From 8a97534ff542f1ba6516a2164648b6a0a6094c3c Mon Sep 17 00:00:00 2001
From: Jordi Baylina <jordi@baylina.cat>
Date: Wed, 28 Nov 2018 10:25:24 +0100
Subject: [PATCH] Small fixes

---
 src/bigint.js           | 43 ++++++++++++++++++++++++++++++++++++++++-
 src/calculateWitness.js |  2 +-
 2 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/src/bigint.js b/src/bigint.js
index 75df0b4..cbb2c0f 100644
--- a/src/bigint.js
+++ b/src/bigint.js
@@ -169,12 +169,26 @@ if (typeof(BigInt) != "undefined") {
         return this & m;
     };
 
+    wBigInt.prototype.div = function(c) {
+        return this / c;
+    };
+
     wBigInt.prototype.mod = function(c) {
         return this % c;
     };
 
     wBigInt.prototype.modPow = function(e, m) {
-        return this ** e % m;
+        let acc = wBigInt.one;
+        let exp = this;
+        let rem = e;
+        while (rem) {
+            if (rem & wBigInt.one) {
+                acc = (acc * exp) %m;
+            }
+            exp = (exp * exp) % m;
+            rem = rem >> wBigInt.one;
+        }
+        return acc;
     };
 
     wBigInt.prototype.greaterOrEquals = function(b) {
@@ -218,6 +232,10 @@ if (typeof(BigInt) != "undefined") {
     wBigInt.zero = bigInt.zero;
     wBigInt.prototype = oldProto;
 
+    wBigInt.prototype.div = function(c) {
+        return this.divide(c);
+    };
+
     // Affine
     wBigInt.genAffine = (q) => {
         const nq = wBigInt.zero.minus(q);
@@ -432,6 +450,29 @@ wBigInt.prototype.isZero = function (q) {
     return wBigInt.genIsZero(q)(this);
 };
 
+wBigInt.leBuff2int = function(buff) {
+    let res = wBigInt.zero;
+    for (let i=0; i<buff.length; i++) {
+        const n = wBigInt(buff[i]);
+        res = res.add(n.shl(i*8));
+    }
+    return res;
+};
+
+wBigInt.leInt2Buff = function(n, len) {
+    let r = n;
+    let o =0;
+    const buff = Buffer.alloc(len);
+    while ((r.greater(wBigInt.zero))&&(o<buff.length)) {
+        let c = Number(r.and(wBigInt("255")));
+        buff[o] = c;
+        o++;
+        r = r.shr(8);
+    }
+    if (r.greater(wBigInt.zero)) throw new Error("Number does not feed in buffer");
+    return buff;
+};
+
 
 module.exports = wBigInt;
 
diff --git a/src/calculateWitness.js b/src/calculateWitness.js
index 0940e5c..6fa8f64 100644
--- a/src/calculateWitness.js
+++ b/src/calculateWitness.js
@@ -52,7 +52,7 @@ function calculateWitness(circuit, inputSignals, log) {
     for (let i=0; i<circuit.nInputs; i++) {
         const idx = circuit.inputIdx(i);
         if (typeof(ctx.witness[idx]) == "undefined") {
-            throw new Error("Input Signal not assigned: " + circuit.signalNames(i));
+            throw new Error("Input Signal not assigned: " + circuit.signalNames(idx));
         }
     }