Method deflate

packages/alphatab/src/zip/Deflater.ts:152–199

* Deflates the current input block to the given array. * @param output Buffer to store the compressed data. * @param offset Offset into the output array. * @param length The maximum number of bytes that may be stored. * @returns The number of compressed bytes added to the output,

(output: Uint8Array, offset: number, length: number)

     * needsInput() or finished() returns true or length is zero.
     */
    public deflate(output: Uint8Array, offset: number, length: number): number {
        const origLength = length;

        while (true) {
            const count = this._pending.flush(output, offset, length);
            offset += count;
            length -= count;

            if (length === 0 || this._state === Deflater._finishedState) {
                break;
            }

            if (
                !this._engine.deflate(
                    (this._state & Deflater._isFlushing) !== 0,
                    (this._state & Deflater.isFinishing) !== 0
                )
            ) {
                switch (this._state) {
                    case Deflater._busyState:
                        // We need more input now
                        return origLength - length;

                    case Deflater._flushingState:
                        /* We have to supply some lookahead.  8 bit lookahead
                         * is needed by the zlib inflater, and we must fill
                         * the next byte, so that all bits are flushed.
                         */
                        let neededbits = 8 + (-this._pending.bitCount & 7);
                        while (neededbits > 0) {
                            /* write a static tree block consisting solely of
                             * an EOF:
                             */
                            this._pending.writeBits(2, 10);
                            neededbits -= 10;
                        }
                        this._state = Deflater._busyState;
                        break;

                    case Deflater._finishingState:
                        this._pending.alignToByte();
                        this._state = Deflater._finishedState;
                        break;
                }
            }
        }
        return origLength - length;
    }

    /**
     * Finishes the deflater with the current input block.  It is an error