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-rw-r--r--src/ldo.js163
1 files changed, 163 insertions, 0 deletions
diff --git a/src/ldo.js b/src/ldo.js
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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
+} \ No newline at end of file