Refactoring

cr2_replace.py

@@ -25,6 +25,29 @@
 sys.path.append(os.path.join(os.path.dirname(os.path.realpath(__file__)),'pyshared'))
 import jbtiff
 
+## component functions
+
+def replace_ifd(tiff, k, data):
+ print "IFD#%d: Replacing data strip with length %d" % (k, len(data))
+ # get references to required IFD
+ IFD, ifd_offset, strips = tiff.data[k]
+ # replace data strips with new data
+ assert strips
+ del strips[:]
+ strips.append(data)
+ # update IFD data
+ if 273 in IFD:
+ assert 279 in IFD
+ assert 513 not in IFD and 514 not in IFD
+ IFD[279] = (4, 1, [len(data)], 0)
+ elif 513 in IFD:
+ assert 514 in IFD
+ assert 273 not in IFD and 279 not in IFD
+ IFD[514] = (4, 1, [len(data)], 0)
+ else:
+ raise AssertionError("Reference to data strip not found in IFD#%d" % k)
+ return
+
 ## main program
 
 def main():
@@ -40,29 +63,12 @@ def main():
 
  # read input raw file
  tiff = jbtiff.tiff_file(open(args.input, 'rb'))
- # replace data strips for main sensor image (IFD#3)
- k = 3
- IFD, ifd_offset, strips = tiff.data[k]
-
  # read input data file
  with open(args.sensor, 'rb') as fid:
  data = fid.read()
- print "IFD#%d: Replacing data strip with length %d" % (k, len(data))
- # replace data strips with new data
- assert strips
- del strips[:]
- strips.append(data)
- # update IFD data
- if 273 in IFD:
- assert 279 in IFD
- assert 513 not in IFD and 514 not in IFD
- IFD[279] = (4, 1, [len(data)], 0)
- elif 513 in IFD:
- assert 514 in IFD
- assert 273 not in IFD and 279 not in IFD
- IFD[514] = (4, 1, [len(data)], 0)
- else:
- raise AssertionError("Reference to data strip not found in IFD#%d" % k)
+
+ # replace data strips for main sensor image (IFD#3)
+ replace_ifd(tiff, 3, data)
 
  # save updated CR2 file
  tiff.write(open(args.output,'wb'))