text: /*
  ** $Id: lundump.c,v 2.7.1.4 2008/04/04 19:51:41 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;
  
  #ifdef LUAC_TRUST_BINARIES
  #define IF(c,s)
  #define error(S,s)
  #else
  #define IF(c,s)		if (c) error(S,s)
  
  static void error(LoadState* S, const char* why)
  {
   luaO_pushfstring(S->L,"%s: %s in precompiled chunk",S->name,why);
   luaD_throw(S->L,LUA_ERRSYNTAX);
  }
  #endif
  
  #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)
  
  static void LoadBlock(LoadState* S, void* b, size_t size)
  {
   size_t r=luaZ_read(S->Z,b,size);
   IF (r!=0, "unexpected end");
  }
  
  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, "bad integer");
   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);
    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 Proto* LoadFunction(LoadState* S, TString* p);
  
  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)!=0);
  	break;
     case LUA_TNUMBER:
  	setnvalue(o,LoadNumber(S));
  	break;
     case LUA_TSTRING:
  	setsvalue2n(S->L,o,LoadString(S));
  	break;
     default:
  	error(S,"bad constant");
  	break;
    }
   }
   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]=LoadFunction(S,f->source);
  }
  
  static void LoadDebug(LoadState* S, Proto* f)
  {
   int i,n;
   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);
   f->upvalues=luaM_newvector(S->L,n,TString*);
   f->sizeupvalues=n;
   for (i=0; i<n; i++) f->upvalues[i]=NULL;
   for (i=0; i<n; i++) f->upvalues[i]=LoadString(S);
  }
  
  static Proto* LoadFunction(LoadState* S, TString* p)
  {
   Proto* f;
   if (++S->L->nCcalls > LUAI_MAXCCALLS) error(S,"code too deep");
   f=luaF_newproto(S->L);
   setptvalue2s(S->L,S->L->top,f); incr_top(S->L);
   f->source=LoadString(S); if (f->source==NULL) f->source=p;
   f->linedefined=LoadInt(S);
   f->lastlinedefined=LoadInt(S);
   f->nups=LoadByte(S);
   f->numparams=LoadByte(S);
   f->is_vararg=LoadByte(S);
   f->maxstacksize=LoadByte(S);
   LoadCode(S,f);
   LoadConstants(S,f);
   LoadDebug(S,f);
   IF (!luaG_checkcode(f), "bad code");
   S->L->top--;
   S->L->nCcalls--;
   return f;
  }
  
  static void LoadHeader(LoadState* S)
  {
   char h[LUAC_HEADERSIZE];
   char s[LUAC_HEADERSIZE];
   luaU_header(h);
   LoadBlock(S,s,LUAC_HEADERSIZE);
   IF (memcmp(h,s,LUAC_HEADERSIZE)!=0, "bad header");
  }
  
  /*
  ** load precompiled chunk
  */
  Proto* luaU_undump (lua_State* L, ZIO* Z, Mbuffer* buff, const char* name)
  {
   LoadState S;
   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);
   return LoadFunction(&S,luaS_newliteral(L,"=?"));
  }
  
  /*
  * make header
  */
  void luaU_header (char* h)
  {
   int x=1;
   memcpy(h,LUA_SIGNATURE,sizeof(LUA_SIGNATURE)-1);
   h+=sizeof(LUA_SIGNATURE)-1;
   *h++=(char)LUAC_VERSION;
   *h++=(char)LUAC_FORMAT;
   *h++=(char)*(char*)&x;				/* endianness */
   *h++=(char)sizeof(int);
   *h++=(char)sizeof(size_t);
   *h++=(char)sizeof(Instruction);
   *h++=(char)sizeof(lua_Number);
   *h++=(char)(((lua_Number)0.5)==0);		/* is lua_Number integral? */
  }
  