1/*
2** $Id: lfunc.c,v 2.30 2012/10/03 12:36:46 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 n) {
24  Closure *c = &luaC_newobj(L, LUA_TCCL, sizeCclosure(n), NULL, 0)->cl;
25  c->c.nupvalues = cast_byte(n);
26  return c;
27}
28
29
30Closure *luaF_newLclosure (lua_State *L, int n) {
31  Closure *c = &luaC_newobj(L, LUA_TLCL, sizeLclosure(n), NULL, 0)->cl;
32  c->l.p = NULL;
33  c->l.nupvalues = cast_byte(n);
34  while (n--) c->l.upvals[n] = NULL;
35  return c;
36}
37
38
39UpVal *luaF_newupval (lua_State *L) {
40  UpVal *uv = &luaC_newobj(L, LUA_TUPVAL, sizeof(UpVal), NULL, 0)->uv;
41  uv->v = &uv->u.value;
42  setnilvalue(uv->v);
43  return uv;
44}
45
46
47UpVal *luaF_findupval (lua_State *L, StkId level) {
48  global_State *g = G(L);
49  GCObject **pp = &L->openupval;
50  UpVal *p;
51  UpVal *uv;
52  while (*pp != NULL && (p = gco2uv(*pp))->v >= level) {
53    GCObject *o = obj2gco(p);
54    lua_assert(p->v != &p->u.value);
55    lua_assert(!isold(o) || isold(obj2gco(L)));
56    if (p->v == level) {  /* found a corresponding upvalue? */
57      if (isdead(g, o))  /* is it dead? */
58        changewhite(o);  /* resurrect it */
59      return p;
60    }
61    pp = &p->next;
62  }
63  /* not found: create a new one */
64  uv = &luaC_newobj(L, LUA_TUPVAL, sizeof(UpVal), pp, 0)->uv;
65  uv->v = level;  /* current value lives in the stack */
66  uv->u.l.prev = &g->uvhead;  /* double link it in `uvhead' list */
67  uv->u.l.next = g->uvhead.u.l.next;
68  uv->u.l.next->u.l.prev = uv;
69  g->uvhead.u.l.next = uv;
70  lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
71  return uv;
72}
73
74
75static void unlinkupval (UpVal *uv) {
76  lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
77  uv->u.l.next->u.l.prev = uv->u.l.prev;  /* remove from `uvhead' list */
78  uv->u.l.prev->u.l.next = uv->u.l.next;
79}
80
81
82void luaF_freeupval (lua_State *L, UpVal *uv) {
83  if (uv->v != &uv->u.value)  /* is it open? */
84    unlinkupval(uv);  /* remove from open list */
85  luaM_free(L, uv);  /* free upvalue */
86}
87
88
89void luaF_close (lua_State *L, StkId level) {
90  UpVal *uv;
91  global_State *g = G(L);
92  while (L->openupval != NULL && (uv = gco2uv(L->openupval))->v >= level) {
93    GCObject *o = obj2gco(uv);
94    lua_assert(!isblack(o) && uv->v != &uv->u.value);
95    L->openupval = uv->next;  /* remove from `open' list */
96    if (isdead(g, o))
97      luaF_freeupval(L, uv);  /* free upvalue */
98    else {
99      unlinkupval(uv);  /* remove upvalue from 'uvhead' list */
100      setobj(L, &uv->u.value, uv->v);  /* move value to upvalue slot */
101      uv->v = &uv->u.value;  /* now current value lives here */
102      gch(o)->next = g->allgc;  /* link upvalue into 'allgc' list */
103      g->allgc = o;
104      luaC_checkupvalcolor(g, uv);
105    }
106  }
107}
108
109
110Proto *luaF_newproto (lua_State *L) {
111  Proto *f = &luaC_newobj(L, LUA_TPROTO, sizeof(Proto), NULL, 0)->p;
112  f->k = NULL;
113  f->sizek = 0;
114  f->p = NULL;
115  f->sizep = 0;
116  f->code = NULL;
117  f->cache = NULL;
118  f->sizecode = 0;
119  f->lineinfo = NULL;
120  f->sizelineinfo = 0;
121  f->upvalues = NULL;
122  f->sizeupvalues = 0;
123  f->numparams = 0;
124  f->is_vararg = 0;
125  f->maxstacksize = 0;
126  f->locvars = NULL;
127  f->sizelocvars = 0;
128  f->linedefined = 0;
129  f->lastlinedefined = 0;
130  f->source = NULL;
131  return f;
132}
133
134
135void luaF_freeproto (lua_State *L, Proto *f) {
136  luaM_freearray(L, f->code, f->sizecode);
137  luaM_freearray(L, f->p, f->sizep);
138  luaM_freearray(L, f->k, f->sizek);
139  luaM_freearray(L, f->lineinfo, f->sizelineinfo);
140  luaM_freearray(L, f->locvars, f->sizelocvars);
141  luaM_freearray(L, f->upvalues, f->sizeupvalues);
142  luaM_free(L, f);
143}
144
145
146/*
147** Look for n-th local variable at line `line' in function `func'.
148** Returns NULL if not found.
149*/
150const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
151  int i;
152  for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
153    if (pc < f->locvars[i].endpc) {  /* is variable active? */
154      local_number--;
155      if (local_number == 0)
156        return getstr(f->locvars[i].varname);
157    }
158  }
159  return NULL;  /* not found */
160}
161
162