lua/lfunc.c
author Ryan C. Gordon <icculus@icculus.org>
Sun, 18 Jun 2017 19:50:43 -0400
changeset 57 4974e5368a29
parent 0 d7ee4e2ed49d
permissions -rw-r--r--
Minor type cleanup ("unsigned char" -> "uint8_t").
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/*
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** $Id: lfunc.c,v 2.30.1.1 2013/04/12 18:48:47 roberto Exp $
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** Auxiliary functions to manipulate prototypes and closures
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** See Copyright Notice in lua.h
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*/
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#include <stddef.h>
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#define lfunc_c
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#define LUA_CORE
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#include "lua.h"
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#include "lfunc.h"
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#include "lgc.h"
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#include "lmem.h"
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#include "lobject.h"
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#include "lstate.h"
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Closure *luaF_newCclosure (lua_State *L, int n) {
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  Closure *c = &luaC_newobj(L, LUA_TCCL, sizeCclosure(n), NULL, 0)->cl;
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  c->c.nupvalues = cast_byte(n);
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  return c;
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}
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Closure *luaF_newLclosure (lua_State *L, int n) {
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  Closure *c = &luaC_newobj(L, LUA_TLCL, sizeLclosure(n), NULL, 0)->cl;
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  c->l.p = NULL;
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  c->l.nupvalues = cast_byte(n);
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  while (n--) c->l.upvals[n] = NULL;
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  return c;
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}
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UpVal *luaF_newupval (lua_State *L) {
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  UpVal *uv = &luaC_newobj(L, LUA_TUPVAL, sizeof(UpVal), NULL, 0)->uv;
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  uv->v = &uv->u.value;
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  setnilvalue(uv->v);
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  return uv;
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}
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UpVal *luaF_findupval (lua_State *L, StkId level) {
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  global_State *g = G(L);
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  GCObject **pp = &L->openupval;
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  UpVal *p;
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  UpVal *uv;
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  while (*pp != NULL && (p = gco2uv(*pp))->v >= level) {
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    GCObject *o = obj2gco(p);
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    lua_assert(p->v != &p->u.value);
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    lua_assert(!isold(o) || isold(obj2gco(L)));
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    if (p->v == level) {  /* found a corresponding upvalue? */
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      if (isdead(g, o))  /* is it dead? */
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        changewhite(o);  /* resurrect it */
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      return p;
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    }
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    pp = &p->next;
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  }
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  /* not found: create a new one */
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  uv = &luaC_newobj(L, LUA_TUPVAL, sizeof(UpVal), pp, 0)->uv;
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  uv->v = level;  /* current value lives in the stack */
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  uv->u.l.prev = &g->uvhead;  /* double link it in `uvhead' list */
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  uv->u.l.next = g->uvhead.u.l.next;
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  uv->u.l.next->u.l.prev = uv;
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  g->uvhead.u.l.next = uv;
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  lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
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  return uv;
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}
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static void unlinkupval (UpVal *uv) {
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  lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
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  uv->u.l.next->u.l.prev = uv->u.l.prev;  /* remove from `uvhead' list */
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  uv->u.l.prev->u.l.next = uv->u.l.next;
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}
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void luaF_freeupval (lua_State *L, UpVal *uv) {
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  if (uv->v != &uv->u.value)  /* is it open? */
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    unlinkupval(uv);  /* remove from open list */
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  luaM_free(L, uv);  /* free upvalue */
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}
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void luaF_close (lua_State *L, StkId level) {
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  UpVal *uv;
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  global_State *g = G(L);
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  while (L->openupval != NULL && (uv = gco2uv(L->openupval))->v >= level) {
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    GCObject *o = obj2gco(uv);
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    lua_assert(!isblack(o) && uv->v != &uv->u.value);
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    L->openupval = uv->next;  /* remove from `open' list */
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    if (isdead(g, o))
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      luaF_freeupval(L, uv);  /* free upvalue */
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    else {
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      unlinkupval(uv);  /* remove upvalue from 'uvhead' list */
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      setobj(L, &uv->u.value, uv->v);  /* move value to upvalue slot */
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      uv->v = &uv->u.value;  /* now current value lives here */
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      gch(o)->next = g->allgc;  /* link upvalue into 'allgc' list */
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      g->allgc = o;
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      luaC_checkupvalcolor(g, uv);
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    }
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  }
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}
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Proto *luaF_newproto (lua_State *L) {
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  Proto *f = &luaC_newobj(L, LUA_TPROTO, sizeof(Proto), NULL, 0)->p;
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  f->k = NULL;
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  f->sizek = 0;
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  f->p = NULL;
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  f->sizep = 0;
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  f->code = NULL;
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  f->cache = NULL;
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  f->sizecode = 0;
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  f->lineinfo = NULL;
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  f->sizelineinfo = 0;
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  f->upvalues = NULL;
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  f->sizeupvalues = 0;
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  f->numparams = 0;
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  f->is_vararg = 0;
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  f->maxstacksize = 0;
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  f->locvars = NULL;
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  f->sizelocvars = 0;
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  f->linedefined = 0;
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  f->lastlinedefined = 0;
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  f->source = NULL;
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  return f;
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}
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void luaF_freeproto (lua_State *L, Proto *f) {
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  luaM_freearray(L, f->code, f->sizecode);
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  luaM_freearray(L, f->p, f->sizep);
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  luaM_freearray(L, f->k, f->sizek);
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  luaM_freearray(L, f->lineinfo, f->sizelineinfo);
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  luaM_freearray(L, f->locvars, f->sizelocvars);
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  luaM_freearray(L, f->upvalues, f->sizeupvalues);
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  luaM_free(L, f);
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}
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/*
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** Look for n-th local variable at line `line' in function `func'.
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** Returns NULL if not found.
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*/
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const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
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  int i;
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  for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
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    if (pc < f->locvars[i].endpc) {  /* is variable active? */
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      local_number--;
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      if (local_number == 0)
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        return getstr(f->locvars[i].varname);
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    }
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  }
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  return NULL;  /* not found */
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}
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