/*!@file
  \brief   HENGE Memory Definition in common with STON Asset Packages
  \details C Aligned memory structures used to define datatypes in the STON
           Asset Package format, used for reading asset packages as runtime 
           memory.
  \author  Ken Grimes
  \date    Feb 2017
  ----------------------------------------------------------------------------*/
#ifndef _HENGE_H_
#define _HENGE_H_

/* Henge Generic Hashtable 

   Hashtables are stored as dynamically sized two dimensional arrays, whose
   columns are provided, and whose rows, and sizes, are derived.

   ht_size = header.ht_columns << header.ht_2pow;
   ht_rows = 0x1 << header.ht_2pow;

   All generic hashtables in henge must have a power-of-two number of rows.  An
   ht_columns value that is also a power-of-two will result in a power-of-two
   sized memory imprint for the structure, making it easy to page align.

   Elements in the columns may be of any arbitrary size.

   typedef uint32_t my_ht_type;
   ht_bytes = ht_size * sizeof(my_ht_type);
*/
struct hng_ht_header_t
{ uint16_t ht_columns;
  uint8_t  ht_2pow, ht_flags;
};

#define hng_ht_size(_HEADER)             ((_HEADER)->ht_columns << (_HEADER)->ht_2pow)
#define hng_ht_rows(_HEADER)             (0x1 << (_HEADER)->ht_2pow)
#define hng_ht_cols(_HEADER)             (_HEADER->ht_columns)
#define hng_ht_start(_HEADER)            (_HEADER + sizeof(*_HEADER))
#define hng_ht_array(_HEADER,_UNIT)      ((_UNIT*)hng_ht_start(_HEADER))
#define hng_ht_bytes(_HEADER,_UNIT)      (hng_ht_size(_HEADER) * sizeof(_UNIT))
#define hng_ht_2bytes(_HEADER,_UNIT2POW) (hng_ht_size(_HEADER) << _UNIT2POW)

#endif //_HENGE_H_