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lua/lobject.c
Roberto Ierusalimschy f5c690b684 details in comments
2014-08-01 14:24:02 -03:00

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/*
** $Id: lobject.c,v 2.88 2014/07/30 14:00:14 roberto Exp roberto $
** Some generic functions over Lua objects
** See Copyright Notice in lua.h
*/
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define lobject_c
#define LUA_CORE
#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 >= 0x10) {
x = (x+1) >> 1;
e++;
}
return ((e+1) << 3) | (cast_int(x) - 8);
}
/* converts back */
int luaO_fb2int (int x) {
int e = (x >> 3) & 0x1f;
if (e == 0) return x;
else return ((x & 7) + 8) << (e - 1);
}
int luaO_ceillog2 (unsigned int x) {
static const lu_byte log_2[256] = {
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_OPADD: return luai_numadd(L, v1, v2);
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_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_OPIDIV: case LUA_OPBAND: case LUA_OPBOR:
case LUA_OPBXOR: case LUA_OPSHL: case LUA_OPSHR:
case LUA_OPBNOT: { /* operates 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) */
luaT_trybinTM(L, p1, p2, res, cast(TMS, op - LUA_OPADD + TM_ADD));
}
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_strx2number converts an hexadecimal numeric string to a number.
** In C99, 'strtod' does both conversions. C89, however, has no function
** to convert floating hexadecimal strings to numbers. For these
** systems, you can leave 'lua_strx2number' undefined and Lua will
** provide its own implementation.
** =======================================================
*/
#if !defined(lua_strx2number) /* { */
#if defined(LUA_USE_C99) /* { */
#define lua_strx2number(s,p) lua_str2number(s,p)
#else /* }{ */
/* Lua's implementation for 'lua_strx2number' */
#include <math.h>
/* 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) {
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 = 0; /* 1 if number is negative */
int dot = 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 == '.') {
if (dot) break; /* second dot? stop loop */
else dot = 1;
}
else if (lisxdigit(cast_uchar(*s))) {
if (sigdig == 0 && *s == '0') { /* non-significant zero? */
nosigdig++;
if (dot) e--; /* zero after dot? correct exponent */
}
else {
if (++sigdig <= MAXSIGDIG) { /* can read it without overflow? */
r = (r * cast_num(16.0)) + luaO_hexavalue(cast_uchar(*s));
if (dot) e--; /* decimal digit */
}
else /* too many digits; ignore */
if (!dot) e++; /* still count it for 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 /* } */
#endif /* } */
/* }====================================================== */
static const char *l_str2d (const char *s, lua_Number *result) {
char *endptr;
if (strpbrk(s, "nN")) /* reject 'inf' and 'nan' */
return NULL;
else if (strpbrk(s, "xX")) /* hex? */
*result = lua_strx2number(s, &endptr);
else
*result = lua_str2number(s, &endptr);
if (endptr == s) return 0; /* nothing recognized */
while (lisspace(cast_uchar(*endptr))) endptr++;
return (*endptr == '\0' ? endptr : NULL); /* OK if no trailing characters */
}
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(cast_uchar(*s));
empty = 0;
}
}
else { /* decimal */
for (; lisdigit(cast_uchar(*s)); s++) {
a = a * 10 + luaO_hexavalue(cast_uchar(*s));
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 int x) {
int n = 1; /* number of bytes put in buffer (backwards) */
if (x < 0x80) /* ascii? */
buff[UTF8BUFFSZ - 1] = x;
else { /* need continuation bytes */
unsigned int mfb = 0x3f; /* maximum that fits in first byte */
do {
buff[UTF8BUFFSZ - (n++)] = 0x80 | (x & 0x3f); /* add continuation byte */
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] = (~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, ivalue(obj));
else {
len = lua_number2str(buff, fltvalue(obj));
#if !defined(LUA_COMPAT_FLOATSTRING)
if (buff[strspn(buff, "-0123456789")] == '\0') { /* looks like an int? */
buff[len++] = '.';
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;
luaD_checkstack(L, 2); /* fmt + item */
pushstr(L, fmt, e - fmt);
switch (*(e+1)) {
case 's': {
const char *s = va_arg(argp, char *);
if (s == NULL) s = "(null)";
pushstr(L, s, strlen(s));
break;
}
case 'c': {
char buff = cast(char, va_arg(argp, int));
pushstr(L, &buff, 1);
break;
}
case 'd': {
setivalue(L->top++, va_arg(argp, int));
luaO_tostring(L, L->top - 1);
break;
}
case 'I': {
setivalue(L->top++, cast(lua_Integer, va_arg(argp, l_uacInt)));
luaO_tostring(L, L->top - 1);
break;
}
case 'f': {
setfltvalue(L->top++, cast_num(va_arg(argp, l_uacNumber)));
luaO_tostring(L, L->top - 1);
break;
}
case 'p': {
char buff[4*sizeof(void *) + 8]; /* should be enough space for a `%p' */
int l = sprintf(buff, "%p", va_arg(argp, void *));
pushstr(L, buff, l);
break;
}
case 'U': {
char buff[UTF8BUFFSZ];
int l = luaO_utf8esc(buff, va_arg(argp, int));
pushstr(L, buff + UTF8BUFFSZ - l, l);
break;
}
case '%': {
pushstr(L, "%", 1);
break;
}
default: {
luaG_runerror(L,
"invalid option " LUA_QL("%%%c") " to " LUA_QL("lua_pushfstring"),
*(e + 1));
}
}
n += 2;
fmt = e+2;
}
luaD_checkstack(L, 1);
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 */
addstr(out, RETS, LL(RETS));
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) */
addstr(out, PRE, LL(PRE)); /* add prefix */
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;
addstr(out, source, l);
addstr(out, RETS, LL(RETS));
}
memcpy(out, POS, (LL(POS) + 1) * sizeof(char));
}
}
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