Lua 5.3.4 里的 lobject.c

/*
** Extra tags for non-values
*/
#define LUA_TPROTO  LUA_NUMTAGS   /* function prototypes */
#define LUA_TDEADKEY  (LUA_NUMTAGS+1)   /* removed keys in tables */

/*
** number of all possible tags (including LUA_TNONE but excluding DEADKEY)
*/
#define LUA_TOTALTAGS (LUA_TPROTO + 2)


/*
** tags for Tagged Values have the following use of bits:
** bits 0-3: actual tag (a LUA_T* value)
** bits 4-5: variant bits
** bit 6: whether value is collectable
*/


/*
** LUA_TFUNCTION variants:
** 0 - Lua function
** 1 - light C function
** 2 - regular C function (closure)
*/

/* Variant tags for functions */
#define LUA_TLCL  (LUA_TFUNCTION | (0 << 4))  /* Lua closure */
#define LUA_TLCF  (LUA_TFUNCTION | (1 << 4))  /* light C function */
#define LUA_TCCL  (LUA_TFUNCTION | (2 << 4))  /* C closure */


/* Variant tags for strings */
#define LUA_TSHRSTR (LUA_TSTRING | (0 << 4))  /* short strings */
#define LUA_TLNGSTR (LUA_TSTRING | (1 << 4))  /* long strings */


/* Variant tags for numbers */
#define LUA_TNUMFLT (LUA_TNUMBER | (0 << 4))  /* float numbers */
#define LUA_TNUMINT (LUA_TNUMBER | (1 << 4))  /* integer numbers */


/* Bit mark for collectable types */
#define BIT_ISCOLLECTABLE (1 << 6)

/* mark a tag as collectable */
#define ctb(t)      ((t) | BIT_ISCOLLECTABLE)

/*
** Common type for all collectable objects
*/
typedef struct GCObject GCObject;


/*
** Common Header for all collectable objects (in macro form, to be
** included in other objects)
*/
#define CommonHeader  GCObject *next; lu_byte tt; lu_byte marked


/*
** Common type has only the common header
*/
struct GCObject {
  CommonHeader;
};




/*
** Tagged Values. This is the basic representation of values in Lua,
** an actual value plus a tag with its type.
*/

/*
** Union of all Lua values
*/
typedef union Value {
  GCObject *gc;    /* collectable objects */
  void *p;         /* light userdata */
  int b;           /* booleans */
  lua_CFunction f; /* light C functions */
  lua_Integer i;   /* integer numbers */
  lua_Number n;    /* float numbers */
} Value;


#define TValuefields  Value value_; int tt_


typedef struct lua_TValue {
  TValuefields;
} TValue;

/* macro defining a nil value */
#define NILCONSTANT {NULL}, LUA_TNIL

#define val_(o)   ((o)->value_)


/* raw type tag of a TValue */
#define rttype(o) ((o)->tt_)

/* tag with no variants (bits 0-3) */
#define novariant(x)  ((x) & 0x0F)

/* type tag of a TValue (bits 0-3 for tags + variant bits 4-5) */
#define ttype(o)  (rttype(o) & 0x3F)

/* type tag of a TValue with no variants (bits 0-3) */
#define ttnov(o)  (novariant(rttype(o)))


/* Macros to test type */
#define checktag(o,t)   (rttype(o) == (t))
#define checktype(o,t)    (ttnov(o) == (t))
#define ttisnumber(o)   checktype((o), LUA_TNUMBER)
#define ttisfloat(o)    checktag((o), LUA_TNUMFLT)
#define ttisinteger(o)    checktag((o), LUA_TNUMINT)
#define ttisnil(o)    checktag((o), LUA_TNIL)
#define ttisboolean(o)    checktag((o), LUA_TBOOLEAN)
#define ttislightuserdata(o)  checktag((o), LUA_TLIGHTUSERDATA)
#define ttisstring(o)   checktype((o), LUA_TSTRING)
#define ttisshrstring(o)  checktag((o), ctb(LUA_TSHRSTR))
#define ttislngstring(o)  checktag((o), ctb(LUA_TLNGSTR))
#define ttistable(o)    checktag((o), ctb(LUA_TTABLE))
#define ttisfunction(o)   checktype(o, LUA_TFUNCTION)
#define ttisclosure(o)    ((rttype(o) & 0x1F) == LUA_TFUNCTION)
#define ttisCclosure(o)   checktag((o), ctb(LUA_TCCL))
#define ttisLclosure(o)   checktag((o), ctb(LUA_TLCL))
#define ttislcf(o)    checktag((o), LUA_TLCF)
#define ttisfulluserdata(o) checktag((o), ctb(LUA_TUSERDATA))
#define ttisthread(o)   checktag((o), ctb(LUA_TTHREAD))
#define ttisdeadkey(o)    checktag((o), LUA_TDEADKEY)


/* Macros to access values */
#define ivalue(o) check_exp(ttisinteger(o), val_(o).i)
#define fltvalue(o) check_exp(ttisfloat(o), val_(o).n)
#define nvalue(o) check_exp(ttisnumber(o), \
  (ttisinteger(o) ? cast_num(ivalue(o)) : fltvalue(o)))
#define gcvalue(o)  check_exp(iscollectable(o), val_(o).gc)
#define pvalue(o) check_exp(ttislightuserdata(o), val_(o).p)
#define tsvalue(o)  check_exp(ttisstring(o), gco2ts(val_(o).gc))
#define uvalue(o) check_exp(ttisfulluserdata(o), gco2u(val_(o).gc))
#define clvalue(o)  check_exp(ttisclosure(o), gco2cl(val_(o).gc))
#define clLvalue(o) check_exp(ttisLclosure(o), gco2lcl(val_(o).gc))
#define clCvalue(o) check_exp(ttisCclosure(o), gco2ccl(val_(o).gc))
#define fvalue(o) check_exp(ttislcf(o), val_(o).f)
#define hvalue(o) check_exp(ttistable(o), gco2t(val_(o).gc))
#define bvalue(o) check_exp(ttisboolean(o), val_(o).b)
#define thvalue(o)  check_exp(ttisthread(o), gco2th(val_(o).gc))
/* a dead value may get the 'gc' field, but cannot access its contents */
#define deadvalue(o)  check_exp(ttisdeadkey(o), cast(void *, val_(o).gc))

#define l_isfalse(o)  (ttisnil(o) || (ttisboolean(o) && bvalue(o) == 0))


#define iscollectable(o)  (rttype(o) & BIT_ISCOLLECTABLE)


/* Macros for internal tests */
#define righttt(obj)    (ttype(obj) == gcvalue(obj)->tt)

#define checkliveness(L,obj) \
  lua_longassert(!iscollectable(obj) || \
    (righttt(obj) && (L == NULL || !isdead(G(L),gcvalue(obj)))))


/* Macros to set values */
#define settt_(o,t) ((o)->tt_=(t))

#define setfltvalue(obj,x) \
  { TValue *io=(obj); val_(io).n=(x); settt_(io, LUA_TNUMFLT); }

#define chgfltvalue(obj,x) \
  { TValue *io=(obj); lua_assert(ttisfloat(io)); val_(io).n=(x); }

#define setivalue(obj,x) \
  { TValue *io=(obj); val_(io).i=(x); settt_(io, LUA_TNUMINT); }

#define chgivalue(obj,x) \
  { TValue *io=(obj); lua_assert(ttisinteger(io)); val_(io).i=(x); }

#define setnilvalue(obj) settt_(obj, LUA_TNIL)

#define setfvalue(obj,x) \
  { TValue *io=(obj); val_(io).f=(x); settt_(io, LUA_TLCF); }

#define setpvalue(obj,x) \
  { TValue *io=(obj); val_(io).p=(x); settt_(io, LUA_TLIGHTUSERDATA); }

#define setbvalue(obj,x) \
  { TValue *io=(obj); val_(io).b=(x); settt_(io, LUA_TBOOLEAN); }

#define setgcovalue(L,obj,x) \
  { TValue *io = (obj); GCObject *i_g=(x); \
    val_(io).gc = i_g; settt_(io, ctb(i_g->tt)); }

#define setsvalue(L,obj,x) \
  { TValue *io = (obj); TString *x_ = (x); \
    val_(io).gc = obj2gco(x_); settt_(io, ctb(x_->tt)); \
    checkliveness(L,io); }

#define setuvalue(L,obj,x) \
  { TValue *io = (obj); Udata *x_ = (x); \
    val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_TUSERDATA)); \
    checkliveness(L,io); }

#define setthvalue(L,obj,x) \
  { TValue *io = (obj); lua_State *x_ = (x); \
    val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_TTHREAD)); \
    checkliveness(L,io); }

#define setclLvalue(L,obj,x) \
  { TValue *io = (obj); LClosure *x_ = (x); \
    val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_TLCL)); \
    checkliveness(L,io); }

#define setclCvalue(L,obj,x) \
  { TValue *io = (obj); CClosure *x_ = (x); \
    val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_TCCL)); \
    checkliveness(L,io); }

#define sethvalue(L,obj,x) \
  { TValue *io = (obj); Table *x_ = (x); \
    val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_TTABLE)); \
    checkliveness(L,io); }

#define setdeadvalue(obj) settt_(obj, LUA_TDEADKEY)



#define setobj(L,obj1,obj2) \
  { TValue *io1=(obj1); *io1 = *(obj2); \
    (void)L; checkliveness(L,io1); }


/*
** different types of assignments, according to destination
*/

/* from stack to (same) stack */
#define setobjs2s setobj
/* to stack (not from same stack) */
#define setobj2s  setobj
#define setsvalue2s setsvalue
#define sethvalue2s sethvalue
#define setptvalue2s  setptvalue
/* from table to same table */
#define setobjt2t setobj
/* to new object */
#define setobj2n  setobj
#define setsvalue2n setsvalue

/* to table (define it as an expression to be used in macros) */
#define setobj2t(L,o1,o2)  ((void)L, *(o1)=*(o2), checkliveness(L,(o1)))

/*
** Union of all collectable objects (only for conversions)
*/
union GCUnion {
  GCObject gc;  /* common header */
  struct TString ts;
  struct Udata u;
  union Closure cl;
  struct Table h;
  struct Proto p;
  struct lua_State th;  /* thread */
};


#define cast_u(o) cast(union GCUnion *, (o))

/* macros to convert a GCObject into a specific value */
#define gco2ts(o)  \
  check_exp(novariant((o)->tt) == LUA_TSTRING, &((cast_u(o))->ts))
#define gco2u(o)  check_exp((o)->tt == LUA_TUSERDATA, &((cast_u(o))->u))
#define gco2lcl(o)  check_exp((o)->tt == LUA_TLCL, &((cast_u(o))->cl.l))
#define gco2ccl(o)  check_exp((o)->tt == LUA_TCCL, &((cast_u(o))->cl.c))
#define gco2cl(o)  \
  check_exp(novariant((o)->tt) == LUA_TFUNCTION, &((cast_u(o))->cl))
#define gco2t(o)  check_exp((o)->tt == LUA_TTABLE, &((cast_u(o))->h))
#define gco2p(o)  check_exp((o)->tt == LUA_TPROTO, &((cast_u(o))->p))
#define gco2th(o)  check_exp((o)->tt == LUA_TTHREAD, &((cast_u(o))->th))

/*
** {======================================================
** types and prototypes
** =======================================================
*/


typedef TValue *StkId;  /* index to stack elements */




/*
** Header for string value; string bytes follow the end of this structure
** (aligned according to 'UTString'; see next).
*/
typedef struct TString {
  CommonHeader;
  lu_byte extra;  /* reserved words for short strings; "has hash" for longs */
  lu_byte shrlen;  /* length for short strings */
  unsigned int hash;
  union {
    size_t lnglen;  /* length for long strings */
    struct TString *hnext;  /* linked list for hash table */
  } u;
} TString;


/*
** Ensures that address after this type is always fully aligned.
*/
typedef union UTString {
  L_Umaxalign dummy;  /* ensures maximum alignment for strings */
  TString tsv;
} UTString;


/*
** Get the actual string (array of bytes) from a 'TString'.
** (Access to 'extra' ensures that value is really a 'TString'.)
*/
#define getstr(ts)  \
  check_exp(sizeof((ts)->extra), cast(char *, (ts)) + sizeof(UTString))


/* get the actual string (array of bytes) from a Lua value */
#define svalue(o)       getstr(tsvalue(o))

/* get string length from 'TString *s' */
#define tsslen(s) ((s)->tt == LUA_TSHRSTR ? (s)->shrlen : (s)->u.lnglen)

/* get string length from 'TValue *o' */
#define vslen(o)  tsslen(tsvalue(o))


/*
** Header for userdata; memory area follows the end of this structure
** (aligned according to 'UUdata'; see next).
*/
typedef struct Udata {
  CommonHeader;
  lu_byte ttuv_;  /* user value's tag */
  struct Table *metatable;
  size_t len;  /* number of bytes */
  union Value user_;  /* user value */
} Udata;


/*
** Ensures that address after this type is always fully aligned.
*/
typedef union UUdata {
  L_Umaxalign dummy;  /* ensures maximum alignment for 'local' udata */
  Udata uv;
} UUdata;


/*
**  Get the address of memory block inside 'Udata'.
** (Access to 'ttuv_' ensures that value is really a 'Udata'.)
*/
#define getudatamem(u)  \
  check_exp(sizeof((u)->ttuv_), (cast(char*, (u)) + sizeof(UUdata)))

#define setuservalue(L,u,o) \
  { const TValue *io=(o); Udata *iu = (u); \
    iu->user_ = io->value_; iu->ttuv_ = rttype(io); \
    checkliveness(L,io); }


#define getuservalue(L,u,o) \
  { TValue *io=(o); const Udata *iu = (u); \
    io->value_ = iu->user_; settt_(io, iu->ttuv_); \
    checkliveness(L,io); }


/*
** Description of an upvalue for function prototypes
*/
typedef struct Upvaldesc {
  TString *name;  /* upvalue name (for debug information) */
  lu_byte instack;  /* whether it is in stack (register) */
  lu_byte idx;  /* index of upvalue (in stack or in outer function's list) */
} Upvaldesc;


/*
** Description of a local variable for function prototypes
** (used for debug information)
*/
typedef struct LocVar {
  TString *varname;
  int startpc;  /* first point where variable is active */
  int endpc;    /* first point where variable is dead */
} LocVar;


/*
** Function Prototypes
*/
typedef struct Proto {
  CommonHeader;
  lu_byte numparams;  /* number of fixed parameters */
  lu_byte is_vararg;
  lu_byte maxstacksize;  /* number of registers needed by this function */
  int sizeupvalues;  /* size of 'upvalues' */
  int sizek;  /* size of 'k' */
  int sizecode;
  int sizelineinfo;
  int sizep;  /* size of 'p' */
  int sizelocvars;
  int linedefined;  /* debug information  */
  int lastlinedefined;  /* debug information  */
  TValue *k;  /* constants used by the function */
  Instruction *code;  /* opcodes */
  struct Proto **p;  /* functions defined inside the function */
  int *lineinfo;  /* map from opcodes to source lines (debug information) */
  LocVar *locvars;  /* information about local variables (debug information) */
  Upvaldesc *upvalues;  /* upvalue information */
  struct LClosure *cache;  /* last-created closure with this prototype */
  TString  *source;  /* used for debug information */
  GCObject *gclist;
} Proto;



/*
** Lua Upvalues
*/
typedef struct UpVal UpVal;


/*
** Closures
*/

#define ClosureHeader \
  CommonHeader; lu_byte nupvalues; GCObject *gclist

typedef struct CClosure {
  ClosureHeader;
  lua_CFunction f;
  TValue upvalue[1];  /* list of upvalues */
} CClosure;


typedef struct LClosure {
  ClosureHeader;
  struct Proto *p;
  UpVal *upvals[1];  /* list of upvalues */
} LClosure;


typedef union Closure {
  CClosure c;
  LClosure l;
} Closure;


#define isLfunction(o)  ttisLclosure(o)

#define getproto(o) (clLvalue(o)->p)


/*
** Tables
*/

typedef union TKey {
  struct {
    TValuefields;
    int next;  /* for chaining (offset for next node) */
  } nk;
  TValue tvk;
} TKey;


/* copy a value into a key without messing up field 'next' */
#define setnodekey(L,key,obj) \
  { TKey *k_=(key); const TValue *io_=(obj); \
    k_->nk.value_ = io_->value_; k_->nk.tt_ = io_->tt_; \
    (void)L; checkliveness(L,io_); }


typedef struct Node {
  TValue i_val;
  TKey i_key;
} Node;


typedef struct Table {
  CommonHeader;
  lu_byte flags;  /* 1<<p means tagmethod(p) is not present */
  lu_byte lsizenode;  /* log2 of size of 'node' array */
  unsigned int sizearray;  /* size of 'array' array */
  TValue *array;  /* array part */
  Node *node;
  Node *lastfree;  /* any free position is before this position */
  struct Table *metatable;
  GCObject *gclist;
} Table;



/*
** 'module' operation for hashing (size is always a power of 2)
*/
#define lmod(s,size) \
  (check_exp((size&(size-1))==0, (cast(int, (s) & ((size)-1)))))


#define twoto(x)  (1<<(x))
#define sizenode(t) (twoto((t)->lsizenode))


/*
** (address of) a fixed nil value
*/
#define luaO_nilobject    (&luaO_nilobject_)


LUAI_DDEC const TValue luaO_nilobject_;

/* size of buffer for 'luaO_utf8esc' function */
#define UTF8BUFFSZ  8

LUAI_FUNC int luaO_int2fb (unsigned int x);
LUAI_FUNC int luaO_fb2int (int x);
LUAI_FUNC int luaO_utf8esc (char *buff, unsigned long x);
LUAI_FUNC int luaO_ceillog2 (unsigned int x);
LUAI_FUNC void luaO_arith (lua_State *L, int op, const TValue *p1,
                           const TValue *p2, TValue *res);
LUAI_FUNC size_t luaO_str2num (const char *s, TValue *o);
LUAI_FUNC int luaO_hexavalue (int c);
LUAI_FUNC void luaO_tostring (lua_State *L, StkId obj);
LUAI_FUNC const char *luaO_pushvfstring (lua_State *L, const char *fmt,
                                                       va_list argp);
LUAI_FUNC const char *luaO_pushfstring (lua_State *L, const char *fmt, ...);
LUAI_FUNC void luaO_chunkid (char *out, const char *source, size_t len);

/*
** converts an integer to a "floating point byte", represented as
** (eeeeexxx), where the real value is (1xxx) * 2^(eeeee - 1) if
** eeeee != 0 and (xxx) otherwise.
*/
int luaO_int2fb (unsigned int x) {
  int e = 0;  /* exponent */
  if (x < 8) return x;
  while (x >= (8 << 4)) {  /* coarse steps */
    x = (x + 0xf) >> 4;  /* x = ceil(x / 16) */
    e += 4;
  }
  while (x >= (8 << 1)) {  /* fine steps */
    x = (x + 1) >> 1;  /* x = ceil(x / 2) */
    e++;
  }
  return ((e+1) << 3) | (cast_int(x) - 8);
}


/* converts back */
int luaO_fb2int (int x) {
  return (x < 8) ? x : ((x & 7) + 8) << ((x >> 3) - 1);
}

/*
** Computes ceil(log2(x))
*/
int luaO_ceillog2 (unsigned int x) {
  static const lu_byte log_2[256] = {  /* log_2[i] = ceil(log2(i - 1)) */
    0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
    6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
    7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
    7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
    8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
    8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
    8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
    8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8
  };
  int l = 0;
  x--;
  while (x >= 256) { l += 8; x >>= 8; }
  return l + log_2[x];
}

static lua_Integer intarith (lua_State *L, int op, lua_Integer v1,
                                                   lua_Integer v2) {
  switch (op) {
    case LUA_OPADD: return intop(+, v1, v2);
    case LUA_OPSUB:return intop(-, v1, v2);
    case LUA_OPMUL:return intop(*, v1, v2);
    case LUA_OPMOD: return luaV_mod(L, v1, v2);
    case LUA_OPIDIV: return luaV_div(L, v1, v2);
    case LUA_OPBAND: return intop(&, v1, v2);
    case LUA_OPBOR: return intop(|, v1, v2);
    case LUA_OPBXOR: return intop(^, v1, v2);
    case LUA_OPSHL: return luaV_shiftl(v1, v2);
    case LUA_OPSHR: return luaV_shiftl(v1, -v2);
    case LUA_OPUNM: return intop(-, 0, v1);
    case LUA_OPBNOT: return intop(^, ~l_castS2U(0), v1);
    default: lua_assert(0); return 0;
  }
}


static lua_Number numarith (lua_State *L, int op, lua_Number v1,
                                                  lua_Number v2) {
  switch (op) {
    case LUA_OPADD: return luai_numadd(L, v1, v2);
    case LUA_OPSUB: return luai_numsub(L, v1, v2);
    case LUA_OPMUL: return luai_nummul(L, v1, v2);
    case LUA_OPDIV: return luai_numdiv(L, v1, v2);
    case LUA_OPPOW: return luai_numpow(L, v1, v2);
    case LUA_OPIDIV: return luai_numidiv(L, v1, v2);
    case LUA_OPUNM: return luai_numunm(L, v1);
    case LUA_OPMOD: {
      lua_Number m;
      luai_nummod(L, v1, v2, m);
      return m;
    }
    default: lua_assert(0); return 0;
  }
}


void luaO_arith (lua_State *L, int op, const TValue *p1, const TValue *p2,
                 TValue *res) {
  switch (op) {
    case LUA_OPBAND: case LUA_OPBOR: case LUA_OPBXOR:
    case LUA_OPSHL: case LUA_OPSHR:
    case LUA_OPBNOT: {  /* operate only on integers */
      lua_Integer i1; lua_Integer i2;
      if (tointeger(p1, &i1) && tointeger(p2, &i2)) {
        setivalue(res, intarith(L, op, i1, i2));
        return;
      }
      else break;  /* go to the end */
    }
    case LUA_OPDIV: case LUA_OPPOW: {  /* operate only on floats */
      lua_Number n1; lua_Number n2;
      if (tonumber(p1, &n1) && tonumber(p2, &n2)) {
        setfltvalue(res, numarith(L, op, n1, n2));
        return;
      }
      else break;  /* go to the end */
    }
    default: {  /* other operations */
      lua_Number n1; lua_Number n2;
      if (ttisinteger(p1) && ttisinteger(p2)) {
        setivalue(res, intarith(L, op, ivalue(p1), ivalue(p2)));
        return;
      }
      else if (tonumber(p1, &n1) && tonumber(p2, &n2)) {
        setfltvalue(res, numarith(L, op, n1, n2));
        return;
      }
      else break;  /* go to the end */
    }
  }
  /* could not perform raw operation; try metamethod */
  lua_assert(L != NULL);  /* should not fail when folding (compile time) */
  luaT_trybinTM(L, p1, p2, res, cast(TMS, (op - LUA_OPADD) + TM_ADD));
}

int luaO_hexavalue (int c) {
  if (lisdigit(c)) return c - '0';
  else return (ltolower(c) - 'a') + 10;
}

static int isneg (const char **s) {
  if (**s == '-') { (*s)++; return 1; }
  else if (**s == '+') (*s)++;
  return 0;
}



/*
** {==================================================================
** Lua's implementation for 'lua_strx2number'
** ===================================================================
*/

#if !defined(lua_strx2number)

/* maximum number of significant digits to read (to avoid overflows
   even with single floats) */
#define MAXSIGDIG 30

/*
** convert an hexadecimal numeric string to a number, following
** C99 specification for 'strtod'
*/
static lua_Number lua_strx2number (const char *s, char **endptr) {
  int dot = lua_getlocaledecpoint();
  lua_Number r = 0.0;  /* result (accumulator) */
  int sigdig = 0;  /* number of significant digits */
  int nosigdig = 0;  /* number of non-significant digits */
  int e = 0;  /* exponent correction */
  int neg;  /* 1 if number is negative */
  int hasdot = 0;  /* true after seen a dot */
  *endptr = cast(char *, s);  /* nothing is valid yet */
  while (lisspace(cast_uchar(*s))) s++;  /* skip initial spaces */
  neg = isneg(&s);  /* check signal */
  if (!(*s == '0' && (*(s + 1) == 'x' || *(s + 1) == 'X')))  /* check '0x' */
    return 0.0;  /* invalid format (no '0x') */
  for (s += 2; ; s++) {  /* skip '0x' and read numeral */
    if (*s == dot) {
      if (hasdot) break;  /* second dot? stop loop */
      else hasdot = 1;
    }
    else if (lisxdigit(cast_uchar(*s))) {
      if (sigdig == 0 && *s == '0')  /* non-significant digit (zero)? */
        nosigdig++;
      else if (++sigdig <= MAXSIGDIG)  /* can read it without overflow? */
          r = (r * cast_num(16.0)) + luaO_hexavalue(*s);
      else e++; /* too many digits; ignore, but still count for exponent */
      if (hasdot) e--;  /* decimal digit? correct exponent */
    }
    else break;  /* neither a dot nor a digit */
  }
  if (nosigdig + sigdig == 0)  /* no digits? */
    return 0.0;  /* invalid format */
  *endptr = cast(char *, s);  /* valid up to here */
  e *= 4;  /* each digit multiplies/divides value by 2^4 */
  if (*s == 'p' || *s == 'P') {  /* exponent part? */
    int exp1 = 0;  /* exponent value */
    int neg1;  /* exponent signal */
    s++;  /* skip 'p' */
    neg1 = isneg(&s);  /* signal */
    if (!lisdigit(cast_uchar(*s)))
      return 0.0;  /* invalid; must have at least one digit */
    while (lisdigit(cast_uchar(*s)))  /* read exponent */
      exp1 = exp1 * 10 + *(s++) - '0';
    if (neg1) exp1 = -exp1;
    e += exp1;
    *endptr = cast(char *, s);  /* valid up to here */
  }
  if (neg) r = -r;
  return l_mathop(ldexp)(r, e);
}

#endif
/* }====================================================== */


/* maximum length of a numeral */
#if !defined (L_MAXLENNUM)
#define L_MAXLENNUM 200
#endif

static const char *l_str2dloc (const char *s, lua_Number *result, int mode) {
  char *endptr;
  *result = (mode == 'x') ? lua_strx2number(s, &endptr)  /* try to convert */
                          : lua_str2number(s, &endptr);
  if (endptr == s) return NULL;  /* nothing recognized? */
  while (lisspace(cast_uchar(*endptr))) endptr++;  /* skip trailing spaces */
  return (*endptr == '\0') ? endptr : NULL;  /* OK if no trailing characters */
}


/*
** Convert string 's' to a Lua number (put in 'result'). Return NULL
** on fail or the address of the ending '\0' on success.
** 'pmode' points to (and 'mode' contains) special things in the string:
** - 'x'/'X' means an hexadecimal numeral
** - 'n'/'N' means 'inf' or 'nan' (which should be rejected)
** - '.' just optimizes the search for the common case (nothing special)
** This function accepts both the current locale or a dot as the radix
** mark. If the convertion fails, it may mean number has a dot but
** locale accepts something else. In that case, the code copies 's'
** to a buffer (because 's' is read-only), changes the dot to the
** current locale radix mark, and tries to convert again.
*/
static const char *l_str2d (const char *s, lua_Number *result) {
  const char *endptr;
  const char *pmode = strpbrk(s, ".xXnN");
  int mode = pmode ? ltolower(cast_uchar(*pmode)) : 0;
  if (mode == 'n')  /* reject 'inf' and 'nan' */
    return NULL;
  endptr = l_str2dloc(s, result, mode);  /* try to convert */
  if (endptr == NULL) {  /* failed? may be a different locale */
    char buff[L_MAXLENNUM + 1];
    const char *pdot = strchr(s, '.');
    if (strlen(s) > L_MAXLENNUM || pdot == NULL)
      return NULL;  /* string too long or no dot; fail */
    strcpy(buff, s);  /* copy string to buffer */
    buff[pdot - s] = lua_getlocaledecpoint();  /* correct decimal point */
    endptr = l_str2dloc(buff, result, mode);  /* try again */
    if (endptr != NULL)
      endptr = s + (endptr - buff);  /* make relative to 's' */
  }
  return endptr;
}


#define MAXBY10   cast(lua_Unsigned, LUA_MAXINTEGER / 10)
#define MAXLASTD  cast_int(LUA_MAXINTEGER % 10)

static const char *l_str2int (const char *s, lua_Integer *result) {
  lua_Unsigned a = 0;
  int empty = 1;
  int neg;
  while (lisspace(cast_uchar(*s))) s++;  /* skip initial spaces */
  neg = isneg(&s);
  if (s[0] == '0' &&
      (s[1] == 'x' || s[1] == 'X')) {  /* hex? */
    s += 2;  /* skip '0x' */
    for (; lisxdigit(cast_uchar(*s)); s++) {
      a = a * 16 + luaO_hexavalue(*s);
      empty = 0;
    }
  }
  else {  /* decimal */
    for (; lisdigit(cast_uchar(*s)); s++) {
      int d = *s - '0';
      if (a >= MAXBY10 && (a > MAXBY10 || d > MAXLASTD + neg))  /* overflow? */
        return NULL;  /* do not accept it (as integer) */
      a = a * 10 + d;
      empty = 0;
    }
  }
  while (lisspace(cast_uchar(*s))) s++;  /* skip trailing spaces */
  if (empty || *s != '\0') return NULL;  /* something wrong in the numeral */
  else {
    *result = l_castU2S((neg) ? 0u - a : a);
    return s;
  }
}


size_t luaO_str2num (const char *s, TValue *o) {
  lua_Integer i; lua_Number n;
  const char *e;
  if ((e = l_str2int(s, &i)) != NULL) {  /* try as an integer */
    setivalue(o, i);
  }
  else if ((e = l_str2d(s, &n)) != NULL) {  /* else try as a float */
    setfltvalue(o, n);
  }
  else
    return 0;  /* conversion failed */
  return (e - s) + 1;  /* success; return string size */
}

int luaO_utf8esc (char *buff, unsigned long x) {
  int n = 1;  /* number of bytes put in buffer (backwards) */
  lua_assert(x <= 0x10FFFF);
  if (x < 0x80)  /* ascii? */
    buff[UTF8BUFFSZ - 1] = cast(char, x);
  else {  /* need continuation bytes */
    unsigned int mfb = 0x3f;  /* maximum that fits in first byte */
    do {  /* add continuation bytes */
      buff[UTF8BUFFSZ - (n++)] = cast(char, 0x80 | (x & 0x3f));
      x >>= 6;  /* remove added bits */
      mfb >>= 1;  /* now there is one less bit available in first byte */
    } while (x > mfb);  /* still needs continuation byte? */
    buff[UTF8BUFFSZ - n] = cast(char, (~mfb << 1) | x);  /* add first byte */
  }
  return n;
}

int luaO_utf8esc (char *buff, unsigned long x) {
  int n = 1;  /* number of bytes put in buffer (backwards) */
  lua_assert(x <= 0x10FFFF);
  if (x < 0x80)  /* ascii? */
    buff[UTF8BUFFSZ - 1] = cast(char, x);
  else {  /* need continuation bytes */
    unsigned int mfb = 0x3f;  /* maximum that fits in first byte */
    do {  /* add continuation bytes */
      buff[UTF8BUFFSZ - (n++)] = cast(char, 0x80 | (x & 0x3f));
      x >>= 6;  /* remove added bits */
      mfb >>= 1;  /* now there is one less bit available in first byte */
    } while (x > mfb);  /* still needs continuation byte? */
    buff[UTF8BUFFSZ - n] = cast(char, (~mfb << 1) | x);  /* add first byte */
  }
  return n;
}


/* maximum length of the conversion of a number to a string */
#define MAXNUMBER2STR 50


/*
** Convert a number object to a string
*/
void luaO_tostring (lua_State *L, StkId obj) {
  char buff[MAXNUMBER2STR];
  size_t len;
  lua_assert(ttisnumber(obj));
  if (ttisinteger(obj))
    len = lua_integer2str(buff, sizeof(buff), ivalue(obj));
  else {
    len = lua_number2str(buff, sizeof(buff), fltvalue(obj));
#if !defined(LUA_COMPAT_FLOATSTRING)
    if (buff[strspn(buff, "-0123456789")] == '\0') {  /* looks like an int? */
      buff[len++] = lua_getlocaledecpoint();
      buff[len++] = '0';  /* adds '.0' to result */
    }
#endif
  }
  setsvalue2s(L, obj, luaS_newlstr(L, buff, len));
}


static void pushstr (lua_State *L, const char *str, size_t l) {
  setsvalue2s(L, L->top, luaS_newlstr(L, str, l));
  luaD_inctop(L);
}


/*
** this function handles only '%d', '%c', '%f', '%p', and '%s'
   conventional formats, plus Lua-specific '%I' and '%U'
*/
const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
  int n = 0;
  for (;;) {
    const char *e = strchr(fmt, '%');
    if (e == NULL) break;
    pushstr(L, fmt, e - fmt);
    switch (*(e+1)) {
      case 's': {  /* zero-terminated string */
        const char *s = va_arg(argp, char *);
        if (s == NULL) s = "(null)";
        pushstr(L, s, strlen(s));
        break;
      }
      case 'c': {  /* an 'int' as a character */
        char buff = cast(char, va_arg(argp, int));
        if (lisprint(cast_uchar(buff)))
          pushstr(L, &buff, 1);
        else  /* non-printable character; print its code */
          luaO_pushfstring(L, "<\\%d>", cast_uchar(buff));
        break;
      }
      case 'd': {  /* an 'int' */
        setivalue(L->top, va_arg(argp, int));
        goto top2str;
      }
      case 'I': {  /* a 'lua_Integer' */
        setivalue(L->top, cast(lua_Integer, va_arg(argp, l_uacInt)));
        goto top2str;
      }
      case 'f': {  /* a 'lua_Number' */
        setfltvalue(L->top, cast_num(va_arg(argp, l_uacNumber)));
      top2str:  /* convert the top element to a string */
        luaD_inctop(L);
        luaO_tostring(L, L->top - 1);
        break;
      }
      case 'p': {  /* a pointer */
        char buff[4*sizeof(void *) + 8]; /* should be enough space for a '%p' */
        int l = l_sprintf(buff, sizeof(buff), "%p", va_arg(argp, void *));
        pushstr(L, buff, l);
        break;
      }
      case 'U': {  /* an 'int' as a UTF-8 sequence */
        char buff[UTF8BUFFSZ];
        int l = luaO_utf8esc(buff, cast(long, va_arg(argp, long)));
        pushstr(L, buff + UTF8BUFFSZ - l, l);
        break;
      }
      case '%': {
        pushstr(L, "%", 1);
        break;
      }
      default: {
        luaG_runerror(L, "invalid option '%%%c' to 'lua_pushfstring'",
                         *(e + 1));
      }
    }
    n += 2;
    fmt = e+2;
  }
  luaD_checkstack(L, 1);
  pushstr(L, fmt, strlen(fmt));
  if (n > 0) luaV_concat(L, n + 1);
  return svalue(L->top - 1);
}


const char *luaO_pushfstring (lua_State *L, const char *fmt, ...) {
  const char *msg;
  va_list argp;
  va_start(argp, fmt);
  msg = luaO_pushvfstring(L, fmt, argp);
  va_end(argp);
  return msg;
}

/* number of chars of a literal string without the ending \0 */
#define LL(x) (sizeof(x)/sizeof(char) - 1)

#define RETS  "..."
#define PRE "[string \""
#define POS "\"]"

#define addstr(a,b,l) ( memcpy(a,b,(l) * sizeof(char)), a += (l) )

void luaO_chunkid (char *out, const char *source, size_t bufflen) {
  size_t l = strlen(source);
  if (*source == '=') {  /* 'literal' source */
    if (l <= bufflen)  /* small enough? */
      memcpy(out, source + 1, l * sizeof(char));
    else {  /* truncate it */
      addstr(out, source + 1, bufflen - 1);
      *out = '\0';
    }
  }
  else if (*source == '@') {  /* file name */
    if (l <= bufflen)  /* small enough? */
      memcpy(out, source + 1, l * sizeof(char));
    else {  /* add '...' before rest of name */
      addstr(out, RETS, LL(RETS));
      bufflen -= LL(RETS);
      memcpy(out, source + 1 + l - bufflen, bufflen * sizeof(char));
    }
  }
  else {  /* string; format as [string "source"] */
    const char *nl = strchr(source, '\n');  /* find first new line (if any) */
    addstr(out, PRE, LL(PRE));  /* add prefix */
    bufflen -= LL(PRE RETS POS) + 1;  /* save space for prefix+suffix+'\0' */
    if (l < bufflen && nl == NULL) {  /* small one-line source? */
      addstr(out, source, l);  /* keep it */
    }
    else {
      if (nl != NULL) l = nl - source;  /* stop at first newline */
      if (l > bufflen) l = bufflen;
      addstr(out, source, l);
      addstr(out, RETS, LL(RETS));
    }
    memcpy(out, POS, (LL(POS) + 1) * sizeof(char));
  }
}