Small issues with Dict (dict.cpp, dict2.cpp)

Thomas Stüfe thomas.stuefe at
Tue Apr 1 13:11:07 UTC 2014


I see some smallish issues in the "Dict" class which can be found
share/vm/libadt/dict.cpp and in slightly different form in

Nothing major, and of course I may be wrong...

1) Dict &Dict::operator =( const Dict &d ):
  if( _size < d._size ) {       // If must have more buckets
    _arena = d._arena;
    _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*_size,
sizeof(bucket)*d._size );
    memset( &_bin[_size], 0, (d._size-_size)*sizeof(bucket) );
    _size = d._size;

Both Arealloc and memset seem pointless to me, as the buckets are cleared
anyway below.
Also, we leak the old content if the arena is different - we could at least
attempt to Afree() the old bucket list in the old arena.

2) void *Dict::Delete(void *key) :
  b->_cnt--;                // Remove key/value from lo bucket
  b->_keyvals[j+j  ] = b->_keyvals[b->_cnt+b->_cnt  ];
  b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];

  if bucket only had one entry (hopefully the rule, if hash works well),
the copying is unnecessary.

3) int32 Dict::operator ==(const Dict &d2) const

This uses memcmp to compare buckets, so it depends on the order of bucket
list entries; I am not sure this was intended.

I also did not find any use for these methods, are they actually used

Kind Regards,

Thomas Stüfe

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