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/*jshint esversion: 6 */
"use strict";
const OC = require('./lopcodes.js');
const lua = require('./lua.js');
const CT = lua.constant_types;
const LUA_MULTRET = lua.LUA_MULTRET;
const lobject = require('./lobject.js');
const TValue = lobject.TValue;
const Table = lobject.Table;
const LClosure = lobject.LClosure;
const lfunc = require('./lfunc.js');
const UpVal = lfunc.UpVal;
const lstate = require('./lstate.js');
const CallInfo = lstate.CallInfo;
const llimit = require('./llimit.js');
const nil = new TValue(CT.LUA_TNIL, null);
const precall = function(L, off, func, nresults) {
let ci;
switch(func.type) {
case CT.LUA_TCCL: // JS function ?
throw new Error("LUA_TCCL not implemeted yet");
break;
case CT.LUA_TLCF: // still JS function ?
throw new Error("LUA_TLCF not implemeted yet");
break;
case CT.LUA_TLCL: {
let p = func.p;
let n = L.top - off - 1;
let fsize = p.maxstacksize;
let base;
if (p.is_vararg) {
base = adjust_varargs(L, p, n);
} else {
for (; n < p.numparams; n++)
L.stack[L.top++] = nil; // complete missing arguments
base = off + 1;
}
// next_ci
if (L.ci.next) {
L.ci = L.ci.next;
ci = L.ci;
} else {
ci = new CallInfo(off);
L.ci.next = ci;
ci.previous = L.ci;
ci.next = null;
L.ci = ci;
L.ciOff++;
}
ci.nresults = nresults;
ci.func = func;
ci.u.l.base = base;
ci.top = base + fsize;
L.top = ci.top;
ci.u.l.savedpc = p.code;
ci.callstatus = lstate.CIST_LUA;
return false;
break;
}
default:
// __call
return false;
}
}
const postcall = function(L, ci, firstResult, nres) {
let wanted = ci.nresults;
let res = ci.funcOff;
L.ci = ci.previous;
L.ciOff--;
return moveresults(L, firstResult, res, nres, wanted);
}
const moveresults = function(L, firstResult, res, nres, wanted) {
switch (wanted) {
case 0:
break;
case 1: {
if (nres == 0)
firstResult = nil;
L.stack[res] = L.stack[firstResult];
break;
}
case LUA_MULTRET: {
for (let i = 0; i < nres; i++)
L.stack[res + i] = L.stack[firstResult + i];
L.top = res + nres;
return false;
}
default: {
let i;
if (wanted <= nres) {
for (i = 0; i < wanted; i++)
L.stack[res + i] = L.stack[firstResult + i];
for (; i < wanted; i++)
L.stack[res + i] = nil;
}
break;
}
}
return true;
}
const adjust_varargs = function(L, p, actual) {
let nfixargs = p.numparams;
/* move fixed parameters to final position */
let fixed = L.top - actual; /* first fixed argument */
let base = L.top; /* final position of first argument */
let i;
for (i = 0; i < nfixargs && i < actual; i++) {
L.stack[L.top++] = L.stack[fixed + i];
L.stack[fixed + i] = nil;
}
for (; i < nfixargs; i++)
L.stack[L.top++] = nil;
return base;
}
/*
** Check appropriate error for stack overflow ("regular" overflow or
** overflow while handling stack overflow). If 'nCalls' is larger than
** LUAI_MAXCCALLS (which means it is handling a "regular" overflow) but
** smaller than 9/8 of LUAI_MAXCCALLS, does not report an error (to
** allow overflow handling to work)
*/
const stackerror = function(L) {
if (L.nCcalls === LUAI_MAXCCALLS)
throw new Error("JS stack overflow");
else if (L.nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) /* error while handing stack error */
throw new Error("stack overflow") // TODO: luaD_throw(L, LUA_ERRERR);
}
/*
** Call a function (JS 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.
*/
// const luaD_call = function(L, func, nResults) {
// if (++L->nCcalls >= LUAI_MAXCCALLS)
// stackerror(L);
// if ()
// }
module.exports = {
precall: precall,
postcall: postcall,
moveresults: moveresults,
adjust_varargs: adjust_varargs
}
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