[python] [ref] Patch for libstdcxx printer's Tr1HashtableIterator

[Phil Muldoon <pmuldoon at redhat dot com>]

Please find enclosed patch for Tr1HashtableIterator.  This is used by 
both Tr1UnorderedSetPrinter and Tr1UnorderedMapPrinter.

Two small fixes:

- The first Tom pointed out a few weeks ago.  The number of buckets was 
sourcing the count from the incorrect variable.
- The second fix concerns iterating through the buckets in the class.  
Both the increment of self.count, and the comparison to self.n_buckets 
should have been done outside of the loop.  Otherwise self.count will be 
incorrect (it will be the cumulative count between buckets, not the 
count of buckets that have been iterated.)

Thanks

Phil

2009-02-20  Phil Muldoon  <pmuldoon@redhat.com>

   * python/lib/gdb/libstdcxx/v6/printers.py
   (Tr1HashtableIterator.update): Only increment self.count after
   self.node == 0.
   (Tr1HashtableIterator.__init__): Source number of buckets from
   _M_element_count.
  
diff --git a/gdb/python/lib/gdb/libstdcxx/v6/printers.py b/gdb/python/lib/gdb/libstdcxx/v6/printers.py
index b8c6d6f..701eec2 100644
--- a/gdb/python/lib/gdb/libstdcxx/v6/printers.py
+++ b/gdb/python/lib/gdb/libstdcxx/v6/printers.py
@@ -464,7 +464,7 @@ class StdStringPrinter:
 class Tr1HashtableIterator:
     def __init__ (self, hash):
         self.count = 0
-        self.n_buckets = hash['_M_bucket_count']
+        self.n_buckets = hash['_M_element_count']
         if self.n_buckets == 0:
             self.node = False
         else:
@@ -481,11 +481,13 @@ class Tr1HashtableIterator:
         while self.node == 0:
             self.bucket = self.bucket + 1
             self.node = self.bucket[0]
+
+       # If we advanced off the end of the bucket array, then
+       # we're done.
+        if self.count == self.n_buckets:
+            self.node = False
+        else:
             self.count = self.count + 1
-            # If we advanced off the end of the bucket array, then
-            # we're done.
-            if self.count == self.n_buckets:
-                self.node = False
 
     def next (self):
         if not self.node: