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/*
** String handling.
** Copyright (C) 2005-2009 Mike Pall. See Copyright Notice in luajit.h
**
** Portions taken verbatim or adapted from the Lua interpreter.
** Copyright (C) 1994-2008 Lua.org, PUC-Rio. See Copyright Notice in lua.h
*/
#include <stdio.h>
#define lj_str_c
#define LUA_CORE
#include "lj_obj.h"
#include "lj_gc.h"
#include "lj_err.h"
#include "lj_str.h"
#include "lj_state.h"
#include "lj_ctype.h"
/* -- String interning ---------------------------------------------------- */
/* Ordered compare of strings. Assumes string data is 4-byte aligned. */
int32_t lj_str_cmp(GCstr *a, GCstr *b)
{
MSize i, n = a->len > b->len ? b->len : a->len;
for (i = 0; i < n; i += 4) {
/* Note: innocuous access up to end of string + 3. */
uint32_t va = *(const uint32_t *)(strdata(a)+i);
uint32_t vb = *(const uint32_t *)(strdata(b)+i);
if (va != vb) {
#if LJ_ARCH_ENDIAN == LUAJIT_LE
va = lj_bswap(va); vb = lj_bswap(vb);
#endif
i -= n;
if ((int32_t)i >= -3) {
va >>= 32+(i<<3); vb >>= 32+(i<<3);
if (va == vb) break;
}
return (int32_t)(va - vb);
}
}
return (int32_t)(a->len - b->len);
}
/* Resize the string hash table (grow and shrink). */
void lj_str_resize(lua_State *L, MSize newmask)
{
global_State *g = G(L);
GCRef *newhash;
MSize i;
if (g->gc.state == GCSsweepstring || newmask >= LJ_MAX_STRTAB-1)
return; /* No resizing during GC traversal or if already too big. */
newhash = lj_mem_newvec(L, newmask+1, GCRef);
memset(newhash, 0, (newmask+1)*sizeof(GCRef));
for (i = g->strmask; i != ~(MSize)0; i--) { /* Rehash old table. */
GCobj *p = gcref(g->strhash[i]);
while (p) { /* Follow each hash chain and reinsert all strings. */
MSize h = gco2str(p)->hash & newmask;
GCobj *next = gcnext(p);
/* NOBARRIER: The string table is a GC root. */
setgcrefr(p->gch.nextgc, newhash[h]);
setgcref(newhash[h], p);
p = next;
}
}
lj_mem_freevec(g, g->strhash, g->strmask+1, GCstr *);
g->strmask = newmask;
g->strhash = newhash;
}
/* Intern a string and return string object. */
GCstr *lj_str_new(lua_State *L, const char *str, size_t lenx)
{
global_State *g;
GCstr *s;
GCobj *o;
MSize len = (MSize)lenx;
MSize h = len;
MSize step = (len>>5)+1; /* Partial hash. */
MSize l1;
if (lenx >= LJ_MAX_STR)
lj_err_msg(L, LJ_ERR_STROV);
for (l1 = len; l1 >= step; l1 -= step) /* Compute string hash. */
h = h ^ ((h<<5)+(h>>2)+cast(unsigned char, str[l1-1]));
/* Check if the string has already been interned. */
g = G(L);
for (o = gcref(g->strhash[h & g->strmask]); o != NULL; o = gcnext(o)) {
GCstr *tso = gco2str(o);
if (tso->len == len && (memcmp(str, strdata(tso), len) == 0)) {
if (isdead(g, o)) flipwhite(o); /* Resurrect if dead. */
return tso; /* Return existing string. */
}
}
/* Nope, create a new string. */
s = lj_mem_newt(L, sizeof(GCstr)+len+1, GCstr);
newwhite(g, s);
s->gct = ~LJ_TSTR;
s->len = len;
s->hash = h;
s->reserved = 0;
memcpy(strdatawr(s), str, len);
strdatawr(s)[len] = '\0'; /* Zero-terminate string. */
/* Add it to string hash table. */
h &= g->strmask;
s->nextgc = g->strhash[h];
/* NOBARRIER: The string table is a GC root. */
setgcref(g->strhash[h], obj2gco(s));
if (g->strnum++ > g->strmask) /* Allow a 100% load factor. */
lj_str_resize(L, (g->strmask<<1)+1); /* Grow string table. */
return s; /* Return newly interned string. */
}
void LJ_FASTCALL lj_str_free(global_State *g, GCstr *s)
{
g->strnum--;
lj_mem_free(g, s, sizestring(s));
}
/* -- Type conversions ---------------------------------------------------- */
/* Convert string to number. */
int lj_str_numconv(const char *s, TValue *n)
{
lua_Number sign = 1;
const uint8_t *p = (const uint8_t *)s;
while (lj_ctype_isspace(*p)) p++;
if (*p == '-') { p++; sign = -1; } else if (*p == '+') { p++; }
if ((uint32_t)(*p - '0') < 10) {
uint32_t k = (uint32_t)(*p++ - '0');
if (k == 0 && ((*p & ~0x20) == 'X')) {
p++;
while (lj_ctype_isxdigit(*p)) {
if (k >= 0x10000000) goto parsedbl;
k = (k << 4) + (*p & 15u);
if (!lj_ctype_isdigit(*p)) k += 9;
p++;
}
} else {
while ((uint32_t)(*p - '0') < 10) {
if (k >= 0x19999999) goto parsedbl;
k = k * 10u + (uint32_t)(*p++ - '0');
}
}
while (LJ_UNLIKELY(lj_ctype_isspace(*p))) p++;
if (LJ_LIKELY(*p == '\0')) {
setnumV(n, sign * cast_num(k));
return 1;
}
}
parsedbl:
{
TValue tv;
char *endptr;
setnumV(&tv, lua_str2number(s, &endptr));
if (endptr == s) return 0; /* conversion failed */
if (LJ_UNLIKELY(*endptr != '\0')) {
while (lj_ctype_isspace((uint8_t)*endptr)) endptr++;
if (*endptr != '\0') return 0; /* invalid trailing characters? */
}
if (LJ_LIKELY(!tvisnan(&tv)))
setnumV(n, numV(&tv));
else
setnanV(n); /* Canonicalize injected NaNs. */
return 1;
}
}
/* Convert number to string. */
GCstr *lj_str_fromnum(lua_State *L, const lua_Number *np)
{
char s[LUAI_MAXNUMBER2STR];
lua_Number n = *np;
size_t len = (size_t)lua_number2str(s, n);
return lj_str_new(L, s, len);
}
/* Convert integer to string. */
GCstr *lj_str_fromint(lua_State *L, int32_t k)
{
char s[1+10];
char *p = s+sizeof(s);
uint32_t i = (uint32_t)(k < 0 ? -k : k);
do { *--p = (char)('0' + i % 10); } while (i /= 10);
if (k < 0) *--p = '-';
return lj_str_new(L, p, (size_t)(s+sizeof(s)-p));
}
/* -- String formatting --------------------------------------------------- */
static void addstr(lua_State *L, SBuf *sb, const char *str, MSize len)
{
char *p;
MSize i;
if (sb->n + len > sb->sz) {
MSize sz = sb->sz * 2;
while (sb->n + len > sz) sz = sz * 2;
lj_str_resizebuf(L, sb, sz);
}
p = sb->buf + sb->n;
sb->n += len;
for (i = 0; i < len; i++) p[i] = str[i];
}
static void addchar(lua_State *L, SBuf *sb, int c)
{
if (sb->n + 1 > sb->sz) {
MSize sz = sb->sz * 2;
lj_str_resizebuf(L, sb, sz);
}
sb->buf[sb->n++] = cast(char, c);
}
/* Push formatted message as a string object to Lua stack. va_list variant. */
const char *lj_str_pushvf(lua_State *L, const char *fmt, va_list argp)
{
SBuf *sb = &G(L)->tmpbuf;
lj_str_needbuf(L, sb, (MSize)strlen(fmt));
lj_str_resetbuf(sb);
for (;;) {
const char *e = strchr(fmt, '%');
if (e == NULL) break;
addstr(L, sb, fmt, (MSize)(e-fmt));
/* This function only handles %s, %c, %d, %f and %p formats. */
switch (e[1]) {
case 's': {
const char *s = va_arg(argp, char *);
if (s == NULL) s = "(null)";
addstr(L, sb, s, (MSize)strlen(s));
break;
}
case 'c':
addchar(L, sb, va_arg(argp, int));
break;
case 'd': {
char buff[1+10];
char *p = buff+sizeof(buff);
int32_t k = va_arg(argp, int32_t);
uint32_t i = (uint32_t)(k < 0 ? -k : k);
do { *--p = (char)('0' + i % 10); } while (i /= 10);
if (k < 0) *--p = '-';
addstr(L, sb, p, (MSize)(buff+sizeof(buff)-p));
break;
}
case 'f': {
char buff[LUAI_MAXNUMBER2STR];
lua_Number n = cast_num(va_arg(argp, LUAI_UACNUMBER));
MSize len = (MSize)lua_number2str(buff, n);
addstr(L, sb, buff, len);
break;
}
case 'p': {
#define FMTP_CHARS (2*sizeof(ptrdiff_t))
char buff[2+FMTP_CHARS];
ptrdiff_t p = (ptrdiff_t)(va_arg(argp, void *));
int i;
buff[0] = '0';
buff[1] = 'x';
for (i = 2+FMTP_CHARS-1; i >= 2; i--, p >>= 4)
buff[i] = "0123456789abcdef"[(p & 15)];
addstr(L, sb, buff, 2+FMTP_CHARS);
break;
}
case '%':
addchar(L, sb, '%');
break;
default:
addchar(L, sb, '%');
addchar(L, sb, e[1]);
break;
}
fmt = e+2;
}
addstr(L, sb, fmt, (MSize)strlen(fmt));
setstrV(L, L->top, lj_str_new(L, sb->buf, sb->n));
incr_top(L);
return strVdata(L->top - 1);
}
/* Push formatted message as a string object to Lua stack. Vararg variant. */
const char *lj_str_pushf(lua_State *L, const char *fmt, ...)
{
const char *msg;
va_list argp;
va_start(argp, fmt);
msg = lj_str_pushvf(L, fmt, argp);
va_end(argp);
return msg;
}
/* -- Buffer handling ----------------------------------------------------- */
char *lj_str_needbuf(lua_State *L, SBuf *sb, MSize sz)
{
if (sz > sb->sz) {
if (sz < LJ_MIN_SBUF) sz = LJ_MIN_SBUF;
lj_str_resizebuf(L, sb, sz);
}
return sb->buf;
}
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