src/lj_tab.h

   1 /*
   2 ** Table handling.
   3 ** Copyright (C) 2005-2023 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 /* Hash values are masked with the table hash mask and used as an index. */
  35 static LJ_AINLINE Node *hashmask(const GCtab *t, uint32_t hash)
  36 {
  37   Node *n = noderef(t->node);
  38   return &n[hash & t->hmask];
  39 }
  40
  41 /* String IDs are generated when a string is interned. */
  42 #define hashstr(t, s)           hashmask(t, (s)->sid)
  43
  44 #define hashlohi(t, lo, hi)     hashmask((t), hashrot((lo), (hi)))
  45 #define hashnum(t, o)           hashlohi((t), (o)->u32.lo, ((o)->u32.hi << 1))
  46 #if LJ_GC64
  47 #define hashgcref(t, r) \
  48   hashlohi((t), (uint32_t)gcrefu(r), (uint32_t)(gcrefu(r) >> 32))
  49 #else
  50 #define hashgcref(t, r)         hashlohi((t), gcrefu(r), gcrefu(r) + HASH_BIAS)
  51 #endif
  52
  53 #define hsize2hbits(s)  ((s) ? ((s)==1 ? 1 : 1+lj_fls((uint32_t)((s)-1))) : 0)
  54
  55 LJ_FUNCA GCtab *lj_tab_new(lua_State *L, uint32_t asize, uint32_t hbits);
  56 LJ_FUNC GCtab *lj_tab_new_ah(lua_State *L, int32_t a, int32_t h);
  57 #if LJ_HASJIT
  58 LJ_FUNC GCtab * LJ_FASTCALL lj_tab_new1(lua_State *L, uint32_t ahsize);
  59 #endif
  60 LJ_FUNCA GCtab * LJ_FASTCALL lj_tab_dup(lua_State *L, const GCtab *kt);
  61 LJ_FUNC void LJ_FASTCALL lj_tab_clear(GCtab *t);
  62 LJ_FUNC void LJ_FASTCALL lj_tab_free(global_State *g, GCtab *t);
  63 #if LJ_HASFFI
  64 LJ_FUNC void lj_tab_rehash(lua_State *L, GCtab *t);
  65 #endif
  66 LJ_FUNC void lj_tab_resize(lua_State *L, GCtab *t, uint32_t asize, uint32_t hbits);
  67 LJ_FUNCA void lj_tab_reasize(lua_State *L, GCtab *t, uint32_t nasize);
  68
  69 /* Caveat: all getters except lj_tab_get() can return NULL! */
  70
  71 LJ_FUNCA cTValue * LJ_FASTCALL lj_tab_getinth(GCtab *t, int32_t key);
  72 LJ_FUNC cTValue *lj_tab_getstr(GCtab *t, const GCstr *key);
  73 LJ_FUNCA cTValue *lj_tab_get(lua_State *L, GCtab *t, cTValue *key);
  74
  75 /* Caveat: all setters require a write barrier for the stored value. */
  76
  77 LJ_FUNCA TValue *lj_tab_newkey(lua_State *L, GCtab *t, cTValue *key);
  78 LJ_FUNCA TValue *lj_tab_setinth(lua_State *L, GCtab *t, int32_t key);
  79 LJ_FUNC TValue *lj_tab_setstr(lua_State *L, GCtab *t, const GCstr *key);
  80 LJ_FUNC TValue *lj_tab_set(lua_State *L, GCtab *t, cTValue *key);
  81
  82 #define inarray(t, key)         ((MSize)(key) < (MSize)(t)->asize)
  83 #define arrayslot(t, i)         (&tvref((t)->array)[(i)])
  84 #define lj_tab_getint(t, key) \
  85   (inarray((t), (key)) ? arrayslot((t), (key)) : lj_tab_getinth((t), (key)))
  86 #define lj_tab_setint(L, t, key) \
  87   (inarray((t), (key)) ? arrayslot((t), (key)) : lj_tab_setinth(L, (t), (key)))
  88
  89 LJ_FUNC uint32_t LJ_FASTCALL lj_tab_keyindex(GCtab *t, cTValue *key);
  90 LJ_FUNCA int lj_tab_next(GCtab *t, cTValue *key, TValue *o);
  91 LJ_FUNCA MSize LJ_FASTCALL lj_tab_len(GCtab *t);
  92 #if LJ_HASJIT
  93 LJ_FUNC MSize LJ_FASTCALL lj_tab_len_hint(GCtab *t, size_t hint);
  94 #endif
  95
  96 #endif