ConfigStack.js

import GLConfig, { DAT_MASKS, DAT_SIZE } from './GLConfig';
const MIN_ALLOC = 16, LEN = DAT_SIZE;
class ConfigStack {
    constructor() {
        this._stack = new Uint16Array(((LEN | 0) * MIN_ALLOC) | 0);
        this._sets = new Uint32Array(MIN_ALLOC | 0);
        this._size = MIN_ALLOC | 0;
        this._ptr = 0;
        this._headPos = 0;
        this._wcfg = new GLConfig();
    }
    initFromGL(gl) {
        this._ptr = 0;
        this._wcfg.fromGL(gl);
        this._sets[0] = 0;
        this._stack.set(this._wcfg._dat);
    }
    push(cfg) {
        if (this._ptr + 1 === this._size) {
            this._grow();
        }
        const lset = cfg._set, ptr = ++this._ptr, sptr = ptr * (0 | LEN), ldat = cfg._dat, sdat = this._stack;
        this._sets[ptr] = this._sets[ptr - 1] | lset;
        for (var i = 0; i < (LEN | 0); i++) {
            var sbit = DAT_MASKS[i];
            var val;
            if (0 !== (lset & sbit)) {
                val = ldat[i];
            }
            else {
                val = sdat[sptr + i - (0 | LEN)];
            }
            sdat[sptr + i] = val;
        }
    }
    pop() {
        const ptr = --this._ptr;
        if (this._headPos > ptr) {
            this._sets[ptr] |= this._sets[ptr + 1];
            this._headPos = ptr;
        }
    }
    flush() {
        while (this._ptr > 0) {
            this.pop();
        }
    }
    commit(patch) {
        const ptr = this._ptr;
        this.copyConfig(ptr, patch);
        this._headPos = ptr;
        if (ptr > 0) {
            this._sets[ptr - 1] |= this._sets[ptr];
        }
        this._sets[ptr] = 0;
    }
    copyConfig(at, cfg) {
        const cdat = cfg._dat, sdat = this._stack, off = 0 | (at * (LEN | 0));
        for (var i = 0; i < (LEN | 0); i++) {
            cdat[i] = sdat[off + i];
        }
        cfg._set = this._sets[at];
    }
    _grow() {
        const s = this._size << 1, stack = new Uint16Array(s * (0 | LEN)), sets = new Uint32Array(s);
        stack.set(this._stack, 0);
        sets.set(this._sets, 0);
        this._stack = stack;
        this._sets = sets;
        this._size = s;
    }
}
;
export default ConfigStack;