ffjavascript/src/engine_applykey.js

import BigBuffer from "./bigbuffer.js";

export default function buildBatchApplyKey(curve, groupName) {
    const G = curve[groupName];
    const Fr = curve.Fr;
    const tm = curve.tm;

    curve[groupName].batchApplyKey = async function(buff, first, inc, inType, outType) {
        inType = inType || "affine";
        outType = outType || "affine";
        let fnName, fnAffine;
        let sGin, sGmid, sGout;
        if (groupName == "G1") {
            if (inType == "jacobian") {
                sGin = G.F.n8*3;
                fnName = "g1m_batchApplyKey";
            } else {
                sGin = G.F.n8*2;
                fnName = "g1m_batchApplyKeyMixed";
            }
            sGmid = G.F.n8*3;
            if (outType == "jacobian") {
                sGout = G.F.n8*3;
            } else {
                fnAffine = "g1m_batchToAffine";
                sGout = G.F.n8*2;
            }
        } else if (groupName == "G2") {
            if (inType == "jacobian") {
                sGin = G.F.n8*3;
                fnName = "g2m_batchApplyKey";
            } else {
                sGin = G.F.n8*2;
                fnName = "g2m_batchApplyKeyMixed";
            }
            sGmid = G.F.n8*3;
            if (outType == "jacobian") {
                sGout = G.F.n8*3;
            } else {
                fnAffine = "g2m_batchToAffine";
                sGout = G.F.n8*2;
            }
        } else if (groupName == "Fr") {
            fnName = "frm_batchApplyKey";
            sGin = G.n8;
            sGmid = G.n8;
            sGout = G.n8;
        } else {
            throw new Error("Invalid group: " + groupName);
        }
        const nPoints = Math.floor(buff.byteLength / sGin);
        const pointsPerChunk = Math.floor(nPoints/tm.concurrency);
        const opPromises = [];
        inc = Fr.e(inc);
        let t = Fr.e(first);
        for (let i=0; i<tm.concurrency; i++) {
            let n;
            if (i< tm.concurrency-1) {
                n = pointsPerChunk;
            } else {
                n = nPoints - i*pointsPerChunk;
            }
            if (n==0) continue;

            const task = [];

            task.push({
                cmd: "ALLOCSET",
                var: 0,
                buff: buff.slice(i*pointsPerChunk*sGin, i*pointsPerChunk*sGin + n*sGin)
            });
            task.push({cmd: "ALLOCSET", var: 1, buff: t});
            task.push({cmd: "ALLOCSET", var: 2, buff: inc});
            task.push({cmd: "ALLOC", var: 3, len: n*Math.max(sGmid, sGout)});
            task.push({
                cmd: "CALL",
                fnName: fnName,
                params: [
                    {var: 0},
                    {val: n},
                    {var: 1},
                    {var: 2},
                    {var:3}
                ]
            });
            if (fnAffine) {
                task.push({
                    cmd: "CALL",
                    fnName: fnAffine,
                    params: [
                        {var: 3},
                        {val: n},
                        {var: 3},
                    ]
                });
            }
            task.push({cmd: "GET", out: 0, var: 3, len: n*sGout});

            opPromises.push(tm.queueAction(task));
            t = Fr.mul(t, Fr.exp(inc, n));
        }

        const result = await Promise.all(opPromises);

        let outBuff;
        if (buff instanceof BigBuffer) {
            outBuff = new BigBuffer(nPoints*sGout);
        } else {
            outBuff = new Uint8Array(nPoints*sGout);
        }

        let p=0;
        for (let i=0; i<result.length; i++) {
            outBuff.set(result[i][0], p);
            p += result[i][0].byteLength;
        }

        return outBuff;
    };
}