From 07d15af3d893e5eecc1baffaf47fe512d6218d0b Mon Sep 17 00:00:00 2001
From: Benoit Giannangeli <benoit.giannangeli@boursorama.fr>
Date: Mon, 13 Feb 2017 12:37:37 +0100
Subject: CONCAT
---
src/lvm.js | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 55 insertions(+)
(limited to 'src')
diff --git a/src/lvm.js b/src/lvm.js
index 8d6f5c7..a23f295 100644
--- a/src/lvm.js
+++ b/src/lvm.js
@@ -11,6 +11,7 @@ const LUA_MULTRET = lua.LUA_MULTRET;
const lobject = require('./lobject.js');
const TValue = lobject.TValue;
const Table = lobject.Table;
+const TString = lobject.TString;
const LClosure = lobject.LClosure;
const lfunc = require('./lfunc.js');
const UpVal = lfunc.UpVal;
@@ -381,6 +382,16 @@ const luaV_execute = function(L) {
break;
}
case "OP_CONCAT": {
+ let b = i.B;
+ let c = i.C;
+ let rb;
+ L.top = base + c + 1; /* mark the end of concat operands */
+ luaV_concat(L, c - b + 1);
+ base = ci.u.l.base;
+ ra = RA(L, base, i); /* 'luaV_concat' may invoke TMs and move the stack */
+ rb = base + b;
+ L.stack[ra] = L.stack[rb];
+ L.top = ci.top; /* restore top */
break;
}
case "OP_JMP": {
@@ -873,12 +884,56 @@ const luaV_objlen = function(L, ra, rb) {
ltm.luaT_callTM(L, tm, rb, rb, ra, 1);
};
+const tostring = function(L, i) {
+ let o = L.stack[i];
+ let str = `${o.value}`;
+
+ if (o.ttisstring() || (o.ttisnumber() && !isNaN(parseFloat(`${str}`)))) {
+ L.stack[i] = new TString(str);
+ return true;
+ }
+
+ return false;
+};
+
/*
** Main operation for concatenation: concat 'total' values in the stack,
** from 'L->top - total' up to 'L->top - 1'.
*/
const luaV_concat = function(L, total) {
assert(total >= 2);
+ do {
+ let top = L.top;
+ let n = 2; /* number of elements handled in this pass (at least 2) */
+ let v = L.stack[top-2];
+ let v2 = L.stack[top-1];
+
+ if (!(v.ttisstring() || v.ttisnumber()) || !tostring(L, top - 2)) // TODO: tostring
+ ltm.luaT_trybinTM(L, v, v2, top-2, TMS.TM_CONCAT);
+ else if (v2.ttisstring() && v2.value.length === 0)
+ tostring(L, top - 2)
+ else if (v.ttisstring() && v.value.length === 0)
+ L.stack[top - 2] = L.stack[top - 1];
+ else {
+ /* at least two non-empty string values; get as many as possible */
+ let tl = v.value.length;
+ /* collect total length and number of strings */
+ for (n = 1; n < total && tostring(L, top - n - 1); n++) {
+ let l = L.stack[top - n - 1].value.length;
+ // TODO: string length overflow ?
+ tl += l;
+ }
+
+ let ts = new TString("");
+ for (let i = n; i > 0; i--) {
+ ts.value = `${ts.value}${L.stack[top - i].value}`;
+ }
+
+ L.stack[top - n] = ts;
+ }
+ total -= n - 1; /* got 'n' strings to create 1 new */
+ L.top -= n - 1; /* popped 'n' strings and pushed one */
+ } while (total > 1); /* repeat until only 1 result left */
};
/*
--
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