/script_binding/lua/lua/lgc.h

  1/*
  2** $Id: lgc.h,v 2.15.1.1 2007/12/27 13:02:25 roberto Exp $
  3** Garbage Collector
  4** See Copyright Notice in lua.h
  5*/
  6
  7#ifndef lgc_h
  8#define lgc_h
  9
 10
 11#include "lobject.h"
 12
 13
 14/*
 15** Possible states of the Garbage Collector
 16*/
 17#define GCSpause	0
 18#define GCSpropagate	1
 19#define GCSsweepstring	2
 20#define GCSsweep	3
 21#define GCSfinalize	4
 22
 23
 24/*
 25** some userful bit tricks
 26*/
 27#define resetbits(x,m)	((x) &= cast(lu_byte, ~(m)))
 28#define setbits(x,m)	((x) |= (m))
 29#define testbits(x,m)	((x) & (m))
 30#define bitmask(b)	(1<<(b))
 31#define bit2mask(b1,b2)	(bitmask(b1) | bitmask(b2))
 32#define l_setbit(x,b)	setbits(x, bitmask(b))
 33#define resetbit(x,b)	resetbits(x, bitmask(b))
 34#define testbit(x,b)	testbits(x, bitmask(b))
 35#define set2bits(x,b1,b2)	setbits(x, (bit2mask(b1, b2)))
 36#define reset2bits(x,b1,b2)	resetbits(x, (bit2mask(b1, b2)))
 37#define test2bits(x,b1,b2)	testbits(x, (bit2mask(b1, b2)))
 38
 39
 40
 41/*
 42** Layout for bit use in `marked' field:
 43** bit 0 - object is white (type 0)
 44** bit 1 - object is white (type 1)
 45** bit 2 - object is black
 46** bit 3 - for userdata: has been finalized
 47** bit 3 - for tables: has weak keys
 48** bit 4 - for tables: has weak values
 49** bit 5 - object is fixed (should not be collected)
 50** bit 6 - object is "super" fixed (only the main thread)
 51*/
 52
 53
 54#define WHITE0BIT	0
 55#define WHITE1BIT	1
 56#define BLACKBIT	2
 57#define FINALIZEDBIT	3
 58#define KEYWEAKBIT	3
 59#define VALUEWEAKBIT	4
 60#define FIXEDBIT	5
 61#define SFIXEDBIT	6
 62#define WHITEBITS	bit2mask(WHITE0BIT, WHITE1BIT)
 63
 64
 65#define iswhite(x)      test2bits((x)->gch.marked, WHITE0BIT, WHITE1BIT)
 66#define isblack(x)      testbit((x)->gch.marked, BLACKBIT)
 67#define isgray(x)	(!isblack(x) && !iswhite(x))
 68
 69#define otherwhite(g)	(g->currentwhite ^ WHITEBITS)
 70#define isdead(g,v)	((v)->gch.marked & otherwhite(g) & WHITEBITS)
 71
 72#define changewhite(x)	((x)->gch.marked ^= WHITEBITS)
 73#define gray2black(x)	l_setbit((x)->gch.marked, BLACKBIT)
 74
 75#define valiswhite(x)	(iscollectable(x) && iswhite(gcvalue(x)))
 76
 77#define luaC_white(g)	cast(lu_byte, (g)->currentwhite & WHITEBITS)
 78
 79
 80#define luaC_checkGC(L) { \
 81  condhardstacktests(luaD_reallocstack(L, L->stacksize - EXTRA_STACK - 1)); \
 82  if (G(L)->totalbytes >= G(L)->GCthreshold) \
 83	luaC_step(L); }
 84
 85
 86#define luaC_barrier(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p)))  \
 87	luaC_barrierf(L,obj2gco(p),gcvalue(v)); }
 88
 89#define luaC_barriert(L,t,v) { if (valiswhite(v) && isblack(obj2gco(t)))  \
 90	luaC_barrierback(L,t); }
 91
 92#define luaC_objbarrier(L,p,o)  \
 93	{ if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) \
 94		luaC_barrierf(L,obj2gco(p),obj2gco(o)); }
 95
 96#define luaC_objbarriert(L,t,o)  \
 97   { if (iswhite(obj2gco(o)) && isblack(obj2gco(t))) luaC_barrierback(L,t); }
 98
 99LUAI_FUNC size_t luaC_separateudata (lua_State *L, int all);
100LUAI_FUNC void luaC_callGCTM (lua_State *L);
101LUAI_FUNC void luaC_freeall (lua_State *L);
102LUAI_FUNC void luaC_step (lua_State *L);
103LUAI_FUNC void luaC_fullgc (lua_State *L);
104LUAI_FUNC void luaC_link (lua_State *L, GCObject *o, lu_byte tt);
105LUAI_FUNC void luaC_linkupval (lua_State *L, UpVal *uv);
106LUAI_FUNC void luaC_barrierf (lua_State *L, GCObject *o, GCObject *v);
107LUAI_FUNC void luaC_barrierback (lua_State *L, Table *t);
108
109
110#endif