1/*	$NetBSD$	*/
2
3/*
4** Id: lgc.h,v 2.15.1.1 2007/12/27 13:02:25 roberto Exp
5** Garbage Collector
6** See Copyright Notice in lua.h
7*/
8
9#ifndef lgc_h
10#define lgc_h
11
12
13#include "lobject.h"
14
15
16/*
17** Possible states of the Garbage Collector
18*/
19#define GCSpause	0
20#define GCSpropagate	1
21#define GCSsweepstring	2
22#define GCSsweep	3
23#define GCSfinalize	4
24
25
26/*
27** some userful bit tricks
28*/
29#define resetbits(x,m)	((x) &= cast(lu_byte, ~(m)))
30#define setbits(x,m)	((x) |= (m))
31#define testbits(x,m)	((x) & (m))
32#define bitmask(b)	(1<<(b))
33#define bit2mask(b1,b2)	(bitmask(b1) | bitmask(b2))
34#define l_setbit(x,b)	setbits(x, bitmask(b))
35#define resetbit(x,b)	resetbits(x, bitmask(b))
36#define testbit(x,b)	testbits(x, bitmask(b))
37#define set2bits(x,b1,b2)	setbits(x, (bit2mask(b1, b2)))
38#define reset2bits(x,b1,b2)	resetbits(x, (bit2mask(b1, b2)))
39#define test2bits(x,b1,b2)	testbits(x, (bit2mask(b1, b2)))
40
41
42
43/*
44** Layout for bit use in `marked' field:
45** bit 0 - object is white (type 0)
46** bit 1 - object is white (type 1)
47** bit 2 - object is black
48** bit 3 - for userdata: has been finalized
49** bit 3 - for tables: has weak keys
50** bit 4 - for tables: has weak values
51** bit 5 - object is fixed (should not be collected)
52** bit 6 - object is "super" fixed (only the main thread)
53*/
54
55
56#define WHITE0BIT	0
57#define WHITE1BIT	1
58#define BLACKBIT	2
59#define FINALIZEDBIT	3
60#define KEYWEAKBIT	3
61#define VALUEWEAKBIT	4
62#define FIXEDBIT	5
63#define SFIXEDBIT	6
64#define WHITEBITS	bit2mask(WHITE0BIT, WHITE1BIT)
65
66
67#define iswhite(x)      test2bits((x)->gch.marked, WHITE0BIT, WHITE1BIT)
68#define isblack(x)      testbit((x)->gch.marked, BLACKBIT)
69#define isgray(x)	(!isblack(x) && !iswhite(x))
70
71#define otherwhite(g)	(g->currentwhite ^ WHITEBITS)
72#define isdead(g,v)	((v)->gch.marked & otherwhite(g) & WHITEBITS)
73
74#define changewhite(x)	((x)->gch.marked ^= WHITEBITS)
75#define gray2black(x)	l_setbit((x)->gch.marked, BLACKBIT)
76
77#define valiswhite(x)	(iscollectable(x) && iswhite(gcvalue(x)))
78
79#define luaC_white(g)	cast(lu_byte, (g)->currentwhite & WHITEBITS)
80
81
82#define luaC_checkGC(L) { \
83  condhardstacktests(luaD_reallocstack(L, L->stacksize - EXTRA_STACK - 1)); \
84  if (G(L)->totalbytes >= G(L)->GCthreshold) \
85	luaC_step(L); }
86
87
88#define luaC_barrier(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p)))  \
89	luaC_barrierf(L,obj2gco(p),gcvalue(v)); }
90
91#define luaC_barriert(L,t,v) { if (valiswhite(v) && isblack(obj2gco(t)))  \
92	luaC_barrierback(L,t); }
93
94#define luaC_objbarrier(L,p,o)  \
95	{ if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) \
96		luaC_barrierf(L,obj2gco(p),obj2gco(o)); }
97
98#define luaC_objbarriert(L,t,o)  \
99   { if (iswhite(obj2gco(o)) && isblack(obj2gco(t))) luaC_barrierback(L,t); }
100
101LUAI_FUNC size_t luaC_separateudata (lua_State *L, int all);
102LUAI_FUNC void luaC_callGCTM (lua_State *L);
103LUAI_FUNC void luaC_freeall (lua_State *L);
104LUAI_FUNC void luaC_step (lua_State *L);
105LUAI_FUNC void luaC_fullgc (lua_State *L);
106LUAI_FUNC void luaC_link (lua_State *L, GCObject *o, lu_byte tt);
107LUAI_FUNC void luaC_linkupval (lua_State *L, UpVal *uv);
108LUAI_FUNC void luaC_barrierf (lua_State *L, GCObject *o, GCObject *v);
109LUAI_FUNC void luaC_barrierback (lua_State *L, Table *t);
110
111
112#endif
113