/src/middleware/lua/lfunc.c

  1/*
  2** $Id: lfunc.c,v 2.12.1.2 2007/12/28 14:58:43 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
 23Closure *luaF_newCclosure (lua_State *L, int nelems, Table *e) {
 24  Closure *c = cast(Closure *, luaM_malloc(L, sizeCclosure(nelems)));
 25  luaC_link(L, obj2gco(c), LUA_TFUNCTION);
 26  c->c.isC = 1;
 27  c->c.env = e;
 28  c->c.nupvalues = cast_byte(nelems);
 29  return c;
 30}
 31
 32
 33Closure *luaF_newLclosure (lua_State *L, int nelems, Table *e) {
 34  Closure *c = cast(Closure *, luaM_malloc(L, sizeLclosure(nelems)));
 35  luaC_link(L, obj2gco(c), LUA_TFUNCTION);
 36  c->l.isC = 0;
 37  c->l.env = e;
 38  c->l.nupvalues = cast_byte(nelems);
 39  while (nelems--) c->l.upvals[nelems] = NULL;
 40  return c;
 41}
 42
 43
 44UpVal *luaF_newupval (lua_State *L) {
 45  UpVal *uv = luaM_new(L, UpVal);
 46  luaC_link(L, obj2gco(uv), LUA_TUPVAL);
 47  uv->v = &uv->u.value;
 48  setnilvalue(uv->v);
 49  return uv;
 50}
 51
 52
 53UpVal *luaF_findupval (lua_State *L, StkId level) {
 54  global_State *g = G(L);
 55  GCObject **pp = &L->openupval;
 56  UpVal *p;
 57  UpVal *uv;
 58  while (*pp != NULL && (p = ngcotouv(*pp))->v >= level) {
 59    lua_assert(p->v != &p->u.value);
 60    if (p->v == level) {  /* found a corresponding upvalue? */
 61      if (isdead(g, obj2gco(p)))  /* is it dead? */
 62        changewhite(obj2gco(p));  /* ressurect it */
 63      return p;
 64    }
 65    pp = &p->next;
 66  }
 67  uv = luaM_new(L, UpVal);  /* not found: create a new one */
 68  uv->tt = LUA_TUPVAL;
 69  uv->marked = luaC_white(g);
 70  uv->v = level;  /* current value lives in the stack */
 71  uv->next = *pp;  /* chain it in the proper position */
 72  *pp = obj2gco(uv);
 73  uv->u.l.prev = &g->uvhead;  /* double link it in `uvhead' list */
 74  uv->u.l.next = g->uvhead.u.l.next;
 75  uv->u.l.next->u.l.prev = uv;
 76  g->uvhead.u.l.next = uv;
 77  lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
 78  return uv;
 79}
 80
 81
 82static void unlinkupval (UpVal *uv) {
 83  lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
 84  uv->u.l.next->u.l.prev = uv->u.l.prev;  /* remove from `uvhead' list */
 85  uv->u.l.prev->u.l.next = uv->u.l.next;
 86}
 87
 88
 89void luaF_freeupval (lua_State *L, UpVal *uv) {
 90  if (uv->v != &uv->u.value)  /* is it open? */
 91    unlinkupval(uv);  /* remove from open list */
 92  luaM_free(L, uv);  /* free upvalue */
 93}
 94
 95
 96void luaF_close (lua_State *L, StkId level) {
 97  UpVal *uv;
 98  global_State *g = G(L);
 99  while (L->openupval != NULL && (uv = ngcotouv(L->openupval))->v >= level) {
100    GCObject *o = obj2gco(uv);
101    lua_assert(!isblack(o) && uv->v != &uv->u.value);
102    L->openupval = uv->next;  /* remove from `open' list */
103    if (isdead(g, o))
104      luaF_freeupval(L, uv);  /* free upvalue */
105    else {
106      unlinkupval(uv);
107      setobj(L, &uv->u.value, uv->v);
108      uv->v = &uv->u.value;  /* now current value lives here */
109      luaC_linkupval(L, uv);  /* link upvalue into `gcroot' list */
110    }
111  }
112}
113
114
115Proto *luaF_newproto (lua_State *L) {
116  Proto *f = luaM_new(L, Proto);
117  luaC_link(L, obj2gco(f), LUA_TPROTO);
118  f->k = NULL;
119  f->sizek = 0;
120  f->p = NULL;
121  f->sizep = 0;
122  f->code = NULL;
123  f->sizecode = 0;
124  f->sizelineinfo = 0;
125  f->sizeupvalues = 0;
126  f->nups = 0;
127  f->upvalues = NULL;
128  f->numparams = 0;
129  f->is_vararg = 0;
130  f->maxstacksize = 0;
131  f->lineinfo = NULL;
132  f->sizelocvars = 0;
133  f->locvars = NULL;
134  f->linedefined = 0;
135  f->lastlinedefined = 0;
136  f->source = NULL;
137  return f;
138}
139
140
141void luaF_freeproto (lua_State *L, Proto *f) {
142  luaM_freearray(L, f->code, f->sizecode, Instruction);
143  luaM_freearray(L, f->p, f->sizep, Proto *);
144  luaM_freearray(L, f->k, f->sizek, TValue);
145  luaM_freearray(L, f->lineinfo, f->sizelineinfo, int);
146  luaM_freearray(L, f->locvars, f->sizelocvars, struct LocVar);
147  luaM_freearray(L, f->upvalues, f->sizeupvalues, TString *);
148  luaM_free(L, f);
149}
150
151
152void luaF_freeclosure (lua_State *L, Closure *c) {
153  int size = (c->c.isC) ? sizeCclosure(c->c.nupvalues) :
154                          sizeLclosure(c->l.nupvalues);
155  luaM_freemem(L, c, size);
156}
157
158
159/*
160** Look for n-th local variable at line `line' in function `func'.
161** Returns NULL if not found.
162*/
163const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
164  int i;
165  for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
166    if (pc < f->locvars[i].endpc) {  /* is variable active? */
167      local_number--;
168      if (local_number == 0)
169        return getstr(f->locvars[i].varname);
170    }
171  }
172  return NULL;  /* not found */
173}
174