Add verbosity, ignore phantom slices, small important bugfix

Sometimes code reuse is a Bad Thing(tm).  The masking step for "next" was
needed, but that should be rounding *down* and *not* up.  Ignore phantom
slices if asked to turn them into chunks, most likely they would be
requested by running with `image2chunks *` so this seems the right
approach.

Add verbosity.  A rather important part of UI design is you want to
provide feedback and indications you're doing something.  While the data
output isn't too crucial, it at least hints we're actively doing
something.

image2chunks.py

@@ -80,6 +80,10 @@ def loadParams(self, name):
 		self.paramsFile.close()
 		del self.paramsFile
 
+		if 'phantom' in params and params['phantom']:
+			print("[!] {:s} is a phantom slice, skipping!".format(name))
+			return False
+
 		for k in 'blockShift', 'startLBA', 'endLBA', 'lastWipe':
 			if k not in params:
 				print("Parameter value \"{:s}\" is missing, unable to continue".format(k))
@@ -91,6 +95,8 @@ def loadParams(self, name):
 		self.endLBA	= params['endLBA']
 		self.lastWipe	= params['lastWipe']
 
+		return True
+
 
 	def makeChunks(self, name):
 		"""
@@ -111,18 +117,22 @@ def makeChunks(self, name):
 			hole = (self.file.seek(current, SEEK_HOLE) + self.blockSize-1) & ~(self.blockSize-1)
 			# Python's handling of this condition is suboptimal
 			try:
-				next = (self.file.seek(hole, SEEK_DATA) + self.blockSize-1) & ~(self.blockSize-1)
+				next = self.file.seek(hole, SEEK_DATA) & ~(self.blockSize-1)
 				wipeCount = (next - current) >> self.blockShift
 			except IOError:
 				next = eof
 				wipeCount = self.lastWipe - targetAddr
+
 			md5 = hashlib.md5()
 			crc = crc32(b"")
 			zobj = zlib.compressobj(1)
 			self.file.seek(current, io.SEEK_SET)
 
 			chunkName = baseName + str(targetAddr) + ".bin"
 			out = io.FileIO(chunkName + ".chunk", "wb")
+
+			print("[+] Compressing {:s} to {:s} ({:d} empty blocks)".format(name, chunkName, (next - hole) >> self.blockShift))
+
 			chunkName = chunkName.encode("utf8")
 			out.seek(self._dz_length, io.SEEK_SET)
 			zlen = 0
@@ -162,6 +172,8 @@ def makeChunks(self, name):
 			current = next
 			targetAddr = self.startLBA + (current >> self.blockShift)
 
+		print("[+] done\n")
+
 
 	def __init__(self, name):
 		"""
@@ -172,9 +184,9 @@ def __init__(self, name):
 
 		self.openFiles(name)
 
-		self.loadParams(name)
+		if self.loadParams(name):
 
-		self.makeChunks(name)
+			self.makeChunks(name)
 
 
 if __name__ == "__main__":