module/lua/lfunc.c

   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 #define lfunc_c
   9 #define LUA_CORE
  10
  11 #include <sys/lua/lua.h>
  12
  13 #include "lfunc.h"
  14 #include "lgc.h"
  15 #include "lmem.h"
  16 #include "lobject.h"
  17 #include "lstate.h"
  18
  19
  20
  21 Closure *luaF_newCclosure (lua_State *L, int n) {
  22   Closure *c = &luaC_newobj(L, LUA_TCCL, sizeCclosure(n), NULL, 0)->cl;
  23   c->c.nupvalues = cast_byte(n);
  24   return c;
  25 }
  26
  27
  28 Closure *luaF_newLclosure (lua_State *L, int n) {
  29   Closure *c = &luaC_newobj(L, LUA_TLCL, sizeLclosure(n), NULL, 0)->cl;
  30   c->l.p = NULL;
  31   c->l.nupvalues = cast_byte(n);
  32   while (n--) c->l.upvals[n] = NULL;
  33   return c;
  34 }
  35
  36
  37 UpVal *luaF_newupval (lua_State *L) {
  38   UpVal *uv = &luaC_newobj(L, LUA_TUPVAL, sizeof(UpVal), NULL, 0)->uv;
  39   uv->v = &uv->u.value;
  40   setnilvalue(uv->v);
  41   return uv;
  42 }
  43
  44
  45 UpVal *luaF_findupval (lua_State *L, StkId level) {
  46   global_State *g = G(L);
  47   GCObject **pp = &L->openupval;
  48   UpVal *p;
  49   UpVal *uv;
  50   while (*pp != NULL && (p = gco2uv(*pp))->v >= level) {
  51     GCObject *o = obj2gco(p);
  52     lua_assert(p->v != &p->u.value);
  53     lua_assert(!isold(o) || isold(obj2gco(L)));
  54     if (p->v == level) {  /* found a corresponding upvalue? */
  55       if (isdead(g, o))  /* is it dead? */
  56         changewhite(o);  /* resurrect it */
  57       return p;
  58     }
  59     pp = &p->next;
  60   }
  61   /* not found: create a new one */
  62   uv = &luaC_newobj(L, LUA_TUPVAL, sizeof(UpVal), pp, 0)->uv;
  63   uv->v = level;  /* current value lives in the stack */
  64   uv->u.l.prev = &g->uvhead;  /* double link it in `uvhead' list */
  65   uv->u.l.next = g->uvhead.u.l.next;
  66   uv->u.l.next->u.l.prev = uv;
  67   g->uvhead.u.l.next = uv;
  68   lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
  69   return uv;
  70 }
  71
  72
  73 static void unlinkupval (UpVal *uv) {
  74   lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
  75   uv->u.l.next->u.l.prev = uv->u.l.prev;  /* remove from `uvhead' list */
  76   uv->u.l.prev->u.l.next = uv->u.l.next;
  77 }
  78
  79
  80 void luaF_freeupval (lua_State *L, UpVal *uv) {
  81   if (uv->v != &uv->u.value)  /* is it open? */
  82     unlinkupval(uv);  /* remove from open list */
  83   luaM_free(L, uv);  /* free upvalue */
  84 }
  85
  86
  87 void luaF_close (lua_State *L, StkId level) {
  88   UpVal *uv;
  89   global_State *g = G(L);
  90   while (L->openupval != NULL && (uv = gco2uv(L->openupval))->v >= level) {
  91     GCObject *o = obj2gco(uv);
  92     lua_assert(!isblack(o) && uv->v != &uv->u.value);
  93     L->openupval = uv->next;  /* remove from `open' list */
  94     if (isdead(g, o))
  95       luaF_freeupval(L, uv);  /* free upvalue */
  96     else {
  97       unlinkupval(uv);  /* remove upvalue from 'uvhead' list */
  98       setobj(L, &uv->u.value, uv->v);  /* move value to upvalue slot */
  99       uv->v = &uv->u.value;  /* now current value lives here */
 100       gch(o)->next = g->allgc;  /* link upvalue into 'allgc' list */
 101       g->allgc = o;
 102       luaC_checkupvalcolor(g, uv);
 103     }
 104   }
 105 }
 106
 107
 108 Proto *luaF_newproto (lua_State *L) {
 109   Proto *f = &luaC_newobj(L, LUA_TPROTO, sizeof(Proto), NULL, 0)->p;
 110   f->k = NULL;
 111   f->sizek = 0;
 112   f->p = NULL;
 113   f->sizep = 0;
 114   f->code = NULL;
 115   f->cache = NULL;
 116   f->sizecode = 0;
 117   f->lineinfo = NULL;
 118   f->sizelineinfo = 0;
 119   f->upvalues = NULL;
 120   f->sizeupvalues = 0;
 121   f->numparams = 0;
 122   f->is_vararg = 0;
 123   f->maxstacksize = 0;
 124   f->locvars = NULL;
 125   f->sizelocvars = 0;
 126   f->linedefined = 0;
 127   f->lastlinedefined = 0;
 128   f->source = NULL;
 129   return f;
 130 }
 131
 132
 133 void luaF_freeproto (lua_State *L, Proto *f) {
 134   luaM_freearray(L, f->code, f->sizecode);
 135   luaM_freearray(L, f->p, f->sizep);
 136   luaM_freearray(L, f->k, f->sizek);
 137   luaM_freearray(L, f->lineinfo, f->sizelineinfo);
 138   luaM_freearray(L, f->locvars, f->sizelocvars);
 139   luaM_freearray(L, f->upvalues, f->sizeupvalues);
 140   luaM_free(L, f);
 141 }
 142
 143
 144 /*
 145 ** Look for n-th local variable at line `line' in function `func'.
 146 ** Returns NULL if not found.
 147 */
 148 const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
 149   int i;
 150   for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
 151     if (pc < f->locvars[i].endpc) {  /* is variable active? */
 152       local_number--;
 153       if (local_number == 0)
 154         return getstr(f->locvars[i].varname);
 155     }
 156   }
 157   return NULL;  /* not found */
 158 }