Reorder zoneinfo processing to ensure all transitions are handled.

This reorders the transition index lookup to ensure that all timestamps
are referenced, or an error is thrown, rather than silently erroring at
some later point.

Refs #11093

mythtv/bindings/python/MythTV/utility/dt.py

@@ -121,16 +121,22 @@ def _process(self, fd, version=1, skip=False):
         # read in transition type indexes
         types = [None]*counts.transitions
         for i in range(counts.transitions):
-            types[i] = unpack('!b', fd.read(1))[0]
+            types[i] = t = unpack('!b', fd.read(1))[0]
+            if t >= counts.types:
+                raise RuntimeError(("Transition has out-of-bounds definition "
+                            "index (given: {0}, max: {0}")\
+                                .format(t,counts.types-1))
 
         # read in type definitions
+        typedefs = []
         for i in range(counts.types):
             offset, isdst, _ = unpack('!lbB', fd.read(6))
-            for j in range(counts.transitions):
-                if types[j] == i:
-                    transitions[j][2] = time.gmtime(transitions[j][0]+offset)
-                    transitions[j][3] = offset
-                    transitions[j][5] = isdst
+            typedefs.append([offset, isdst])
+        for i in range(counts.transitions):
+            offset,isdst = typedefs[types[i]]
+            transitions[i][2] = time.gmtime(transitions[i][0] + offset)
+            transitions[i][3] = offset
+            transitions[i][5] = isdst
 
         # read in type names
         for i, name in enumerate(fd.read(counts.abbrevs)[:-1].split('\0')):