Function decodeBlockTypeAndLength

js/decode.ts:545–567

(s: State, treeType: number, numBlockTypes: number)

  return numTrees;
}
function decodeBlockTypeAndLength(s: State, treeType: number, numBlockTypes: number): number {
  const ringBuffers: Int32Array = s.rings;
  const offset: number = 4 + treeType * 2;
  if (s.bitOffset >= 16) {
    s.accumulator32 = (s.shortBuffer[s.halfOffset++] << 16) | (s.accumulator32 >>> 16);
    s.bitOffset -= 16;
  }
  let blockType: number = readSymbol(s.blockTrees, 2 * treeType, s);
  const result: number = readBlockLength(s.blockTrees, 2 * treeType + 1, s);
  if (blockType === 1) {
    blockType = ringBuffers[offset + 1] + 1;
  } else if (blockType === 0) {
    blockType = ringBuffers[offset];
  } else {
    blockType -= 2;
  }
  if (blockType >= numBlockTypes) {
    blockType -= numBlockTypes;
  }
  ringBuffers[offset] = ringBuffers[offset + 1];
  ringBuffers[offset + 1] = blockType;
  return result;
}
function decodeLiteralBlockSwitch(s: State): void {
  s.literalBlockLength = decodeBlockTypeAndLength(s, 0, s.numLiteralBlockTypes);
  const literalBlockType: number = s.rings[5];