Add luaproc and LuaJIT libraries.

Two versions of LuaJIT, the stable release, and the dev version.  Try the dev version first, until ih fails badly.

1 files changed, 855 insertions, 0 deletions

diff --git a/libraries/luajit-2.0/src/lib_string.c b/libraries/luajit-2.0/src/lib_string.c
new file mode 100644
index 0000000..5cbe6e4
--- /dev/null
+++ b/libraries/luajit-2.0/src/lib_string.c
@@ -0,0 +1,855 @@
+/*
+** String library.
+** Copyright (C) 2005-2011 Mike Pall. See Copyright Notice in luajit.h
+**
+** Major 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 lib_string_c
+#define LUA_LIB
+
+#include "lua.h"
+#include "lauxlib.h"
+#include "lualib.h"
+
+#include "lj_obj.h"
+#include "lj_gc.h"
+#include "lj_err.h"
+#include "lj_str.h"
+#include "lj_tab.h"
+#include "lj_state.h"
+#include "lj_ff.h"
+#include "lj_bcdump.h"
+#include "lj_char.h"
+#include "lj_lib.h"
+
+/* ------------------------------------------------------------------------ */
+
+#define LJLIB_MODULE_string
+
+LJLIB_ASM(string_len)           LJLIB_REC(.)
+{
+  lj_lib_checkstr(L, 1);
+  return FFH_RETRY;
+}
+
+LJLIB_ASM(string_byte)          LJLIB_REC(string_range 0)
+{
+  GCstr *s = lj_lib_checkstr(L, 1);
+  int32_t len = (int32_t)s->len;
+  int32_t start = lj_lib_optint(L, 2, 1);
+  int32_t stop = lj_lib_optint(L, 3, start);
+  int32_t n, i;
+  const unsigned char *p;
+  if (stop < 0) stop += len+1;
+  if (start < 0) start += len+1;
+  if (start <= 0) start = 1;
+  if (stop > len) stop = len;
+  if (start > stop) return FFH_RES(0);  /* Empty interval: return no results. */
+  start--;
+  n = stop - start;
+  if ((uint32_t)n > LUAI_MAXCSTACK)
+    lj_err_caller(L, LJ_ERR_STRSLC);
+  lj_state_checkstack(L, (MSize)n);
+  p = (const unsigned char *)strdata(s) + start;
+  for (i = 0; i < n; i++)
+    setintV(L->base + i-1, p[i]);
+  return FFH_RES(n);
+}
+
+LJLIB_ASM(string_char)
+{
+  int i, nargs = (int)(L->top - L->base);
+  char *buf = lj_str_needbuf(L, &G(L)->tmpbuf, (size_t)nargs);
+  for (i = 1; i <= nargs; i++) {
+    int32_t k = lj_lib_checkint(L, i);
+    if (!checku8(k))
+      lj_err_arg(L, i, LJ_ERR_BADVAL);
+    buf[i-1] = (char)k;
+  }
+  setstrV(L, L->base-1, lj_str_new(L, buf, (size_t)nargs));
+  return FFH_RES(1);
+}
+
+LJLIB_ASM(string_sub)           LJLIB_REC(string_range 1)
+{
+  lj_lib_checkstr(L, 1);
+  lj_lib_checkint(L, 2);
+  setintV(L->base+2, lj_lib_optint(L, 3, -1));
+  return FFH_RETRY;
+}
+
+LJLIB_ASM(string_rep)
+{
+  GCstr *s = lj_lib_checkstr(L, 1);
+  int32_t len = (int32_t)s->len;
+  int32_t k = lj_lib_checkint(L, 2);
+  int64_t tlen = (int64_t)k * len;
+  const char *src;
+  char *buf;
+  if (k <= 0) return FFH_RETRY;
+  if (tlen > LJ_MAX_STR)
+    lj_err_caller(L, LJ_ERR_STROV);
+  buf = lj_str_needbuf(L, &G(L)->tmpbuf, (MSize)tlen);
+  if (len <= 1) return FFH_RETRY;  /* ASM code only needed buffer resize. */
+  src = strdata(s);
+  do {
+    int32_t i = 0;
+    do { *buf++ = src[i++]; } while (i < len);
+  } while (--k > 0);
+  setstrV(L, L->base-1, lj_str_new(L, G(L)->tmpbuf.buf, (size_t)tlen));
+  return FFH_RES(1);
+}
+
+LJLIB_ASM(string_reverse)
+{
+  GCstr *s = lj_lib_checkstr(L, 1);
+  lj_str_needbuf(L, &G(L)->tmpbuf, s->len);
+  return FFH_RETRY;
+}
+LJLIB_ASM_(string_lower)
+LJLIB_ASM_(string_upper)
+
+/* ------------------------------------------------------------------------ */
+
+static int writer_buf(lua_State *L, const void *p, size_t size, void *b)
+{
+  luaL_addlstring((luaL_Buffer *)b, (const char *)p, size);
+  UNUSED(L);
+  return 0;
+}
+
+LJLIB_CF(string_dump)
+{
+  GCfunc *fn = lj_lib_checkfunc(L, 1);
+  int strip = L->base+1 < L->top && tvistruecond(L->base+1);
+  luaL_Buffer b;
+  L->top = L->base+1;
+  luaL_buffinit(L, &b);
+  if (!isluafunc(fn) || lj_bcwrite(L, funcproto(fn), writer_buf, &b, strip))
+    lj_err_caller(L, LJ_ERR_STRDUMP);
+  luaL_pushresult(&b);
+  return 1;
+}
+
+/* ------------------------------------------------------------------------ */
+
+/* macro to `unsign' a character */
+#define uchar(c)        ((unsigned char)(c))
+
+#define CAP_UNFINISHED  (-1)
+#define CAP_POSITION    (-2)
+
+typedef struct MatchState {
+  const char *src_init;  /* init of source string */
+  const char *src_end;  /* end (`\0') of source string */
+  lua_State *L;
+  int level;  /* total number of captures (finished or unfinished) */
+  struct {
+    const char *init;
+    ptrdiff_t len;
+  } capture[LUA_MAXCAPTURES];
+} MatchState;
+
+#define L_ESC           '%'
+#define SPECIALS        "^$*+?.([%-"
+
+static int check_capture(MatchState *ms, int l)
+{
+  l -= '1';
+  if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED)
+    lj_err_caller(ms->L, LJ_ERR_STRCAPI);
+  return l;
+}
+
+static int capture_to_close(MatchState *ms)
+{
+  int level = ms->level;
+  for (level--; level>=0; level--)
+    if (ms->capture[level].len == CAP_UNFINISHED) return level;
+  lj_err_caller(ms->L, LJ_ERR_STRPATC);
+  return 0;  /* unreachable */
+}
+
+static const char *classend(MatchState *ms, const char *p)
+{
+  switch (*p++) {
+  case L_ESC:
+    if (*p == '\0')
+      lj_err_caller(ms->L, LJ_ERR_STRPATE);
+    return p+1;
+  case '[':
+    if (*p == '^') p++;
+    do {  /* look for a `]' */
+      if (*p == '\0')
+        lj_err_caller(ms->L, LJ_ERR_STRPATM);
+      if (*(p++) == L_ESC && *p != '\0')
+        p++;  /* skip escapes (e.g. `%]') */
+    } while (*p != ']');
+    return p+1;
+  default:
+    return p;
+  }
+}
+
+static const unsigned char match_class_map[32] = {
+  0,LJ_CHAR_ALPHA,0,LJ_CHAR_CNTRL,LJ_CHAR_DIGIT,0,0,LJ_CHAR_GRAPH,0,0,0,0,
+  LJ_CHAR_LOWER,0,0,0,LJ_CHAR_PUNCT,0,0,LJ_CHAR_SPACE,0,
+  LJ_CHAR_UPPER,0,LJ_CHAR_ALNUM,LJ_CHAR_XDIGIT,0,0,0,0,0,0,0
+};
+
+static int match_class(int c, int cl)
+{
+  if ((cl & 0xc0) == 0x40) {
+    int t = match_class_map[(cl&0x1f)];
+    if (t) {
+      t = lj_char_isa(c, t);
+      return (cl & 0x20) ? t : !t;
+    }
+    if (cl == 'z') return c == 0;
+    if (cl == 'Z') return c != 0;
+  }
+  return (cl == c);
+}
+
+static int matchbracketclass(int c, const char *p, const char *ec)
+{
+  int sig = 1;
+  if (*(p+1) == '^') {
+    sig = 0;
+    p++;  /* skip the `^' */
+  }
+  while (++p < ec) {
+    if (*p == L_ESC) {
+      p++;
+      if (match_class(c, uchar(*p)))
+        return sig;
+    }
+    else if ((*(p+1) == '-') && (p+2 < ec)) {
+      p+=2;
+      if (uchar(*(p-2)) <= c && c <= uchar(*p))
+        return sig;
+    }
+    else if (uchar(*p) == c) return sig;
+  }
+  return !sig;
+}
+
+static int singlematch(int c, const char *p, const char *ep)
+{
+  switch (*p) {
+  case '.': return 1;  /* matches any char */
+  case L_ESC: return match_class(c, uchar(*(p+1)));
+  case '[': return matchbracketclass(c, p, ep-1);
+  default:  return (uchar(*p) == c);
+  }
+}
+
+static const char *match(MatchState *ms, const char *s, const char *p);
+
+static const char *matchbalance(MatchState *ms, const char *s, const char *p)
+{
+  if (*p == 0 || *(p+1) == 0)
+    lj_err_caller(ms->L, LJ_ERR_STRPATU);
+  if (*s != *p) {
+    return NULL;
+  } else {
+    int b = *p;
+    int e = *(p+1);
+    int cont = 1;
+    while (++s < ms->src_end) {
+      if (*s == e) {
+        if (--cont == 0) return s+1;
+      } else if (*s == b) {
+        cont++;
+      }
+    }
+  }
+  return NULL;  /* string ends out of balance */
+}
+
+static const char *max_expand(MatchState *ms, const char *s,
+                              const char *p, const char *ep)
+{
+  ptrdiff_t i = 0;  /* counts maximum expand for item */
+  while ((s+i)<ms->src_end && singlematch(uchar(*(s+i)), p, ep))
+    i++;
+  /* keeps trying to match with the maximum repetitions */
+  while (i>=0) {
+    const char *res = match(ms, (s+i), ep+1);
+    if (res) return res;
+    i--;  /* else didn't match; reduce 1 repetition to try again */
+  }
+  return NULL;
+}
+
+static const char *min_expand(MatchState *ms, const char *s,
+                              const char *p, const char *ep)
+{
+  for (;;) {
+    const char *res = match(ms, s, ep+1);
+    if (res != NULL)
+      return res;
+    else if (s<ms->src_end && singlematch(uchar(*s), p, ep))
+      s++;  /* try with one more repetition */
+    else
+      return NULL;
+  }
+}
+
+static const char *start_capture(MatchState *ms, const char *s,
+                                 const char *p, int what)
+{
+  const char *res;
+  int level = ms->level;
+  if (level >= LUA_MAXCAPTURES) lj_err_caller(ms->L, LJ_ERR_STRCAPN);
+  ms->capture[level].init = s;
+  ms->capture[level].len = what;
+  ms->level = level+1;
+  if ((res=match(ms, s, p)) == NULL)  /* match failed? */
+    ms->level--;  /* undo capture */
+  return res;
+}
+
+static const char *end_capture(MatchState *ms, const char *s,
+                               const char *p)
+{
+  int l = capture_to_close(ms);
+  const char *res;
+  ms->capture[l].len = s - ms->capture[l].init;  /* close capture */
+  if ((res = match(ms, s, p)) == NULL)  /* match failed? */
+    ms->capture[l].len = CAP_UNFINISHED;  /* undo capture */
+  return res;
+}
+
+static const char *match_capture(MatchState *ms, const char *s, int l)
+{
+  size_t len;
+  l = check_capture(ms, l);
+  len = (size_t)ms->capture[l].len;
+  if ((size_t)(ms->src_end-s) >= len &&
+      memcmp(ms->capture[l].init, s, len) == 0)
+    return s+len;
+  else
+    return NULL;
+}
+
+static const char *match(MatchState *ms, const char *s, const char *p)
+{
+  init: /* using goto's to optimize tail recursion */
+  switch (*p) {
+  case '(':  /* start capture */
+    if (*(p+1) == ')')  /* position capture? */
+      return start_capture(ms, s, p+2, CAP_POSITION);
+    else
+      return start_capture(ms, s, p+1, CAP_UNFINISHED);
+  case ')':  /* end capture */
+    return end_capture(ms, s, p+1);
+  case L_ESC:
+    switch (*(p+1)) {
+    case 'b':  /* balanced string? */
+      s = matchbalance(ms, s, p+2);
+      if (s == NULL) return NULL;
+      p+=4;
+      goto init;  /* else return match(ms, s, p+4); */
+    case 'f': {  /* frontier? */
+      const char *ep; char previous;
+      p += 2;
+      if (*p != '[')
+        lj_err_caller(ms->L, LJ_ERR_STRPATB);
+      ep = classend(ms, p);  /* points to what is next */
+      previous = (s == ms->src_init) ? '\0' : *(s-1);
+      if (matchbracketclass(uchar(previous), p, ep-1) ||
+         !matchbracketclass(uchar(*s), p, ep-1)) return NULL;
+      p=ep;
+      goto init;  /* else return match(ms, s, ep); */
+      }
+    default:
+      if (lj_char_isdigit(uchar(*(p+1)))) {  /* capture results (%0-%9)? */
+        s = match_capture(ms, s, uchar(*(p+1)));
+        if (s == NULL) return NULL;
+        p+=2;
+        goto init;  /* else return match(ms, s, p+2) */
+      }
+      goto dflt;  /* case default */
+    }
+  case '\0':  /* end of pattern */
+    return s;  /* match succeeded */
+  case '$':
+    if (*(p+1) == '\0')  /* is the `$' the last char in pattern? */
+      return (s == ms->src_end) ? s : NULL;  /* check end of string */
+    else
+      goto dflt;
+  default: dflt: {  /* it is a pattern item */
+    const char *ep = classend(ms, p);  /* points to what is next */
+    int m = s<ms->src_end && singlematch(uchar(*s), p, ep);
+    switch (*ep) {
+    case '?': {  /* optional */
+      const char *res;
+      if (m && ((res=match(ms, s+1, ep+1)) != NULL))
+        return res;
+      p=ep+1;
+      goto init;  /* else return match(ms, s, ep+1); */
+      }
+    case '*':  /* 0 or more repetitions */
+      return max_expand(ms, s, p, ep);
+    case '+':  /* 1 or more repetitions */
+      return (m ? max_expand(ms, s+1, p, ep) : NULL);
+    case '-':  /* 0 or more repetitions (minimum) */
+      return min_expand(ms, s, p, ep);
+    default:
+      if (!m) return NULL;
+      s++; p=ep;
+      goto init;  /* else return match(ms, s+1, ep); */
+    }
+    }
+  }
+}
+
+static const char *lmemfind(const char *s1, size_t l1,
+                            const char *s2, size_t l2)
+{
+  if (l2 == 0) {
+    return s1;  /* empty strings are everywhere */
+  } else if (l2 > l1) {
+    return NULL;  /* avoids a negative `l1' */
+  } else {
+    const char *init;  /* to search for a `*s2' inside `s1' */
+    l2--;  /* 1st char will be checked by `memchr' */
+    l1 = l1-l2;  /* `s2' cannot be found after that */
+    while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {
+      init++;   /* 1st char is already checked */
+      if (memcmp(init, s2+1, l2) == 0) {
+        return init-1;
+      } else {  /* correct `l1' and `s1' to try again */
+        l1 -= (size_t)(init-s1);
+        s1 = init;
+      }
+    }
+    return NULL;  /* not found */
+  }
+}
+
+static void push_onecapture(MatchState *ms, int i, const char *s, const char *e)
+{
+  if (i >= ms->level) {
+    if (i == 0)  /* ms->level == 0, too */
+      lua_pushlstring(ms->L, s, (size_t)(e - s));  /* add whole match */
+    else
+      lj_err_caller(ms->L, LJ_ERR_STRCAPI);
+  } else {
+    ptrdiff_t l = ms->capture[i].len;
+    if (l == CAP_UNFINISHED) lj_err_caller(ms->L, LJ_ERR_STRCAPU);
+    if (l == CAP_POSITION)
+      lua_pushinteger(ms->L, ms->capture[i].init - ms->src_init + 1);
+    else
+      lua_pushlstring(ms->L, ms->capture[i].init, (size_t)l);
+  }
+}
+
+static int push_captures(MatchState *ms, const char *s, const char *e)
+{
+  int i;
+  int nlevels = (ms->level == 0 && s) ? 1 : ms->level;
+  luaL_checkstack(ms->L, nlevels, "too many captures");
+  for (i = 0; i < nlevels; i++)
+    push_onecapture(ms, i, s, e);
+  return nlevels;  /* number of strings pushed */
+}
+
+static ptrdiff_t posrelat(ptrdiff_t pos, size_t len)
+{
+  /* relative string position: negative means back from end */
+  if (pos < 0) pos += (ptrdiff_t)len + 1;
+  return (pos >= 0) ? pos : 0;
+}
+
+static int str_find_aux(lua_State *L, int find)
+{
+  size_t l1, l2;
+  const char *s = luaL_checklstring(L, 1, &l1);
+  const char *p = luaL_checklstring(L, 2, &l2);
+  ptrdiff_t init = posrelat(luaL_optinteger(L, 3, 1), l1) - 1;
+  if (init < 0)
+    init = 0;
+  else if ((size_t)(init) > l1)
+    init = (ptrdiff_t)l1;
+  if (find && (lua_toboolean(L, 4) ||  /* explicit request? */
+      strpbrk(p, SPECIALS) == NULL)) {  /* or no special characters? */
+    /* do a plain search */
+    const char *s2 = lmemfind(s+init, l1-(size_t)init, p, l2);
+    if (s2) {
+      lua_pushinteger(L, s2-s+1);
+      lua_pushinteger(L, s2-s+(ptrdiff_t)l2);
+      return 2;
+    }
+  } else {
+    MatchState ms;
+    int anchor = (*p == '^') ? (p++, 1) : 0;
+    const char *s1=s+init;
+    ms.L = L;
+    ms.src_init = s;
+    ms.src_end = s+l1;
+    do {
+      const char *res;
+      ms.level = 0;
+      if ((res=match(&ms, s1, p)) != NULL) {
+        if (find) {
+          lua_pushinteger(L, s1-s+1);  /* start */
+          lua_pushinteger(L, res-s);   /* end */
+          return push_captures(&ms, NULL, 0) + 2;
+        } else {
+          return push_captures(&ms, s1, res);
+        }
+      }
+    } while (s1++ < ms.src_end && !anchor);
+  }
+  lua_pushnil(L);  /* not found */
+  return 1;
+}
+
+LJLIB_CF(string_find)
+{
+  return str_find_aux(L, 1);
+}
+
+LJLIB_CF(string_match)
+{
+  return str_find_aux(L, 0);
+}
+
+LJLIB_NOREG LJLIB_CF(string_gmatch_aux)
+{
+  const char *p = strVdata(lj_lib_upvalue(L, 2));
+  GCstr *str = strV(lj_lib_upvalue(L, 1));
+  const char *s = strdata(str);
+  TValue *tvpos = lj_lib_upvalue(L, 3);
+  const char *src = s + tvpos->u32.lo;
+  MatchState ms;
+  ms.L = L;
+  ms.src_init = s;
+  ms.src_end = s + str->len;
+  for (; src <= ms.src_end; src++) {
+    const char *e;
+    ms.level = 0;
+    if ((e = match(&ms, src, p)) != NULL) {
+      int32_t pos = (int32_t)(e - s);
+      if (e == src) pos++;  /* Ensure progress for empty match. */
+      tvpos->u32.lo = (uint32_t)pos;
+      return push_captures(&ms, src, e);
+    }
+  }
+  return 0;  /* not found */
+}
+
+LJLIB_CF(string_gmatch)
+{
+  lj_lib_checkstr(L, 1);
+  lj_lib_checkstr(L, 2);
+  L->top = L->base+3;
+  (L->top-1)->u64 = 0;
+  lj_lib_pushcc(L, lj_cf_string_gmatch_aux, FF_string_gmatch_aux, 3);
+  return 1;
+}
+
+static void add_s(MatchState *ms, luaL_Buffer *b, const char *s, const char *e)
+{
+  size_t l, i;
+  const char *news = lua_tolstring(ms->L, 3, &l);
+  for (i = 0; i < l; i++) {
+    if (news[i] != L_ESC) {
+      luaL_addchar(b, news[i]);
+    } else {
+      i++;  /* skip ESC */
+      if (!lj_char_isdigit(uchar(news[i]))) {
+        luaL_addchar(b, news[i]);
+      } else if (news[i] == '0') {
+        luaL_addlstring(b, s, (size_t)(e - s));
+      } else {
+        push_onecapture(ms, news[i] - '1', s, e);
+        luaL_addvalue(b);  /* add capture to accumulated result */
+      }
+    }
+  }
+}
+
+static void add_value(MatchState *ms, luaL_Buffer *b,
+                      const char *s, const char *e)
+{
+  lua_State *L = ms->L;
+  switch (lua_type(L, 3)) {
+    case LUA_TNUMBER:
+    case LUA_TSTRING: {
+      add_s(ms, b, s, e);
+      return;
+    }
+    case LUA_TFUNCTION: {
+      int n;
+      lua_pushvalue(L, 3);
+      n = push_captures(ms, s, e);
+      lua_call(L, n, 1);
+      break;
+    }
+    case LUA_TTABLE: {
+      push_onecapture(ms, 0, s, e);
+      lua_gettable(L, 3);
+      break;
+    }
+  }
+  if (!lua_toboolean(L, -1)) {  /* nil or false? */
+    lua_pop(L, 1);
+    lua_pushlstring(L, s, (size_t)(e - s));  /* keep original text */
+  } else if (!lua_isstring(L, -1)) {
+    lj_err_callerv(L, LJ_ERR_STRGSRV, luaL_typename(L, -1));
+  }
+  luaL_addvalue(b);  /* add result to accumulator */
+}
+
+LJLIB_CF(string_gsub)
+{
+  size_t srcl;
+  const char *src = luaL_checklstring(L, 1, &srcl);
+  const char *p = luaL_checkstring(L, 2);
+  int  tr = lua_type(L, 3);
+  int max_s = luaL_optint(L, 4, (int)(srcl+1));
+  int anchor = (*p == '^') ? (p++, 1) : 0;
+  int n = 0;
+  MatchState ms;
+  luaL_Buffer b;
+  if (!(tr == LUA_TNUMBER || tr == LUA_TSTRING ||
+        tr == LUA_TFUNCTION || tr == LUA_TTABLE))
+    lj_err_arg(L, 3, LJ_ERR_NOSFT);
+  luaL_buffinit(L, &b);
+  ms.L = L;
+  ms.src_init = src;
+  ms.src_end = src+srcl;
+  while (n < max_s) {
+    const char *e;
+    ms.level = 0;
+    e = match(&ms, src, p);
+    if (e) {
+      n++;
+      add_value(&ms, &b, src, e);
+    }
+    if (e && e>src) /* non empty match? */
+      src = e;  /* skip it */
+    else if (src < ms.src_end)
+      luaL_addchar(&b, *src++);
+    else
+      break;
+    if (anchor)
+      break;
+  }
+  luaL_addlstring(&b, src, (size_t)(ms.src_end-src));
+  luaL_pushresult(&b);
+  lua_pushinteger(L, n);  /* number of substitutions */
+  return 2;
+}
+
+/* ------------------------------------------------------------------------ */
+
+/* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
+#define MAX_FMTITEM     512
+/* valid flags in a format specification */
+#define FMT_FLAGS       "-+ #0"
+/*
+** maximum size of each format specification (such as '%-099.99d')
+** (+10 accounts for %99.99x plus margin of error)
+*/
+#define MAX_FMTSPEC     (sizeof(FMT_FLAGS) + sizeof(LUA_INTFRMLEN) + 10)
+
+static void addquoted(lua_State *L, luaL_Buffer *b, int arg)
+{
+  GCstr *str = lj_lib_checkstr(L, arg);
+  int32_t len = (int32_t)str->len;
+  const char *s = strdata(str);
+  luaL_addchar(b, '"');
+  while (len--) {
+    if (*s == '"' || *s == '\\' || *s == '\n') {
+      luaL_addchar(b, '\\');
+      luaL_addchar(b, *s);
+    } else if (lj_char_iscntrl(uchar(*s))) {
+      uint32_t c1, c2, c3;
+      luaL_addchar(b, '\\');
+      c1 = uchar(*s); c3 = c1 % 10; c1 /= 10; c2 = c1 % 10; c1 /= 10;
+      if (c1 + lj_char_isdigit(uchar(s[1]))) luaL_addchar(b, '0' + c1);
+      if (c2 + (c1 + lj_char_isdigit(uchar(s[1])))) luaL_addchar(b, '0' + c2);
+      luaL_addchar(b, '0' + c3);
+    } else {
+      luaL_addchar(b, *s);
+    }
+    s++;
+  }
+  luaL_addchar(b, '"');
+}
+
+static const char *scanformat(lua_State *L, const char *strfrmt, char *form)
+{
+  const char *p = strfrmt;
+  while (*p != '\0' && strchr(FMT_FLAGS, *p) != NULL) p++;  /* skip flags */
+  if ((size_t)(p - strfrmt) >= sizeof(FMT_FLAGS))
+    lj_err_caller(L, LJ_ERR_STRFMTR);
+  if (lj_char_isdigit(uchar(*p))) p++;  /* skip width */
+  if (lj_char_isdigit(uchar(*p))) p++;  /* (2 digits at most) */
+  if (*p == '.') {
+    p++;
+    if (lj_char_isdigit(uchar(*p))) p++;  /* skip precision */
+    if (lj_char_isdigit(uchar(*p))) p++;  /* (2 digits at most) */
+  }
+  if (lj_char_isdigit(uchar(*p)))
+    lj_err_caller(L, LJ_ERR_STRFMTW);
+  *(form++) = '%';
+  strncpy(form, strfrmt, (size_t)(p - strfrmt + 1));
+  form += p - strfrmt + 1;
+  *form = '\0';
+  return p;
+}
+
+static void addintlen(char *form)
+{
+  size_t l = strlen(form);
+  char spec = form[l - 1];
+  strcpy(form + l - 1, LUA_INTFRMLEN);
+  form[l + sizeof(LUA_INTFRMLEN) - 2] = spec;
+  form[l + sizeof(LUA_INTFRMLEN) - 1] = '\0';
+}
+
+static unsigned LUA_INTFRM_T num2intfrm(lua_State *L, int arg)
+{
+  if (sizeof(LUA_INTFRM_T) == 4) {
+    return (LUA_INTFRM_T)lj_lib_checkbit(L, arg);
+  } else {
+    cTValue *o;
+    lj_lib_checknumber(L, arg);
+    o = L->base+arg-1;
+    if (tvisint(o))
+      return (LUA_INTFRM_T)intV(o);
+    else
+      return (LUA_INTFRM_T)numV(o);
+  }
+}
+
+static unsigned LUA_INTFRM_T num2uintfrm(lua_State *L, int arg)
+{
+  if (sizeof(LUA_INTFRM_T) == 4) {
+    return (unsigned LUA_INTFRM_T)lj_lib_checkbit(L, arg);
+  } else {
+    cTValue *o;
+    lj_lib_checknumber(L, arg);
+    o = L->base+arg-1;
+    if (tvisint(o))
+      return (unsigned LUA_INTFRM_T)intV(o);
+    else if ((int32_t)o->u32.hi < 0)
+      return (unsigned LUA_INTFRM_T)(LUA_INTFRM_T)numV(o);
+    else
+      return (unsigned LUA_INTFRM_T)numV(o);
+  }
+}
+
+LJLIB_CF(string_format)
+{
+  int arg = 1, top = (int)(L->top - L->base);
+  GCstr *fmt = lj_lib_checkstr(L, arg);
+  const char *strfrmt = strdata(fmt);
+  const char *strfrmt_end = strfrmt + fmt->len;
+  luaL_Buffer b;
+  luaL_buffinit(L, &b);
+  while (strfrmt < strfrmt_end) {
+    if (*strfrmt != L_ESC) {
+      luaL_addchar(&b, *strfrmt++);
+    } else if (*++strfrmt == L_ESC) {
+      luaL_addchar(&b, *strfrmt++);  /* %% */
+    } else { /* format item */
+      char form[MAX_FMTSPEC];  /* to store the format (`%...') */
+      char buff[MAX_FMTITEM];  /* to store the formatted item */
+      if (++arg > top)
+        luaL_argerror(L, arg, lj_obj_typename[0]);
+      strfrmt = scanformat(L, strfrmt, form);
+      switch (*strfrmt++) {
+      case 'c':
+        sprintf(buff, form, lj_lib_checkint(L, arg));
+        break;
+      case 'd':  case 'i':
+        addintlen(form);
+        sprintf(buff, form, num2intfrm(L, arg));
+        break;
+      case 'o':  case 'u':  case 'x':  case 'X':
+        addintlen(form);
+        sprintf(buff, form, num2uintfrm(L, arg));
+        break;
+      case 'e':  case 'E': case 'f': case 'g': case 'G': {
+        TValue tv;
+        tv.n = lj_lib_checknum(L, arg);
+        if (LJ_UNLIKELY((tv.u32.hi << 1) >= 0xffe00000)) {
+          /* Canonicalize output of non-finite values. */
+          char *p, nbuf[LJ_STR_NUMBUF];
+          size_t len = lj_str_bufnum(nbuf, &tv);
+          if (strfrmt[-1] == 'E' || strfrmt[-1] == 'G') {
+            nbuf[len-3] = nbuf[len-3] - 0x20;
+            nbuf[len-2] = nbuf[len-2] - 0x20;
+            nbuf[len-1] = nbuf[len-1] - 0x20;
+          }
+          nbuf[len] = '\0';
+          for (p = form; *p < 'e' && *p != '.'; p++) ;
+          *p++ = 's'; *p = '\0';
+          sprintf(buff, form, nbuf);
+          break;
+        }
+        sprintf(buff, form, (double)tv.n);
+        break;
+        }
+      case 'q':
+        addquoted(L, &b, arg);
+        continue;
+      case 'p':
+        lj_str_pushf(L, "%p", lua_topointer(L, arg));
+        luaL_addvalue(&b);
+        continue;
+      case 's': {
+        GCstr *str = lj_lib_checkstr(L, arg);
+        if (!strchr(form, '.') && str->len >= 100) {
+          /* no precision and string is too long to be formatted;
+             keep original string */
+          setstrV(L, L->top++, str);
+          luaL_addvalue(&b);
+          continue;
+        }
+        sprintf(buff, form, strdata(str));
+        break;
+        }
+      default:
+        lj_err_callerv(L, LJ_ERR_STRFMTO, *(strfrmt -1));
+        break;
+      }
+      luaL_addlstring(&b, buff, strlen(buff));
+    }
+  }
+  luaL_pushresult(&b);
+  return 1;
+}
+
+/* ------------------------------------------------------------------------ */
+
+#include "lj_libdef.h"
+
+LUALIB_API int luaopen_string(lua_State *L)
+{
+  GCtab *mt;
+  global_State *g;
+  LJ_LIB_REG(L, LUA_STRLIBNAME, string);
+#if defined(LUA_COMPAT_GFIND)
+  lua_getfield(L, -1, "gmatch");
+  lua_setfield(L, -2, "gfind");
+#endif
+  mt = lj_tab_new(L, 0, 1);
+  /* NOBARRIER: basemt is a GC root. */
+  g = G(L);
+  setgcref(basemt_it(g, LJ_TSTR), obj2gco(mt));
+  settabV(L, lj_tab_setstr(L, mt, mmname_str(g, MM_index)), tabV(L->top-1));
+  mt->nomm = (uint8_t)(~(1u<<MM_index));
+  return 1;
+}
+