Method _deflateSlow

packages/alphatab/src/zip/DeflaterEngine.ts:198–283

(flush: boolean, finish: boolean)

    }

    private _deflateSlow(flush: boolean, finish: boolean): boolean {
        if (this._lookahead < DeflaterConstants.minLookahead && !flush) {
            return false;
        }

        while (this._lookahead >= DeflaterConstants.minLookahead || flush) {
            if (this._lookahead === 0) {
                if (this._prevAvailable) {
                    this._huffman.tallyLit(this._window[this._strstart - 1] & 0xff);
                }
                this._prevAvailable = false;

                // We are flushing everything
                this._huffman.flushBlock(this._window, this._blockStart, this._strstart - this._blockStart, finish);
                this._blockStart = this._strstart;
                return false;
            }

            if (this._strstart >= 2 * DeflaterConstants.wsize - DeflaterConstants.minLookahead) {
                /* slide window, as FindLongestMatch needs this.
                 * This should only happen when flushing and the window
                 * is almost full.
                 */
                this._slideWindow();
            }

            const prevMatch = this._matchStart;
            let prevLen = this._matchLen;
            if (this._lookahead >= DeflaterConstants.minMatch) {
                const hashHead = this._insertString();

                if (
                    hashHead !== 0 &&
                    this._strstart - hashHead <= DeflaterConstants.maxDist &&
                    this._findLongestMatch(hashHead)
                ) {
                    // longestMatch sets matchStart and matchLen

                    // Discard match if too small and too far away
                    if (
                        this._matchLen === DeflaterConstants.minMatch &&
                        this._strstart - this._matchStart > DeflaterEngine._tooFar
                    ) {
                        this._matchLen = DeflaterConstants.minMatch - 1;
                    }
                }
            }

            // previous match was better
            if (prevLen >= DeflaterConstants.minMatch && this._matchLen <= prevLen) {
                this._huffman.tallyDist(this._strstart - 1 - prevMatch, prevLen);
                prevLen -= 2;
                do {
                    this._strstart++;
                    this._lookahead--;
                    if (this._lookahead >= DeflaterConstants.minMatch) {
                        this._insertString();
                    }