Home | History | Annotate | Download | only in src
      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 
    288