liblua/lobject.c

   1 /*
   2 ** $Id: lobject.c,v 2.58 2013/02/20 14:08:56 roberto Exp $
   3 ** Some generic functions over Lua objects
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7 #include <stdarg.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11
  12 #define lobject_c
  13 #define LUA_CORE
  14
  15 #include "lua.h"
  16
  17 #include "lctype.h"
  18 #include "ldebug.h"
  19 #include "ldo.h"
  20 #include "lmem.h"
  21 #include "lobject.h"
  22 #include "lstate.h"
  23 #include "lstring.h"
  24 #include "lvm.h"
  25
  26
  27
  28 LUAI_DDEF const TValue luaO_nilobject_ = {NILCONSTANT};
  29
  30
  31 /*
  32 ** converts an integer to a "floating point byte", represented as
  33 ** (eeeeexxx), where the real value is (1xxx) * 2^(eeeee - 1) if
  34 ** eeeee != 0 and (xxx) otherwise.
  35 */
  36 int luaO_int2fb (unsigned int x) {
  37   int e = 0;  /* exponent */
  38   if (x < 8) return x;
  39   while (x >= 0x10) {
  40     x = (x+1) >> 1;
  41     e++;
  42   }
  43   return ((e+1) << 3) | (cast_int(x) - 8);
  44 }
  45
  46
  47 /* converts back */
  48 int luaO_fb2int (int x) {
  49   int e = (x >> 3) & 0x1f;
  50   if (e == 0) return x;
  51   else return ((x & 7) + 8) << (e - 1);
  52 }
  53
  54
  55 int luaO_ceillog2 (unsigned int x) {
  56   static const lu_byte log_2[256] = {
  57     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,
  58     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,
  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     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,
  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     8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8
  65   };
  66   int l = 0;
  67   x--;
  68   while (x >= 256) { l += 8; x >>= 8; }
  69   return l + log_2[x];
  70 }
  71
  72
  73 lua_Number luaO_arith (int op, lua_Number v1, lua_Number v2) {
  74   switch (op) {
  75     case LUA_OPADD: return luai_numadd(NULL, v1, v2);
  76     case LUA_OPSUB: return luai_numsub(NULL, v1, v2);
  77     case LUA_OPMUL: return luai_nummul(NULL, v1, v2);
  78     case LUA_OPDIV: return luai_numdiv(NULL, v1, v2);
  79     case LUA_OPMOD: return luai_nummod(NULL, v1, v2);
  80     case LUA_OPPOW: return luai_numpow(NULL, v1, v2);
  81     case LUA_OPUNM: return luai_numunm(NULL, v1);
  82     default: lua_assert(0); return 0;
  83   }
  84 }
  85
  86
  87 int luaO_hexavalue (int c) {
  88   if (lisdigit(c)) return c - '0';
  89   else return ltolower(c) - 'a' + 10;
  90 }
  91
  92
  93 #if !defined(lua_strx2number)
  94
  95 #include <math.h>
  96
  97
  98 static int isneg (const char **s) {
  99   if (**s == '-') { (*s)++; return 1; }
 100   else if (**s == '+') (*s)++;
 101   return 0;
 102 }
 103
 104
 105 static lua_Number readhexa (const char **s, lua_Number r, int *count) {
 106   for (; lisxdigit(cast_uchar(**s)); (*s)++) {  /* read integer part */
 107     r = (r * cast_num(16.0)) + cast_num(luaO_hexavalue(cast_uchar(**s)));
 108     (*count)++;
 109   }
 110   return r;
 111 }
 112
 113
 114 /*
 115 ** convert an hexadecimal numeric string to a number, following
 116 ** C99 specification for 'strtod'
 117 */
 118 static lua_Number lua_strx2number (const char *s, char **endptr) {
 119   lua_Number r = 0.0;
 120   int e = 0, i = 0;
 121   int neg = 0;  /* 1 if number is negative */
 122   *endptr = cast(char *, s);  /* nothing is valid yet */
 123   while (lisspace(cast_uchar(*s))) s++;  /* skip initial spaces */
 124   neg = isneg(&s);  /* check signal */
 125   if (!(*s == '0' && (*(s + 1) == 'x' || *(s + 1) == 'X')))  /* check '0x' */
 126     return 0.0;  /* invalid format (no '0x') */
 127   s += 2;  /* skip '0x' */
 128   r = readhexa(&s, r, &i);  /* read integer part */
 129   if (*s == '.') {
 130     s++;  /* skip dot */
 131     r = readhexa(&s, r, &e);  /* read fractional part */
 132   }
 133   if (i == 0 && e == 0)
 134     return 0.0;  /* invalid format (no digit) */
 135   e *= -4;  /* each fractional digit divides value by 2^-4 */
 136   *endptr = cast(char *, s);  /* valid up to here */
 137   if (*s == 'p' || *s == 'P') {  /* exponent part? */
 138     int exp1 = 0;
 139     int neg1;
 140     s++;  /* skip 'p' */
 141     neg1 = isneg(&s);  /* signal */
 142     if (!lisdigit(cast_uchar(*s)))
 143       goto ret;  /* must have at least one digit */
 144     while (lisdigit(cast_uchar(*s)))  /* read exponent */
 145       exp1 = exp1 * 10 + *(s++) - '0';
 146     if (neg1) exp1 = -exp1;
 147     e += exp1;
 148   }
 149   *endptr = cast(char *, s);  /* valid up to here */
 150  ret:
 151   if (neg) r = -r;
 152   return l_mathop(ldexp)(r, e);
 153 }
 154
 155 #endif
 156
 157
 158 int luaO_str2d (const char *s, size_t len, lua_Number *result) {
 159   char *endptr;
 160   if (strpbrk(s, "nN"))  /* reject 'inf' and 'nan' */
 161     return 0;
 162   else if (strpbrk(s, "xX"))  /* hexa? */
 163     *result = lua_strx2number(s, &endptr);
 164   else
 165     *result = lua_str2number(s, &endptr);
 166   if (endptr == s) return 0;  /* nothing recognized */
 167   while (lisspace(cast_uchar(*endptr))) endptr++;
 168   return (endptr == s + len);  /* OK if no trailing characters */
 169 }
 170
 171
 172
 173 static void pushstr (lua_State *L, const char *str, size_t l) {
 174   setsvalue2s(L, L->top++, luaS_newlstr(L, str, l));
 175 }
 176
 177
 178 /* this function handles only `%d', `%c', %f, %p, and `%s' formats */
 179 const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
 180   int n = 0;
 181   for (;;) {
 182     const char *e = strchr(fmt, '%');
 183     if (e == NULL) break;
 184     luaD_checkstack(L, 2);  /* fmt + item */
 185     pushstr(L, fmt, e - fmt);
 186     switch (*(e+1)) {
 187       case 's': {
 188         const char *s = va_arg(argp, char *);
 189         if (s == NULL) s = "(null)";
 190         pushstr(L, s, strlen(s));
 191         break;
 192       }
 193       case 'c': {
 194         char buff;
 195         buff = cast(char, va_arg(argp, int));
 196         pushstr(L, &buff, 1);
 197         break;
 198       }
 199       case 'd': {
 200         setnvalue(L->top++, cast_num(va_arg(argp, int)));
 201         break;
 202       }
 203       case 'f': {
 204         setnvalue(L->top++, cast_num(va_arg(argp, l_uacNumber)));
 205         break;
 206       }
 207       case 'p': {
 208         char buff[4*sizeof(void *) + 8]; /* should be enough space for a `%p' */
 209         int l = sprintf(buff, "%p", va_arg(argp, void *));
 210         pushstr(L, buff, l);
 211         break;
 212       }
 213       case '%': {
 214         pushstr(L, "%", 1);
 215         break;
 216       }
 217       default: {
 218         luaG_runerror(L,
 219             "invalid option " LUA_QL("%%%c") " to " LUA_QL("lua_pushfstring"),
 220             *(e + 1));
 221       }
 222     }
 223     n += 2;
 224     fmt = e+2;
 225   }
 226   luaD_checkstack(L, 1);
 227   pushstr(L, fmt, strlen(fmt));
 228   if (n > 0) luaV_concat(L, n + 1);
 229   return svalue(L->top - 1);
 230 }
 231
 232
 233 const char *luaO_pushfstring (lua_State *L, const char *fmt, ...) {
 234   const char *msg;
 235   va_list argp;
 236   va_start(argp, fmt);
 237   msg = luaO_pushvfstring(L, fmt, argp);
 238   va_end(argp);
 239   return msg;
 240 }
 241
 242
 243 /* number of chars of a literal string without the ending \0 */
 244 #define LL(x)   (sizeof(x)/sizeof(char) - 1)
 245
 246 #define RETS    "..."
 247 #define PRE     "[string \""
 248 #define POS     "\"]"
 249
 250 #define addstr(a,b,l)   ( memcpy(a,b,(l) * sizeof(char)), a += (l) )
 251
 252 void luaO_chunkid (char *out, const char *source, size_t bufflen) {
 253   size_t l = strlen(source);
 254   if (*source == '=') {  /* 'literal' source */
 255     if (l <= bufflen)  /* small enough? */
 256       memcpy(out, source + 1, l * sizeof(char));
 257     else {  /* truncate it */
 258       addstr(out, source + 1, bufflen - 1);
 259       *out = '\0';
 260     }
 261   }
 262   else if (*source == '@') {  /* file name */
 263     if (l <= bufflen)  /* small enough? */
 264       memcpy(out, source + 1, l * sizeof(char));
 265     else {  /* add '...' before rest of name */
 266       addstr(out, RETS, LL(RETS));
 267       bufflen -= LL(RETS);
 268       memcpy(out, source + 1 + l - bufflen, bufflen * sizeof(char));
 269     }
 270   }
 271   else {  /* string; format as [string "source"] */
 272     const char *nl = strchr(source, '\n');  /* find first new line (if any) */
 273     addstr(out, PRE, LL(PRE));  /* add prefix */
 274     bufflen -= LL(PRE RETS POS) + 1;  /* save space for prefix+suffix+'\0' */
 275     if (l < bufflen && nl == NULL) {  /* small one-line source? */
 276       addstr(out, source, l);  /* keep it */
 277     }
 278     else {
 279       if (nl != NULL) l = nl - source;  /* stop at first newline */
 280       if (l > bufflen) l = bufflen;
 281       addstr(out, source, l);
 282       addstr(out, RETS, LL(RETS));
 283     }
 284     memcpy(out, POS, (LL(POS) + 1) * sizeof(char));
 285   }
 286 }
 287