# lobject.c (5.3.5)

```/*
** \$Id: lobject.c,v 2.113.1.1 2017/04/19 17:29:57 roberto Exp \$
** Some generic functions over Lua objects
** See Copyright Notice in lua.h
*/

#define lobject_c
#define LUA_CORE

#include "lprefix.h"

#include <locale.h>
#include <math.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "lua.h"

#include "lctype.h"
#include "ldebug.h"
#include "ldo.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "lstring.h"
#include "lvm.h"

LUAI_DDEF const TValue luaO_nilobject_ = {NILCONSTANT};

/*
** converts an integer to a "floating point byte", represented as
** (eeeeexxx), where the real value is (1xxx) * 2^(eeeee - 1) if
** eeeee != 0 and (xxx) otherwise.
*/
int luaO_int2fb (unsigned int x) {
int e = 0;  /* exponent */
if (x < 8) return x;
while (x >= (8 << 4)) {  /* coarse steps */
x = (x + 0xf) >> 4;  /* x = ceil(x / 16) */
e += 4;
}
while (x >= (8 << 1)) {  /* fine steps */
x = (x + 1) >> 1;  /* x = ceil(x / 2) */
e++;
}
return ((e+1) << 3) | (cast_int(x) - 8);
}

/* converts back */
int luaO_fb2int (int x) {
return (x < 8) ? x : ((x & 7) + 8) << ((x >> 3) - 1);
}

/*
** Computes ceil(log2(x))
*/
int luaO_ceillog2 (unsigned int x) {
static const lu_byte log_2[256] = {  /* log_2[i] = ceil(log2(i - 1)) */
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,
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,
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,
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,
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,
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,
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,
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
};
int l = 0;
x--;
while (x >= 256) { l += 8; x >>= 8; }
return l + log_2[x];
}

static lua_Integer intarith (lua_State *L, int op, lua_Integer v1,
lua_Integer v2) {
switch (op) {
case LUA_OPADD: return intop(+, v1, v2);
case LUA_OPSUB:return intop(-, v1, v2);
case LUA_OPMUL:return intop(*, v1, v2);
case LUA_OPMOD: return luaV_mod(L, v1, v2);
case LUA_OPIDIV: return luaV_div(L, v1, v2);
case LUA_OPBAND: return intop(&, v1, v2);
case LUA_OPBOR: return intop(|, v1, v2);
case LUA_OPBXOR: return intop(^, v1, v2);
case LUA_OPSHL: return luaV_shiftl(v1, v2);
case LUA_OPSHR: return luaV_shiftl(v1, -v2);
case LUA_OPUNM: return intop(-, 0, v1);
case LUA_OPBNOT: return intop(^, ~l_castS2U(0), v1);
default: lua_assert(0); return 0;
}
}

static lua_Number numarith (lua_State *L, int op, lua_Number v1,
lua_Number v2) {
switch (op) {
case LUA_OPSUB: return luai_numsub(L, v1, v2);
case LUA_OPMUL: return luai_nummul(L, v1, v2);
case LUA_OPDIV: return luai_numdiv(L, v1, v2);
case LUA_OPPOW: return luai_numpow(L, v1, v2);
case LUA_OPIDIV: return luai_numidiv(L, v1, v2);
case LUA_OPUNM: return luai_numunm(L, v1);
case LUA_OPMOD: {
lua_Number m;
luai_nummod(L, v1, v2, m);
return m;
}
default: lua_assert(0); return 0;
}
}

void luaO_arith (lua_State *L, int op, const TValue *p1, const TValue *p2,
TValue *res) {
switch (op) {
case LUA_OPBAND: case LUA_OPBOR: case LUA_OPBXOR:
case LUA_OPSHL: case LUA_OPSHR:
case LUA_OPBNOT: {  /* operate only on integers */
lua_Integer i1; lua_Integer i2;
if (tointeger(p1, &i1) && tointeger(p2, &i2)) {
setivalue(res, intarith(L, op, i1, i2));
return;
}
else break;  /* go to the end */
}
case LUA_OPDIV: case LUA_OPPOW: {  /* operate only on floats */
lua_Number n1; lua_Number n2;
if (tonumber(p1, &n1) && tonumber(p2, &n2)) {
setfltvalue(res, numarith(L, op, n1, n2));
return;
}
else break;  /* go to the end */
}
default: {  /* other operations */
lua_Number n1; lua_Number n2;
if (ttisinteger(p1) && ttisinteger(p2)) {
setivalue(res, intarith(L, op, ivalue(p1), ivalue(p2)));
return;
}
else if (tonumber(p1, &n1) && tonumber(p2, &n2)) {
setfltvalue(res, numarith(L, op, n1, n2));
return;
}
else break;  /* go to the end */
}
}
/* could not perform raw operation; try metamethod */
lua_assert(L != NULL);  /* should not fail when folding (compile time) */
}

int luaO_hexavalue (int c) {
if (lisdigit(c)) return c - '0';
else return (ltolower(c) - 'a') + 10;
}

static int isneg (const char **s) {
if (**s == '-') { (*s)++; return 1; }
else if (**s == '+') (*s)++;
return 0;
}

/*
** {==================================================================
** Lua's implementation for 'lua_strx2number'
** ===================================================================
*/

#if !defined(lua_strx2number)

/* maximum number of significant digits to read (to avoid overflows
even with single floats) */
#define MAXSIGDIG       30

/*
** convert an hexadecimal numeric string to a number, following
** C99 specification for 'strtod'
*/
static lua_Number lua_strx2number (const char *s, char **endptr) {
int dot = lua_getlocaledecpoint();
lua_Number r = 0.0;  /* result (accumulator) */
int sigdig = 0;  /* number of significant digits */
int nosigdig = 0;  /* number of non-significant digits */
int e = 0;  /* exponent correction */
int neg;  /* 1 if number is negative */
int hasdot = 0;  /* true after seen a dot */
*endptr = cast(char *, s);  /* nothing is valid yet */
while (lisspace(cast_uchar(*s))) s++;  /* skip initial spaces */
neg = isneg(&s);  /* check signal */
if (!(*s == '0' && (*(s + 1) == 'x' || *(s + 1) == 'X')))  /* check '0x' */
return 0.0;  /* invalid format (no '0x') */
for (s += 2; ; s++) {  /* skip '0x' and read numeral */
if (*s == dot) {
if (hasdot) break;  /* second dot? stop loop */
else hasdot = 1;
}
else if (lisxdigit(cast_uchar(*s))) {
if (sigdig == 0 && *s == '0')  /* non-significant digit (zero)? */
nosigdig++;
else if (++sigdig <= MAXSIGDIG)  /* can read it without overflow? */
r = (r * cast_num(16.0)) + luaO_hexavalue(*s);
else e++; /* too many digits; ignore, but still count for exponent */
if (hasdot) e--;  /* decimal digit? correct exponent */
}
else break;  /* neither a dot nor a digit */
}
if (nosigdig + sigdig == 0)  /* no digits? */
return 0.0;  /* invalid format */
*endptr = cast(char *, s);  /* valid up to here */
e *= 4;  /* each digit multiplies/divides value by 2^4 */
if (*s == 'p' || *s == 'P') {  /* exponent part? */
int exp1 = 0;  /* exponent value */
int neg1;  /* exponent signal */
s++;  /* skip 'p' */
neg1 = isneg(&s);  /* signal */
if (!lisdigit(cast_uchar(*s)))
return 0.0;  /* invalid; must have at least one digit */
while (lisdigit(cast_uchar(*s)))  /* read exponent */
exp1 = exp1 * 10 + *(s++) - '0';
if (neg1) exp1 = -exp1;
e += exp1;
*endptr = cast(char *, s);  /* valid up to here */
}
if (neg) r = -r;
return l_mathop(ldexp)(r, e);
}

#endif
/* }====================================================== */

/* maximum length of a numeral */
#if !defined (L_MAXLENNUM)
#define L_MAXLENNUM     200
#endif

static const char *l_str2dloc (const char *s, lua_Number *result, int mode) {
char *endptr;
*result = (mode == 'x') ? lua_strx2number(s, &endptr)  /* try to convert */
: lua_str2number(s, &endptr);
if (endptr == s) return NULL;  /* nothing recognized? */
while (lisspace(cast_uchar(*endptr))) endptr++;  /* skip trailing spaces */
return (*endptr == '\0') ? endptr : NULL;  /* OK if no trailing characters */
}

/*
** Convert string 's' to a Lua number (put in 'result'). Return NULL
** on fail or the address of the ending '\0' on success.
** 'pmode' points to (and 'mode' contains) special things in the string:
** - 'x'/'X' means an hexadecimal numeral
** - 'n'/'N' means 'inf' or 'nan' (which should be rejected)
** - '.' just optimizes the search for the common case (nothing special)
** This function accepts both the current locale or a dot as the radix
** mark. If the convertion fails, it may mean number has a dot but
** locale accepts something else. In that case, the code copies 's'
** to a buffer (because 's' is read-only), changes the dot to the
** current locale radix mark, and tries to convert again.
*/
static const char *l_str2d (const char *s, lua_Number *result) {
const char *endptr;
const char *pmode = strpbrk(s, ".xXnN");
int mode = pmode ? ltolower(cast_uchar(*pmode)) : 0;
if (mode == 'n')  /* reject 'inf' and 'nan' */
return NULL;
endptr = l_str2dloc(s, result, mode);  /* try to convert */
if (endptr == NULL) {  /* failed? may be a different locale */
char buff[L_MAXLENNUM + 1];
const char *pdot = strchr(s, '.');
if (strlen(s) > L_MAXLENNUM || pdot == NULL)
return NULL;  /* string too long or no dot; fail */
strcpy(buff, s);  /* copy string to buffer */
buff[pdot - s] = lua_getlocaledecpoint();  /* correct decimal point */
endptr = l_str2dloc(buff, result, mode);  /* try again */
if (endptr != NULL)
endptr = s + (endptr - buff);  /* make relative to 's' */
}
return endptr;
}

#define MAXBY10         cast(lua_Unsigned, LUA_MAXINTEGER / 10)
#define MAXLASTD        cast_int(LUA_MAXINTEGER % 10)

static const char *l_str2int (const char *s, lua_Integer *result) {
lua_Unsigned a = 0;
int empty = 1;
int neg;
while (lisspace(cast_uchar(*s))) s++;  /* skip initial spaces */
neg = isneg(&s);
if (s[0] == '0' &&
(s[1] == 'x' || s[1] == 'X')) {  /* hex? */
s += 2;  /* skip '0x' */
for (; lisxdigit(cast_uchar(*s)); s++) {
a = a * 16 + luaO_hexavalue(*s);
empty = 0;
}
}
else {  /* decimal */
for (; lisdigit(cast_uchar(*s)); s++) {
int d = *s - '0';
if (a >= MAXBY10 && (a > MAXBY10 || d > MAXLASTD + neg))  /* overflow? */
return NULL;  /* do not accept it (as integer) */
a = a * 10 + d;
empty = 0;
}
}
while (lisspace(cast_uchar(*s))) s++;  /* skip trailing spaces */
if (empty || *s != '\0') return NULL;  /* something wrong in the numeral */
else {
*result = l_castU2S((neg) ? 0u - a : a);
return s;
}
}

size_t luaO_str2num (const char *s, TValue *o) {
lua_Integer i; lua_Number n;
const char *e;
if ((e = l_str2int(s, &i)) != NULL) {  /* try as an integer */
setivalue(o, i);
}
else if ((e = l_str2d(s, &n)) != NULL) {  /* else try as a float */
setfltvalue(o, n);
}
else
return 0;  /* conversion failed */
return (e - s) + 1;  /* success; return string size */
}

int luaO_utf8esc (char *buff, unsigned long x) {
int n = 1;  /* number of bytes put in buffer (backwards) */
lua_assert(x <= 0x10FFFF);
if (x < 0x80)  /* ascii? */
buff[UTF8BUFFSZ - 1] = cast(char, x);
else {  /* need continuation bytes */
unsigned int mfb = 0x3f;  /* maximum that fits in first byte */
do {  /* add continuation bytes */
buff[UTF8BUFFSZ - (n++)] = cast(char, 0x80 | (x & 0x3f));
x >>= 6;  /* remove added bits */
mfb >>= 1;  /* now there is one less bit available in first byte */
} while (x > mfb);  /* still needs continuation byte? */
buff[UTF8BUFFSZ - n] = cast(char, (~mfb << 1) | x);  /* add first byte */
}
return n;
}

/* maximum length of the conversion of a number to a string */
#define MAXNUMBER2STR   50

/*
** Convert a number object to a string
*/
void luaO_tostring (lua_State *L, StkId obj) {
char buff[MAXNUMBER2STR];
size_t len;
lua_assert(ttisnumber(obj));
if (ttisinteger(obj))
len = lua_integer2str(buff, sizeof(buff), ivalue(obj));
else {
len = lua_number2str(buff, sizeof(buff), fltvalue(obj));
#if !defined(LUA_COMPAT_FLOATSTRING)
if (buff[strspn(buff, "-0123456789")] == '\0') {  /* looks like an int? */
buff[len++] = lua_getlocaledecpoint();
buff[len++] = '0';  /* adds '.0' to result */
}
#endif
}
setsvalue2s(L, obj, luaS_newlstr(L, buff, len));
}

static void pushstr (lua_State *L, const char *str, size_t l) {
setsvalue2s(L, L->top, luaS_newlstr(L, str, l));
}

/*
** this function handles only '%d', '%c', '%f', '%p', and '%s'
conventional formats, plus Lua-specific '%I' and '%U'
*/
const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
int n = 0;
for (;;) {
const char *e = strchr(fmt, '%');
if (e == NULL) break;
pushstr(L, fmt, e - fmt);
switch (*(e+1)) {
case 's': {  /* zero-terminated string */
const char *s = va_arg(argp, char *);
if (s == NULL) s = "(null)";
pushstr(L, s, strlen(s));
break;
}
case 'c': {  /* an 'int' as a character */
char buff = cast(char, va_arg(argp, int));
if (lisprint(cast_uchar(buff)))
pushstr(L, &buff, 1);
else  /* non-printable character; print its code */
luaO_pushfstring(L, "<\\%d>", cast_uchar(buff));
break;
}
case 'd': {  /* an 'int' */
setivalue(L->top, va_arg(argp, int));
goto top2str;
}
case 'I': {  /* a 'lua_Integer' */
setivalue(L->top, cast(lua_Integer, va_arg(argp, l_uacInt)));
goto top2str;
}
case 'f': {  /* a 'lua_Number' */
setfltvalue(L->top, cast_num(va_arg(argp, l_uacNumber)));
top2str:  /* convert the top element to a string */
luaO_tostring(L, L->top - 1);
break;
}
case 'p': {  /* a pointer */
char buff[4*sizeof(void *) + 8]; /* should be enough space for a '%p' */
void *p = va_arg(argp, void *);
int l = lua_pointer2str(buff, sizeof(buff), p);
pushstr(L, buff, l);
break;
}
case 'U': {  /* an 'int' as a UTF-8 sequence */
char buff[UTF8BUFFSZ];
int l = luaO_utf8esc(buff, cast(long, va_arg(argp, long)));
pushstr(L, buff + UTF8BUFFSZ - l, l);
break;
}
case '%': {
pushstr(L, "%", 1);
break;
}
default: {
luaG_runerror(L, "invalid option '%%%c' to 'lua_pushfstring'",
*(e + 1));
}
}
n += 2;
fmt = e+2;
}
pushstr(L, fmt, strlen(fmt));
if (n > 0) luaV_concat(L, n + 1);
return svalue(L->top - 1);
}

const char *luaO_pushfstring (lua_State *L, const char *fmt, ...) {
const char *msg;
va_list argp;
va_start(argp, fmt);
msg = luaO_pushvfstring(L, fmt, argp);
va_end(argp);
return msg;
}

/* number of chars of a literal string without the ending \0 */
#define LL(x)   (sizeof(x)/sizeof(char) - 1)

#define RETS    "..."
#define PRE     "[string \""
#define POS     "\"]"

#define addstr(a,b,l)   ( memcpy(a,b,(l) * sizeof(char)), a += (l) )

void luaO_chunkid (char *out, const char *source, size_t bufflen) {
size_t l = strlen(source);
if (*source == '=') {  /* 'literal' source */
if (l <= bufflen)  /* small enough? */
memcpy(out, source + 1, l * sizeof(char));
else {  /* truncate it */
addstr(out, source + 1, bufflen - 1);
*out = '\0';
}
}
else if (*source == '@') {  /* file name */
if (l <= bufflen)  /* small enough? */
memcpy(out, source + 1, l * sizeof(char));
else {  /* add '...' before rest of name */
bufflen -= LL(RETS);
memcpy(out, source + 1 + l - bufflen, bufflen * sizeof(char));
}
}
else {  /* string; format as [string "source"] */
const char *nl = strchr(source, '\n');  /* find first new line (if any) */
bufflen -= LL(PRE RETS POS) + 1;  /* save space for prefix+suffix+'\0' */
if (l < bufflen && nl == NULL) {  /* small one-line source? */
addstr(out, source, l);  /* keep it */
}
else {
if (nl != NULL) l = nl - source;  /* stop at first newline */
if (l > bufflen) l = bufflen;