide1',
+        36: 'Underwater Macro',
+        39: 'High Key',
+        40: 'Digital Image Stabilization',
+        44: 'Underwater Wide2',
+        45: 'Low Key',
+        46: 'Children',
+        48: 'Nature Macro'}),
+    0x050a: ('NoiseReduction',
+       {0: 'Off',
+        1: 'Noise Reduction',
+        2: 'Noise Filter',
+        3: 'Noise Reduction + Noise Filter',
+        4: 'Noise Filter (ISO Boost)',
+        5: 'Noise Reduction + Noise Filter (ISO Boost)'}),
+    0x050b: ('DistortionCorrection',
+       {0: 'Off',
+        1: 'On'}),
+    0x050c: ('ShadingCompensation',
+       {0: 'Off',
+        1: 'On'}),
+    0x050d: ('CompressionFactor', ),
+    0x050f: ('Gradation',
+       {'-1 -1 1': 'Low Key',
+        '0 -1 1': 'Normal',
+        '1 -1 1': 'High Key'}),
+    0x0520: ('PictureMode',
+       {1: 'Vivid',
+        2: 'Natural',
+        3: 'Muted',
+        256: 'Monotone',
+        512: 'Sepia'}),
+    0x0521: ('PictureModeSaturation', ),
+    0x0522: ('PictureModeHue?', ),
+    0x0523: ('PictureModeContrast', ),
+    0x0524: ('PictureModeSharpness', ),
+    0x0525: ('PictureModeBWFilter',
+       {0: 'n/a',
+        1: 'Neutral',
+        2: 'Yellow',
+        3: 'Orange',
+        4: 'Red',
+        5: 'Green'}),
+    0x0526: ('PictureModeTone',
+       {0: 'n/a',
+        1: 'Neutral',
+        2: 'Sepia',
+        3: 'Blue',
+        4: 'Purple',
+        5: 'Green'}),
+    0x0600: ('Sequence', ), # 2 or 3 numbers: 1. Mode, 2. Shot number, 3. Mode bits
+    0x0601: ('PanoramaMode', ), # (2 numbers: 1. Mode, 2. Shot number)
+    0x0603: ('ImageQuality2',
+       {1: 'SQ',
+        2: 'HQ',
+        3: 'SHQ',
+        4: 'RAW'}),
+    0x0901: ('ManometerReading', ),
+    }
+
+
+MAKERNOTE_CASIO_TAGS={
+    0x0001: ('RecordingMode',
+             {1: 'Single Shutter',
+              2: 'Panorama',
+              3: 'Night Scene',
+              4: 'Portrait',
+              5: 'Landscape'}),
+    0x0002: ('Quality',
+             {1: 'Economy',
+              2: 'Normal',
+              3: 'Fine'}),
+    0x0003: ('FocusingMode',
+             {2: 'Macro',
+              3: 'Auto Focus',
+              4: 'Manual Focus',
+              5: 'Infinity'}),
+    0x0004: ('FlashMode',
+             {1: 'Auto',
+              2: 'On',
+              3: 'Off',
+              4: 'Red Eye Reduction'}),
+    0x0005: ('FlashIntensity',
+             {11: 'Weak',
+              13: 'Normal',
+              15: 'Strong'}),
+    0x0006: ('Object Distance', ),
+    0x0007: ('WhiteBalance',
+             {1: 'Auto',
+              2: 'Tungsten',
+              3: 'Daylight',
+              4: 'Fluorescent',
+              5: 'Shade',
+              129: 'Manual'}),
+    0x000B: ('Sharpness',
+             {0: 'Normal',
+              1: 'Soft',
+              2: 'Hard'}),
+    0x000C: ('Contrast',
+             {0: 'Normal',
+              1: 'Low',
+              2: 'High'}),
+    0x000D: ('Saturation',
+             {0: 'Normal',
+              1: 'Low',
+              2: 'High'}),
+    0x0014: ('CCDSpeed',
+             {64: 'Normal',
+              80: 'Normal',
+              100: 'High',
+              125: '+1.0',
+              244: '+3.0',
+              250: '+2.0'}),
+    }
+
+MAKERNOTE_FUJIFILM_TAGS={
+    0x0000: ('NoteVersion', make_string),
+    0x1000: ('Quality', ),
+    0x1001: ('Sharpness',
+             {1: 'Soft',
+              2: 'Soft',
+              3: 'Normal',
+              4: 'Hard',
+              5: 'Hard'}),
+    0x1002: ('WhiteBalance',
+             {0: 'Auto',
+              256: 'Daylight',
+              512: 'Cloudy',
+              768: 'DaylightColor-Fluorescent',
+              769: 'DaywhiteColor-Fluorescent',
+              770: 'White-Fluorescent',
+              1024: 'Incandescent',
+              3840: 'Custom'}),
+    0x1003: ('Color',
+             {0: 'Normal',
+              256: 'High',
+              512: 'Low'}),
+    0x1004: ('Tone',
+             {0: 'Normal',
+              256: 'High',
+              512: 'Low'}),
+    0x1010: ('FlashMode',
+             {0: 'Auto',
+              1: 'On',
+              2: 'Off',
+              3: 'Red Eye Reduction'}),
+    0x1011: ('FlashStrength', ),
+    0x1020: ('Macro',
+             {0: 'Off',
+              1: 'On'}),
+    0x1021: ('FocusMode',
+             {0: 'Auto',
+              1: 'Manual'}),
+    0x1030: ('SlowSync',
+             {0: 'Off',
+              1: 'On'}),
+    0x1031: ('PictureMode',
+             {0: 'Auto',
+              1: 'Portrait',
+              2: 'Landscape',
+              4: 'Sports',
+              5: 'Night',
+              6: 'Program AE',
+              256: 'Aperture Priority AE',
+              512: 'Shutter Priority AE',
+              768: 'Manual Exposure'}),
+    0x1100: ('MotorOrBracket',
+             {0: 'Off',
+              1: 'On'}),
+    0x1300: ('BlurWarning',
+             {0: 'Off',
+              1: 'On'}),
+    0x1301: ('FocusWarning',
+             {0: 'Off',
+              1: 'On'}),
+    0x1302: ('AEWarning',
+             {0: 'Off',
+              1: 'On'}),
+    }
+
+MAKERNOTE_CANON_TAGS = {
+    0x0006: ('ImageType', ),
+    0x0007: ('FirmwareVersion', ),
+    0x0008: ('ImageNumber', ),
+    0x0009: ('OwnerName', ),
+    }
+
+# this is in element offset, name, optional value dictionary format
+MAKERNOTE_CANON_TAG_0x001 = {
+    1: ('Macromode',
+        {1: 'Macro',
+         2: 'Normal'}),
+    2: ('SelfTimer', ),
+    3: ('Quality',
+        {2: 'Normal',
+         3: 'Fine',
+         5: 'Superfine'}),
+    4: ('FlashMode',
+        {0: 'Flash Not Fired',
+         1: 'Auto',
+         2: 'On',
+         3: 'Red-Eye Reduction',
+         4: 'Slow Synchro',
+         5: 'Auto + Red-Eye Reduction',
+         6: 'On + Red-Eye Reduction',
+         16: 'external flash'}),
+    5: ('ContinuousDriveMode',
+        {0: 'Single Or Timer',
+         1: 'Continuous'}),
+    7: ('FocusMode',
+        {0: 'One-Shot',
+         1: 'AI Servo',
+         2: 'AI Focus',
+         3: 'MF',
+         4: 'Single',
+         5: 'Continuous',
+         6: 'MF'}),
+    10: ('ImageSize',
+         {0: 'Large',
+          1: 'Medium',
+          2: 'Small'}),
+    11: ('EasyShootingMode',
+         {0: 'Full Auto',
+          1: 'Manual',
+          2: 'Landscape',
+          3: 'Fast Shutter',
+          4: 'Slow Shutter',
+          5: 'Night',
+          6: 'B&W',
+          7: 'Sepia',
+          8: 'Portrait',
+          9: 'Sports',
+          10: 'Macro/Close-Up',
+          11: 'Pan Focus'}),
+    12: ('DigitalZoom',
+         {0: 'None',
+          1: '2x',
+          2: '4x'}),
+    13: ('Contrast',
+         {0xFFFF: 'Low',
+          0: 'Normal',
+          1: 'High'}),
+    14: ('Saturation',
+         {0xFFFF: 'Low',
+          0: 'Normal',
+          1: 'High'}),
+    15: ('Sharpness',
+         {0xFFFF: 'Low',
+          0: 'Normal',
+          1: 'High'}),
+    16: ('ISO',
+         {0: 'See ISOSpeedRatings Tag',
+          15: 'Auto',
+          16: '50',
+          17: '100',
+          18: '200',
+          19: '400'}),
+    17: ('MeteringMode',
+         {3: 'Evaluative',
+          4: 'Partial',
+          5: 'Center-weighted'}),
+    18: ('FocusType',
+         {0: 'Manual',
+          1: 'Auto',
+          3: 'Close-Up (Macro)',
+          8: 'Locked (Pan Mode)'}),
+    19: ('AFPointSelected',
+         {0x3000: 'None (MF)',
+          0x3001: 'Auto-Selected',
+          0x3002: 'Right',
+          0x3003: 'Center',
+          0x3004: 'Left'}),
+    20: ('ExposureMode',
+         {0: 'Easy Shooting',
+          1: 'Program',
+          2: 'Tv-priority',
+          3: 'Av-priority',
+          4: 'Manual',
+          5: 'A-DEP'}),
+    23: ('LongFocalLengthOfLensInFocalUnits', ),
+    24: ('ShortFocalLengthOfLensInFocalUnits', ),
+    25: ('FocalUnitsPerMM', ),
+    28: ('FlashActivity',
+         {0: 'Did Not Fire',
+          1: 'Fired'}),
+    29: ('FlashDetails',
+         {14: 'External E-TTL',
+          13: 'Internal Flash',
+          11: 'FP Sync Used',
+          7: '2nd("Rear")-Curtain Sync Used',
+          4: 'FP Sync Enabled'}),
+    32: ('FocusMode',
+         {0: 'Single',
+          1: 'Continuous'}),
+    }
+
+MAKERNOTE_CANON_TAG_0x004 = {
+    7: ('WhiteBalance',
+        {0: 'Auto',
+         1: 'Sunny',
+         2: 'Cloudy',
+         3: 'Tungsten',
+         4: 'Fluorescent',
+         5: 'Flash',
+         6: 'Custom'}),
+    9: ('SequenceNumber', ),
+    14: ('AFPointUsed', ),
+    15: ('FlashBias',
+        {0XFFC0: '-2 EV',
+         0XFFCC: '-1.67 EV',
+         0XFFD0: '-1.50 EV',
+         0XFFD4: '-1.33 EV',
+         0XFFE0: '-1 EV',
+         0XFFEC: '-0.67 EV',
+         0XFFF0: '-0.50 EV',
+         0XFFF4: '-0.33 EV',
+         0X0000: '0 EV',
+         0X000C: '0.33 EV',
+         0X0010: '0.50 EV',
+         0X0014: '0.67 EV',
+         0X0020: '1 EV',
+         0X002C: '1.33 EV',
+         0X0030: '1.50 EV',
+         0X0034: '1.67 EV',
+         0X0040: '2 EV'}),
+    19: ('SubjectDistance', ),
+    }
+
+# extract multibyte integer in Motorola format (little endian)
+def s2n_motorola(str):
+    x = 0
+    for c in str:
+        x = (x << 8) | ord(c)
+    return x
+
+# extract multibyte integer in Intel format (big endian)
+def s2n_intel(str):
+    x = 0
+    y = 0L
+    for c in str:
+        x = x | (ord(c) << y)
+        y = y + 8
+    return x
+
+# ratio object that eventually will be able to reduce itself to lowest
+# common denominator for printing
+def gcd(a, b):
+    if b == 0:
+        return a
+    else:
+        return gcd(b, a % b)
+
+class Ratio:
+    def __init__(self, num, den):
+        self.num = num
+        self.den = den
+
+    def __repr__(self):
+        self.reduce()
+        if self.den == 1:
+            return str(self.num)
+        return '%d/%d' % (self.num, self.den)
+
+    def reduce(self):
+        div = gcd(self.num, self.den)
+        if div > 1:
+            self.num = self.num / div
+            self.den = self.den / div
+
+# for ease of dealing with tags
+class IFD_Tag:
+    def __init__(self, printable, tag, field_type, values, field_offset,
+                 field_length):
+        # printable version of data
+        self.printable = printable
+        # tag ID number
+        self.tag = tag
+        # field type as index into FIELD_TYPES
+        self.field_type = field_type
+        # offset of start of field in bytes from beginning of IFD
+        self.field_offset = field_offset
+        # length of data field in bytes
+        self.field_length = field_length
+        # either a string or array of data items
+        self.values = values
+
+    def __str__(self):
+        return self.printable
+
+    def __repr__(self):
+        return '(0x%04X) %s=%s @ %d' % (self.tag,
+                                        FIELD_TYPES[self.field_type][2],
+                                        self.printable,
+                                        self.field_offset)
+
+# class that handles an EXIF header
+class EXIF_header:
+    def __init__(self, file, endian, offset, fake_exif, debug=0):
+        self.file = file
+        self.endian = endian
+        self.offset = offset
+        self.fake_exif = fake_exif
+        self.debug = debug
+        self.tags = {}
+
+    # convert slice to integer, based on sign and endian flags
+    # usually this offset is assumed to be relative to the beginning of the
+    # start of the EXIF information.  For some cameras that use relative tags,
+    # this offset may be relative to some other starting point.
+    def s2n(self, offset, length, signed=0):
+        self.file.seek(self.offset+offset)
+        slice=self.file.read(length)
+        if self.endian == 'I':
+            val=s2n_intel(slice)
+        else:
+            val=s2n_motorola(slice)
+        # Sign extension ?
+        if signed:
+            msb=1L << (8*length-1)
+            if val & msb:
+                val=val-(msb << 1)
+        return val
+
+    # convert offset to string
+    def n2s(self, offset, length):
+        s = ''
+        for dummy in range(length):
+            if self.endian == 'I':
+                s = s + chr(offset & 0xFF)
+            else:
+                s = chr(offset & 0xFF) + s
+            offset = offset >> 8
+        return s
+
+    # return first IFD
+    def first_IFD(self):
+        return self.s2n(4, 4)
+
+    # return pointer to next IFD
+    def next_IFD(self, ifd):
+        entries=self.s2n(ifd, 2)
+        return self.s2n(ifd+2+12*entries, 4)
+
+    # return list of IFDs in header
+    def list_IFDs(self):
+        i=self.first_IFD()
+        a=[]
+        while i:
+            a.append(i)
+            i=self.next_IFD(i)
+        return a
+
+    # return list of entries in this IFD
+    def dump_IFD(self, ifd, ifd_name, dict=EXIF_TAGS, relative=0, stop_tag='UNDEF'):
+        entries=self.s2n(ifd, 2)
+        for i in range(entries):
+            # entry is index of start of this IFD in the file
+            entry = ifd + 2 + 12 * i
+            tag = self.s2n(entry, 2)
+
+            # get tag name early to avoid errors, help debug
+            tag_entry = dict.get(tag)
+            if tag_entry:
+                tag_name = tag_entry[0]
+            else:
+                tag_name = 'Tag 0x%04X' % tag
+
+            # ignore certain tags for faster processing
+            if not (not detailed and tag in IGNORE_TAGS):
+                field_type = self.s2n(entry + 2, 2)
+                if not 0 < field_type < len(FIELD_TYPES):
+                    # unknown field type
+                    raise ValueError('unknown type %d in tag 0x%04X' % (field_type, tag))
+                typelen = FIELD_TYPES[field_type][0]
+                count = self.s2n(entry + 4, 4)
+                offset = entry + 8
+                if count * typelen > 4:
+                    # offset is not the value; it's a pointer to the value
+                    # if relative we set things up so s2n will seek to the right
+                    # place when it adds self.offset.  Note that this 'relative'
+                    # is for the Nikon type 3 makernote.  Other cameras may use
+                    # other relative offsets, which would have to be computed here
+                    # slightly differently.
+                    if relative:
+                        tmp_offset = self.s2n(offset, 4)
+                        offset = tmp_offset + ifd - self.offset + 4
+                        if self.fake_exif:
+                            offset = offset + 18
+                    else:
+                        offset = self.s2n(offset, 4)
+                field_offset = offset
+                if field_type == 2:
+                    # special case: null-terminated ASCII string
+                    if count != 0:
+                        self.file.seek(self.offset + offset)
+                        values = self.file.read(count)
+                        values = values.strip().replace('\x00', '')
+                    else:
+                        values = ''
+                else:
+                    values = []
+                    signed = (field_type in [6, 8, 9, 10])
+                    for dummy in range(count):
+                        if field_type in (5, 10):
+                            # a ratio
+                            value = Ratio(self.s2n(offset, 4, signed),
+                                          self.s2n(offset + 4, 4, signed))
+                        else:
+                            value = self.s2n(offset, typelen, signed)
+                        values.append(value)
+                        offset = offset + typelen
+                # now "values" is either a string or an array
+                if count == 1 and field_type != 2:
+                    printable=str(values[0])
+                else:
+                    printable=str(values)
+                # compute printable version of values
+                if tag_entry:
+                    if len(tag_entry) != 1:
+                        # optional 2nd tag element is present
+                        if callable(tag_entry[1]):
+                            # call mapping function
+                            printable = tag_entry[1](values)
+                        else:
+                            printable = ''
+                            for i in values:
+                                # use lookup table for this tag
+                                printable += tag_entry[1].get(i, repr(i))
+
+                self.tags[ifd_name + ' ' + tag_name] = IFD_Tag(printable, tag,
+                                                          field_type,
+                                                          values, field_offset,
+                                                          count * typelen)
+                if self.debug:
+                    print ' debug:   %s: %s' % (tag_name,
+                                                repr(self.tags[ifd_name + ' ' + tag_name]))
+
+            if tag_name == stop_tag:
+                break
+
+    # extract uncompressed TIFF thumbnail (like pulling teeth)
+    # we take advantage of the pre-existing layout in the thumbnail IFD as
+    # much as possible
+    def extract_TIFF_thumbnail(self, thumb_ifd):
+        entries = self.s2n(thumb_ifd, 2)
+        # this is header plus offset to IFD ...
+        if self.endian == 'M':
+            tiff = 'MM\x00*\x00\x00\x00\x08'
+        else:
+            tiff = 'II*\x00\x08\x00\x00\x00'
+        # ... plus thumbnail IFD data plus a null "next IFD" pointer
+        self.file.seek(self.offset+thumb_ifd)
+        tiff += self.file.read(entries*12+2)+'\x00\x00\x00\x00'
+
+        # fix up large value offset pointers into data area
+        for i in range(entries):
+            entry = thumb_ifd + 2 + 12 * i
+            tag = self.s2n(entry, 2)
+            field_type = self.s2n(entry+2, 2)
+            typelen = FIELD_TYPES[field_type][0]
+            count = self.s2n(entry+4, 4)
+            oldoff = self.s2n(entry+8, 4)
+            # start of the 4-byte pointer area in entry
+            ptr = i * 12 + 18
+            # remember strip offsets location
+            if tag == 0x0111:
+                strip_off = ptr
+                strip_len = count * typelen
+            # is it in the data area?
+            if count * typelen > 4:
+                # update offset pointer (nasty "strings are immutable" crap)
+                # should be able to say "tiff[ptr:ptr+4]=newoff"
+                newoff = len(tiff)
+                tiff = tiff[:ptr] + self.n2s(newoff, 4) + tiff[ptr+4:]
+                # remember strip offsets location
+                if tag == 0x0111:
+                    strip_off = newoff
+                    strip_len = 4
+                # get original data and store it
+                self.file.seek(self.offset + oldoff)
+                tiff += self.file.read(count * typelen)
+
+        # add pixel strips and update strip offset info
+        old_offsets = self.tags['Thumbnail StripOffsets'].values
+        old_counts = self.tags['Thumbnail StripByteCounts'].values
+        for i in range(len(old_offsets)):
+            # update offset pointer (more nasty "strings are immutable" crap)
+            offset = self.n2s(len(tiff), strip_len)
+            tiff = tiff[:strip_off] + offset + tiff[strip_off + strip_len:]
+            strip_off += strip_len
+            # add pixel strip to end
+            self.file.seek(self.offset + old_offsets[i])
+            tiff += self.file.read(old_counts[i])
+
+        self.tags['TIFFThumbnail'] = tiff
+
+    # decode all the camera-specific MakerNote formats
+
+    # Note is the data that comprises this MakerNote.  The MakerNote will
+    # likely have pointers in it that point to other parts of the file.  We'll
+    # use self.offset as the starting point for most of those pointers, since
+    # they are relative to the beginning of the file.
+    #
+    # If the MakerNote is in a newer format, it may use relative addressing
+    # within the MakerNote.  In that case we'll use relative addresses for the
+    # pointers.
+    #
+    # As an aside: it's not just to be annoying that the manufacturers use
+    # relative offsets.  It's so that if the makernote has to be moved by the
+    # picture software all of the offsets don't have to be adjusted.  Overall,
+    # this is probably the right strategy for makernotes, though the spec is
+    # ambiguous.  (The spec does not appear to imagine that makernotes would
+    # follow EXIF format internally.  Once they did, it's ambiguous whether
+    # the offsets should be from the header at the start of all the EXIF info,
+    # or from the header at the start of the makernote.)
+    def decode_maker_note(self):
+        note = self.tags['EXIF MakerNote']
+        make = self.tags['Image Make'].printable
+        # model = self.tags['Image Model'].printable # unused
+
+        # Nikon
+        # The maker note usually starts with the word Nikon, followed by the
+        # type of the makernote (1 or 2, as a short).  If the word Nikon is
+        # not at the start of the makernote, it's probably type 2, since some
+        # cameras work that way.
+        if make in ('NIKON', 'NIKON CORPORATION'):
+            if note.values[0:7] == [78, 105, 107, 111, 110, 0, 1]:
+                if self.debug:
+                    print "Looks like a type 1 Nikon MakerNote."
+                self.dump_IFD(note.field_offset+8, 'MakerNote',
+                              dict=MAKERNOTE_NIKON_OLDER_TAGS)
+            elif note.values[0:7] == [78, 105, 107, 111, 110, 0, 2]:
+                if self.debug:
+                    print "Looks like a labeled type 2 Nikon MakerNote"
+                if note.values[12:14] != [0, 42] and note.values[12:14] != [42L, 0L]:
+                    raise ValueError("Missing marker tag '42' in MakerNote.")
+                # skip the Makernote label and the TIFF header
+                self.dump_IFD(note.field_offset+10+8, 'MakerNote',
+                              dict=MAKERNOTE_NIKON_NEWER_TAGS, relative=1)
+            else:
+                # E99x or D1
+                if self.debug:
+                    print "Looks like an unlabeled type 2 Nikon MakerNote"
+                self.dump_IFD(note.field_offset, 'MakerNote',
+                              dict=MAKERNOTE_NIKON_NEWER_TAGS)
+            return
+
+        # Olympus
+        if make.startswith('OLYMPUS'):
+            self.dump_IFD(note.field_offset+8, 'MakerNote',
+                          dict=MAKERNOTE_OLYMPUS_TAGS)
+            # TODO
+            #for i in (('MakerNote Tag 0x2020', MAKERNOTE_OLYMPUS_TAG_0x2020),):
+            #    self.decode_olympus_tag(self.tags[i[0]].values, i[1])
+            #return
+
+        # Casio
+        if make == 'Casio':
+            self.dump_IFD(note.field_offset, 'MakerNote',
+                          dict=MAKERNOTE_CASIO_TAGS)
+            return
+
+        # Fujifilm
+        if make == 'FUJIFILM':
+            # bug: everything else is "Motorola" endian, but the MakerNote
+            # is "Intel" endian
+            endian = self.endian
+            self.endian = 'I'
+            # bug: IFD offsets are from beginning of MakerNote, not
+            # beginning of file header
+            offset = self.offset
+            self.offset += note.field_offset
+            # process note with bogus values (note is actually at offset 12)
+            self.dump_IFD(12, 'MakerNote', dict=MAKERNOTE_FUJIFILM_TAGS)
+            # reset to correct values
+            self.endian = endian
+            self.offset = offset
+            return
+
+        # Canon
+        if make == 'Canon':
+            self.dump_IFD(note.field_offset, 'MakerNote',
+                          dict=MAKERNOTE_CANON_TAGS)
+            for i in (('MakerNote Tag 0x0001', MAKERNOTE_CANON_TAG_0x001),
+                      ('MakerNote Tag 0x0004', MAKERNOTE_CANON_TAG_0x004)):
+                self.canon_decode_tag(self.tags[i[0]].values, i[1])
+            return
+
+    # decode Olympus MakerNote tag based on offset within tag
+    def olympus_decode_tag(self, value, dict):
+        pass
+
+    # decode Canon MakerNote tag based on offset within tag
+    # see http://www.burren.cx/david/canon.html by David Burren
+    def canon_decode_tag(self, value, dict):
+        for i in range(1, len(value)):
+            x=dict.get(i, ('Unknown', ))
+            if self.debug:
+                print i, x
+            name=x[0]
+            if len(x) > 1:
+                val=x[1].get(value[i], 'Unknown')
+            else:
+                val=value[i]
+            # it's not a real IFD Tag but we fake one to make everybody
+            # happy. this will have a "proprietary" type
+            self.tags['MakerNote '+name]=IFD_Tag(str(val), None, 0, None,
+                                                 None, None)
+
+# process an image file (expects an open file object)
+# this is the function that has to deal with all the arbitrary nasty bits
+# of the EXIF standard
+def process_file(f, stop_tag='UNDEF', details=True, debug=False):
+    # yah it's cheesy...
+    global detailed
+    detailed = details
+
+    # by default do not fake an EXIF beginning
+    fake_exif = 0
+
+    # determine whether it's a JPEG or TIFF
+    data = f.read(12)
+    if data[0:4] in ['II*\x00', 'MM\x00*']:
+        # it's a TIFF file
+        f.seek(0)
+        endian = f.read(1)
+        f.read(1)
+        offset = 0
+    elif data[0:2] == '\xFF\xD8':
+        # it's a JPEG file
+        while data[2] == '\xFF' and data[6:10] in ('JFIF', 'JFXX', 'OLYM', 'Phot'):
+            length = ord(data[4])*256+ord(data[5])
+            f.read(length-8)
+            # fake an EXIF beginning of file
+            data = '\xFF\x00'+f.read(10)
+            fake_exif = 1
+        if data[2] == '\xFF' and data[6:10] == 'Exif':
+            # detected EXIF header
+            offset = f.tell()
+            endian = f.read(1)
+        else:
+            # no EXIF information
+            return {}
+    else:
+        # file format not recognized
+        return {}
+
+    # deal with the EXIF info we found
+    if debug:
+        print {'I': 'Intel', 'M': 'Motorola'}[endian], 'format'
+    hdr = EXIF_header(f, endian, offset, fake_exif, debug)
+    ifd_list = hdr.list_IFDs()
+    ctr = 0
+    for i in ifd_list:
+        if ctr == 0:
+            IFD_name = 'Image'
+        elif ctr == 1:
+            IFD_name = 'Thumbnail'
+            thumb_ifd = i
+        else:
+            IFD_name = 'IFD %d' % ctr
+        if debug:
+            print ' IFD %d (%s) at offset %d:' % (ctr, IFD_name, i)
+        hdr.dump_IFD(i, IFD_name, stop_tag=stop_tag)
+        # EXIF IFD
+        exif_off = hdr.tags.get(IFD_name+' ExifOffset')
+        if exif_off:
+            if debug:
+                print ' EXIF SubIFD at offset %d:' % exif_off.values[0]
+            hdr.dump_IFD(exif_off.values[0], 'EXIF', stop_tag=stop_tag)
+            # Interoperability IFD contained in EXIF IFD
+            intr_off = hdr.tags.get('EXIF SubIFD InteroperabilityOffset')
+            if intr_off:
+                if debug:
+                    print ' EXIF Interoperability SubSubIFD at offset %d:' \
+                          % intr_off.values[0]
+                hdr.dump_IFD(intr_off.values[0], 'EXIF Interoperability',
+                             dict=INTR_TAGS, stop_tag=stop_tag)
+        # GPS IFD
+        gps_off = hdr.tags.get(IFD_name+' GPSInfo')
+        if gps_off:
+            if debug:
+                print ' GPS SubIFD at offset %d:' % gps_off.values[0]
+            hdr.dump_IFD(gps_off.values[0], 'GPS', dict=GPS_TAGS, stop_tag=stop_tag)
+        ctr += 1
+
+    # extract uncompressed TIFF thumbnail
+    thumb = hdr.tags.get('Thumbnail Compression')
+    if thumb and thumb.printable == 'Uncompressed TIFF':
+        hdr.extract_TIFF_thumbnail(thumb_ifd)
+
+    # JPEG thumbnail (thankfully the JPEG data is stored as a unit)
+    thumb_off = hdr.tags.get('Thumbnail JPEGInterchangeFormat')
+    if thumb_off:
+        f.seek(offset+thumb_off.values[0])
+        size = hdr.tags['Thumbnail JPEGInterchangeFormatLength'].values[0]
+        hdr.tags['JPEGThumbnail'] = f.read(size)
+
+    # deal with MakerNote contained in EXIF IFD
+    if 'EXIF MakerNote' in hdr.tags and detailed:
+        hdr.decode_maker_note()
+
+    # Sometimes in a TIFF file, a JPEG thumbnail is hidden in the MakerNote
+    # since it's not allowed in a uncompressed TIFF IFD
+    if 'JPEGThumbnail' not in hdr.tags:
+        thumb_off=hdr.tags.get('MakerNote JPEGThumbnail')
+        if thumb_off:
+            f.seek(offset+thumb_off.values[0])
+            hdr.tags['JPEGThumbnail']=file.read(thumb_off.field_length)
+
+    return hdr.tags
+
+
+# show command line usage
+def usage(exit_status):
+    msg = 'Usage: EXIF.py [OPTIONS] file1 [file2 ...]\n'
+    msg += 'Extract EXIF information from digital camera image files.\n\nOptions:\n'
+    msg += '-q --quick   Do not process MakerNotes.\n'
+    msg += '-t TAG --stop-tag TAG   Stop processing when this tag is retrieved.\n'
+    msg += '-d --debug   Run in debug mode.\n'
+    print msg
+    sys.exit(exit_status)
+
+# library test/debug function (dump given files)
+if __name__ == '__main__':
+    import sys
+    import getopt
+
+    # parse command line options/arguments
+    try:
+        opts, args = getopt.getopt(sys.argv[1:], "hqdt:v", ["help", "quick", "debug", "stop-tag="])
+    except getopt.GetoptError:
+        usage(2)
+    if args == []:
+        usage(2)
+    detailed = True
+    stop_tag = 'UNDEF'
+    debug = False
+    for o, a in opts:
+        if o in ("-h", "--help"):
+            usage(0)
+        if o in ("-q", "--quick"):
+            detailed = False
+        if o in ("-t", "--stop-tag"):
+            stop_tag = a
+        if o in ("-d", "--debug"):
+            debug = True
+
+    # output info for each file
+    for filename in args:
+        try:
+            file=open(filename, 'rb')
+        except:
+            print "'%s' is unreadable\n"%filename
+            continue
+        print filename + ':'
+        # get the tags
+        data = process_file(file, stop_tag=stop_tag, details=detailed, debug=debug)
+        if not data:
+            print 'No EXIF information found'
+            continue
+
+        x=data.keys()
+        x.sort()
+        for i in x:
+            if i in ('JPEGThumbnail', 'TIFFThumbnail'):
+                continue
+            try:
+                print '   %s (%s): %s' % \
+                      (i, FIELD_TYPES[data[i].field_type][2], data[i].printable)
+            except:
+                print 'error', i, '"', data[i], '"'
+        if 'JPEGThumbnail' in data:
+            print 'File has JPEG thumbnail'
+        print
+