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Root/lua/lfunc.cc

1/*
2** $Id: lfunc.c,v 2.12 2005/12/22 16:19:56 roberto Exp $
3** Auxiliary functions to manipulate prototypes and closures
4** See Copyright Notice in lua.h
5*/
6
7
8#include <stddef.h>
9
10#define lfunc_c
11#define LUA_CORE
12
13#include "lua.h"
14
15#include "lfunc.h"
16#include "lgc.h"
17#include "lmem.h"
18#include "lobject.h"
19#include "lstate.h"
20
21
22
23Closure *luaF_newCclosure (lua_State *L, int nelems, Table *e) {
24 Closure *c = cast(Closure *, luaM_malloc(L, sizeCclosure(nelems)));
25 luaC_link(L, obj2gco(c), LUA_TFUNCTION);
26 c->c.isC = 1;
27 c->c.env = e;
28 c->c.nupvalues = cast_byte(nelems);
29 return c;
30}
31
32
33Closure *luaF_newLclosure (lua_State *L, int nelems, Table *e) {
34 Closure *c = cast(Closure *, luaM_malloc(L, sizeLclosure(nelems)));
35 luaC_link(L, obj2gco(c), LUA_TFUNCTION);
36 c->l.isC = 0;
37 c->l.env = e;
38 c->l.nupvalues = cast_byte(nelems);
39 while (nelems--) c->l.upvals[nelems] = NULL;
40 return c;
41}
42
43
44UpVal *luaF_newupval (lua_State *L) {
45 UpVal *uv = luaM_new(L, UpVal);
46 luaC_link(L, obj2gco(uv), LUA_TUPVAL);
47 uv->v = &uv->u.value;
48 setnilvalue(uv->v);
49 return uv;
50}
51
52
53UpVal *luaF_findupval (lua_State *L, StkId level) {
54 global_State *g = G(L);
55 GCObject **pp = &L->openupval;
56 UpVal *p;
57 UpVal *uv;
58 while ((p = ngcotouv(*pp)) != NULL && p->v >= level) {
59 lua_assert(p->v != &p->u.value);
60 if (p->v == level) { /* found a corresponding upvalue? */
61 if (isdead(g, obj2gco(p))) /* is it dead? */
62 changewhite(obj2gco(p)); /* ressurect it */
63 return p;
64 }
65 pp = &p->next;
66 }
67 uv = luaM_new(L, UpVal); /* not found: create a new one */
68 uv->tt = LUA_TUPVAL;
69 uv->marked = luaC_white(g);
70 uv->v = level; /* current value lives in the stack */
71 uv->next = *pp; /* chain it in the proper position */
72 *pp = obj2gco(uv);
73 uv->u.l.prev = &g->uvhead; /* double link it in `uvhead' list */
74 uv->u.l.next = g->uvhead.u.l.next;
75 uv->u.l.next->u.l.prev = uv;
76 g->uvhead.u.l.next = uv;
77 lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
78 return uv;
79}
80
81
82static void unlinkupval (UpVal *uv) {
83 lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
84 uv->u.l.next->u.l.prev = uv->u.l.prev; /* remove from `uvhead' list */
85 uv->u.l.prev->u.l.next = uv->u.l.next;
86}
87
88
89void luaF_freeupval (lua_State *L, UpVal *uv) {
90 if (uv->v != &uv->u.value) /* is it open? */
91 unlinkupval(uv); /* remove from open list */
92 luaM_free(L, uv); /* free upvalue */
93}
94
95
96void luaF_close (lua_State *L, StkId level) {
97 UpVal *uv;
98 global_State *g = G(L);
99 while ((uv = ngcotouv(L->openupval)) != NULL && uv->v >= level) {
100 GCObject *o = obj2gco(uv);
101 lua_assert(!isblack(o) && uv->v != &uv->u.value);
102 L->openupval = uv->next; /* remove from `open' list */
103 if (isdead(g, o))
104 luaF_freeupval(L, uv); /* free upvalue */
105 else {
106 unlinkupval(uv);
107 setobj(L, &uv->u.value, uv->v);
108 uv->v = &uv->u.value; /* now current value lives here */
109 luaC_linkupval(L, uv); /* link upvalue into `gcroot' list */
110 }
111 }
112}
113
114
115Proto *luaF_newproto (lua_State *L) {
116 Proto *f = luaM_new(L, Proto);
117 luaC_link(L, obj2gco(f), LUA_TPROTO);
118 f->k = NULL;
119 f->sizek = 0;
120 f->p = NULL;
121 f->sizep = 0;
122 f->code = NULL;
123 f->sizecode = 0;
124 f->sizelineinfo = 0;
125 f->sizeupvalues = 0;
126 f->nups = 0;
127 f->upvalues = NULL;
128 f->numparams = 0;
129 f->is_vararg = 0;
130 f->maxstacksize = 0;
131 f->lineinfo = NULL;
132 f->sizelocvars = 0;
133 f->locvars = NULL;
134 f->linedefined = 0;
135 f->lastlinedefined = 0;
136 f->source = NULL;
137 return f;
138}
139
140
141void luaF_freeproto (lua_State *L, Proto *f) {
142 luaM_freearray(L, f->code, f->sizecode, Instruction);
143 luaM_freearray(L, f->p, f->sizep, Proto *);
144 luaM_freearray(L, f->k, f->sizek, TValue);
145 luaM_freearray(L, f->lineinfo, f->sizelineinfo, int);
146 luaM_freearray(L, f->locvars, f->sizelocvars, struct LocVar);
147 luaM_freearray(L, f->upvalues, f->sizeupvalues, TString *);
148 luaM_free(L, f);
149}
150
151
152void luaF_freeclosure (lua_State *L, Closure *c) {
153 int size = (c->c.isC) ? sizeCclosure(c->c.nupvalues) :
154 sizeLclosure(c->l.nupvalues);
155 luaM_freemem(L, c, size);
156}
157
158
159/*
160** Look for n-th local variable at line `line' in function `func'.
161** Returns NULL if not found.
162*/
163const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
164 int i;
165 for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
166 if (pc < f->locvars[i].endpc) { /* is variable active? */
167 local_number--;
168 if (local_number == 0)
169 return getstr(f->locvars[i].varname);
170 }
171 }
172 return NULL; /* not found */
173}
174

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