1 /*

     2 ** $Id: lobject.c,v 2.22.1.1 2007/12/27 13:02:25 roberto Exp $

     3 ** Some generic functions over Lua objects

     4 ** See Copyright Notice in lua.h

     5 */

     6 

     7 #include <ctype.h>

     8 #include <stdarg.h>

     9 #include <stdio.h>

    10 #include <stdlib.h>

    11 #include <string.h>

    12 

    13 #define lobject_c

    14 #define LUA_CORE

    15 

    16 #include "lua.h"

    17 

    18 #include "ldo.h"

    19 #include "lmem.h"

    20 #include "lobject.h"

    21 #include "lstate.h"

    22 #include "lstring.h"

    23 #include "lvm.h"

    24 

    25 

    26 

    27 const TValue luaO_nilobject_ = {{NULL}, LUA_TNIL};

    28 

    29 

    30 /*

    31 ** converts an integer to a "floating point byte", represented as

    32 ** (eeeeexxx), where the real value is (1xxx) * 2^(eeeee - 1) if

    33 ** eeeee != 0 and (xxx) otherwise.

    34 */

    35 int luaO_int2fb (unsigned int x) {

    36   int e = 0;  /* expoent */

    37   while (x >= 16) {

    38     x = (x+1) >> 1;

    39     e++;

    40   }

    41   if (x < 8) return x;

    42   else return ((e+1) << 3) | (cast_int(x) - 8);

    43 }

    44 

    45 

    46 /* converts back */

    47 int luaO_fb2int (int x) {

    48   int e = (x >> 3) & 31;

    49   if (e == 0) return x;

    50   else return ((x & 7)+8) << (e - 1);

    51 }

    52 

    53 

    54 int luaO_log2 (unsigned int x) {

    55   static const lu_byte log_2[256] = {

    56     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,

    57     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,

    58     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,

    59     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,

    60     8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,

    61     8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,

    62     8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,

    63     8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8

    64   };

    65   int l = -1;

    66   while (x >= 256) { l += 8; x >>= 8; }

    67   return l + log_2[x];

    68 

    69 }

    70 

    71 

    72 int luaO_rawequalObj (const TValue *t1, const TValue *t2) {

    73   if (ttype(t1) != ttype(t2)) return 0;

    74   else switch (ttype(t1)) {

    75     case LUA_TNIL:

    76       return 1;

    77     case LUA_TNUMBER:

    78       return luai_numeq(nvalue(t1), nvalue(t2));

    79     case LUA_TBOOLEAN:

    80       return bvalue(t1) == bvalue(t2);  /* boolean true must be 1 !! */

    81     case LUA_TLIGHTUSERDATA:

    82       return pvalue(t1) == pvalue(t2);

    83     default:

    84       lua_assert(iscollectable(t1));

    85       return gcvalue(t1) == gcvalue(t2);

    86   }

    87 }

    88 

    89 

    90 int luaO_str2d (const char *s, lua_Number *result) {

    91   char *endptr;

    92   *result = lua_str2number(s, &endptr);

    93   if (endptr == s) return 0;  /* conversion failed */

    94   if (*endptr == 'x' || *endptr == 'X')  /* maybe an hexadecimal constant? */

    95     *result = cast_num(strtoul(s, &endptr, 16));

    96   if (*endptr == '\0') return 1;  /* most common case */

    97   while (isspace(cast(unsigned char, *endptr))) endptr++;

    98   if (*endptr != '\0') return 0;  /* invalid trailing characters? */

    99   return 1;

   100 }

   101 

   102 

   103 

   104 static void pushstr (lua_State *L, const char *str) {

   105   setsvalue2s(L, L->top, luaS_new(L, str));

   106   incr_top(L);

   107 }

   108 

   109 

   110 /* this function handles only `%d', `%c', %f, %p, and `%s' formats */

   111 const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {

   112   int n = 1;

   113   pushstr(L, "");

   114   for (;;) {

   115     const char *e = strchr(fmt, '%');

   116     if (e == NULL) break;

   117     setsvalue2s(L, L->top, luaS_newlstr(L, fmt, e-fmt));

   118     incr_top(L);

   119     switch (*(e+1)) {

   120       case 's': {

   121         const char *s = va_arg(argp, char *);

   122         if (s == NULL) s = "(null)";

   123         pushstr(L, s);

   124         break;

   125       }

   126       case 'c': {

   127         char buff[2];

   128         buff[0] = cast(char, va_arg(argp, int));

   129         buff[1] = '\0';

   130         pushstr(L, buff);

   131         break;

   132       }

   133       case 'd': {

   134         setnvalue(L->top, cast_num(va_arg(argp, int)));

   135         incr_top(L);

   136         break;

   137       }

   138       case 'f': {

   139         setnvalue(L->top, cast_num(va_arg(argp, l_uacNumber)));

   140         incr_top(L);

   141         break;

   142       }

   143       case 'p': {

   144         char buff[4*sizeof(void *) + 8]; /* should be enough space for a `%p' */

   145         sprintf(buff, "%p", va_arg(argp, void *));

   146         pushstr(L, buff);

   147         break;

   148       }

   149       case '%': {

   150         pushstr(L, "%");

   151         break;

   152       }

   153       default: {

   154         char buff[3];

   155         buff[0] = '%';

   156         buff[1] = *(e+1);

   157         buff[2] = '\0';

   158         pushstr(L, buff);

   159         break;

   160       }

   161     }

   162     n += 2;

   163     fmt = e+2;

   164   }

   165   pushstr(L, fmt);

   166   luaV_concat(L, n+1, cast_int(L->top - L->base) - 1);

   167   L->top -= n;

   168   return svalue(L->top - 1);

   169 }

   170 

   171 

   172 const char *luaO_pushfstring (lua_State *L, const char *fmt, ...) {

   173   const char *msg;

   174   va_list argp;

   175   va_start(argp, fmt);

   176   msg = luaO_pushvfstring(L, fmt, argp);

   177   va_end(argp);

   178   return msg;

   179 }

   180 

   181 

   182 void luaO_chunkid (char *out, const char *source, size_t bufflen) {

   183   if (*source == '=') {

   184     strncpy(out, source+1, bufflen);  /* remove first char */

   185     out[bufflen-1] = '\0';  /* ensures null termination */

   186   }

   187   else {  /* out = "source", or "...source" */

   188     if (*source == '@') {

   189       size_t l;

   190       source++;  /* skip the `@' */

   191       bufflen -= sizeof(" '...' ");

   192       l = strlen(source);

   193       strcpy(out, "");

   194       if (l > bufflen) {

   195         source += (l-bufflen);  /* get last part of file name */

   196         strcat(out, "...");

   197       }

   198       strcat(out, source);

   199     }

   200     else {  /* out = [string "string"] */

   201       size_t len = strcspn(source, "\n\r");  /* stop at first newline */

   202       bufflen -= sizeof(" [string \"...\"] ");

   203       if (len > bufflen) len = bufflen;

   204       strcpy(out, "[string \"");

   205       if (source[len] != '\0') {  /* must truncate? */

   206         strncat(out, source, len);

   207         strcat(out, "...");

   208       }

   209       else

   210         strcat(out, source);

   211       strcat(out, "\"]");

   212     }

   213   }

   214 }