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  1. /*
  2. ** $Id: lfunc.c,v 2.27 2010/06/30 14:11:17 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_TFUNCTION, sizeCclosure(n), NULL, 0)->cl;
  25.   c->c.isC = 1;
  26.   c->c.nupvalues = cast_byte(n);
  27.   return c;
  28. }
  29.  
  30.  
  31. Closure *luaF_newLclosure (lua_State *L, Proto *p) {
  32.   int n = p->sizeupvalues;
  33.   Closure *c = &luaC_newobj(L, LUA_TFUNCTION, sizeLclosure(n), NULL, 0)->cl;
  34.   c->l.isC = 0;
  35.   c->l.p = p;
  36.   c->l.nupvalues = cast_byte(n);
  37.   while (n--) c->l.upvals[n] = NULL;
  38.   return c;
  39. }
  40.  
  41.  
  42. UpVal *luaF_newupval (lua_State *L) {
  43.   UpVal *uv = &luaC_newobj(L, LUA_TUPVAL, sizeof(UpVal), NULL, 0)->uv;
  44.   uv->v = &uv->u.value;
  45.   setnilvalue(uv->v);
  46.   return uv;
  47. }
  48.  
  49.  
  50. UpVal *luaF_findupval (lua_State *L, StkId level) {
  51.   global_State *g = G(L);
  52.   GCObject **pp = &L->openupval;
  53.   UpVal *p;
  54.   UpVal *uv;
  55.   while (*pp != NULL && (p = gco2uv(*pp))->v >= level) {
  56.     GCObject *o = obj2gco(p);
  57.     lua_assert(p->v != &p->u.value);
  58.     if (p->v == level) {  /* found a corresponding upvalue? */
  59.       if (isdead(g, o))  /* is it dead? */
  60.         changewhite(o);  /* resurrect it */
  61.       return p;
  62.     }
  63.     resetoldbit(o);  /* may create a newer upval after this one */
  64.     pp = &p->next;
  65.   }
  66.   /* not found: create a new one */
  67.   uv = &luaC_newobj(L, LUA_TUPVAL, sizeof(UpVal), pp, 0)->uv;
  68.   uv->v = level;  /* current value lives in the stack */
  69.   uv->u.l.prev = &g->uvhead;  /* double link it in `uvhead' list */
  70.   uv->u.l.next = g->uvhead.u.l.next;
  71.   uv->u.l.next->u.l.prev = uv;
  72.   g->uvhead.u.l.next = uv;
  73.   lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
  74.   return uv;
  75. }
  76.  
  77.  
  78. static void unlinkupval (UpVal *uv) {
  79.   lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
  80.   uv->u.l.next->u.l.prev = uv->u.l.prev;  /* remove from `uvhead' list */
  81.   uv->u.l.prev->u.l.next = uv->u.l.next;
  82. }
  83.  
  84.  
  85. void luaF_freeupval (lua_State *L, UpVal *uv) {
  86.   if (uv->v != &uv->u.value)  /* is it open? */
  87.     unlinkupval(uv);  /* remove from open list */
  88.   luaM_free(L, uv);  /* free upvalue */
  89. }
  90.  
  91.  
  92. void luaF_close (lua_State *L, StkId level) {
  93.   UpVal *uv;
  94.   global_State *g = G(L);
  95.   while (L->openupval != NULL && (uv = gco2uv(L->openupval))->v >= level) {
  96.     GCObject *o = obj2gco(uv);
  97.     lua_assert(!isblack(o) && uv->v != &uv->u.value);
  98.     L->openupval = uv->next;  /* remove from `open' list */
  99.     if (isdead(g, o))
  100.       luaF_freeupval(L, uv);  /* free upvalue */
  101.     else {
  102.       unlinkupval(uv);  /* remove upvalue from 'uvhead' list */
  103.       setobj(L, &uv->u.value, uv->v);  /* move value to upvalue slot */
  104.       uv->v = &uv->u.value;  /* now current value lives here */
  105.       gch(o)->next = g->allgc;  /* link upvalue into 'allgc' list */
  106.       g->allgc = o;
  107.       luaC_checkupvalcolor(g, uv);
  108.     }
  109.   }
  110. }
  111.  
  112.  
  113. Proto *luaF_newproto (lua_State *L) {
  114.   Proto *f = &luaC_newobj(L, LUA_TPROTO, sizeof(Proto), NULL, 0)->p;
  115.   f->k = NULL;
  116.   f->sizek = 0;
  117.   f->p = NULL;
  118.   f->sizep = 0;
  119.   f->code = NULL;
  120.   f->cache = NULL;
  121.   f->sizecode = 0;
  122.   f->lineinfo = NULL;
  123.   f->sizelineinfo = 0;
  124.   f->upvalues = NULL;
  125.   f->sizeupvalues = 0;
  126.   f->numparams = 0;
  127.   f->is_vararg = 0;
  128.   f->maxstacksize = 0;
  129.   f->locvars = NULL;
  130.   f->sizelocvars = 0;
  131.   f->linedefined = 0;
  132.   f->lastlinedefined = 0;
  133.   f->source = NULL;
  134.   return f;
  135. }
  136.  
  137.  
  138. void luaF_freeproto (lua_State *L, Proto *f) {
  139.   luaM_freearray(L, f->code, f->sizecode);
  140.   luaM_freearray(L, f->p, f->sizep);
  141.   luaM_freearray(L, f->k, f->sizek);
  142.   luaM_freearray(L, f->lineinfo, f->sizelineinfo);
  143.   luaM_freearray(L, f->locvars, f->sizelocvars);
  144.   luaM_freearray(L, f->upvalues, f->sizeupvalues);
  145.   luaM_free(L, f);
  146. }
  147.  
  148.  
  149. void luaF_freeclosure (lua_State *L, Closure *c) {
  150.   int size = (c->c.isC) ? sizeCclosure(c->c.nupvalues) :
  151.                           sizeLclosure(c->l.nupvalues);
  152.   luaM_freemem(L, c, size);
  153. }
  154.  
  155.  
  156. /*
  157. ** Look for n-th local variable at line `line' in function `func'.
  158. ** Returns NULL if not found.
  159. */
  160. const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
  161.   int i;
  162.   for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
  163.     if (pc < f->locvars[i].endpc) {  /* is variable active? */
  164.       local_number--;
  165.       if (local_number == 0)
  166.         return getstr(f->locvars[i].varname);
  167.     }
  168.   }
  169.   return NULL;  /* not found */
  170. }
  171.  
  172.