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  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.  
  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.  
  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. */
  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.  
  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.  
  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.  
  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.  
  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. */
  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.