text: /*
  ** $Id: lobject.c,v 2.22.1.1 2007/12/27 13:02:25 roberto Exp $
  ** Some generic functions over Lua objects
  ** See Copyright Notice in lua.h
  */
  
  #include <ctype.h>
  #include <stdarg.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #define lobject_c
  #define LUA_CORE
  
  #include "lua.h"
  
  #include "ldo.h"
  #include "lmem.h"
  #include "lobject.h"
  #include "lstate.h"
  #include "lstring.h"
  #include "lvm.h"
  
  
  
  const TValue luaO_nilobject_ = {{NULL}, LUA_TNIL};
  
  
  /*
  ** 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;  /* expoent */
    while (x >= 16) {
      x = (x+1) >> 1;
      e++;
    }
    if (x < 8) return x;
    else return ((e+1) << 3) | (cast_int(x) - 8);
  }
  
  
  /* converts back */
  int luaO_fb2int (int x) {
    int e = (x >> 3) & 31;
    if (e == 0) return x;
    else return ((x & 7)+8) << (e - 1);
  }
  
  
  int luaO_log2 (unsigned int x) {
    static const lu_byte log_2[256] = {
      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 = -1;
    while (x >= 256) { l += 8; x >>= 8; }
    return l + log_2[x];
  
  }
  
  
  int luaO_rawequalObj (const TValue *t1, const TValue *t2) {
    if (ttype(t1) != ttype(t2)) return 0;
    else switch (ttype(t1)) {
      case LUA_TNIL:
        return 1;
      case LUA_TNUMBER:
        return luai_numeq(nvalue(t1), nvalue(t2));
      case LUA_TBOOLEAN:
        return bvalue(t1) == bvalue(t2);  /* boolean true must be 1 !! */
      case LUA_TLIGHTUSERDATA:
      case LUA_TROTABLE:
      case LUA_TLIGHTFUNCTION:
        return pvalue(t1) == pvalue(t2);
      default:
        lua_assert(iscollectable(t1));
        return gcvalue(t1) == gcvalue(t2);
    }
  }
  
  
  int luaO_str2d (const char *s, lua_Number *result) {
    char *endptr;
    *result = lua_str2number(s, &endptr);
    if (endptr == s) return 0;  /* conversion failed */
    if (*endptr == 'x' || *endptr == 'X')  /* maybe an hexadecimal constant? */
      *result = cast_num(strtoul(s, &endptr, 16));
    if (*endptr == '\0') return 1;  /* most common case */
    while (isspace(cast(unsigned char, *endptr))) endptr++;
    if (*endptr != '\0') return 0;  /* invalid trailing characters? */
    return 1;
  }
  
  
  
  static void pushstr (lua_State *L, const char *str) {
    setsvalue2s(L, L->top, luaS_new(L, str));
    incr_top(L);
  }
  
  
  /* this function handles only `%d', `%c', %f, %p, and `%s' formats */
  const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
    int n = 1;
    pushstr(L, "");
    for (;;) {
      const char *e = strchr(fmt, '%');
      if (e == NULL) break;
      setsvalue2s(L, L->top, luaS_newlstr(L, fmt, e-fmt));
      incr_top(L);
      switch (*(e+1)) {
        case 's': {
          const char *s = va_arg(argp, char *);
          if (s == NULL) s = "(null)";
          pushstr(L, s);
          break;
        }
        case 'c': {
          char buff[2];
          buff[0] = cast(char, va_arg(argp, int));
          buff[1] = '\0';
          pushstr(L, buff);
          break;
        }
        case 'd': {
          setnvalue(L->top, cast_num(va_arg(argp, int)));
          incr_top(L);
          break;
        }
        case 'f': {
          setnvalue(L->top, cast_num(va_arg(argp, l_uacNumber)));
          incr_top(L);
          break;
        }
        case 'p': {
          char buff[4*sizeof(void *) + 8]; /* should be enough space for a `%p' */
          sprintf(buff, "%p", va_arg(argp, void *));
          pushstr(L, buff);
          break;
        }
        case '%': {
          pushstr(L, "%");
          break;
        }
        default: {
          char buff[3];
          buff[0] = '%';
          buff[1] = *(e+1);
          buff[2] = '\0';
          pushstr(L, buff);
          break;
        }
      }
      n += 2;
      fmt = e+2;
    }
    pushstr(L, fmt);
    luaV_concat(L, n+1, cast_int(L->top - L->base) - 1);
    L->top -= n;
    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;
  }
  
  
  void luaO_chunkid (char *out, const char *source, size_t bufflen) {
    if (*source == '=') {
      strncpy(out, source+1, bufflen);  /* remove first char */
      out[bufflen-1] = '\0';  /* ensures null termination */
    }
    else {  /* out = "source", or "...source" */
      if (*source == '@') {
        size_t l;
        source++;  /* skip the `@' */
        bufflen -= sizeof(" '...' ");
        l = strlen(source);
        strcpy(out, "");
        if (l > bufflen) {
          source += (l-bufflen);  /* get last part of file name */
          strcat(out, "...");
        }
        strcat(out, source);
      }
      else {  /* out = [string "string"] */
        size_t len = strcspn(source, "\n\r");  /* stop at first newline */
        bufflen -= sizeof(" [string \"...\"] ");
        if (len > bufflen) len = bufflen;
        strcpy(out, "[string \"");
        if (source[len] != '\0') {  /* must truncate? */
          strncat(out, source, len);
          strcat(out, "...");
        }
        else
          strcat(out, source);
        strcat(out, "\"]");
      }
    }
  }
  