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 
luaF_newCclosure(lua_State * L,int n)25 CClosure *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 
luaF_newLclosure(lua_State * L,int n)33 LClosure *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 */
luaF_initupvals(lua_State * L,LClosure * cl)45 void 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 
luaF_findupval(lua_State * L,StkId level)57 UpVal *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 
luaF_close(lua_State * L,StkId level)83 void 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 
luaF_newproto(lua_State * L)99 Proto *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 
luaF_freeproto(lua_State * L,Proto * f)125 void 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 */
luaF_getlocalname(const Proto * f,int local_number,int pc)140 const 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