root/lj_tab.h

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INCLUDED FROM


DEFINITIONS

This source file includes following definitions.
  1. hashrot

   1 /*
   2 ** Table handling.
   3 ** Copyright (C) 2005-2017 Mike Pall. See Copyright Notice in luajit.h
   4 */
   5 
   6 #ifndef _LJ_TAB_H
   7 #define _LJ_TAB_H
   8 
   9 #include "lj_obj.h"
  10 
  11 /* Hash constants. Tuned using a brute force search. */
  12 #define HASH_BIAS       (-0x04c11db7)
  13 #define HASH_ROT1       14
  14 #define HASH_ROT2       5
  15 #define HASH_ROT3       13
  16 
  17 /* Scramble the bits of numbers and pointers. */
  18 static LJ_AINLINE uint32_t hashrot(uint32_t lo, uint32_t hi)
  19 {
  20 #if LJ_TARGET_X86ORX64
  21   /* Prefer variant that compiles well for a 2-operand CPU. */
  22   lo ^= hi; hi = lj_rol(hi, HASH_ROT1);
  23   lo -= hi; hi = lj_rol(hi, HASH_ROT2);
  24   hi ^= lo; hi -= lj_rol(lo, HASH_ROT3);
  25 #else
  26   lo ^= hi;
  27   lo = lo - lj_rol(hi, HASH_ROT1);
  28   hi = lo ^ lj_rol(hi, HASH_ROT1 + HASH_ROT2);
  29   hi = hi - lj_rol(lo, HASH_ROT3);
  30 #endif
  31   return hi;
  32 }
  33 
  34 #define hsize2hbits(s)  ((s) ? ((s)==1 ? 1 : 1+lj_fls((uint32_t)((s)-1))) : 0)
  35 
  36 LJ_FUNCA GCtab *lj_tab_new(lua_State *L, uint32_t asize, uint32_t hbits);
  37 #if LJ_HASJIT
  38 LJ_FUNC GCtab * LJ_FASTCALL lj_tab_new1(lua_State *L, uint32_t ahsize);
  39 #endif
  40 LJ_FUNCA GCtab * LJ_FASTCALL lj_tab_dup(lua_State *L, const GCtab *kt);
  41 LJ_FUNC void LJ_FASTCALL lj_tab_free(global_State *g, GCtab *t);
  42 #if LJ_HASFFI
  43 LJ_FUNC void lj_tab_rehash(lua_State *L, GCtab *t);
  44 #endif
  45 LJ_FUNCA void lj_tab_reasize(lua_State *L, GCtab *t, uint32_t nasize);
  46 
  47 /* Caveat: all getters except lj_tab_get() can return NULL! */
  48 
  49 LJ_FUNCA cTValue * LJ_FASTCALL lj_tab_getinth(GCtab *t, int32_t key);
  50 LJ_FUNC cTValue *lj_tab_getstr(GCtab *t, GCstr *key);
  51 LJ_FUNCA cTValue *lj_tab_get(lua_State *L, GCtab *t, cTValue *key);
  52 
  53 /* Caveat: all setters require a write barrier for the stored value. */
  54 
  55 LJ_FUNCA TValue *lj_tab_newkey(lua_State *L, GCtab *t, cTValue *key);
  56 LJ_FUNC TValue *lj_tab_setinth(lua_State *L, GCtab *t, int32_t key);
  57 LJ_FUNC TValue *lj_tab_setstr(lua_State *L, GCtab *t, GCstr *key);
  58 LJ_FUNC TValue *lj_tab_set(lua_State *L, GCtab *t, cTValue *key);
  59 
  60 #define inarray(t, key)         ((MSize)(key) < (MSize)(t)->asize)
  61 #define arrayslot(t, i)         (&tvref((t)->array)[(i)])
  62 #define lj_tab_getint(t, key) \
  63   (inarray((t), (key)) ? arrayslot((t), (key)) : lj_tab_getinth((t), (key)))
  64 #define lj_tab_setint(L, t, key) \
  65   (inarray((t), (key)) ? arrayslot((t), (key)) : lj_tab_setinth(L, (t), (key)))
  66 
  67 LJ_FUNCA int lj_tab_next(lua_State *L, GCtab *t, TValue *key);
  68 LJ_FUNCA MSize LJ_FASTCALL lj_tab_len(GCtab *t);
  69 
  70 #endif

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