Alias Check and Babyjub adapted

src/utils.js

@@ -0,0 +1,87 @@
+const bigInt = require("big-integer");
+
+module.exports.leBuff2int = leBuff2int;
+module.exports.leInt2Buff = leInt2Buff;
+module.exports.beBuff2int = beBuff2int;
+module.exports.beInt2Buff = beInt2Buff;
+module.exports.stringifyBigInts = stringifyBigInts;
+module.exports.unstringifyBigInts = unstringifyBigInts;
+
+function leBuff2int (buff) {
+    let res = bigInt.zero;
+    for (let i=0; i<buff.length; i++) {
+        const n = bigInt(buff[i]);
+        res = res.add(n.shiftLeft(i*8));
+    }
+    return res;
+}
+
+function leInt2Buff(n, len) {
+    let r = n;
+    let o =0;
+    const buff = Buffer.alloc(len);
+    while ((r.gt(bigInt.zero))&&(o<buff.length)) {
+        let c = Number(r.and(bigInt(255)));
+        buff[o] = c;
+        o++;
+        r = r.shiftRight(8);
+    }
+    if (r.gt(bigInt.zero)) throw new Error("Number does not feed in buffer");
+    return buff;
+}
+
+function beBuff2int (buff) {
+    let res = bigInt.zero;
+    for (let i=0; i<buff.length; i++) {
+        const n = bigInt(buff[buff.length - i - 1]);
+        res = res.add(n.shiftLeft(i*8));
+    }
+    return res;
+}
+
+function beInt2Buff(n, len) {
+    let r = n;
+    let o =len-1;
+    const buff = Buffer.alloc(len);
+    while ((r.greater(bigInt.zero))&&(o>=0)) {
+        let c = Number(r.and(bigInt(255)));
+        buff[o] = c;
+        o--;
+        r = r.shiftRight(8);
+    }
+    if (r.gt(bigInt.zero)) throw new Error("Number does not feed in buffer");
+    return buff;
+}
+
+
+function stringifyBigInts(o) {
+    if ((typeof(o) == "bigint") || o.isZero !== undefined)  {
+        return o.toString(10);
+    } else if (Array.isArray(o)) {
+        return o.map(stringifyBigInts);
+    } else if (typeof o == "object") {
+        const res = {};
+        for (let k in o) {
+            res[k] = stringifyBigInts(o[k]);
+        }
+        return res;
+    } else {
+        return o;
+    }
+}
+
+function unstringifyBigInts(o) {
+    if ((typeof(o) == "string") && (/^[0-9]+$/.test(o) ))  {
+        return bigInt(o);
+    } else if (Array.isArray(o)) {
+        return o.map(unstringifyBigInts);
+    } else if (typeof o == "object") {
+        const res = {};
+        for (let k in o) {
+            res[k] = unstringifyBigInts(o[k]);
+        }
+        return res;
+    } else {
+        return o;
+    }
+}