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
111