src/henge.h

   1 /*!@file
   2   \brief   HENGE Memory Definition in common with STON Asset Packages
   3   \details C Aligned memory structures used to define datatypes in the STON
   4            Asset Package format, used for reading asset packages as runtime
   5            memory.
   6   \author  Ken Grimes
   7   \date    Feb 2017
   8   ----------------------------------------------------------------------------*/
   9 #ifndef _HENGE_H_
  10 #define _HENGE_H_
  11
  12 /* Henge Generic Hashtable
  13
  14    Hashtables are stored as dynamically sized two dimensional arrays, whose
  15    columns are provided, and whose rows, and sizes, are derived.
  16
  17    ht_size = header.ht_columns << header.ht_2pow;
  18    ht_rows = 0x1 << header.ht_2pow;
  19
  20    All generic hashtables in henge must have a power-of-two number of rows.  An
  21    ht_columns value that is also a power-of-two will result in a power-of-two
  22    sized memory imprint for the structure, making it easy to page align.
  23
  24    Elements in the columns may be of any arbitrary size.
  25
  26    typedef uint32_t my_ht_type;
  27    ht_bytes = ht_size * sizeof(my_ht_type);
  28 */
  29 struct hng_ht_header_t
  30 { uint16_t ht_columns;
  31   uint8_t  ht_2pow, ht_flags;
  32 };
  33
  34 #define hng_ht_size(_HEADER)             ((_HEADER)->ht_columns << (_HEADER)->ht_2pow)
  35 #define hng_ht_rows(_HEADER)             (0x1 << (_HEADER)->ht_2pow)
  36 #define hng_ht_cols(_HEADER)             (_HEADER->ht_columns)
  37 #define hng_ht_start(_HEADER)            (_HEADER + sizeof(*_HEADER))
  38 #define hng_ht_array(_HEADER,_UNIT)      ((_UNIT*)hng_ht_start(_HEADER))
  39 #define hng_ht_bytes(_HEADER,_UNIT)      (hng_ht_size(_HEADER) * sizeof(_UNIT))
  40 #define hng_ht_2bytes(_HEADER,_UNIT2POW) (hng_ht_size(_HEADER) << _UNIT2POW)
  41
  42 #endif //_HENGE_H_