text: /*
  ** $Id: lobject.c $
  ** Some generic functions over Lua objects
  ** See Copyright Notice in lua.h
  */
  
  #define lobject_c
  #define LUA_CORE
  
  #include "lprefix.h"
  
  
  #include <locale.h>
  #include <math.h>
  #include <stdarg.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include "lua.h"
  
  #include "lctype.h"
  #include "ldebug.h"
  #include "ldo.h"
  #include "lmem.h"
  #include "lobject.h"
  #include "lstate.h"
  #include "lstring.h"
  #include "lvm.h"
  
  
  /*
  ** 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_idiv(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: return luaV_modf(L, v1, v2);
      default: lua_assert(0); return 0;
    }
  }
  
  
  int luaO_rawarith (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 (tointegerns(p1, &i1) && tointegerns(p2, &i2)) {
          setivalue(res, intarith(L, op, i1, i2));
          return 1;
        }
        else return 0;  /* fail */
      }
      case LUA_OPDIV: case LUA_OPPOW: {  /* operate only on floats */
        lua_Number n1; lua_Number n2;
        if (tonumberns(p1, n1) && tonumberns(p2, n2)) {
          setfltvalue(res, numarith(L, op, n1, n2));
          return 1;
        }
        else return 0;  /* fail */
      }
      default: {  /* other operations */
        lua_Number n1; lua_Number n2;
        if (ttisinteger(p1) && ttisinteger(p2)) {
          setivalue(res, intarith(L, op, ivalue(p1), ivalue(p2)));
          return 1;
        }
        else if (tonumberns(p1, n1) && tonumberns(p2, n2)) {
          setfltvalue(res, numarith(L, op, n1, n2));
          return 1;
        }
        else return 0;  /* fail */
      }
    }
  }
  
  
  void luaO_arith (lua_State *L, int op, const TValue *p1, const TValue *p2,
                   StkId res) {
    if (!luaO_rawarith(L, op, p1, p2, s2v(res))) {
      /* could not perform raw operation; try metamethod */
      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 a 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_charp(s);  /* nothing is valid yet */
    while (lisspace(cast_uchar(*s))) s++;  /* skip initial spaces */
    neg = isneg(&s);  /* check sign */
    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_charp(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 sign */
      s++;  /* skip 'p' */
      neg1 = isneg(&s);  /* sign */
      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_charp(s);  /* valid up to here */
    }
    if (neg) r = -r;
    return l_mathop(ldexp)(r, e);
  }
  
  #endif
  /* }====================================================== */
  
  
  /* maximum length of a numeral to be converted to a number */
  #if !defined (L_MAXLENNUM)
  #define L_MAXLENNUM	200
  #endif
  
  /*
  ** Convert string 's' to a Lua number (put in 'result'). Return NULL on
  ** fail or the address of the ending '\0' on success. ('mode' == 'x')
  ** means a hexadecimal numeral.
  */
  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 iff no trailing chars */
  }
  
  
  /*
  ** Convert string 's' to a Lua number (put in 'result') handling the
  ** current locale.
  ** This function accepts both the current locale or a dot as the radix
  ** mark. If the conversion 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.
  ** The variable 'mode' checks for special characters in the string:
  ** - 'n' means 'inf' or 'nan' (which should be rejected)
  ** - 'x' means a hexadecimal numeral
  ** - '.' just optimizes the search for the common case (no special chars)
  */
  static const char *l_str2d (const char *s, lua_Number *result) {
    const char *endptr;
    const char *pmode = strpbrk(s, ".xXnN");  /* look for special chars */
    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 <= 0x7FFFFFFFu);
    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. Must be
  ** enough to accommodate both LUA_INTEGER_FMT and LUA_NUMBER_FMT.
  ** (For a long long int, this is 19 digits plus a sign and a final '\0',
  ** adding to 21. For a long double, it can go to a sign, 33 digits,
  ** the dot, an exponent letter, an exponent sign, 5 exponent digits,
  ** and a final '\0', adding to 43.)
  */
  #define MAXNUMBER2STR	44
  
  
  /*
  ** Convert a number object to a string, adding it to a buffer
  */
  static int tostringbuff (TValue *obj, char *buff) {
    int len;
    lua_assert(ttisnumber(obj));
    if (ttisinteger(obj))
      len = lua_integer2str(buff, MAXNUMBER2STR, ivalue(obj));
    else {
      len = lua_number2str(buff, MAXNUMBER2STR, fltvalue(obj));
      if (buff[strspn(buff, "-0123456789")] == '\0') {  /* looks like an int? */
        buff[len++] = lua_getlocaledecpoint();
        buff[len++] = '0';  /* adds '.0' to result */
      }
    }
    return len;
  }
  
  
  /*
  ** Convert a number object to a Lua string, replacing the value at 'obj'
  */
  void luaO_tostring (lua_State *L, TValue *obj) {
    char buff[MAXNUMBER2STR];
    int len = tostringbuff(obj, buff);
    setsvalue(L, obj, luaS_newlstr(L, buff, len));
  }
  
  
  
  
  /*
  ** {==================================================================
  ** 'luaO_pushvfstring'
  ** ===================================================================
  */
  
  /* size for buffer space used by 'luaO_pushvfstring' */
  #define BUFVFS		200
  
  /* buffer used by 'luaO_pushvfstring' */
  typedef struct BuffFS {
    lua_State *L;
    int pushed;  /* number of string pieces already on the stack */
    int blen;  /* length of partial string in 'space' */
    char space[BUFVFS];  /* holds last part of the result */
  } BuffFS;
  
  
  /*
  ** Push given string to the stack, as part of the buffer, and
  ** join the partial strings in the stack into one.
  */
  static void pushstr (BuffFS *buff, const char *str, size_t l) {
    lua_State *L = buff->L;
    setsvalue2s(L, L->top, luaS_newlstr(L, str, l));
    L->top++;  /* may use one extra slot */
    buff->pushed++;
    luaV_concat(L, buff->pushed);  /* join partial results into one */
    buff->pushed = 1;
  }
  
  
  /*
  ** empty the buffer space into the stack
  */
  static void clearbuff (BuffFS *buff) {
    pushstr(buff, buff->space, buff->blen);  /* push buffer contents */
    buff->blen = 0;  /* space now is empty */
  }
  
  
  /*
  ** Get a space of size 'sz' in the buffer. If buffer has not enough
  ** space, empty it. 'sz' must fit in an empty buffer.
  */
  static char *getbuff (BuffFS *buff, int sz) {
    lua_assert(buff->blen <= BUFVFS); lua_assert(sz <= BUFVFS);
    if (sz > BUFVFS - buff->blen)  /* not enough space? */
      clearbuff(buff);
    return buff->space + buff->blen;
  }
  
  
  #define addsize(b,sz)	((b)->blen += (sz))
  
  
  /*
  ** Add 'str' to the buffer. If string is larger than the buffer space,
  ** push the string directly to the stack.
  */
  static void addstr2buff (BuffFS *buff, const char *str, size_t slen) {
    if (slen <= BUFVFS) {  /* does string fit into buffer? */
      char *bf = getbuff(buff, cast_int(slen));
      memcpy(bf, str, slen);  /* add string to buffer */
      addsize(buff, cast_int(slen));
    }
    else {  /* string larger than buffer */
      clearbuff(buff);  /* string comes after buffer's content */
      pushstr(buff, str, slen);  /* push string */
    }
  }
  
  
  /*
  ** Add a number to the buffer.
  */
  static void addnum2buff (BuffFS *buff, TValue *num) {
    char *numbuff = getbuff(buff, MAXNUMBER2STR);
    int len = tostringbuff(num, numbuff);  /* format number into 'numbuff' */
    addsize(buff, len);
  }
  
  
  /*
  ** this function handles only '%d', '%c', '%f', '%p', '%s', and '%%'
     conventional formats, plus Lua-specific '%I' and '%U'
  */
  const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
    BuffFS buff;  /* holds last part of the result */
    const char *e;  /* points to next '%' */
    buff.pushed = buff.blen = 0;
    buff.L = L;
    while ((e = strchr(fmt, '%')) != NULL) {
      addstr2buff(&buff, fmt, e - fmt);  /* add 'fmt' up to '%' */
      switch (*(e + 1)) {  /* conversion specifier */
        case 's': {  /* zero-terminated string */
          const char *s = va_arg(argp, char *);
          if (s == NULL) s = "(null)";
          addstr2buff(&buff, s, strlen(s));
          break;
        }
        case 'c': {  /* an 'int' as a character */
          char c = cast_uchar(va_arg(argp, int));
          addstr2buff(&buff, &c, sizeof(char));
          break;
        }
        case 'd': {  /* an 'int' */
          TValue num;
          setivalue(&num, va_arg(argp, int));
          addnum2buff(&buff, &num);
          break;
        }
        case 'I': {  /* a 'lua_Integer' */
          TValue num;
          setivalue(&num, cast(lua_Integer, va_arg(argp, l_uacInt)));
          addnum2buff(&buff, &num);
          break;
        }
        case 'f': {  /* a 'lua_Number' */
          TValue num;
          setfltvalue(&num, cast_num(va_arg(argp, l_uacNumber)));
          addnum2buff(&buff, &num);
          break;
        }
        case 'p': {  /* a pointer */
          const int sz = 3 * sizeof(void*) + 8; /* enough space for '%p' */
          char *bf = getbuff(&buff, sz);
          void *p = va_arg(argp, void *);
          int len = lua_pointer2str(bf, sz, p);
          addsize(&buff, len);
          break;
        }
        case 'U': {  /* a 'long' as a UTF-8 sequence */
          char bf[UTF8BUFFSZ];
          int len = luaO_utf8esc(bf, va_arg(argp, long));
          addstr2buff(&buff, bf + UTF8BUFFSZ - len, len);
          break;
        }
        case '%': {
          addstr2buff(&buff, "%", 1);
          break;
        }
        default: {
          luaG_runerror(L, "invalid option '%%%c' to 'lua_pushfstring'",
                           *(e + 1));
        }
      }
      fmt = e + 2;  /* skip '%' and the specifier */
    }
    addstr2buff(&buff, fmt, strlen(fmt));  /* rest of 'fmt' */
    clearbuff(&buff);  /* empty buffer into the stack */
    lua_assert(buff.pushed == 1);
    return svalue(s2v(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;
  }
  
  /* }================================================================== */
  
  
  #define RETS	"..."
  #define PRE	""
  #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 srclen) {
    size_t bufflen = LUA_IDSIZE;  /* free space in buffer */
    if (*source == '=') {  /* 'literal' source */
      if (srclen <= bufflen)  /* small enough? */
        memcpy(out, source + 1, srclen * sizeof(char));
      else {  /* truncate it */
        addstr(out, source + 1, bufflen - 1);
        *out = '\0';
      }
    }
    else if (*source == '@') {  /* file name */
      if (srclen <= bufflen)  /* small enough? */
        memcpy(out, source + 1, srclen * sizeof(char));
      else {  /* add '...' before rest of name */
        addstr(out, RETS, LL(RETS));
        bufflen -= LL(RETS);
        memcpy(out, source + 1 + srclen - 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 (srclen < bufflen && nl == NULL) {  /* small one-line source? */
        addstr(out, source, srclen);  /* keep it */
      }
      else {
        if (nl != NULL) srclen = nl - source;  /* stop at first newline */
        if (srclen > bufflen) srclen = bufflen;
        addstr(out, source, srclen);
        addstr(out, RETS, LL(RETS));
      }
      memcpy(out, POS, (LL(POS) + 1) * sizeof(char));
    }
  }
  
  