Lua 5.1.4: lfunc.c


L0001    /*
L0002    ** $Id: lfunc.c,v 2.12.1.2 2007/12/28 14:58:43 roberto Exp $
L0003    ** Auxiliary functions to manipulate prototypes and closures
L0004    ** See Copyright Notice in lua.h
L0005    */
L0006    
L0007    
L0008    #include <stddef.h>
L0009    
L0010    #define lfunc_c
L0011    #define LUA_CORE
L0012    
L0013    #include "lua.h"
L0014    
L0015    #include "lfunc.h"
L0016    #include "lgc.h"
L0017    #include "lmem.h"
L0018    #include "lobject.h"
L0019    #include "lstate.h"
L0020    
L0021    
L0022    
L0023    Closure *luaF_newCclosure (lua_State *L, int nelems, Table *e) {
L0024      Closure *c = cast(Closure *, luaM_malloc(L, sizeCclosure(nelems)));
L0025      luaC_link(L, obj2gco(c), LUA_TFUNCTION);
L0026      c->c.isC = 1;
L0027      c->c.env = e;
L0028      c->c.nupvalues = cast_byte(nelems);
L0029      return c;
L0030    }
L0031    
L0032    
L0033    Closure *luaF_newLclosure (lua_State *L, int nelems, Table *e) {
L0034      Closure *c = cast(Closure *, luaM_malloc(L, sizeLclosure(nelems)));
L0035      luaC_link(L, obj2gco(c), LUA_TFUNCTION);
L0036      c->l.isC = 0;
L0037      c->l.env = e;
L0038      c->l.nupvalues = cast_byte(nelems);
L0039      while (nelems--) c->l.upvals[nelems] = NULL;
L0040      return c;
L0041    }
L0042    
L0043    
L0044    UpVal *luaF_newupval (lua_State *L) {
L0045      UpVal *uv = luaM_new(L, UpVal);
L0046      luaC_link(L, obj2gco(uv), LUA_TUPVAL);
L0047      uv->v = &uv->u.value;
L0048      setnilvalue(uv->v);
L0049      return uv;
L0050    }
L0051    
L0052    
L0053    UpVal *luaF_findupval (lua_State *L, StkId level) {
L0054      global_State *g = G(L);
L0055      GCObject **pp = &L->openupval;
L0056      UpVal *p;
L0057      UpVal *uv;
L0058      while (*pp != NULL && (p = ngcotouv(*pp))->v >= level) {
L0059        lua_assert(p->v != &p->u.value);
L0060        if (p->v == level) {  /* found a corresponding upvalue? */
L0061          if (isdead(g, obj2gco(p)))  /* is it dead? */
L0062            changewhite(obj2gco(p));  /* ressurect it */
L0063          return p;
L0064        }
L0065        pp = &p->next;
L0066      }
L0067      uv = luaM_new(L, UpVal);  /* not found: create a new one */
L0068      uv->tt = LUA_TUPVAL;
L0069      uv->marked = luaC_white(g);
L0070      uv->v = level;  /* current value lives in the stack */
L0071      uv->next = *pp;  /* chain it in the proper position */
L0072      *pp = obj2gco(uv);
L0073      uv->u.l.prev = &g->uvhead;  /* double link it in `uvhead' list */
L0074      uv->u.l.next = g->uvhead.u.l.next;
L0075      uv->u.l.next->u.l.prev = uv;
L0076      g->uvhead.u.l.next = uv;
L0077      lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
L0078      return uv;
L0079    }
L0080    
L0081    
L0082    static void unlinkupval (UpVal *uv) {
L0083      lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
L0084      uv->u.l.next->u.l.prev = uv->u.l.prev;  /* remove from `uvhead' list */
L0085      uv->u.l.prev->u.l.next = uv->u.l.next;
L0086    }
L0087    
L0088    
L0089    void luaF_freeupval (lua_State *L, UpVal *uv) {
L0090      if (uv->v != &uv->u.value)  /* is it open? */
L0091        unlinkupval(uv);  /* remove from open list */
L0092      luaM_free(L, uv);  /* free upvalue */
L0093    }
L0094    
L0095    
L0096    void luaF_close (lua_State *L, StkId level) {
L0097      UpVal *uv;
L0098      global_State *g = G(L);
L0099      while (L->openupval != NULL && (uv = ngcotouv(L->openupval))->v >= level) {
L0100        GCObject *o = obj2gco(uv);
L0101        lua_assert(!isblack(o) && uv->v != &uv->u.value);
L0102        L->openupval = uv->next;  /* remove from `open' list */
L0103        if (isdead(g, o))
L0104          luaF_freeupval(L, uv);  /* free upvalue */
L0105        else {
L0106          unlinkupval(uv);
L0107          setobj(L, &uv->u.value, uv->v);
L0108          uv->v = &uv->u.value;  /* now current value lives here */
L0109          luaC_linkupval(L, uv);  /* link upvalue into `gcroot' list */
L0110        }
L0111      }
L0112    }
L0113    
L0114    
L0115    Proto *luaF_newproto (lua_State *L) {
L0116      Proto *f = luaM_new(L, Proto);
L0117      luaC_link(L, obj2gco(f), LUA_TPROTO);
L0118      f->k = NULL;
L0119      f->sizek = 0;
L0120      f->p = NULL;
L0121      f->sizep = 0;
L0122      f->code = NULL;
L0123      f->sizecode = 0;
L0124      f->sizelineinfo = 0;
L0125      f->sizeupvalues = 0;
L0126      f->nups = 0;
L0127      f->upvalues = NULL;
L0128      f->numparams = 0;
L0129      f->is_vararg = 0;
L0130      f->maxstacksize = 0;
L0131      f->lineinfo = NULL;
L0132      f->sizelocvars = 0;
L0133      f->locvars = NULL;
L0134      f->linedefined = 0;
L0135      f->lastlinedefined = 0;
L0136      f->source = NULL;
L0137      return f;
L0138    }
L0139    
L0140    
L0141    void luaF_freeproto (lua_State *L, Proto *f) {
L0142      luaM_freearray(L, f->code, f->sizecode, Instruction);
L0143      luaM_freearray(L, f->p, f->sizep, Proto *);
L0144      luaM_freearray(L, f->k, f->sizek, TValue);
L0145      luaM_freearray(L, f->lineinfo, f->sizelineinfo, int);
L0146      luaM_freearray(L, f->locvars, f->sizelocvars, struct LocVar);
L0147      luaM_freearray(L, f->upvalues, f->sizeupvalues, TString *);
L0148      luaM_free(L, f);
L0149    }
L0150    
L0151    
L0152    void luaF_freeclosure (lua_State *L, Closure *c) {
L0153      int size = (c->c.isC) ? sizeCclosure(c->c.nupvalues) :
L0154                              sizeLclosure(c->l.nupvalues);
L0155      luaM_freemem(L, c, size);
L0156    }
L0157    
L0158    
L0159    /*
L0160    ** Look for n-th local variable at line `line' in function `func'.
L0161    ** Returns NULL if not found.
L0162    */
L0163    const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
L0164      int i;
L0165      for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
L0166        if (pc < f->locvars[i].endpc) {  /* is variable active? */
L0167          local_number--;
L0168          if (local_number == 0)
L0169            return getstr(f->locvars[i].varname);
L0170        }
L0171      }
L0172      return NULL;  /* not found */
L0173    }
L0174    

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