lfunc.c revision 344220 
1/*
2** $Id: lfunc.c,v 2.45.1.1 2017/04/19 17:39:34 roberto Exp $
3** Auxiliary functions to manipulate prototypes and closures
4** See Copyright Notice in lua.h
5*/
6
7#define lfunc_c
8#define LUA_CORE
9
10#include "lprefix.h"
11
12
13#include <stddef.h>
14
15#include "lua.h"
16
17#include "lfunc.h"
18#include "lgc.h"
19#include "lmem.h"
20#include "lobject.h"
21#include "lstate.h"
22
23
24
25CClosure *luaF_newCclosure (lua_State *L, int n) {
26  GCObject *o = luaC_newobj(L, LUA_TCCL, sizeCclosure(n));
27  CClosure *c = gco2ccl(o);
28  c->nupvalues = cast_byte(n);
29  return c;
30}
31
32
33LClosure *luaF_newLclosure (lua_State *L, int n) {
34  GCObject *o = luaC_newobj(L, LUA_TLCL, sizeLclosure(n));
35  LClosure *c = gco2lcl(o);
36  c->p = NULL;
37  c->nupvalues = cast_byte(n);
38  while (n--) c->upvals[n] = NULL;
39  return c;
40}
41
42/*
43** fill a closure with new closed upvalues
44*/
45void luaF_initupvals (lua_State *L, LClosure *cl) {
46  int i;
47  for (i = 0; i < cl->nupvalues; i++) {
48    UpVal *uv = luaM_new(L, UpVal);
49    uv->refcount = 1;
50    uv->v = &uv->u.value;  /* make it closed */
51    setnilvalue(uv->v);
52    cl->upvals[i] = uv;
53  }
54}
55
56
57UpVal *luaF_findupval (lua_State *L, StkId level) {
58  UpVal **pp = &L->openupval;
59  UpVal *p;
60  UpVal *uv;
61  lua_assert(isintwups(L) || L->openupval == NULL);
62  while (*pp != NULL && (p = *pp)->v >= level) {
63    lua_assert(upisopen(p));
64    if (p->v == level)  /* found a corresponding upvalue? */
65      return p;  /* return it */
66    pp = &p->u.open.next;
67  }
68  /* not found: create a new upvalue */
69  uv = luaM_new(L, UpVal);
70  uv->refcount = 0;
71  uv->u.open.next = *pp;  /* link it to list of open upvalues */
72  uv->u.open.touched = 1;
73  *pp = uv;
74  uv->v = level;  /* current value lives in the stack */
75  if (!isintwups(L)) {  /* thread not in list of threads with upvalues? */
76    L->twups = G(L)->twups;  /* link it to the list */
77    G(L)->twups = L;
78  }
79  return uv;
80}
81
82
83void luaF_close (lua_State *L, StkId level) {
84  UpVal *uv;
85  while (L->openupval != NULL && (uv = L->openupval)->v >= level) {
86    lua_assert(upisopen(uv));
87    L->openupval = uv->u.open.next;  /* remove from 'open' list */
88    if (uv->refcount == 0)  /* no references? */
89      luaM_free(L, uv);  /* free upvalue */
90    else {
91      setobj(L, &uv->u.value, uv->v);  /* move value to upvalue slot */
92      uv->v = &uv->u.value;  /* now current value lives here */
93      luaC_upvalbarrier(L, uv);
94    }
95  }
96}
97
98
99Proto *luaF_newproto (lua_State *L) {
100  GCObject *o = luaC_newobj(L, LUA_TPROTO, sizeof(Proto));
101  Proto *f = gco2p(o);
102  f->k = NULL;
103  f->sizek = 0;
104  f->p = NULL;
105  f->sizep = 0;
106  f->code = NULL;
107  f->cache = NULL;
108  f->sizecode = 0;
109  f->lineinfo = NULL;
110  f->sizelineinfo = 0;
111  f->upvalues = NULL;
112  f->sizeupvalues = 0;
113  f->numparams = 0;
114  f->is_vararg = 0;
115  f->maxstacksize = 0;
116  f->locvars = NULL;
117  f->sizelocvars = 0;
118  f->linedefined = 0;
119  f->lastlinedefined = 0;
120  f->source = NULL;
121  return f;
122}
123
124
125void luaF_freeproto (lua_State *L, Proto *f) {
126  luaM_freearray(L, f->code, f->sizecode);
127  luaM_freearray(L, f->p, f->sizep);
128  luaM_freearray(L, f->k, f->sizek);
129  luaM_freearray(L, f->lineinfo, f->sizelineinfo);
130  luaM_freearray(L, f->locvars, f->sizelocvars);
131  luaM_freearray(L, f->upvalues, f->sizeupvalues);
132  luaM_free(L, f);
133}
134
135
136/*
137** Look for n-th local variable at line 'line' in function 'func'.
138** Returns NULL if not found.
139*/
140const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
141  int i;
142  for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
143    if (pc < f->locvars[i].endpc) {  /* is variable active? */
144      local_number--;
145      if (local_number == 0)
146        return getstr(f->locvars[i].varname);
147    }
148  }
149  return NULL;  /* not found */
150}
151
152