mudgangster

Tiny, scriptable MUD client
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lobject.cc (16512B)


      1 /*
      2 ** $Id: lobject.c,v 2.113.1.1 2017/04/19 17:29:57 roberto Exp $
      3 ** Some generic functions over Lua objects
      4 ** See Copyright Notice in lua.h
      5 */
      6 
      7 #define lobject_c
      8 #define LUA_CORE
      9 
     10 #include "lprefix.h"
     11 
     12 
     13 #include <locale.h>
     14 #include <math.h>
     15 #include <stdarg.h>
     16 #include <stdio.h>
     17 #include <stdlib.h>
     18 #include <string.h>
     19 
     20 #include "lua.h"
     21 
     22 #include "lctype.h"
     23 #include "ldebug.h"
     24 #include "ldo.h"
     25 #include "lmem.h"
     26 #include "lobject.h"
     27 #include "lstate.h"
     28 #include "lstring.h"
     29 #include "lvm.h"
     30 
     31 
     32 
     33 LUAI_DDEF const TValue luaO_nilobject_ = {NILCONSTANT};
     34 
     35 
     36 /*
     37 ** converts an integer to a "floating point byte", represented as
     38 ** (eeeeexxx), where the real value is (1xxx) * 2^(eeeee - 1) if
     39 ** eeeee != 0 and (xxx) otherwise.
     40 */
     41 int luaO_int2fb (unsigned int x) {
     42   int e = 0;  /* exponent */
     43   if (x < 8) return x;
     44   while (x >= (8 << 4)) {  /* coarse steps */
     45     x = (x + 0xf) >> 4;  /* x = ceil(x / 16) */
     46     e += 4;
     47   }
     48   while (x >= (8 << 1)) {  /* fine steps */
     49     x = (x + 1) >> 1;  /* x = ceil(x / 2) */
     50     e++;
     51   }
     52   return ((e+1) << 3) | (cast_int(x) - 8);
     53 }
     54 
     55 
     56 /* converts back */
     57 int luaO_fb2int (int x) {
     58   return (x < 8) ? x : ((x & 7) + 8) << ((x >> 3) - 1);
     59 }
     60 
     61 
     62 /*
     63 ** Computes ceil(log2(x))
     64 */
     65 int luaO_ceillog2 (unsigned int x) {
     66   static const lu_byte log_2[256] = {  /* log_2[i] = ceil(log2(i - 1)) */
     67     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,
     68     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,
     69     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,
     70     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,
     71     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,
     72     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,
     73     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,
     74     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
     75   };
     76   int l = 0;
     77   x--;
     78   while (x >= 256) { l += 8; x >>= 8; }
     79   return l + log_2[x];
     80 }
     81 
     82 
     83 static lua_Integer intarith (lua_State *L, int op, lua_Integer v1,
     84                                                    lua_Integer v2) {
     85   switch (op) {
     86     case LUA_OPADD: return intop(+, v1, v2);
     87     case LUA_OPSUB:return intop(-, v1, v2);
     88     case LUA_OPMUL:return intop(*, v1, v2);
     89     case LUA_OPMOD: return luaV_mod(L, v1, v2);
     90     case LUA_OPIDIV: return luaV_div(L, v1, v2);
     91     case LUA_OPBAND: return intop(&, v1, v2);
     92     case LUA_OPBOR: return intop(|, v1, v2);
     93     case LUA_OPBXOR: return intop(^, v1, v2);
     94     case LUA_OPSHL: return luaV_shiftl(v1, v2);
     95     case LUA_OPSHR: return luaV_shiftl(v1, -v2);
     96     case LUA_OPUNM: return intop(-, 0, v1);
     97     case LUA_OPBNOT: return intop(^, ~l_castS2U(0), v1);
     98     default: lua_assert(0); return 0;
     99   }
    100 }
    101 
    102 
    103 static lua_Number numarith (lua_State *L, int op, lua_Number v1,
    104                                                   lua_Number v2) {
    105   switch (op) {
    106     case LUA_OPADD: return luai_numadd(L, v1, v2);
    107     case LUA_OPSUB: return luai_numsub(L, v1, v2);
    108     case LUA_OPMUL: return luai_nummul(L, v1, v2);
    109     case LUA_OPDIV: return luai_numdiv(L, v1, v2);
    110     case LUA_OPPOW: return luai_numpow(L, v1, v2);
    111     case LUA_OPIDIV: return luai_numidiv(L, v1, v2);
    112     case LUA_OPUNM: return luai_numunm(L, v1);
    113     case LUA_OPMOD: {
    114       lua_Number m;
    115       luai_nummod(L, v1, v2, m);
    116       return m;
    117     }
    118     default: lua_assert(0); return 0;
    119   }
    120 }
    121 
    122 
    123 void luaO_arith (lua_State *L, int op, const TValue *p1, const TValue *p2,
    124                  TValue *res) {
    125   switch (op) {
    126     case LUA_OPBAND: case LUA_OPBOR: case LUA_OPBXOR:
    127     case LUA_OPSHL: case LUA_OPSHR:
    128     case LUA_OPBNOT: {  /* operate only on integers */
    129       lua_Integer i1; lua_Integer i2;
    130       if (tointeger(p1, &i1) && tointeger(p2, &i2)) {
    131         setivalue(res, intarith(L, op, i1, i2));
    132         return;
    133       }
    134       else break;  /* go to the end */
    135     }
    136     case LUA_OPDIV: case LUA_OPPOW: {  /* operate only on floats */
    137       lua_Number n1; lua_Number n2;
    138       if (tonumber(p1, &n1) && tonumber(p2, &n2)) {
    139         setfltvalue(res, numarith(L, op, n1, n2));
    140         return;
    141       }
    142       else break;  /* go to the end */
    143     }
    144     default: {  /* other operations */
    145       lua_Number n1; lua_Number n2;
    146       if (ttisinteger(p1) && ttisinteger(p2)) {
    147         setivalue(res, intarith(L, op, ivalue(p1), ivalue(p2)));
    148         return;
    149       }
    150       else if (tonumber(p1, &n1) && tonumber(p2, &n2)) {
    151         setfltvalue(res, numarith(L, op, n1, n2));
    152         return;
    153       }
    154       else break;  /* go to the end */
    155     }
    156   }
    157   /* could not perform raw operation; try metamethod */
    158   lua_assert(L != NULL);  /* should not fail when folding (compile time) */
    159   luaT_trybinTM(L, p1, p2, res, cast(TMS, (op - LUA_OPADD) + TM_ADD));
    160 }
    161 
    162 
    163 int luaO_hexavalue (int c) {
    164   if (lisdigit(c)) return c - '0';
    165   else return (ltolower(c) - 'a') + 10;
    166 }
    167 
    168 
    169 static int isneg (const char **s) {
    170   if (**s == '-') { (*s)++; return 1; }
    171   else if (**s == '+') (*s)++;
    172   return 0;
    173 }
    174 
    175 
    176 
    177 /*
    178 ** {==================================================================
    179 ** Lua's implementation for 'lua_strx2number'
    180 ** ===================================================================
    181 */
    182 
    183 #if !defined(lua_strx2number)
    184 
    185 /* maximum number of significant digits to read (to avoid overflows
    186    even with single floats) */
    187 #define MAXSIGDIG	30
    188 
    189 /*
    190 ** convert an hexadecimal numeric string to a number, following
    191 ** C99 specification for 'strtod'
    192 */
    193 static lua_Number lua_strx2number (const char *s, char **endptr) {
    194   int dot = lua_getlocaledecpoint();
    195   lua_Number r = 0.0;  /* result (accumulator) */
    196   int sigdig = 0;  /* number of significant digits */
    197   int nosigdig = 0;  /* number of non-significant digits */
    198   int e = 0;  /* exponent correction */
    199   int neg;  /* 1 if number is negative */
    200   int hasdot = 0;  /* true after seen a dot */
    201   *endptr = cast(char *, s);  /* nothing is valid yet */
    202   while (lisspace(cast_uchar(*s))) s++;  /* skip initial spaces */
    203   neg = isneg(&s);  /* check signal */
    204   if (!(*s == '0' && (*(s + 1) == 'x' || *(s + 1) == 'X')))  /* check '0x' */
    205     return 0.0;  /* invalid format (no '0x') */
    206   for (s += 2; ; s++) {  /* skip '0x' and read numeral */
    207     if (*s == dot) {
    208       if (hasdot) break;  /* second dot? stop loop */
    209       else hasdot = 1;
    210     }
    211     else if (lisxdigit(cast_uchar(*s))) {
    212       if (sigdig == 0 && *s == '0')  /* non-significant digit (zero)? */
    213         nosigdig++;
    214       else if (++sigdig <= MAXSIGDIG)  /* can read it without overflow? */
    215           r = (r * cast_num(16.0)) + luaO_hexavalue(*s);
    216       else e++; /* too many digits; ignore, but still count for exponent */
    217       if (hasdot) e--;  /* decimal digit? correct exponent */
    218     }
    219     else break;  /* neither a dot nor a digit */
    220   }
    221   if (nosigdig + sigdig == 0)  /* no digits? */
    222     return 0.0;  /* invalid format */
    223   *endptr = cast(char *, s);  /* valid up to here */
    224   e *= 4;  /* each digit multiplies/divides value by 2^4 */
    225   if (*s == 'p' || *s == 'P') {  /* exponent part? */
    226     int exp1 = 0;  /* exponent value */
    227     int neg1;  /* exponent signal */
    228     s++;  /* skip 'p' */
    229     neg1 = isneg(&s);  /* signal */
    230     if (!lisdigit(cast_uchar(*s)))
    231       return 0.0;  /* invalid; must have at least one digit */
    232     while (lisdigit(cast_uchar(*s)))  /* read exponent */
    233       exp1 = exp1 * 10 + *(s++) - '0';
    234     if (neg1) exp1 = -exp1;
    235     e += exp1;
    236     *endptr = cast(char *, s);  /* valid up to here */
    237   }
    238   if (neg) r = -r;
    239   return l_mathop(ldexp)(r, e);
    240 }
    241 
    242 #endif
    243 /* }====================================================== */
    244 
    245 
    246 /* maximum length of a numeral */
    247 #if !defined (L_MAXLENNUM)
    248 #define L_MAXLENNUM	200
    249 #endif
    250 
    251 static const char *l_str2dloc (const char *s, lua_Number *result, int mode) {
    252   char *endptr;
    253   *result = (mode == 'x') ? lua_strx2number(s, &endptr)  /* try to convert */
    254                           : lua_str2number(s, &endptr);
    255   if (endptr == s) return NULL;  /* nothing recognized? */
    256   while (lisspace(cast_uchar(*endptr))) endptr++;  /* skip trailing spaces */
    257   return (*endptr == '\0') ? endptr : NULL;  /* OK if no trailing characters */
    258 }
    259 
    260 
    261 /*
    262 ** Convert string 's' to a Lua number (put in 'result'). Return NULL
    263 ** on fail or the address of the ending '\0' on success.
    264 ** 'pmode' points to (and 'mode' contains) special things in the string:
    265 ** - 'x'/'X' means an hexadecimal numeral
    266 ** - 'n'/'N' means 'inf' or 'nan' (which should be rejected)
    267 ** - '.' just optimizes the search for the common case (nothing special)
    268 ** This function accepts both the current locale or a dot as the radix
    269 ** mark. If the convertion fails, it may mean number has a dot but
    270 ** locale accepts something else. In that case, the code copies 's'
    271 ** to a buffer (because 's' is read-only), changes the dot to the
    272 ** current locale radix mark, and tries to convert again.
    273 */
    274 static const char *l_str2d (const char *s, lua_Number *result) {
    275   const char *endptr;
    276   const char *pmode = strpbrk(s, ".xXnN");
    277   int mode = pmode ? ltolower(cast_uchar(*pmode)) : 0;
    278   if (mode == 'n')  /* reject 'inf' and 'nan' */
    279     return NULL;
    280   endptr = l_str2dloc(s, result, mode);  /* try to convert */
    281   if (endptr == NULL) {  /* failed? may be a different locale */
    282     char buff[L_MAXLENNUM + 1];
    283     const char *pdot = strchr(s, '.');
    284     if (strlen(s) > L_MAXLENNUM || pdot == NULL)
    285       return NULL;  /* string too long or no dot; fail */
    286     strcpy(buff, s);  /* copy string to buffer */
    287     buff[pdot - s] = lua_getlocaledecpoint();  /* correct decimal point */
    288     endptr = l_str2dloc(buff, result, mode);  /* try again */
    289     if (endptr != NULL)
    290       endptr = s + (endptr - buff);  /* make relative to 's' */
    291   }
    292   return endptr;
    293 }
    294 
    295 
    296 #define MAXBY10		cast(lua_Unsigned, LUA_MAXINTEGER / 10)
    297 #define MAXLASTD	cast_int(LUA_MAXINTEGER % 10)
    298 
    299 static const char *l_str2int (const char *s, lua_Integer *result) {
    300   lua_Unsigned a = 0;
    301   int empty = 1;
    302   int neg;
    303   while (lisspace(cast_uchar(*s))) s++;  /* skip initial spaces */
    304   neg = isneg(&s);
    305   if (s[0] == '0' &&
    306       (s[1] == 'x' || s[1] == 'X')) {  /* hex? */
    307     s += 2;  /* skip '0x' */
    308     for (; lisxdigit(cast_uchar(*s)); s++) {
    309       a = a * 16 + luaO_hexavalue(*s);
    310       empty = 0;
    311     }
    312   }
    313   else {  /* decimal */
    314     for (; lisdigit(cast_uchar(*s)); s++) {
    315       int d = *s - '0';
    316       if (a >= MAXBY10 && (a > MAXBY10 || d > MAXLASTD + neg))  /* overflow? */
    317         return NULL;  /* do not accept it (as integer) */
    318       a = a * 10 + d;
    319       empty = 0;
    320     }
    321   }
    322   while (lisspace(cast_uchar(*s))) s++;  /* skip trailing spaces */
    323   if (empty || *s != '\0') return NULL;  /* something wrong in the numeral */
    324   else {
    325     *result = l_castU2S((neg) ? 0u - a : a);
    326     return s;
    327   }
    328 }
    329 
    330 
    331 size_t luaO_str2num (const char *s, TValue *o) {
    332   lua_Integer i; lua_Number n;
    333   const char *e;
    334   if ((e = l_str2int(s, &i)) != NULL) {  /* try as an integer */
    335     setivalue(o, i);
    336   }
    337   else if ((e = l_str2d(s, &n)) != NULL) {  /* else try as a float */
    338     setfltvalue(o, n);
    339   }
    340   else
    341     return 0;  /* conversion failed */
    342   return (e - s) + 1;  /* success; return string size */
    343 }
    344 
    345 
    346 int luaO_utf8esc (char *buff, unsigned long x) {
    347   int n = 1;  /* number of bytes put in buffer (backwards) */
    348   lua_assert(x <= 0x10FFFF);
    349   if (x < 0x80)  /* ascii? */
    350     buff[UTF8BUFFSZ - 1] = cast(char, x);
    351   else {  /* need continuation bytes */
    352     unsigned int mfb = 0x3f;  /* maximum that fits in first byte */
    353     do {  /* add continuation bytes */
    354       buff[UTF8BUFFSZ - (n++)] = cast(char, 0x80 | (x & 0x3f));
    355       x >>= 6;  /* remove added bits */
    356       mfb >>= 1;  /* now there is one less bit available in first byte */
    357     } while (x > mfb);  /* still needs continuation byte? */
    358     buff[UTF8BUFFSZ - n] = cast(char, (~mfb << 1) | x);  /* add first byte */
    359   }
    360   return n;
    361 }
    362 
    363 
    364 /* maximum length of the conversion of a number to a string */
    365 #define MAXNUMBER2STR	50
    366 
    367 
    368 /*
    369 ** Convert a number object to a string
    370 */
    371 void luaO_tostring (lua_State *L, StkId obj) {
    372   char buff[MAXNUMBER2STR];
    373   size_t len;
    374   lua_assert(ttisnumber(obj));
    375   if (ttisinteger(obj))
    376     len = lua_integer2str(buff, sizeof(buff), ivalue(obj));
    377   else {
    378     len = lua_number2str(buff, sizeof(buff), fltvalue(obj));
    379 #if !defined(LUA_COMPAT_FLOATSTRING)
    380     if (buff[strspn(buff, "-0123456789")] == '\0') {  /* looks like an int? */
    381       buff[len++] = lua_getlocaledecpoint();
    382       buff[len++] = '0';  /* adds '.0' to result */
    383     }
    384 #endif
    385   }
    386   setsvalue2s(L, obj, luaS_newlstr(L, buff, len));
    387 }
    388 
    389 
    390 static void pushstr (lua_State *L, const char *str, size_t l) {
    391   setsvalue2s(L, L->top, luaS_newlstr(L, str, l));
    392   luaD_inctop(L);
    393 }
    394 
    395 
    396 /*
    397 ** this function handles only '%d', '%c', '%f', '%p', and '%s'
    398    conventional formats, plus Lua-specific '%I' and '%U'
    399 */
    400 const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
    401   int n = 0;
    402   for (;;) {
    403     const char *e = strchr(fmt, '%');
    404     if (e == NULL) break;
    405     pushstr(L, fmt, e - fmt);
    406     switch (*(e+1)) {
    407       case 's': {  /* zero-terminated string */
    408         const char *s = va_arg(argp, char *);
    409         if (s == NULL) s = "(null)";
    410         pushstr(L, s, strlen(s));
    411         break;
    412       }
    413       case 'c': {  /* an 'int' as a character */
    414         char buff = cast(char, va_arg(argp, int));
    415         if (lisprint(cast_uchar(buff)))
    416           pushstr(L, &buff, 1);
    417         else  /* non-printable character; print its code */
    418           luaO_pushfstring(L, "<\\%d>", cast_uchar(buff));
    419         break;
    420       }
    421       case 'd': {  /* an 'int' */
    422         setivalue(L->top, va_arg(argp, int));
    423         goto top2str;
    424       }
    425       case 'I': {  /* a 'lua_Integer' */
    426         setivalue(L->top, cast(lua_Integer, va_arg(argp, l_uacInt)));
    427         goto top2str;
    428       }
    429       case 'f': {  /* a 'lua_Number' */
    430         setfltvalue(L->top, cast_num(va_arg(argp, l_uacNumber)));
    431       top2str:  /* convert the top element to a string */
    432         luaD_inctop(L);
    433         luaO_tostring(L, L->top - 1);
    434         break;
    435       }
    436       case 'p': {  /* a pointer */
    437         char buff[4*sizeof(void *) + 8]; /* should be enough space for a '%p' */
    438         void *p = va_arg(argp, void *);
    439         int l = lua_pointer2str(buff, sizeof(buff), p);
    440         pushstr(L, buff, l);
    441         break;
    442       }
    443       case 'U': {  /* an 'int' as a UTF-8 sequence */
    444         char buff[UTF8BUFFSZ];
    445         int l = luaO_utf8esc(buff, cast(long, va_arg(argp, long)));
    446         pushstr(L, buff + UTF8BUFFSZ - l, l);
    447         break;
    448       }
    449       case '%': {
    450         pushstr(L, "%", 1);
    451         break;
    452       }
    453       default: {
    454         luaG_runerror(L, "invalid option '%%%c' to 'lua_pushfstring'",
    455                          *(e + 1));
    456       }
    457     }
    458     n += 2;
    459     fmt = e+2;
    460   }
    461   luaD_checkstack(L, 1);
    462   pushstr(L, fmt, strlen(fmt));
    463   if (n > 0) luaV_concat(L, n + 1);
    464   return svalue(L->top - 1);
    465 }
    466 
    467 
    468 const char *luaO_pushfstring (lua_State *L, const char *fmt, ...) {
    469   const char *msg;
    470   va_list argp;
    471   va_start(argp, fmt);
    472   msg = luaO_pushvfstring(L, fmt, argp);
    473   va_end(argp);
    474   return msg;
    475 }
    476 
    477 
    478 /* number of chars of a literal string without the ending \0 */
    479 #define LL(x)	(sizeof(x)/sizeof(char) - 1)
    480 
    481 #define RETS	"..."
    482 #define PRE	"[string \""
    483 #define POS	"\"]"
    484 
    485 #define addstr(a,b,l)	( memcpy(a,b,(l) * sizeof(char)), a += (l) )
    486 
    487 void luaO_chunkid (char *out, const char *source, size_t bufflen) {
    488   size_t l = strlen(source);
    489   if (*source == '=') {  /* 'literal' source */
    490     if (l <= bufflen)  /* small enough? */
    491       memcpy(out, source + 1, l * sizeof(char));
    492     else {  /* truncate it */
    493       addstr(out, source + 1, bufflen - 1);
    494       *out = '\0';
    495     }
    496   }
    497   else if (*source == '@') {  /* file name */
    498     if (l <= bufflen)  /* small enough? */
    499       memcpy(out, source + 1, l * sizeof(char));
    500     else {  /* add '...' before rest of name */
    501       addstr(out, RETS, LL(RETS));
    502       bufflen -= LL(RETS);
    503       memcpy(out, source + 1 + l - bufflen, bufflen * sizeof(char));
    504     }
    505   }
    506   else {  /* string; format as [string "source"] */
    507     const char *nl = strchr(source, '\n');  /* find first new line (if any) */
    508     addstr(out, PRE, LL(PRE));  /* add prefix */
    509     bufflen -= LL(PRE RETS POS) + 1;  /* save space for prefix+suffix+'\0' */
    510     if (l < bufflen && nl == NULL) {  /* small one-line source? */
    511       addstr(out, source, l);  /* keep it */
    512     }
    513     else {
    514       if (nl != NULL) l = nl - source;  /* stop at first newline */
    515       if (l > bufflen) l = bufflen;
    516       addstr(out, source, l);
    517       addstr(out, RETS, LL(RETS));
    518     }
    519     memcpy(out, POS, (LL(POS) + 1) * sizeof(char));
    520   }
    521 }
    522