js-dicom/src/dicomParser/parseDicomDataSet.js

this is js-dicom

import readDicomElementExplicit from './readDicomElementExplicit.js';
import readDicomElementImplicit from './readDicomElementImplicit.js';

/**
 * Internal helper functions for parsing implicit and explicit DICOM data sets
 */

/**
 * reads an explicit data set
 * @param byteStream the byte stream to read from
 * @param maxPosition the maximum position to read up to (optional - only needed when reading sequence items)
 */
export function parseDicomDataSetExplicit (dataSet, byteStream, maxPosition, options = {}) {
  maxPosition = (maxPosition === undefined) ? byteStream.byteArray.length : maxPosition;

  if (byteStream === undefined) {
    throw 'dicomParser.parseDicomDataSetExplicit: missing required parameter \'byteStream\'';
  }

  if (maxPosition < byteStream.position || maxPosition > byteStream.byteArray.length) {
    throw 'dicomParser.parseDicomDataSetExplicit: invalid value for parameter \'maxP osition\'';
  }

  const elements = dataSet.elements;

  while (byteStream.position < maxPosition) {
    const element = readDicomElementExplicit(byteStream, dataSet.warnings, options.untilTag);

    elements[element.tag] = element;
    if (element.tag === options.untilTag) {
      return;
    }
  }

  if (byteStream.position > maxPosition) {
    throw 'dicomParser:parseDicomDataSetExplicit: buffer overrun';
  }
}

/**
 * reads an implicit data set
 * @param byteStream the byte stream to read from
 * @param maxPosition the maximum position to read up to (optional - only needed when reading sequence items)
 */
export function parseDicomDataSetImplicit (dataSet, byteStream, maxPosition, options = {}) {
  maxPosition = (maxPosition === undefined) ? dataSet.byteArray.length : maxPosition;

  if (byteStream === undefined) {
    throw 'dicomParser.parseDicomDataSetImplicit: missing required parameter \'byteStream\'';
  }

  if (maxPosition < byteStream.position || maxPosition > byteStream.byteArray.length) {
    throw 'dicomParser.parseDicomDataSetImplicit: invalid value for parameter \'maxPosition\'';
  }

  const elements = dataSet.elements;

  while (byteStream.position < maxPosition) {
    const element = readDicomElementImplicit(byteStream, options.untilTag, options.vrCallback);

    elements[element.tag] = element;
    if (element.tag === options.untilTag) {
      return;
    }
  }
}