lua/src/lobject.c

   1 /*
   2 ** $Id: lobject.c,v 2.22 2006/02/10 17:43:52 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 }