Remove another redundant check for file offset < 0

Fixed four comments.
Changed location of call to containsFileOffset() from Memory.java toMemoryBlockSourceInfo.java.  Changed from print() to println() in thepython file.
GP-782: New API to support converting file offsets to memory addresses, with sample scripts that use it

Ghidra/Features/Base/ghidra_scripts/LocateMemoryAddressesForFileOffset.py

@@ -0,0 +1,64 @@
+## ###
+#  IP: GHIDRA
+# 
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#  
+#       http://www.apache.org/licenses/LICENSE-2.0
+#  
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+##
+# This example script locates a memory address for a file offset.  
+#Prompt user for a file offset.
+#Print the associated memory address to the Ghidra console
+#Print the file offset as a Ghidra comment at the memory address in the Ghidra Listing
+#If multiple addresses are located, then print the addresses to the console (do not set a Ghidra comment)
+# @category Examples   
+
+import sys
+from ghidra.program.model.address import Address
+from ghidra.program.model.listing import CodeUnit
+from ghidra.program.model.listing import Listing
+from ghidra.program.model.mem import Memory
+from java.util import Set
+
+def getFileOffset():
+  userFileOffset = askString('File offset', 'Please provide a hexadecimal file offset')
+  try:
+    int(userFileOffset,16)
+  except ValueError:
+     raise ValueError('Please provide a hexadecimal file offset.')
+  myFileOffset = long(userFileOffset,16) #specify base 16 since we expect address in hex
+  if myFileOffset < 0:
+    raise ValueError('Offset cannot be a negative value.')
+  return myFileOffset
+
+def processAddress(addr, memBlockName, fileOffset):
+  println('File offset ' + hex(fileOffset) + ' is associated with memory block:address ' + memBlockName + ':' + addr.toString());
+  myCodeUnit = currentProgram.getListing().getCodeUnitContaining(addr)
+  comment = myCodeUnit.getComment(0)
+  if not comment:
+    myCodeUnit.setComment(0, getScriptName() + ': File offset: ' + hex(fileOffset) + 
+      ', Memory block:address ' + memBlockName + ':'+ addr.toString())
+  else:
+    myCodeUnit.setComment(0, comment + ' ' + getScriptName() + ': File offset: ' + hex(fileOffset) + 
+      ', Memory block:address ' + memBlockName + ':' + addr.toString())
+
+myFileOffset = getFileOffset()
+mem = currentProgram.getMemory()
+addressSet = mem.locateAddressesForFileOffset(myFileOffset)
+if addressSet.isEmpty():
+  println('No memory address found for: ' + hex(myFileOffset))
+elif addressSet.size() == 1:
+  address = addressSet.iterator().next()
+  processAddress(address, mem.getBlock(address).getName(), myFileOffset)
+#file offset matches to multiple addresses.  Let the user decide which address they want.
+else:
+  println('Possible memory block:address are:')
+  for addr in addressSet:
+    println(mem.getBlock(addr).getName() + ":" + addr.toString())