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  1. /*
  2. ** $Id: lfunc.c,v 2.30.1.1 2013/04/12 18:48:47 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.  
  23. Closure *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.  
  30. Closure *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.  
  39. UpVal *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.  
  47. UpVal *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.  
  75. static 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.  
  82. void 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.  
  89. void 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.  
  110. Proto *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.  
  135. void 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. */
  150. const 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.