text: /*
  ** $Id: lundump.c,v 2.22.1.1 2013/04/12 18:48:47 roberto Exp $
  ** load precompiled Lua chunks
  ** See Copyright Notice in lua.h
  */
  
  #include <string.h>
  
  #define lundump_c
  #define LUA_CORE
  
  #include "lua.h"
  
  #include "ldebug.h"
  #include "ldo.h"
  #include "lfunc.h"
  #include "lmem.h"
  #include "lobject.h"
  #include "lstring.h"
  #include "lundump.h"
  #include "lzio.h"
  
  typedef struct {
   lua_State* L;
   ZIO* Z;
   Mbuffer* b;
   const char* name;
  } LoadState;
  
  static l_noret error(LoadState* S, const char* why)
  {
   luaO_pushfstring(S->L,"%s: %s precompiled chunk",S->name,why);
   luaD_throw(S->L,LUA_ERRSYNTAX);
  }
  
  #define LoadMem(S,b,n,size)	LoadBlock(S,b,(n)*(size))
  #define LoadByte(S)		(lu_byte)LoadChar(S)
  #define LoadVar(S,x)		LoadMem(S,&x,1,sizeof(x))
  #define LoadVector(S,b,n,size)	LoadMem(S,b,n,size)
  
  #if !defined(luai_verifycode)
  #define luai_verifycode(L,b,f)	/* empty */
  #endif
  
  static void LoadBlock(LoadState* S, void* b, size_t size)
  {
   if (luaZ_read(S->Z,b,size)!=0) error(S,"truncated");
  }
  
  static int LoadChar(LoadState* S)
  {
   char x;
   LoadVar(S,x);
   return x;
  }
  
  static int LoadInt(LoadState* S)
  {
   int x;
   LoadVar(S,x);
   if (x<0) error(S,"corrupted");
   return x;
  }
  
  static lua_Number LoadNumber(LoadState* S)
  {
   lua_Number x;
   LoadVar(S,x);
   return x;
  }
  
  static TString* LoadString(LoadState* S)
  {
   size_t size;
   LoadVar(S,size);
   if (size==0)
    return NULL;
   else
   {
    char* s=luaZ_openspace(S->L,S->b,size);
    LoadBlock(S,s,size*sizeof(char));
    return luaS_newlstr(S->L,s,size-1);		/* remove trailing '\0' */
   }
  }
  
  static void LoadCode(LoadState* S, Proto* f)
  {
   int n=LoadInt(S);
   f->code=luaM_newvector(S->L,n,Instruction);
   f->sizecode=n;
   LoadVector(S,f->code,n,sizeof(Instruction));
  }
  
  static void LoadFunction(LoadState* S, Proto* f);
  
  static void LoadConstants(LoadState* S, Proto* f)
  {
   int i,n;
   n=LoadInt(S);
   f->k=luaM_newvector(S->L,n,TValue);
   f->sizek=n;
   for (i=0; i<n; i++) setnilvalue(&f->k[i]);
   for (i=0; i<n; i++)
   {
    TValue* o=&f->k[i];
    int t=LoadChar(S);
    switch (t)
    {
     case LUA_TNIL:
  	setnilvalue(o);
  	break;
     case LUA_TBOOLEAN:
  	setbvalue(o,LoadChar(S));
  	break;
     case LUA_TNUMBER:
  	setnvalue(o,LoadNumber(S));
  	break;
     case LUA_TSTRING:
  	setsvalue2n(S->L,o,LoadString(S));
  	break;
      default: lua_assert(0);
    }
   }
   n=LoadInt(S);
   f->p=luaM_newvector(S->L,n,Proto*);
   f->sizep=n;
   for (i=0; i<n; i++) f->p[i]=NULL;
   for (i=0; i<n; i++)
   {
    f->p[i]=luaF_newproto(S->L);
    LoadFunction(S,f->p[i]);
   }
  }
  
  static void LoadUpvalues(LoadState* S, Proto* f)
  {
   int i,n;
   n=LoadInt(S);
   f->upvalues=luaM_newvector(S->L,n,Upvaldesc);
   f->sizeupvalues=n;
   for (i=0; i<n; i++) f->upvalues[i].name=NULL;
   for (i=0; i<n; i++)
   {
    f->upvalues[i].instack=LoadByte(S);
    f->upvalues[i].idx=LoadByte(S);
   }
  }
  
  static void LoadDebug(LoadState* S, Proto* f)
  {
   int i,n;
   f->source=LoadString(S);
   n=LoadInt(S);
   f->lineinfo=luaM_newvector(S->L,n,int);
   f->sizelineinfo=n;
   LoadVector(S,f->lineinfo,n,sizeof(int));
   n=LoadInt(S);
   f->locvars=luaM_newvector(S->L,n,LocVar);
   f->sizelocvars=n;
   for (i=0; i<n; i++) f->locvars[i].varname=NULL;
   for (i=0; i<n; i++)
   {
    f->locvars[i].varname=LoadString(S);
    f->locvars[i].startpc=LoadInt(S);
    f->locvars[i].endpc=LoadInt(S);
   }
   n=LoadInt(S);
   for (i=0; i<n; i++) f->upvalues[i].name=LoadString(S);
  }
  
  static void LoadFunction(LoadState* S, Proto* f)
  {
   f->linedefined=LoadInt(S);
   f->lastlinedefined=LoadInt(S);
   f->numparams=LoadByte(S);
   f->is_vararg=LoadByte(S);
   f->maxstacksize=LoadByte(S);
   LoadCode(S,f);
   LoadConstants(S,f);
   LoadUpvalues(S,f);
   LoadDebug(S,f);
  }
  
  /* the code below must be consistent with the code in luaU_header */
  #define N0	LUAC_HEADERSIZE
  #define N1	(sizeof(LUA_SIGNATURE)-sizeof(char))
  #define N2	N1+2
  #define N3	N2+6
  
  static void LoadHeader(LoadState* S)
  {
   lu_byte h[LUAC_HEADERSIZE];
   lu_byte s[LUAC_HEADERSIZE];
   luaU_header(h);
   memcpy(s,h,sizeof(char));			/* first char already read */
   LoadBlock(S,s+sizeof(char),LUAC_HEADERSIZE-sizeof(char));
   if (memcmp(h,s,N0)==0) return;
   if (memcmp(h,s,N1)!=0) error(S,"not a");
   if (memcmp(h,s,N2)!=0) error(S,"version mismatch in");
   if (memcmp(h,s,N3)!=0) error(S,"incompatible"); else error(S,"corrupted");
  }
  
  /*
  ** load precompiled chunk
  */
  Closure* luaU_undump (lua_State* L, ZIO* Z, Mbuffer* buff, const char* name)
  {
   LoadState S;
   Closure* cl;
   if (*name=='@' || *name=='=')
    S.name=name+1;
   else if (*name==LUA_SIGNATURE[0])
    S.name="binary string";
   else
    S.name=name;
   S.L=L;
   S.Z=Z;
   S.b=buff;
   LoadHeader(&S);
   cl=luaF_newLclosure(L,1);
   setclLvalue(L,L->top,cl); incr_top(L);
   cl->l.p=luaF_newproto(L);
   LoadFunction(&S,cl->l.p);
   if (cl->l.p->sizeupvalues != 1)
   {
    Proto* p=cl->l.p;
    cl=luaF_newLclosure(L,cl->l.p->sizeupvalues);
    cl->l.p=p;
    setclLvalue(L,L->top-1,cl);
   }
   luai_verifycode(L,buff,cl->l.p);
   return cl;
  }
  
  #define MYINT(s)	(s[0]-'0')
  #define VERSION		MYINT(LUA_VERSION_MAJOR)*16+MYINT(LUA_VERSION_MINOR)
  #define FORMAT		0		/* this is the official format */
  
  /*
  * make header for precompiled chunks
  * if you change the code below be sure to update LoadHeader and FORMAT above
  * and LUAC_HEADERSIZE in lundump.h
  */
  void luaU_header (lu_byte* h)
  {
   int x=1;
   memcpy(h,LUA_SIGNATURE,sizeof(LUA_SIGNATURE)-sizeof(char));
   h+=sizeof(LUA_SIGNATURE)-sizeof(char);
   *h++=cast_byte(VERSION);
   *h++=cast_byte(FORMAT);
   *h++=cast_byte(*(char*)&x);			/* endianness */
   *h++=cast_byte(sizeof(int));
   *h++=cast_byte(sizeof(size_t));
   *h++=cast_byte(sizeof(Instruction));
   *h++=cast_byte(sizeof(lua_Number));
   *h++=cast_byte(((lua_Number)0.5)==0);		/* is lua_Number integral? */
   memcpy(h,LUAC_TAIL,sizeof(LUAC_TAIL)-sizeof(char));
  }
  