1 files changed, 822 insertions, 0 deletions

diff --git a/src/lua/ldo.c b/src/lua/ldo.c
new file mode 100644
index 0000000..c563b1d
--- /dev/null
+++ b/src/lua/ldo.c
@@ -0,0 +1,822 @@
+/*
+** $Id: ldo.c $
+** Stack and Call structure of Lua
+** See Copyright Notice in lua.h
+*/
+
+#define ldo_c
+#define LUA_CORE
+
+#include "lprefix.h"
+
+
+#include <setjmp.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "lua.h"
+
+#include "lapi.h"
+#include "ldebug.h"
+#include "ldo.h"
+#include "lfunc.h"
+#include "lgc.h"
+#include "lmem.h"
+#include "lobject.h"
+#include "lopcodes.h"
+#include "lparser.h"
+#include "lstate.h"
+#include "lstring.h"
+#include "ltable.h"
+#include "ltm.h"
+#include "lundump.h"
+#include "lvm.h"
+#include "lzio.h"
+
+
+
+#define errorstatus(s)  ((s) > LUA_YIELD)
+
+
+/*
+** {======================================================
+** Error-recovery functions
+** =======================================================
+*/
+
+/*
+** LUAI_THROW/LUAI_TRY define how Lua does exception handling. By
+** default, Lua handles errors with exceptions when compiling as
+** C++ code, with _longjmp/_setjmp when asked to use them, and with
+** longjmp/setjmp otherwise.
+*/
+#if !defined(LUAI_THROW)                                /* { */
+
+#if defined(__cplusplus) && !defined(LUA_USE_LONGJMP)   /* { */
+
+/* C++ exceptions */
+#define LUAI_THROW(L,c)         throw(c)
+#define LUAI_TRY(L,c,a) \
+        try { a } catch(...) { if ((c)->status == 0) (c)->status = -1; }
+#define luai_jmpbuf             int  /* dummy variable */
+
+#elif defined(LUA_USE_POSIX)                            /* }{ */
+
+/* in POSIX, try _longjmp/_setjmp (more efficient) */
+#define LUAI_THROW(L,c)         _longjmp((c)->b, 1)
+#define LUAI_TRY(L,c,a)         if (_setjmp((c)->b) == 0) { a }
+#define luai_jmpbuf             jmp_buf
+
+#else                                                   /* }{ */
+
+/* ISO C handling with long jumps */
+#define LUAI_THROW(L,c)         longjmp((c)->b, 1)
+#define LUAI_TRY(L,c,a)         if (setjmp((c)->b) == 0) { a }
+#define luai_jmpbuf             jmp_buf
+
+#endif                                                  /* } */
+
+#endif                                                  /* } */
+
+
+
+/* chain list of long jump buffers */
+struct lua_longjmp {
+  struct lua_longjmp *previous;
+  luai_jmpbuf b;
+  volatile int status;  /* error code */
+};
+
+
+void luaD_seterrorobj (lua_State *L, int errcode, StkId oldtop) {
+  switch (errcode) {
+    case LUA_ERRMEM: {  /* memory error? */
+      setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */
+      break;
+    }
+    case LUA_ERRERR: {
+      setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling"));
+      break;
+    }
+    case CLOSEPROTECT: {
+      setnilvalue(s2v(oldtop));  /* no error message */
+      break;
+    }
+    default: {
+      setobjs2s(L, oldtop, L->top - 1);  /* error message on current top */
+      break;
+    }
+  }
+  L->top = oldtop + 1;
+}
+
+
+l_noret luaD_throw (lua_State *L, int errcode) {
+  if (L->errorJmp) {  /* thread has an error handler? */
+    L->errorJmp->status = errcode;  /* set status */
+    LUAI_THROW(L, L->errorJmp);  /* jump to it */
+  }
+  else {  /* thread has no error handler */
+    global_State *g = G(L);
+    errcode = luaF_close(L, L->stack, errcode);  /* close all upvalues */
+    L->status = cast_byte(errcode);  /* mark it as dead */
+    if (g->mainthread->errorJmp) {  /* main thread has a handler? */
+      setobjs2s(L, g->mainthread->top++, L->top - 1);  /* copy error obj. */
+      luaD_throw(g->mainthread, errcode);  /* re-throw in main thread */
+    }
+    else {  /* no handler at all; abort */
+      if (g->panic) {  /* panic function? */
+        luaD_seterrorobj(L, errcode, L->top);  /* assume EXTRA_STACK */
+        if (L->ci->top < L->top)
+          L->ci->top = L->top;  /* pushing msg. can break this invariant */
+        lua_unlock(L);
+        g->panic(L);  /* call panic function (last chance to jump out) */
+      }
+      abort();
+    }
+  }
+}
+
+
+int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
+  global_State *g = G(L);
+  l_uint32 oldnCcalls = g->Cstacklimit - (L->nCcalls + L->nci);
+  struct lua_longjmp lj;
+  lj.status = LUA_OK;
+  lj.previous = L->errorJmp;  /* chain new error handler */
+  L->errorJmp = &lj;
+  LUAI_TRY(L, &lj,
+    (*f)(L, ud);
+  );
+  L->errorJmp = lj.previous;  /* restore old error handler */
+  L->nCcalls = g->Cstacklimit - oldnCcalls - L->nci;
+  return lj.status;
+}
+
+/* }====================================================== */
+
+
+/*
+** {==================================================================
+** Stack reallocation
+** ===================================================================
+*/
+static void correctstack (lua_State *L, StkId oldstack, StkId newstack) {
+  CallInfo *ci;
+  UpVal *up;
+  if (oldstack == newstack)
+    return;  /* stack address did not change */
+  L->top = (L->top - oldstack) + newstack;
+  for (up = L->openupval; up != NULL; up = up->u.open.next)
+    up->v = s2v((uplevel(up) - oldstack) + newstack);
+  for (ci = L->ci; ci != NULL; ci = ci->previous) {
+    ci->top = (ci->top - oldstack) + newstack;
+    ci->func = (ci->func - oldstack) + newstack;
+    if (isLua(ci))
+      ci->u.l.trap = 1;  /* signal to update 'trap' in 'luaV_execute' */
+  }
+}
+
+
+/* some space for error handling */
+#define ERRORSTACKSIZE  (LUAI_MAXSTACK + 200)
+
+
+int luaD_reallocstack (lua_State *L, int newsize, int raiseerror) {
+  int lim = L->stacksize;
+  StkId newstack = luaM_reallocvector(L, L->stack, lim, newsize, StackValue);
+  lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE);
+  lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK);
+  if (unlikely(newstack == NULL)) {  /* reallocation failed? */
+    if (raiseerror)
+      luaM_error(L);
+    else return 0;  /* do not raise an error */
+  }
+  for (; lim < newsize; lim++)
+    setnilvalue(s2v(newstack + lim)); /* erase new segment */
+  correctstack(L, L->stack, newstack);
+  L->stack = newstack;
+  L->stacksize = newsize;
+  L->stack_last = L->stack + newsize - EXTRA_STACK;
+  return 1;
+}
+
+
+/*
+** Try to grow the stack by at least 'n' elements. when 'raiseerror'
+** is true, raises any error; otherwise, return 0 in case of errors.
+*/
+int luaD_growstack (lua_State *L, int n, int raiseerror) {
+  int size = L->stacksize;
+  int newsize = 2 * size;  /* tentative new size */
+  if (unlikely(size > LUAI_MAXSTACK)) {  /* need more space after extra size? */
+    if (raiseerror)
+      luaD_throw(L, LUA_ERRERR);  /* error inside message handler */
+    else return 0;
+  }
+  else {
+    int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK;
+    if (newsize > LUAI_MAXSTACK)  /* cannot cross the limit */
+      newsize = LUAI_MAXSTACK;
+    if (newsize < needed)  /* but must respect what was asked for */
+      newsize = needed;
+    if (unlikely(newsize > LUAI_MAXSTACK)) {  /* stack overflow? */
+      /* add extra size to be able to handle the error message */
+      luaD_reallocstack(L, ERRORSTACKSIZE, raiseerror);
+      if (raiseerror)
+        luaG_runerror(L, "stack overflow");
+      else return 0;
+    }
+  }  /* else no errors */
+  return luaD_reallocstack(L, newsize, raiseerror);
+}
+
+
+static int stackinuse (lua_State *L) {
+  CallInfo *ci;
+  StkId lim = L->top;
+  for (ci = L->ci; ci != NULL; ci = ci->previous) {
+    if (lim < ci->top) lim = ci->top;
+  }
+  lua_assert(lim <= L->stack_last);
+  return cast_int(lim - L->stack) + 1;  /* part of stack in use */
+}
+
+
+void luaD_shrinkstack (lua_State *L) {
+  int inuse = stackinuse(L);
+  int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK;
+  if (goodsize > LUAI_MAXSTACK)
+    goodsize = LUAI_MAXSTACK;  /* respect stack limit */
+  /* if thread is currently not handling a stack overflow and its
+     good size is smaller than current size, shrink its stack */
+  if (inuse <= (LUAI_MAXSTACK - EXTRA_STACK) &&
+      goodsize < L->stacksize)
+    luaD_reallocstack(L, goodsize, 0);  /* ok if that fails */
+  else  /* don't change stack */
+    condmovestack(L,{},{});  /* (change only for debugging) */
+  luaE_shrinkCI(L);  /* shrink CI list */
+}
+
+
+void luaD_inctop (lua_State *L) {
+  luaD_checkstack(L, 1);
+  L->top++;
+}
+
+/* }================================================================== */
+
+
+/*
+** Call a hook for the given event. Make sure there is a hook to be
+** called. (Both 'L->hook' and 'L->hookmask', which trigger this
+** function, can be changed asynchronously by signals.)
+*/
+void luaD_hook (lua_State *L, int event, int line,
+                              int ftransfer, int ntransfer) {
+  lua_Hook hook = L->hook;
+  if (hook && L->allowhook) {  /* make sure there is a hook */
+    int mask = CIST_HOOKED;
+    CallInfo *ci = L->ci;
+    ptrdiff_t top = savestack(L, L->top);
+    ptrdiff_t ci_top = savestack(L, ci->top);
+    lua_Debug ar;
+    ar.event = event;
+    ar.currentline = line;
+    ar.i_ci = ci;
+    if (ntransfer != 0) {
+      mask |= CIST_TRAN;  /* 'ci' has transfer information */
+      ci->u2.transferinfo.ftransfer = ftransfer;
+      ci->u2.transferinfo.ntransfer = ntransfer;
+    }
+    luaD_checkstack(L, LUA_MINSTACK);  /* ensure minimum stack size */
+    if (L->top + LUA_MINSTACK > ci->top)
+      ci->top = L->top + LUA_MINSTACK;
+    L->allowhook = 0;  /* cannot call hooks inside a hook */
+    ci->callstatus |= mask;
+    lua_unlock(L);
+    (*hook)(L, &ar);
+    lua_lock(L);
+    lua_assert(!L->allowhook);
+    L->allowhook = 1;
+    ci->top = restorestack(L, ci_top);
+    L->top = restorestack(L, top);
+    ci->callstatus &= ~mask;
+  }
+}
+
+
+/*
+** Executes a call hook for Lua functions. This function is called
+** whenever 'hookmask' is not zero, so it checks whether call hooks are
+** active.
+*/
+void luaD_hookcall (lua_State *L, CallInfo *ci) {
+  int hook = (ci->callstatus & CIST_TAIL) ? LUA_HOOKTAILCALL : LUA_HOOKCALL;
+  Proto *p;
+  if (!(L->hookmask & LUA_MASKCALL))  /* some other hook? */
+    return;  /* don't call hook */
+  p = clLvalue(s2v(ci->func))->p;
+  L->top = ci->top;  /* prepare top */
+  ci->u.l.savedpc++;  /* hooks assume 'pc' is already incremented */
+  luaD_hook(L, hook, -1, 1, p->numparams);
+  ci->u.l.savedpc--;  /* correct 'pc' */
+}
+
+
+static StkId rethook (lua_State *L, CallInfo *ci, StkId firstres, int nres) {
+  ptrdiff_t oldtop = savestack(L, L->top);  /* hook may change top */
+  int delta = 0;
+  if (isLuacode(ci)) {
+    Proto *p = clLvalue(s2v(ci->func))->p;
+    if (p->is_vararg)
+      delta = ci->u.l.nextraargs + p->numparams + 1;
+    if (L->top < ci->top)
+      L->top = ci->top;  /* correct top to run hook */
+  }
+  if (L->hookmask & LUA_MASKRET) {  /* is return hook on? */
+    int ftransfer;
+    ci->func += delta;  /* if vararg, back to virtual 'func' */
+    ftransfer = cast(unsigned short, firstres - ci->func);
+    luaD_hook(L, LUA_HOOKRET, -1, ftransfer, nres);  /* call it */
+    ci->func -= delta;
+  }
+  if (isLua(ci->previous))
+    L->oldpc = ci->previous->u.l.savedpc;  /* update 'oldpc' */
+  return restorestack(L, oldtop);
+}
+
+
+/*
+** Check whether 'func' has a '__call' metafield. If so, put it in the
+** stack, below original 'func', so that 'luaD_call' can call it. Raise
+** an error if there is no '__call' metafield.
+*/
+void luaD_tryfuncTM (lua_State *L, StkId func) {
+  const TValue *tm = luaT_gettmbyobj(L, s2v(func), TM_CALL);
+  StkId p;
+  if (unlikely(ttisnil(tm)))
+    luaG_typeerror(L, s2v(func), "call");  /* nothing to call */
+  for (p = L->top; p > func; p--)  /* open space for metamethod */
+    setobjs2s(L, p, p-1);
+  L->top++;  /* stack space pre-allocated by the caller */
+  setobj2s(L, func, tm);  /* metamethod is the new function to be called */
+}
+
+
+/*
+** Given 'nres' results at 'firstResult', move 'wanted' of them to 'res'.
+** Handle most typical cases (zero results for commands, one result for
+** expressions, multiple results for tail calls/single parameters)
+** separated.
+*/
+static void moveresults (lua_State *L, StkId res, int nres, int wanted) {
+  StkId firstresult;
+  int i;
+  switch (wanted) {  /* handle typical cases separately */
+    case 0:  /* no values needed */
+      L->top = res;
+      return;
+    case 1:  /* one value needed */
+      if (nres == 0)   /* no results? */
+        setnilvalue(s2v(res));  /* adjust with nil */
+      else
+        setobjs2s(L, res, L->top - nres);  /* move it to proper place */
+      L->top = res + 1;
+      return;
+    case LUA_MULTRET:
+      wanted = nres;  /* we want all results */
+      break;
+    default:  /* multiple results (or to-be-closed variables) */
+      if (hastocloseCfunc(wanted)) {  /* to-be-closed variables? */
+        ptrdiff_t savedres = savestack(L, res);
+        luaF_close(L, res, LUA_OK);  /* may change the stack */
+        res = restorestack(L, savedres);
+        wanted = codeNresults(wanted);  /* correct value */
+        if (wanted == LUA_MULTRET)
+          wanted = nres;
+      }
+      break;
+  }
+  firstresult = L->top - nres;  /* index of first result */
+  /* move all results to correct place */
+  for (i = 0; i < nres && i < wanted; i++)
+    setobjs2s(L, res + i, firstresult + i);
+  for (; i < wanted; i++)  /* complete wanted number of results */
+    setnilvalue(s2v(res + i));
+  L->top = res + wanted;  /* top points after the last result */
+}
+
+
+/*
+** Finishes a function call: calls hook if necessary, removes CallInfo,
+** moves current number of results to proper place.
+*/
+void luaD_poscall (lua_State *L, CallInfo *ci, int nres) {
+  if (L->hookmask)
+    L->top = rethook(L, ci, L->top - nres, nres);
+  L->ci = ci->previous;  /* back to caller */
+  /* move results to proper place */
+  moveresults(L, ci->func, nres, ci->nresults);
+}
+
+
+
+#define next_ci(L)  (L->ci->next ? L->ci->next : luaE_extendCI(L))
+
+
+/*
+** Prepare a function for a tail call, building its call info on top
+** of the current call info. 'narg1' is the number of arguments plus 1
+** (so that it includes the function itself).
+*/
+void luaD_pretailcall (lua_State *L, CallInfo *ci, StkId func, int narg1) {
+  Proto *p = clLvalue(s2v(func))->p;
+  int fsize = p->maxstacksize;  /* frame size */
+  int nfixparams = p->numparams;
+  int i;
+  for (i = 0; i < narg1; i++)  /* move down function and arguments */
+    setobjs2s(L, ci->func + i, func + i);
+  checkstackGC(L, fsize);
+  func = ci->func;  /* moved-down function */
+  for (; narg1 <= nfixparams; narg1++)
+    setnilvalue(s2v(func + narg1));  /* complete missing arguments */
+  ci->top = func + 1 + fsize;  /* top for new function */
+  lua_assert(ci->top <= L->stack_last);
+  ci->u.l.savedpc = p->code;  /* starting point */
+  ci->callstatus |= CIST_TAIL;
+  L->top = func + narg1;  /* set top */
+}
+
+
+/*
+** Call a function (C or Lua). The function to be called is at *func.
+** The arguments are on the stack, right after the function.
+** When returns, all the results are on the stack, starting at the original
+** function position.
+*/
+void luaD_call (lua_State *L, StkId func, int nresults) {
+  lua_CFunction f;
+ retry:
+  switch (ttypetag(s2v(func))) {
+    case LUA_VCCL:  /* C closure */
+      f = clCvalue(s2v(func))->f;
+      goto Cfunc;
+    case LUA_VLCF:  /* light C function */
+      f = fvalue(s2v(func));
+     Cfunc: {
+      int n;  /* number of returns */
+      CallInfo *ci = next_ci(L);
+      checkstackp(L, LUA_MINSTACK, func);  /* ensure minimum stack size */
+      ci->nresults = nresults;
+      ci->callstatus = CIST_C;
+      ci->top = L->top + LUA_MINSTACK;
+      ci->func = func;
+      L->ci = ci;
+      lua_assert(ci->top <= L->stack_last);
+      if (L->hookmask & LUA_MASKCALL) {
+        int narg = cast_int(L->top - func) - 1;
+        luaD_hook(L, LUA_HOOKCALL, -1, 1, narg);
+      }
+      lua_unlock(L);
+      n = (*f)(L);  /* do the actual call */
+      lua_lock(L);
+      api_checknelems(L, n);
+      luaD_poscall(L, ci, n);
+      break;
+    }
+    case LUA_VLCL: {  /* Lua function */
+      CallInfo *ci = next_ci(L);
+      Proto *p = clLvalue(s2v(func))->p;
+      int narg = cast_int(L->top - func) - 1;  /* number of real arguments */
+      int nfixparams = p->numparams;
+      int fsize = p->maxstacksize;  /* frame size */
+      checkstackp(L, fsize, func);
+      ci->nresults = nresults;
+      ci->u.l.savedpc = p->code;  /* starting point */
+      ci->callstatus = 0;
+      ci->top = func + 1 + fsize;
+      ci->func = func;
+      L->ci = ci;
+      for (; narg < nfixparams; narg++)
+        setnilvalue(s2v(L->top++));  /* complete missing arguments */
+      lua_assert(ci->top <= L->stack_last);
+      luaV_execute(L, ci);  /* run the function */
+      break;
+    }
+    default: {  /* not a function */
+      checkstackp(L, 1, func);  /* space for metamethod */
+      luaD_tryfuncTM(L, func);  /* try to get '__call' metamethod */
+      goto retry;  /* try again with metamethod */
+    }
+  }
+}
+
+
+/*
+** Similar to 'luaD_call', but does not allow yields during the call.
+** If there is a stack overflow, freeing all CI structures will
+** force the subsequent call to invoke 'luaE_extendCI', which then
+** will raise any errors.
+*/
+void luaD_callnoyield (lua_State *L, StkId func, int nResults) {
+  incXCcalls(L);
+  if (getCcalls(L) <= CSTACKERR)  /* possible stack overflow? */
+    luaE_freeCI(L);
+  luaD_call(L, func, nResults);
+  decXCcalls(L);
+}
+
+
+/*
+** Completes the execution of an interrupted C function, calling its
+** continuation function.
+*/
+static void finishCcall (lua_State *L, int status) {
+  CallInfo *ci = L->ci;
+  int n;
+  /* must have a continuation and must be able to call it */
+  lua_assert(ci->u.c.k != NULL && yieldable(L));
+  /* error status can only happen in a protected call */
+  lua_assert((ci->callstatus & CIST_YPCALL) || status == LUA_YIELD);
+  if (ci->callstatus & CIST_YPCALL) {  /* was inside a pcall? */
+    ci->callstatus &= ~CIST_YPCALL;  /* continuation is also inside it */
+    L->errfunc = ci->u.c.old_errfunc;  /* with the same error function */
+  }
+  /* finish 'lua_callk'/'lua_pcall'; CIST_YPCALL and 'errfunc' already
+     handled */
+  adjustresults(L, ci->nresults);
+  lua_unlock(L);
+  n = (*ci->u.c.k)(L, status, ci->u.c.ctx);  /* call continuation function */
+  lua_lock(L);
+  api_checknelems(L, n);
+  luaD_poscall(L, ci, n);  /* finish 'luaD_call' */
+}
+
+
+/*
+** Executes "full continuation" (everything in the stack) of a
+** previously interrupted coroutine until the stack is empty (or another
+** interruption long-jumps out of the loop). If the coroutine is
+** recovering from an error, 'ud' points to the error status, which must
+** be passed to the first continuation function (otherwise the default
+** status is LUA_YIELD).
+*/
+static void unroll (lua_State *L, void *ud) {
+  CallInfo *ci;
+  if (ud != NULL)  /* error status? */
+    finishCcall(L, *(int *)ud);  /* finish 'lua_pcallk' callee */
+  while ((ci = L->ci) != &L->base_ci) {  /* something in the stack */
+    if (!isLua(ci))  /* C function? */
+      finishCcall(L, LUA_YIELD);  /* complete its execution */
+    else {  /* Lua function */
+      luaV_finishOp(L);  /* finish interrupted instruction */
+      luaV_execute(L, ci);  /* execute down to higher C 'boundary' */
+    }
+  }
+}
+
+
+/*
+** Try to find a suspended protected call (a "recover point") for the
+** given thread.
+*/
+static CallInfo *findpcall (lua_State *L) {
+  CallInfo *ci;
+  for (ci = L->ci; ci != NULL; ci = ci->previous) {  /* search for a pcall */
+    if (ci->callstatus & CIST_YPCALL)
+      return ci;
+  }
+  return NULL;  /* no pending pcall */
+}
+
+
+/*
+** Recovers from an error in a coroutine. Finds a recover point (if
+** there is one) and completes the execution of the interrupted
+** 'luaD_pcall'. If there is no recover point, returns zero.
+*/
+static int recover (lua_State *L, int status) {
+  StkId oldtop;
+  CallInfo *ci = findpcall(L);
+  if (ci == NULL) return 0;  /* no recovery point */
+  /* "finish" luaD_pcall */
+  oldtop = restorestack(L, ci->u2.funcidx);
+  luaF_close(L, oldtop, status);  /* may change the stack */
+  oldtop = restorestack(L, ci->u2.funcidx);
+  luaD_seterrorobj(L, status, oldtop);
+  L->ci = ci;
+  L->allowhook = getoah(ci->callstatus);  /* restore original 'allowhook' */
+  luaD_shrinkstack(L);
+  L->errfunc = ci->u.c.old_errfunc;
+  return 1;  /* continue running the coroutine */
+}
+
+
+/*
+** Signal an error in the call to 'lua_resume', not in the execution
+** of the coroutine itself. (Such errors should not be handled by any
+** coroutine error handler and should not kill the coroutine.)
+*/
+static int resume_error (lua_State *L, const char *msg, int narg) {
+  L->top -= narg;  /* remove args from the stack */
+  setsvalue2s(L, L->top, luaS_new(L, msg));  /* push error message */
+  api_incr_top(L);
+  lua_unlock(L);
+  return LUA_ERRRUN;
+}
+
+
+/*
+** Do the work for 'lua_resume' in protected mode. Most of the work
+** depends on the status of the coroutine: initial state, suspended
+** inside a hook, or regularly suspended (optionally with a continuation
+** function), plus erroneous cases: non-suspended coroutine or dead
+** coroutine.
+*/
+static void resume (lua_State *L, void *ud) {
+  int n = *(cast(int*, ud));  /* number of arguments */
+  StkId firstArg = L->top - n;  /* first argument */
+  CallInfo *ci = L->ci;
+  if (L->status == LUA_OK) {  /* starting a coroutine? */
+    luaD_call(L, firstArg - 1, LUA_MULTRET);
+  }
+  else {  /* resuming from previous yield */
+    lua_assert(L->status == LUA_YIELD);
+    L->status = LUA_OK;  /* mark that it is running (again) */
+    if (isLua(ci))  /* yielded inside a hook? */
+      luaV_execute(L, ci);  /* just continue running Lua code */
+    else {  /* 'common' yield */
+      if (ci->u.c.k != NULL) {  /* does it have a continuation function? */
+        lua_unlock(L);
+        n = (*ci->u.c.k)(L, LUA_YIELD, ci->u.c.ctx); /* call continuation */
+        lua_lock(L);
+        api_checknelems(L, n);
+      }
+      luaD_poscall(L, ci, n);  /* finish 'luaD_call' */
+    }
+    unroll(L, NULL);  /* run continuation */
+  }
+}
+
+LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs,
+                                      int *nresults) {
+  int status;
+  lua_lock(L);
+  if (L->status == LUA_OK) {  /* may be starting a coroutine */
+    if (L->ci != &L->base_ci)  /* not in base level? */
+      return resume_error(L, "cannot resume non-suspended coroutine", nargs);
+    else if (L->top - (L->ci->func + 1) == nargs)  /* no function? */
+      return resume_error(L, "cannot resume dead coroutine", nargs);
+  }
+  else if (L->status != LUA_YIELD)  /* ended with errors? */
+    return resume_error(L, "cannot resume dead coroutine", nargs);
+  if (from == NULL)
+    L->nCcalls = CSTACKTHREAD;
+  else  /* correct 'nCcalls' for this thread */
+    L->nCcalls = getCcalls(from) + from->nci - L->nci - CSTACKCF;
+  if (L->nCcalls <= CSTACKERR)
+    return resume_error(L, "C stack overflow", nargs);
+  luai_userstateresume(L, nargs);
+  api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs);
+  status = luaD_rawrunprotected(L, resume, &nargs);
+   /* continue running after recoverable errors */
+  while (errorstatus(status) && recover(L, status)) {
+    /* unroll continuation */
+    status = luaD_rawrunprotected(L, unroll, &status);
+  }
+  if (likely(!errorstatus(status)))
+    lua_assert(status == L->status);  /* normal end or yield */
+  else {  /* unrecoverable error */
+    L->status = cast_byte(status);  /* mark thread as 'dead' */
+    luaD_seterrorobj(L, status, L->top);  /* push error message */
+    L->ci->top = L->top;
+  }
+  *nresults = (status == LUA_YIELD) ? L->ci->u2.nyield
+                                    : cast_int(L->top - (L->ci->func + 1));
+  lua_unlock(L);
+  return status;
+}
+
+
+LUA_API int lua_isyieldable (lua_State *L) {
+  return yieldable(L);
+}
+
+
+LUA_API int lua_yieldk (lua_State *L, int nresults, lua_KContext ctx,
+                        lua_KFunction k) {
+  CallInfo *ci = L->ci;
+  luai_userstateyield(L, nresults);
+  lua_lock(L);
+  api_checknelems(L, nresults);
+  if (unlikely(!yieldable(L))) {
+    if (L != G(L)->mainthread)
+      luaG_runerror(L, "attempt to yield across a C-call boundary");
+    else
+      luaG_runerror(L, "attempt to yield from outside a coroutine");
+  }
+  L->status = LUA_YIELD;
+  if (isLua(ci)) {  /* inside a hook? */
+    lua_assert(!isLuacode(ci));
+    api_check(L, k == NULL, "hooks cannot continue after yielding");
+    ci->u2.nyield = 0;  /* no results */
+  }
+  else {
+    if ((ci->u.c.k = k) != NULL)  /* is there a continuation? */
+      ci->u.c.ctx = ctx;  /* save context */
+    ci->u2.nyield = nresults;  /* save number of results */
+    luaD_throw(L, LUA_YIELD);
+  }
+  lua_assert(ci->callstatus & CIST_HOOKED);  /* must be inside a hook */
+  lua_unlock(L);
+  return 0;  /* return to 'luaD_hook' */
+}
+
+
+/*
+** Call the C function 'func' in protected mode, restoring basic
+** thread information ('allowhook', etc.) and in particular
+** its stack level in case of errors.
+*/
+int luaD_pcall (lua_State *L, Pfunc func, void *u,
+                ptrdiff_t old_top, ptrdiff_t ef) {
+  int status;
+  CallInfo *old_ci = L->ci;
+  lu_byte old_allowhooks = L->allowhook;
+  ptrdiff_t old_errfunc = L->errfunc;
+  L->errfunc = ef;
+  status = luaD_rawrunprotected(L, func, u);
+  if (unlikely(status != LUA_OK)) {  /* an error occurred? */
+    StkId oldtop = restorestack(L, old_top);
+    L->ci = old_ci;
+    L->allowhook = old_allowhooks;
+    status = luaF_close(L, oldtop, status);
+    oldtop = restorestack(L, old_top);  /* previous call may change stack */
+    luaD_seterrorobj(L, status, oldtop);
+    luaD_shrinkstack(L);
+  }
+  L->errfunc = old_errfunc;
+  return status;
+}
+
+
+
+/*
+** Execute a protected parser.
+*/
+struct SParser {  /* data to 'f_parser' */
+  ZIO *z;
+  Mbuffer buff;  /* dynamic structure used by the scanner */
+  Dyndata dyd;  /* dynamic structures used by the parser */
+  const char *mode;
+  const char *name;
+};
+
+
+static void checkmode (lua_State *L, const char *mode, const char *x) {
+  if (mode && strchr(mode, x[0]) == NULL) {
+    luaO_pushfstring(L,
+       "attempt to load a %s chunk (mode is '%s')", x, mode);
+    luaD_throw(L, LUA_ERRSYNTAX);
+  }
+}
+
+
+static void f_parser (lua_State *L, void *ud) {
+  LClosure *cl;
+  struct SParser *p = cast(struct SParser *, ud);
+  int c = zgetc(p->z);  /* read first character */
+  if (c == LUA_SIGNATURE[0]) {
+    checkmode(L, p->mode, "binary");
+    cl = luaU_undump(L, p->z, p->name);
+  }
+  else {
+    checkmode(L, p->mode, "text");
+    cl = luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c);
+  }
+  lua_assert(cl->nupvalues == cl->p->sizeupvalues);
+  luaF_initupvals(L, cl);
+}
+
+
+int luaD_protectedparser (lua_State *L, ZIO *z, const char *name,
+                                        const char *mode) {
+  struct SParser p;
+  int status;
+  incnny(L);  /* cannot yield during parsing */
+  p.z = z; p.name = name; p.mode = mode;
+  p.dyd.actvar.arr = NULL; p.dyd.actvar.size = 0;
+  p.dyd.gt.arr = NULL; p.dyd.gt.size = 0;
+  p.dyd.label.arr = NULL; p.dyd.label.size = 0;
+  luaZ_initbuffer(L, &p.buff);
+  status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc);
+  luaZ_freebuffer(L, &p.buff);
+  luaM_freearray(L, p.dyd.actvar.arr, p.dyd.actvar.size);
+  luaM_freearray(L, p.dyd.gt.arr, p.dyd.gt.size);
+  luaM_freearray(L, p.dyd.label.arr, p.dyd.label.size);
+  decnny(L);
+  return status;
+}
+
+