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dicomParser.js
/*! dicom-parser - v1.5.0 - 2016-05-08 | (c) 2014 Chris Hafey | https://github.com/chafey/dicomParser */
(function (root, factory) {
// node.js
if (typeof module !== 'undefined' && module.exports) {
module.exports = factory();
}
else if (typeof define === 'function' && define.amd) {
// AMD. Register as an anonymous module.
define([], factory);
} else {
// Browser globals
if(typeof cornerstone === 'undefined'){
dicomParser = {};
// meteor
if (typeof Package !== 'undefined') {
root.dicomParser = dicomParser;
}
}
dicomParser = factory();
}
}(this, function () {
/**
* Parses a DICOM P10 byte array and returns a DataSet object with the parsed elements. If the options
* argument is supplied and it contains the untilTag property, parsing will stop once that
* tag is encoutered. This can be used to parse partial byte streams.
*
* @param byteArray the byte array
* @param options object to control parsing behavior (optional)
* @returns {DataSet}
* @throws error if an error occurs while parsing. The exception object will contain a property dataSet with the
* elements successfully parsed before the error.
*/
var dicomParser = (function(dicomParser) {
if(dicomParser === undefined)
{
dicomParser = {};
}
dicomParser.parseDicom = function(byteArray, options) {
if(byteArray === undefined)
{
throw "dicomParser.parseDicom: missing required parameter 'byteArray'";
}
function readTransferSyntax(metaHeaderDataSet) {
if(metaHeaderDataSet.elements.x00020010 === undefined) {
throw 'dicomParser.parseDicom: missing required meta header attribute 0002,0010';
}
var transferSyntaxElement = metaHeaderDataSet.elements.x00020010;
return dicomParser.readFixedString(byteArray, transferSyntaxElement.dataOffset, transferSyntaxElement.length);
}
function isExplicit(transferSyntax) {
if(transferSyntax === '1.2.840.10008.1.2') // implicit little endian
{
return false;
}
// all other transfer syntaxes should be explicit
return true;
}
function getDataSetByteStream(transferSyntax, position) {
if(transferSyntax === '1.2.840.10008.1.2.1.99')
{
// if an infalter callback is registered, use it
if (options && options.inflater) {
var fullByteArrayCallback = options.inflater(byteArray, position);
return new dicomParser.ByteStream(dicomParser.littleEndianByteArrayParser, fullByteArrayCallback, 0);
}
// if running on node, use the zlib library to inflate
// http://stackoverflow.com/questions/4224606/how-to-check-whether-a-script-is-running-under-node-js
else if (typeof module !== 'undefined' && this.module !== module) {
// inflate it
var zlib = require('zlib');
var deflatedBuffer = dicomParser.sharedCopy(byteArray, position, byteArray.length - position);
var inflatedBuffer = zlib.inflateRawSync(deflatedBuffer);
// create a single byte array with the full header bytes and the inflated bytes
var fullByteArrayBuffer = dicomParser.alloc(byteArray, inflatedBuffer.length + position);
byteArray.copy(fullByteArrayBuffer, 0, 0, position);
inflatedBuffer.copy(fullByteArrayBuffer, position);
return new dicomParser.ByteStream(dicomParser.littleEndianByteArrayParser, fullByteArrayBuffer, 0);
}
// if pako is defined - use it. This is the web browser path
// https://github.com/nodeca/pako
else if(typeof pako !== "undefined") {
// inflate it
var deflated = byteArray.slice(position);
var inflated = pako.inflateRaw(deflated);
// create a single byte array with the full header bytes and the inflated bytes
var fullByteArray = dicomParser.alloc(byteArray, inflated.length + position);
fullByteArray.set(byteArray.slice(0, position), 0);
fullByteArray.set(inflated, position);
return new dicomParser.ByteStream(dicomParser.littleEndianByteArrayParser, fullByteArray, 0);
}
// throw exception since no inflater is available
else {
throw 'dicomParser.parseDicom: no inflater available to handle deflate transfer syntax';
}
}
if(transferSyntax === '1.2.840.10008.1.2.2') // explicit big endian
{
return new dicomParser.ByteStream(dicomParser.bigEndianByteArrayParser, byteArray, position);
}
else
{
// all other transfer syntaxes are little endian; only the pixel encoding differs
// make a new stream so the metaheader warnings don't come along for the ride
return new dicomParser.ByteStream(dicomParser.littleEndianByteArrayParser, byteArray, position);
}
}
function mergeDataSets(metaHeaderDataSet, instanceDataSet)
{
for (var propertyName in metaHeaderDataSet.elements)
{
if(metaHeaderDataSet.elements.hasOwnProperty(propertyName))
{
instanceDataSet.elements[propertyName] = metaHeaderDataSet.elements[propertyName];
}
}
if (metaHeaderDataSet.warnings !== undefined) {
instanceDataSet.warnings = metaHeaderDataSet.warnings.concat(instanceDataSet.warnings);
}
return instanceDataSet;
}
function readDataSet(metaHeaderDataSet)
{
var transferSyntax = readTransferSyntax(metaHeaderDataSet);
var explicit = isExplicit(transferSyntax);
var dataSetByteStream = getDataSetByteStream(transferSyntax, metaHeaderDataSet.position);
var elements = {};
var dataSet = new dicomParser.DataSet(dataSetByteStream.byteArrayParser, dataSetByteStream.byteArray, elements);
dataSet.warnings = dataSetByteStream.warnings;
try{
if(explicit) {
dicomParser.parseDicomDataSetExplicit(dataSet, dataSetByteStream, dataSetByteStream.byteArray.length, options);
}
else
{
dicomParser.parseDicomDataSetImplicit(dataSet, dataSetByteStream, dataSetByteStream.byteArray.length, options);
}
}
catch(e) {
var ex = {
exception: e,
dataSet: dataSet
};
throw ex;
}
return dataSet;
}
// main function here
function parseTheByteStream() {
var metaHeaderDataSet = dicomParser.readPart10Header(byteArray, options);
var dataSet = readDataSet(metaHeaderDataSet);
return mergeDataSets(metaHeaderDataSet, dataSet);
}
// This is where we actually start parsing
return parseTheByteStream();
};
return dicomParser;
})(dicomParser);
var dicomParser = (function (dicomParser) {
"use strict";
if (dicomParser === undefined) {
dicomParser = {};
}
/**
* converts an explicit dataSet to a javascript object
* @param dataSet
* @param options
*/
dicomParser.explicitDataSetToJS = function (dataSet, options) {
if(dataSet === undefined) {
throw 'dicomParser.explicitDataSetToJS: missing required parameter dataSet';
}
options = options || {
omitPrivateAttibutes: true, // true if private elements should be omitted
maxElementLength : 128 // maximum element length to try and convert to string format
};
var result = {
};
for(var tag in dataSet.elements) {
var element = dataSet.elements[tag];
// skip this element if it a private element and our options specify that we should
if(options.omitPrivateAttibutes === true && dicomParser.isPrivateTag(tag))
{
continue;
}
if(element.items) {
// handle sequences
var sequenceItems = [];
for(var i=0; i < element.items.length; i++) {
sequenceItems.push(dicomParser.explicitDataSetToJS(element.items[i].dataSet, options));
}
result[tag] = sequenceItems;
} else {
var asString;
asString = undefined;
if(element.length < options.maxElementLength) {
asString = dicomParser.explicitElementToString(dataSet, element);
}
if(asString !== undefined) {
result[tag] = asString;
} else {
result[tag] = {
dataOffset: element.dataOffset,
length : element.length
};
}
}
}
return result;
};
return dicomParser;
}(dicomParser));
var dicomParser = (function (dicomParser) {
"use strict";
if (dicomParser === undefined) {
dicomParser = {};
}
/**
* Converts an explicit VR element to a string or undefined if it is not possible to convert.
* Throws an error if an implicit element is supplied
* @param dataSet
* @param element
* @returns {*}
*/
dicomParser.explicitElementToString = function(dataSet, element)
{
if(dataSet === undefined || element === undefined) {
throw 'dicomParser.explicitElementToString: missing required parameters';
}
if(element.vr === undefined) {
throw 'dicomParser.explicitElementToString: cannot convert implicit element to string';
}
var vr = element.vr;
var tag = element.tag;
var textResult;
function multiElementToString(numItems, func) {
var result = "";
for(var i=0; i < numItems; i++) {
if(i !== 0) {
result += '/';
}
result += func.call(dataSet, tag, i).toString();
}
return result;
}
if(dicomParser.isStringVr(vr) === true)
{
textResult = dataSet.string(tag);
}
else if (vr == 'AT') {
var num = dataSet.uint32(tag);
if(num === undefined) {
return undefined;
}
if (num < 0)
{
num = 0xFFFFFFFF + num + 1;
}
return 'x' + num.toString(16).toUpperCase();
}
else if (vr == 'US')
{
textResult = multiElementToString(element.length / 2, dataSet.uint16);
}
else if(vr === 'SS')
{
textResult = multiElementToString(element.length / 2, dataSet.int16);
}
else if (vr == 'UL')
{
textResult = multiElementToString(element.length / 4, dataSet.uint32);
}
else if(vr === 'SL')
{
textResult = multiElementToString(element.length / 4, dataSet.int32);
}
else if(vr == 'FD')
{
textResult = multiElementToString(element.length / 8, dataSet.double);
}
else if(vr == 'FL')
{
textResult = multiElementToString(element.length / 4, dataSet.float);
}
return textResult;
};
return dicomParser;
}(dicomParser));
/**
* Utility functions for dealing with DICOM
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
// algorithm based on http://stackoverflow.com/questions/1433030/validate-number-of-days-in-a-given-month
function daysInMonth(m, y) { // m is 0 indexed: 0-11
switch (m) {
case 2 :
return (y % 4 == 0 && y % 100) || y % 400 == 0 ? 29 : 28;
case 9 : case 4 : case 6 : case 11 :
return 30;
default :
return 31
}
}
function isValidDate(d, m, y) {
// make year is a number
if(isNaN(y)) {
return false;
}
return m > 0 && m <= 12 && d > 0 && d <= daysInMonth(m, y);
}
/**
* Parses a DA formatted string into a Javascript object
* @param {string} date a string in the DA VR format
* @param {boolean} [validate] - true if an exception should be thrown if the date is invalid
* @returns {*} Javascript object with properties year, month and day or undefined if not present or not 8 bytes long
*/
dicomParser.parseDA = function(date, validate)
{
if(date && date.length === 8)
{
var yyyy = parseInt(date.substring(0, 4), 10);
var mm = parseInt(date.substring(4, 6), 10);
var dd = parseInt(date.substring(6, 8), 10);
if(validate) {
if (isValidDate(dd, mm, yyyy) !== true) {
throw "invalid DA '" + date + "'";
}
}
return {
year: yyyy,
month: mm,
day: dd
};
}
if(validate) {
throw "invalid DA '" + date + "'";
}
return undefined;
};
return dicomParser;
}(dicomParser));
/**
* Utility functions for dealing with DICOM
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
/**
* Parses a TM formatted string into a javascript object with properties for hours, minutes, seconds and fractionalSeconds
* @param {string} time - a string in the TM VR format
* @param {boolean} [validate] - true if an exception should be thrown if the date is invalid
* @returns {*} javascript object with properties for hours, minutes, seconds and fractionalSeconds or undefined if no element or data. Missing fields are set to undefined
*/
dicomParser.parseTM = function(time, validate) {
if (time.length >= 2) // must at least have HH
{
// 0123456789
// HHMMSS.FFFFFF
var hh = parseInt(time.substring(0, 2), 10);
var mm = time.length >= 4 ? parseInt(time.substring(2, 4), 10) : undefined;
var ss = time.length >= 6 ? parseInt(time.substring(4, 6), 10) : undefined;
var ffffff = time.length >= 8 ? parseInt(time.substring(7, 13), 10) : undefined;
if(validate) {
if((isNaN(hh)) ||
(mm !== undefined && isNaN(mm)) ||
(ss !== undefined && isNaN(ss)) ||
(ffffff !== undefined && isNaN(ffffff)) ||
(hh < 0 || hh > 23) ||
(mm && (mm <0 || mm > 59)) ||
(ss && (ss <0 || ss > 59)) ||
(ffffff && (ffffff <0 || ffffff > 999999)))
{
throw "invalid TM '" + time + "'";
}
}
return {
hours: hh,
minutes: mm,
seconds: ss,
fractionalSeconds: ffffff
};
}
if(validate) {
throw "invalid TM '" + time + "'";
}
return undefined;
};
return dicomParser;
}(dicomParser));
/**
* Utility functions for dealing with DICOM
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
var stringVrs = {
AE: true,
AS: true,
AT: false,
CS: true,
DA: true,
DS: true,
DT: true,
FL: false,
FD: false,
IS: true,
LO: true,
LT: true,
OB: false,
OD: false,
OF: false,
OW: false,
PN: true,
SH: true,
SL: false,
SQ: false,
SS: false,
ST: true,
TM: true,
UI: true,
UL: false,
UN: undefined, // dunno
UR: true,
US: false,
UT: true
};
/**
* Tests to see if vr is a string or not.
* @param vr
* @returns true if string, false it not string, undefined if unknown vr or UN type
*/
dicomParser.isStringVr = function(vr)
{
return stringVrs[vr];
};
/**
* Tests to see if a given tag in the format xggggeeee is a private tag or not
* @param tag
* @returns {boolean}
*/
dicomParser.isPrivateTag = function(tag)
{
var lastGroupDigit = parseInt(tag[4]);
var groupIsOdd = (lastGroupDigit % 2) === 1;
return groupIsOdd;
};
/**
* Parses a PN formatted string into a javascript object with properties for givenName, familyName, middleName, prefix and suffix
* @param personName a string in the PN VR format
* @param index
* @returns {*} javascript object with properties for givenName, familyName, middleName, prefix and suffix or undefined if no element or data
*/
dicomParser.parsePN = function(personName) {
if(personName === undefined) {
return undefined;
}
var stringValues = personName.split('^');
return {
familyName: stringValues[0],
givenName: stringValues[1],
middleName: stringValues[2],
prefix: stringValues[3],
suffix: stringValues[4]
};
};
return dicomParser;
}(dicomParser));
/**
* Functionality for extracting encapsulated pixel data
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
function getPixelDataFromFragments(byteStream, fragments, bufferSize)
{
// if there is only one fragment, return a view on this array to avoid copying
if(fragments.length === 1) {
return dicomParser.sharedCopy(byteStream.byteArray, fragments[0].dataOffset, fragments[0].length);
}
// more than one fragment, combine all of the fragments into one buffer
var pixelData = dicomParser.alloc(byteStream.byteArray, bufferSize);
var pixelDataIndex = 0;
for(var i=0; i < fragments.length; i++) {
var fragmentOffset = fragments[i].dataOffset;
for(var j=0; j < fragments[i].length; j++) {
pixelData[pixelDataIndex++] = byteStream.byteArray[fragmentOffset++];
}
}
return pixelData;
}
function readFragmentsUntil(byteStream, endOfFrame) {
// Read fragments until we reach endOfFrame
var fragments = [];
var bufferSize = 0;
while(byteStream.position < endOfFrame && byteStream.position < byteStream.byteArray.length) {
// read the fragment
var item = {
tag : dicomParser.readTag(byteStream),
length : byteStream.readUint32(),
dataOffset : byteStream.position
};
// NOTE: we only encounter this for the sequence delimiter item when extracting the last frame
if(item.tag === 'xfffee0dd') {
break;
}
fragments.push(item);
byteStream.seek(item.length);
bufferSize += item.length;
}
// Convert the fragments into a single pixelData buffer
var pixelData = getPixelDataFromFragments(byteStream, fragments, bufferSize);
return pixelData;
}
function getFragmentOffset(byteStream) {
// read the fragment
var item = {
tag : dicomParser.readTag(byteStream),
length : byteStream.readUint32(),
dataOffset : byteStream.position
};
// NOTE: we only encounter this for the sequence delimiter item when extracting the last frame
if(item.tag === 'xfffee0dd') {
return;
}
byteStream.seek(item.length);
}
function readEncapsulatedPixelDataWithBasicOffsetTable(pixelDataElement, byteStream, frame) {
// validate that we have an offset for this frame
var numFrames = pixelDataElement.basicOffsetTable.length;
if(frame > numFrames) {
throw "dicomParser.readEncapsulatedPixelData: parameter frame exceeds number of frames in basic offset table";
}
// move to the start of this frame
var frameOffset = pixelDataElement.basicOffsetTable[frame];
var firstFragment = byteStream.position;
byteStream.seek(frameOffset);
// Find the end of this frame
var endOfFrameOffset = pixelDataElement.basicOffsetTable[frame + 1];
if(endOfFrameOffset === undefined) { // special case for last frame
endOfFrameOffset = byteStream.position + pixelDataElement.length;
} else {
endOfFrameOffset += firstFragment;
}
// read this frame
var pixelData = readFragmentsUntil(byteStream, endOfFrameOffset);
return pixelData;
}
function readEncapsulatedDataNoBasicOffsetTable(pixelDataElement, byteStream, frame) {
// if the basic offset table is empty, this is a single frame so make sure the requested
// frame is 0
if(frame !== 0) {
throw 'dicomParser.readEncapsulatedPixelData: non zero frame specified for single frame encapsulated pixel data';
}
// read this frame
var endOfFrame = byteStream.position + pixelDataElement.length;
var pixelData = readFragmentsUntil(byteStream, endOfFrame);
return pixelData;
}
/**
* Returns the pixel data for the specified frame in an encapsulated pixel data element
*
* @param dataSet - the dataSet containing the encapsulated pixel data
* @param pixelDataElement - the pixel data element (x7fe00010) to extract the frame from
* @param frame - the zero based frame index
* @returns Uint8Array with the encapsulated pixel data
*/
dicomParser.readEncapsulatedPixelData = function(dataSet, pixelDataElement, frame)
{
if(dataSet === undefined) {
throw "dicomParser.readEncapsulatedPixelData: missing required parameter 'dataSet'";
}
if(pixelDataElement === undefined) {
throw "dicomParser.readEncapsulatedPixelData: missing required parameter 'element'";
}
if(frame === undefined) {
throw "dicomParser.readEncapsulatedPixelData: missing required parameter 'frame'";
}
if(pixelDataElement.tag !== 'x7fe00010') {
throw "dicomParser.readEncapsulatedPixelData: parameter 'element' refers to non pixel data tag (expected tag = x7fe00010'";
}
if(pixelDataElement.encapsulatedPixelData !== true) {
throw "dicomParser.readEncapsulatedPixelData: parameter 'element' refers to pixel data element that does not have encapsulated pixel data";
}
if(pixelDataElement.hadUndefinedLength !== true) {
throw "dicomParser.readEncapsulatedPixelData: parameter 'element' refers to pixel data element that does not have encapsulated pixel data";
}
if(pixelDataElement.basicOffsetTable === undefined) {
throw "dicomParser.readEncapsulatedPixelData: parameter 'element' refers to pixel data element that does not have encapsulated pixel data";
}
if(pixelDataElement.fragments === undefined) {
throw "dicomParser.readEncapsulatedPixelData: parameter 'element' refers to pixel data element that does not have encapsulated pixel data";
}
if(frame < 0) {
throw "dicomParser.readEncapsulatedPixelData: parameter 'frame' must be >= 0";
}
if(pixelDataElement.basicOffsetTable.length === 0 && dataSet.intString('x00280008') && dataSet.intString('x00280008') > 1){
var byteStream2 = new dicomParser.ByteStream(dataSet.byteArrayParser, dataSet.byteArray, pixelDataElement.dataOffset);
var basicOffsetTable2 = dicomParser.readSequenceItem(byteStream2);
byteStream2.seek(basicOffsetTable2.length);
var endOfFrame = byteStream2.position + pixelDataElement.length;
var firstFragment = byteStream2.position;
pixelDataElement.basicOffsetTable[0] = 0;
for(var k=0; k< dataSet.intString('x00280008') - 1; k++){
getFragmentOffset(byteStream2);
pixelDataElement.basicOffsetTable[k + 1] = byteStream2.position - firstFragment;
}
}
// seek past the basic offset table (no need to parse it again since we already have)
var byteStream = new dicomParser.ByteStream(dataSet.byteArrayParser, dataSet.byteArray, pixelDataElement.dataOffset);
var basicOffsetTable = dicomParser.readSequenceItem(byteStream);
if(basicOffsetTable.tag !== 'xfffee000')
{
throw "dicomParser.readEncapsulatedPixelData: missing basic offset table xfffee000";
}
byteStream.seek(basicOffsetTable.length);
// If the basic offset table is empty (no entries), it is a single frame. If it is not empty,
// it has at least one frame so use the basic offset table to find the bytes
if(pixelDataElement.basicOffsetTable.length !== 0)
{
return readEncapsulatedPixelDataWithBasicOffsetTable(pixelDataElement, byteStream, frame);
}
else
{
return readEncapsulatedDataNoBasicOffsetTable(pixelDataElement, byteStream, frame);
}
};
return dicomParser;
}(dicomParser));
/**
*
* Internal helper function to allocate new byteArray buffers
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
/**
* Creates a new byteArray of the same type (Uint8Array or Buffer) of the specified length.
* @param byteArray the underlying byteArray (either Uint8Array or Buffer)
* @param length number of bytes of the Byte Array
* @returns {object} Uint8Array or Buffer depending on the type of byteArray
*/
dicomParser.alloc = function(byteArray, length) {
if (typeof Buffer !== 'undefined' && byteArray instanceof Buffer) {
return Buffer.alloc(length);
}
else if(byteArray instanceof Uint8Array) {
return new Uint8Array(length);
} else {
throw 'dicomParser.alloc: unknown type for byteArray';
}
};
return dicomParser;
}(dicomParser));
/**
* Internal helper functions for parsing different types from a big-endian byte array
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
dicomParser.bigEndianByteArrayParser = {
/**
*
* Parses an unsigned int 16 from a big-endian byte array
*
* @param byteArray the byte array to read from
* @param position the position in the byte array to read from
* @returns {*} the parsed unsigned int 16
* @throws error if buffer overread would occur
* @access private
*/
readUint16: function (byteArray, position) {
if (position < 0) {
throw 'bigEndianByteArrayParser.readUint16: position cannot be less than 0';
}
if (position + 2 > byteArray.length) {
throw 'bigEndianByteArrayParser.readUint16: attempt to read past end of buffer';
}
return (byteArray[position] << 8) + byteArray[position + 1];
},
/**
*
* Parses a signed int 16 from a big-endian byte array
*
* @param byteArray the byte array to read from
* @param position the position in the byte array to read from
* @returns {*} the parsed signed int 16
* @throws error if buffer overread would occur
* @access private
*/
readInt16: function (byteArray, position) {
if (position < 0) {
throw 'bigEndianByteArrayParser.readInt16: position cannot be less than 0';
}
if (position + 2 > byteArray.length) {
throw 'bigEndianByteArrayParser.readInt16: attempt to read past end of buffer';
}
var int16 = (byteArray[position] << 8) + byteArray[position + 1];
// fix sign
if (int16 & 0x8000) {
int16 = int16 - 0xFFFF - 1;
}
return int16;
},
/**
* Parses an unsigned int 32 from a big-endian byte array
*
* @param byteArray the byte array to read from
* @param position the position in the byte array to read from
* @returns {*} the parsed unsigned int 32
* @throws error if buffer overread would occur
* @access private
*/
readUint32: function (byteArray, position) {
if (position < 0) {
throw 'bigEndianByteArrayParser.readUint32: position cannot be less than 0';
}
if (position + 4 > byteArray.length) {
throw 'bigEndianByteArrayParser.readUint32: attempt to read past end of buffer';
}
var uint32 = (256 * (256 * (256 * byteArray[position] +
byteArray[position + 1]) +
byteArray[position + 2]) +
byteArray[position + 3]);
return uint32;
},
/**
* Parses a signed int 32 from a big-endian byte array
*
* @param byteArray the byte array to read from
* @param position the position in the byte array to read from
* @returns {*} the parsed signed int 32
* @throws error if buffer overread would occur
* @access private
*/
readInt32: function (byteArray, position) {
if (position < 0) {
throw 'bigEndianByteArrayParser.readInt32: position cannot be less than 0';
}
if (position + 4 > byteArray.length) {
throw 'bigEndianByteArrayParser.readInt32: attempt to read past end of buffer';
}
var int32 = ((byteArray[position] << 24) +
(byteArray[position + 1] << 16) +
(byteArray[position + 2] << 8) +
byteArray[position + 3]);
return int32;
},
/**
* Parses 32-bit float from a big-endian byte array
*
* @param byteArray the byte array to read from
* @param position the position in the byte array to read from
* @returns {*} the parsed 32-bit float
* @throws error if buffer overread would occur
* @access private
*/
readFloat: function (byteArray, position) {
if (position < 0) {
throw 'bigEndianByteArrayParser.readFloat: position cannot be less than 0';
}
if (position + 4 > byteArray.length) {
throw 'bigEndianByteArrayParser.readFloat: attempt to read past end of buffer';
}
// I am sure there is a better way than this but this should be safe
var byteArrayForParsingFloat = new Uint8Array(4);
byteArrayForParsingFloat[3] = byteArray[position];
byteArrayForParsingFloat[2] = byteArray[position + 1];
byteArrayForParsingFloat[1] = byteArray[position + 2];
byteArrayForParsingFloat[0] = byteArray[position + 3];
var floatArray = new Float32Array(byteArrayForParsingFloat.buffer);
return floatArray[0];
},
/**
* Parses 64-bit float from a big-endian byte array
*
* @param byteArray the byte array to read from
* @param position the position in the byte array to read from
* @returns {*} the parsed 64-bit float
* @throws error if buffer overread would occur
* @access private
*/
readDouble: function (byteArray, position) {
if (position < 0) {
throw 'bigEndianByteArrayParser.readDouble: position cannot be less than 0';
}
if (position + 8 > byteArray.length) {
throw 'bigEndianByteArrayParser.readDouble: attempt to read past end of buffer';
}
// I am sure there is a better way than this but this should be safe
var byteArrayForParsingFloat = new Uint8Array(8);
byteArrayForParsingFloat[7] = byteArray[position];
byteArrayForParsingFloat[6] = byteArray[position + 1];
byteArrayForParsingFloat[5] = byteArray[position + 2];
byteArrayForParsingFloat[4] = byteArray[position + 3];
byteArrayForParsingFloat[3] = byteArray[position + 4];
byteArrayForParsingFloat[2] = byteArray[position + 5];
byteArrayForParsingFloat[1] = byteArray[position + 6];
byteArrayForParsingFloat[0] = byteArray[position + 7];
var floatArray = new Float64Array(byteArrayForParsingFloat.buffer);
return floatArray[0];
}
};
return dicomParser;
}(dicomParser));
/**
* Internal helper functions common to parsing byte arrays of any type
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
/**
* Reads a string of 8-bit characters from an array of bytes and advances
* the position by length bytes. A null terminator will end the string
* but will not effect advancement of the position. Trailing and leading
* spaces are preserved (not trimmed)
* @param byteArray the byteArray to read from
* @param position the position in the byte array to read from
* @param length the maximum number of bytes to parse
* @returns {string} the parsed string
* @throws error if buffer overread would occur
* @access private
*/
dicomParser.readFixedString = function(byteArray, position, length)
{
if(length < 0)
{
throw 'dicomParser.readFixedString - length cannot be less than 0';
}
if(position + length > byteArray.length) {
throw 'dicomParser.readFixedString: attempt to read past end of buffer';
}
var result = "";
var byte;
for(var i=0; i < length; i++)
{
byte = byteArray[position + i];
if(byte === 0) {
position += length;
return result;
}
result += String.fromCharCode(byte);
}
return result;
};
return dicomParser;
}(dicomParser));
/**
*
* Internal helper class to assist with parsing. Supports reading from a byte
* stream contained in a Uint8Array. Example usage:
*
* var byteArray = new Uint8Array(32);
* var byteStream = new dicomParser.ByteStream(dicomParser.littleEndianByteArrayParser, byteArray);
*
* */
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
/**
* Constructor for ByteStream objects.
* @param byteArrayParser a parser for parsing the byte array
* @param byteArray a Uint8Array containing the byte stream
* @param position (optional) the position to start reading from. 0 if not specified
* @constructor
* @throws will throw an error if the byteArrayParser parameter is not present
* @throws will throw an error if the byteArray parameter is not present or invalid
* @throws will throw an error if the position parameter is not inside the byte array
*/
dicomParser.ByteStream = function(byteArrayParser, byteArray, position) {
if(byteArrayParser === undefined)
{
throw "dicomParser.ByteStream: missing required parameter 'byteArrayParser'";
}
if(byteArray === undefined)
{
throw "dicomParser.ByteStream: missing required parameter 'byteArray'";
}
if((byteArray instanceof Uint8Array) === false &&
(byteArray instanceof Buffer) === false ) {
throw 'dicomParser.ByteStream: parameter byteArray is not of type Uint8Array or Buffer';
}
if(position < 0)
{
throw "dicomParser.ByteStream: parameter 'position' cannot be less than 0";
}
if(position >= byteArray.length)
{
throw "dicomParser.ByteStream: parameter 'position' cannot be greater than or equal to 'byteArray' length";
}
this.byteArrayParser = byteArrayParser;
this.byteArray = byteArray;
this.position = position ? position : 0;
this.warnings = []; // array of string warnings encountered while parsing
};
/**
* Safely seeks through the byte stream. Will throw an exception if an attempt
* is made to seek outside of the byte array.
* @param offset the number of bytes to add to the position
* @throws error if seek would cause position to be outside of the byteArray
*/
dicomParser.ByteStream.prototype.seek = function(offset)
{
if(this.position + offset < 0)
{
throw "dicomParser.ByteStream.prototype.seek: cannot seek to position < 0";
}
this.position += offset;
};
/**
* Returns a new ByteStream object from the current position and of the requested number of bytes
* @param numBytes the length of the byte array for the ByteStream to contain
* @returns {dicomParser.ByteStream}
* @throws error if buffer overread would occur
*/
dicomParser.ByteStream.prototype.readByteStream = function(numBytes)
{
if(this.position + numBytes > this.byteArray.length) {
throw 'dicomParser.ByteStream.prototype.readByteStream: readByteStream - buffer overread';
}
var byteArrayView = dicomParser.sharedCopy(this.byteArray, this.position, numBytes);
this.position += numBytes;
return new dicomParser.ByteStream(this.byteArrayParser, byteArrayView);
};
/**
*
* Parses an unsigned int 16 from a byte array and advances
* the position by 2 bytes
*
* @returns {*} the parsed unsigned int 16
* @throws error if buffer overread would occur
*/
dicomParser.ByteStream.prototype.readUint16 = function()
{
var result = this.byteArrayParser.readUint16(this.byteArray, this.position);
this.position += 2;
return result;
};
/**
* Parses an unsigned int 32 from a byte array and advances
* the position by 2 bytes
*
* @returns {*} the parse unsigned int 32
* @throws error if buffer overread would occur
*/
dicomParser.ByteStream.prototype.readUint32 = function()
{
var result = this.byteArrayParser.readUint32(this.byteArray, this.position);
this.position += 4;
return result;
};
/**
* Reads a string of 8-bit characters from an array of bytes and advances
* the position by length bytes. A null terminator will end the string
* but will not effect advancement of the position.
* @param length the maximum number of bytes to parse
* @returns {string} the parsed string
* @throws error if buffer overread would occur
*/
dicomParser.ByteStream.prototype.readFixedString = function(length)
{
var result = dicomParser.readFixedString(this.byteArray, this.position, length);
this.position += length;
return result;
};
return dicomParser;
}(dicomParser));
/**
*
* The DataSet class encapsulates a collection of DICOM Elements and provides various functions
* to access the data in those elements
*
* Rules for handling padded spaces:
* DS = Strip leading and trailing spaces
* DT = Strip trailing spaces
* IS = Strip leading and trailing spaces
* PN = Strip trailing spaces
* TM = Strip trailing spaces
* AE = Strip leading and trailing spaces
* CS = Strip leading and trailing spaces
* SH = Strip leading and trailing spaces
* LO = Strip leading and trailing spaces
* LT = Strip trailing spaces
* ST = Strip trailing spaces
* UT = Strip trailing spaces
*
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
function getByteArrayParser(element, defaultParser)
{
return (element.parser !== undefined ? element.parser : defaultParser);
}
/**
* Constructs a new DataSet given byteArray and collection of elements
* @param byteArrayParser
* @param byteArray
* @param elements
* @constructor
*/
dicomParser.DataSet = function(byteArrayParser, byteArray, elements)
{
this.byteArrayParser = byteArrayParser;
this.byteArray = byteArray;
this.elements = elements;
};
/**
* Finds the element for tag and returns an unsigned int 16 if it exists and has data
* @param tag The DICOM tag in the format xGGGGEEEE
* @param index the index of the value in a multivalued element. Default is index 0 if not supplied
* @returns {*} unsigned int 16 or undefined if the attribute is not present or has data of length 0
*/
dicomParser.DataSet.prototype.uint16 = function(tag, index)
{
var element = this.elements[tag];
index = (index !== undefined) ? index : 0;
if(element && element.length !== 0)
{
return getByteArrayParser(element, this.byteArrayParser).readUint16(this.byteArray, element.dataOffset + (index *2));
}
return undefined;
};
/**
* Finds the element for tag and returns an signed int 16 if it exists and has data
* @param tag The DICOM tag in the format xGGGGEEEE
* @param index the index of the value in a multivalued element. Default is index 0 if not supplied
* @returns {*} signed int 16 or undefined if the attribute is not present or has data of length 0
*/
dicomParser.DataSet.prototype.int16 = function(tag, index)
{
var element = this.elements[tag];
index = (index !== undefined) ? index : 0;
if(element && element.length !== 0)
{
return getByteArrayParser(element, this.byteArrayParser).readInt16(this.byteArray, element.dataOffset + (index * 2));
}
return undefined;
};
/**
* Finds the element for tag and returns an unsigned int 32 if it exists and has data
* @param tag The DICOM tag in the format xGGGGEEEE
* @param index the index of the value in a multivalued element. Default is index 0 if not supplied
* @returns {*} unsigned int 32 or undefined if the attribute is not present or has data of length 0
*/
dicomParser.DataSet.prototype.uint32 = function(tag, index)
{
var element = this.elements[tag];
index = (index !== undefined) ? index : 0;
if(element && element.length !== 0)
{
return getByteArrayParser(element, this.byteArrayParser).readUint32(this.byteArray, element.dataOffset + (index * 4));
}
return undefined;
};
/**
* Finds the element for tag and returns an signed int 32 if it exists and has data
* @param tag The DICOM tag in the format xGGGGEEEE
* @param index the index of the value in a multivalued element. Default is index 0 if not supplied
* @returns {*} signed int 32 or undefined if the attribute is not present or has data of length 0
*/
dicomParser.DataSet.prototype.int32 = function(tag, index)
{
var element = this.elements[tag];
index = (index !== undefined) ? index : 0;
if(element && element.length !== 0)
{
return getByteArrayParser(element, this.byteArrayParser).readInt32(this.byteArray, element.dataOffset + (index * 4));
}
return undefined;
};
/**
* Finds the element for tag and returns a 32 bit floating point number (VR=FL) if it exists and has data
* @param tag The DICOM tag in the format xGGGGEEEE
* @param index the index of the value in a multivalued element. Default is index 0 if not supplied
* @returns {*} float or undefined if the attribute is not present or has data of length 0
*/
dicomParser.DataSet.prototype.float = function(tag, index)
{
var element = this.elements[tag];
index = (index !== undefined) ? index : 0;
if(element && element.length !== 0)
{
return getByteArrayParser(element, this.byteArrayParser).readFloat(this.byteArray, element.dataOffset + (index * 4));
}
return undefined;
};
/**
* Finds the element for tag and returns a 64 bit floating point number (VR=FD) if it exists and has data
* @param tag The DICOM tag in the format xGGGGEEEE
* @param index the index of the value in a multivalued element. Default is index 0 if not supplied
* @returns {*} float or undefined if the attribute is not present or doesn't has data of length 0
*/
dicomParser.DataSet.prototype.double = function(tag, index)
{
var element = this.elements[tag];
index = (index !== undefined) ? index : 0;
if(element && element.length !== 0)
{
return getByteArrayParser(element, this.byteArrayParser).readDouble(this.byteArray, element.dataOffset + (index * 8));
}
return undefined;
};
/**
* Returns the number of string values for the element
* @param tag The DICOM tag in the format xGGGGEEEE
* @returns {*} the number of string values or undefined if the attribute is not present or has zero length data
*/
dicomParser.DataSet.prototype.numStringValues = function(tag)
{
var element = this.elements[tag];
if(element && element.length > 0)
{
var fixedString = dicomParser.readFixedString(this.byteArray, element.dataOffset, element.length);
var numMatching = fixedString.match(/\\/g);
if(numMatching === null)
{
return 1;
}
return numMatching.length + 1;
}
return undefined;
};
/**
* Returns a string for the element. If index is provided, the element is assumed to be
* multi-valued and will return the component specified by index. Undefined is returned
* if there is no component with the specified index, the element does not exist or is zero length.
*
* Use this function for VR types of AE, CS, SH and LO
*
* @param tag The DICOM tag in the format xGGGGEEEE
* @param index the index of the desired value in a multi valued string or undefined for the entire string
* @returns {*}
*/
dicomParser.DataSet.prototype.string = function(tag, index)
{
var element = this.elements[tag];
if(element && element.length > 0)
{
var fixedString = dicomParser.readFixedString(this.byteArray, element.dataOffset, element.length);
if(index >= 0)
{
var values = fixedString.split('\\');
// trim trailing spaces
return values[index].trim();
}
else
{
// trim trailing spaces
return fixedString.trim();
}
}
return undefined;
};
/**
* Returns a string with the leading spaces preserved and trailing spaces removed.
*
* Use this function to access data for VRs of type UT, ST and LT
*
* @param tag
* @param index
* @returns {*}
*/
dicomParser.DataSet.prototype.text = function(tag, index)
{
var element = this.elements[tag];
if(element && element.length > 0)
{
var fixedString = dicomParser.readFixedString(this.byteArray, element.dataOffset, element.length);
if(index >= 0)
{
var values = fixedString.split('\\');
return values[index].replace(/ +$/, '');
}
else
{
return fixedString.replace(/ +$/, '');
}
}
return undefined;
};
/**
* Parses a string to a float for the specified index in a multi-valued element. If index is not specified,
* the first value in a multi-valued VR will be parsed if present.
* @param tag The DICOM tag in the format xGGGGEEEE
* @param index the index of the desired value in a multi valued string or undefined for the first value
* @returns {*} a floating point number or undefined if not present or data not long enough
*/
dicomParser.DataSet.prototype.floatString = function(tag, index)
{
var element = this.elements[tag];
if(element && element.length > 0)
{
index = (index !== undefined) ? index : 0;
var value = this.string(tag, index);
if(value !== undefined) {
return parseFloat(value);
}
}
return undefined;
};
/**
* Parses a string to an integer for the specified index in a multi-valued element. If index is not specified,
* the first value in a multi-valued VR will be parsed if present.
* @param tag The DICOM tag in the format xGGGGEEEE
* @param index the index of the desired value in a multi valued string or undefined for the first value
* @returns {*} an integer or undefined if not present or data not long enough
*/
dicomParser.DataSet.prototype.intString = function(tag, index)
{
var element = this.elements[tag];
if(element && element.length > 0) {
index = (index !== undefined) ? index : 0;
var value = this.string(tag, index);
if(value !== undefined) {
return parseInt(value);
}
}
return undefined;
};
//dicomParser.DataSet = DataSet;
return dicomParser;
}(dicomParser));
/**
* Internal helper functions for parsing DICOM elements
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
/**
* Reads an encapsulated pixel data element and adds an array of fragments to the element
* containing the offset and length of each fragment and any offsets from the basic offset
* table
* @param byteStream
* @param element
*/
dicomParser.findEndOfEncapsulatedElement = function(byteStream, element, warnings)
{
if(byteStream === undefined)
{
throw "dicomParser.findEndOfEncapsulatedElement: missing required parameter 'byteStream'";
}
if(element === undefined)
{
throw "dicomParser.findEndOfEncapsulatedElement: missing required parameter 'element'";
}
element.encapsulatedPixelData = true;
element.basicOffsetTable = [];
element.fragments = [];
var basicOffsetTableItemTag = dicomParser.readTag(byteStream);
if(basicOffsetTableItemTag !== 'xfffee000') {
throw "dicomParser.findEndOfEncapsulatedElement: basic offset table not found";
}
var basicOffsetTableItemlength = byteStream.readUint32();
var numFragments = basicOffsetTableItemlength / 4;
for(var i =0; i < numFragments; i++) {
var offset = byteStream.readUint32();
element.basicOffsetTable.push(offset);
}
var baseOffset = byteStream.position;
while(byteStream.position < byteStream.byteArray.length)
{
var tag = dicomParser.readTag(byteStream);
var length = byteStream.readUint32();
if(tag === 'xfffee0dd')
{
byteStream.seek(length);
element.length = byteStream.position - element.dataOffset;
return;
}
else if(tag === 'xfffee000')
{
element.fragments.push({
offset: byteStream.position - baseOffset - 8,
position : byteStream.position,
length : length
});
}
else {
if(warnings) {
warnings.push('unexpected tag ' + tag + ' while searching for end of pixel data element with undefined length');
}
if(length > byteStream.byteArray.length - byteStream.position)
{
// fix length
length = byteStream.byteArray.length - byteStream.position;
}
element.fragments.push({
offset: byteStream.position - baseOffset - 8,
position : byteStream.position,
length : length
});
byteStream.seek(length);
element.length = byteStream.position - element.dataOffset;
return;
}
byteStream.seek(length);
}
if(warnings) {
warnings.push("pixel data element " + element.tag + " missing sequence delimiter tag xfffee0dd");
}
};
return dicomParser;
}(dicomParser));
/**
* Internal helper functions for parsing DICOM elements
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
/**
* reads from the byte stream until it finds the magic numbers for the item delimitation item
* and then sets the length of the element
* @param byteStream
* @param element
*/
dicomParser.findItemDelimitationItemAndSetElementLength = function(byteStream, element)
{
if(byteStream === undefined)
{
throw "dicomParser.readDicomElementImplicit: missing required parameter 'byteStream'";
}
var itemDelimitationItemLength = 8; // group, element, length
var maxPosition = byteStream.byteArray.length - itemDelimitationItemLength;
while(byteStream.position <= maxPosition)
{
var groupNumber = byteStream.readUint16();
if(groupNumber === 0xfffe)
{
var elementNumber = byteStream.readUint16();
if(elementNumber === 0xe00d)
{
// NOTE: It would be better to also check for the length to be 0 as part of the check above
// but we will just log a warning for now
var itemDelimiterLength = byteStream.readUint32(); // the length
if(itemDelimiterLength !== 0) {
byteStream.warnings('encountered non zero length following item delimiter at position' + byteStream.position - 4 + " while reading element of undefined length with tag ' + element.tag");
}
element.length = byteStream.position - element.dataOffset;
return;
}
}
}
// No item delimitation item - silently set the length to the end of the buffer and set the position past the end of the buffer
element.length = byteStream.byteArray.length - element.dataOffset;
byteStream.seek(byteStream.byteArray.length - byteStream.position);
};
return dicomParser;
}(dicomParser));
/**
* Internal helper functions for parsing different types from a little-endian byte array
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
dicomParser.littleEndianByteArrayParser = {
/**
*
* Parses an unsigned int 16 from a little-endian byte array
*
* @param byteArray the byte array to read from
* @param position the position in the byte array to read from
* @returns {*} the parsed unsigned int 16
* @throws error if buffer overread would occur
* @access private
*/
readUint16: function (byteArray, position) {
if (position < 0) {
throw 'littleEndianByteArrayParser.readUint16: position cannot be less than 0';
}
if (position + 2 > byteArray.length) {
throw 'littleEndianByteArrayParser.readUint16: attempt to read past end of buffer';
}
return byteArray[position] + (byteArray[position + 1] * 256);
},
/**
*
* Parses a signed int 16 from a little-endian byte array
*
* @param byteArray the byte array to read from
* @param position the position in the byte array to read from
* @returns {*} the parsed signed int 16
* @throws error if buffer overread would occur
* @access private
*/
readInt16: function (byteArray, position) {
if (position < 0) {
throw 'littleEndianByteArrayParser.readInt16: position cannot be less than 0';
}
if (position + 2 > byteArray.length) {
throw 'littleEndianByteArrayParser.readInt16: attempt to read past end of buffer';
}
var int16 = byteArray[position] + (byteArray[position + 1] << 8);
// fix sign
if (int16 & 0x8000) {
int16 = int16 - 0xFFFF - 1;
}
return int16;
},
/**
* Parses an unsigned int 32 from a little-endian byte array
*
* @param byteArray the byte array to read from
* @param position the position in the byte array to read from
* @returns {*} the parsed unsigned int 32
* @throws error if buffer overread would occur
* @access private
*/
readUint32: function (byteArray, position) {
if (position < 0) {
throw 'littleEndianByteArrayParser.readUint32: position cannot be less than 0';
}
if (position + 4 > byteArray.length) {
throw 'littleEndianByteArrayParser.readUint32: attempt to read past end of buffer';
}
var uint32 = (byteArray[position] +
(byteArray[position + 1] * 256) +
(byteArray[position + 2] * 256 * 256) +
(byteArray[position + 3] * 256 * 256 * 256 ));
return uint32;
},
/**
* Parses a signed int 32 from a little-endian byte array
*
* @param byteArray the byte array to read from
* @param position the position in the byte array to read from
* @returns {*} the parsed unsigned int 32
* @throws error if buffer overread would occur
* @access private
*/
readInt32: function (byteArray, position) {
if (position < 0) {
throw 'littleEndianByteArrayParser.readInt32: position cannot be less than 0';
}
if (position + 4 > byteArray.length) {
throw 'littleEndianByteArrayParser.readInt32: attempt to read past end of buffer';
}
var int32 = (byteArray[position] +
(byteArray[position + 1] << 8) +
(byteArray[position + 2] << 16) +
(byteArray[position + 3] << 24));
return int32;
},
/**
* Parses 32-bit float from a little-endian byte array
*
* @param byteArray the byte array to read from
* @param position the position in the byte array to read from
* @returns {*} the parsed 32-bit float
* @throws error if buffer overread would occur
* @access private
*/
readFloat: function (byteArray, position) {
if (position < 0) {
throw 'littleEndianByteArrayParser.readFloat: position cannot be less than 0';
}
if (position + 4 > byteArray.length) {
throw 'littleEndianByteArrayParser.readFloat: attempt to read past end of buffer';
}
// I am sure there is a better way than this but this should be safe
var byteArrayForParsingFloat = new Uint8Array(4);
byteArrayForParsingFloat[0] = byteArray[position];
byteArrayForParsingFloat[1] = byteArray[position + 1];
byteArrayForParsingFloat[2] = byteArray[position + 2];
byteArrayForParsingFloat[3] = byteArray[position + 3];
var floatArray = new Float32Array(byteArrayForParsingFloat.buffer);
return floatArray[0];
},
/**
* Parses 64-bit float from a little-endian byte array
*
* @param byteArray the byte array to read from
* @param position the position in the byte array to read from
* @returns {*} the parsed 64-bit float
* @throws error if buffer overread would occur
* @access private
*/
readDouble: function (byteArray, position) {
if (position < 0) {
throw 'littleEndianByteArrayParser.readDouble: position cannot be less than 0';
}
if (position + 8 > byteArray.length) {
throw 'littleEndianByteArrayParser.readDouble: attempt to read past end of buffer';
}
// I am sure there is a better way than this but this should be safe
var byteArrayForParsingFloat = new Uint8Array(8);
byteArrayForParsingFloat[0] = byteArray[position];
byteArrayForParsingFloat[1] = byteArray[position + 1];
byteArrayForParsingFloat[2] = byteArray[position + 2];
byteArrayForParsingFloat[3] = byteArray[position + 3];
byteArrayForParsingFloat[4] = byteArray[position + 4];
byteArrayForParsingFloat[5] = byteArray[position + 5];
byteArrayForParsingFloat[6] = byteArray[position + 6];
byteArrayForParsingFloat[7] = byteArray[position + 7];
var floatArray = new Float64Array(byteArrayForParsingFloat.buffer);
return floatArray[0];
}
};
return dicomParser;
}(dicomParser));
/**
* Internal helper functions for parsing implicit and explicit DICOM data sets
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
/**
* 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)
*/
dicomParser.parseDicomDataSetExplicit = function (dataSet, byteStream, maxPosition, options) {
maxPosition = (maxPosition === undefined) ? byteStream.byteArray.length : maxPosition ;
options = options || {};
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 'maxPosition'";
}
var elements = dataSet.elements;
while(byteStream.position < maxPosition)
{
var element = dicomParser.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)
*/
dicomParser.parseDicomDataSetImplicit = function(dataSet, byteStream, maxPosition, options)
{
maxPosition = (maxPosition === undefined) ? dataSet.byteArray.length : maxPosition ;
options = options || {};
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'";
}
var elements = dataSet.elements;
while(byteStream.position < maxPosition)
{
var element = dicomParser.readDicomElementImplicit(byteStream, options.untilTag, options.vrCallback);
elements[element.tag] = element;
if(element.tag === options.untilTag) {
return;
}
}
};
return dicomParser;
}(dicomParser));
/**
* Internal helper functions for for parsing DICOM elements
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
function getDataLengthSizeInBytesForVR(vr)
{
if( vr === 'OB' ||
vr === 'OW' ||
vr === 'SQ' ||
vr === 'OF' ||
vr === 'UT' ||
vr === 'UN')
{
return 4;
}
else
{
return 2;
}
}
dicomParser.readDicomElementExplicit = function(byteStream, warnings, untilTag)
{
if(byteStream === undefined)
{
throw "dicomParser.readDicomElementExplicit: missing required parameter 'byteStream'";
}
var element = {
tag : dicomParser.readTag(byteStream),
vr : byteStream.readFixedString(2)
// length set below based on VR
// dataOffset set below based on VR and size of length
};
var dataLengthSizeBytes = getDataLengthSizeInBytesForVR(element.vr);
if(dataLengthSizeBytes === 2)
{
element.length = byteStream.readUint16();
element.dataOffset = byteStream.position;
}
else
{
byteStream.seek(2);
element.length = byteStream.readUint32();
element.dataOffset = byteStream.position;
}
if(element.length === 4294967295)
{
element.hadUndefinedLength = true;
}
if(element.tag === untilTag) {
return element;
}
// if VR is SQ, parse the sequence items
if(element.vr === 'SQ')
{
dicomParser.readSequenceItemsExplicit(byteStream, element, warnings);
return element;
}
if(element.length === 4294967295)
{
if(element.tag === 'x7fe00010') {
dicomParser.findEndOfEncapsulatedElement(byteStream, element, warnings);
return element;
} else {
dicomParser.findItemDelimitationItemAndSetElementLength(byteStream, element);
return element;
}
}
byteStream.seek(element.length);
return element;
};
return dicomParser;
}(dicomParser));
/**
* Internal helper functions for for parsing DICOM elements
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
function isSequence(element, byteStream, vrCallback) {
// if a data dictionary callback was provided, use that to verify that the element is a sequence.
if (typeof vrCallback !== 'undefined') {
return (vrCallback(element.tag) === 'SQ');
}
if ((byteStream.position + 4) <= byteStream.byteArray.length) {
var nextTag = dicomParser.readTag(byteStream);
byteStream.seek(-4);
// Item start tag (fffe,e000) or sequence delimiter (i.e. end of sequence) tag (0fffe,e0dd)
// These are the tags that could potentially be found directly after a sequence start tag (the delimiter
// is found in the case of an empty sequence). This is not 100% safe because a non-sequence item
// could have data that has these bytes, but this is how to do it without a data dictionary.
return (nextTag === 'xfffee000') || (nextTag === 'xfffee0dd');
}
byteStream.warnings.push('eof encountered before finding sequence item tag or sequence delimiter tag in peeking to determine VR');
return false;
}
dicomParser.readDicomElementImplicit = function(byteStream, untilTag, vrCallback)
{
if(byteStream === undefined)
{
throw "dicomParser.readDicomElementImplicit: missing required parameter 'byteStream'";
}
var element = {
tag : dicomParser.readTag(byteStream),
length: byteStream.readUint32(),
dataOffset : byteStream.position
};
if(element.length === 4294967295) {
element.hadUndefinedLength = true;
}
if(element.tag === untilTag) {
return element;
}
if (isSequence(element, byteStream, vrCallback)) {
// parse the sequence
dicomParser.readSequenceItemsImplicit(byteStream, element);
return element;
}
// if element is not a sequence and has undefined length, we have to
// scan the data for a magic number to figure out when it ends.
if(element.hadUndefinedLength)
{
dicomParser.findItemDelimitationItemAndSetElementLength(byteStream, element);
return element;
}
// non sequence element with known length, skip over the data part
byteStream.seek(element.length);
return element;
};
return dicomParser;
}(dicomParser));
/**
* Parses a DICOM P10 byte array and returns a DataSet object with the parsed elements. If the options
* argument is supplied and it contains the untilTag property, parsing will stop once that
* tag is encoutered. This can be used to parse partial byte streams.
*
* @param byteArray the byte array
* @param options object to control parsing behavior (optional)
* @returns {DataSet}
* @throws error if an error occurs while parsing. The exception object will contain a property dataSet with the
* elements successfully parsed before the error.
*/
var dicomParser = (function(dicomParser) {
if(dicomParser === undefined)
{
dicomParser = {};
}
dicomParser.readPart10Header = function(byteArray, options) {
if(byteArray === undefined)
{
throw "dicomParser.readPart10Header: missing required parameter 'byteArray'";
}
var littleEndianByteStream = new dicomParser.ByteStream(dicomParser.littleEndianByteArrayParser, byteArray);
function readPrefix()
{
littleEndianByteStream.seek(128);
var prefix = littleEndianByteStream.readFixedString(4);
if(prefix !== "DICM")
{
throw "dicomParser.readPart10Header: DICM prefix not found at location 132 - this is not a valid DICOM P10 file.";
}
}
// main function here
function readTheHeader() {
// Per the DICOM standard, the header is always encoded in Explicit VR Little Endian (see PS3.10, section 7.1)
// so use littleEndianByteStream throughout this method regardless of the transfer syntax
readPrefix();
var warnings = [];
var elements = {};
while(littleEndianByteStream.position < littleEndianByteStream.byteArray.length) {
var position = littleEndianByteStream.position;
var element = dicomParser.readDicomElementExplicit(littleEndianByteStream, warnings);
if(element.tag > 'x0002ffff') {
littleEndianByteStream.position = position;
break;
}
// Cache the littleEndianByteArrayParser for meta header elements, since the rest of the data set may be big endian
// and this parser will be needed later if the meta header values are to be read.
element.parser = dicomParser.littleEndianByteArrayParser;
elements[element.tag] = element;
}
var metaHeaderDataSet = new dicomParser.DataSet(littleEndianByteStream.byteArrayParser, littleEndianByteStream.byteArray, elements);
metaHeaderDataSet.warnings = littleEndianByteStream.warnings;
metaHeaderDataSet.position = littleEndianByteStream.position;
return metaHeaderDataSet;
}
// This is where we actually start parsing
return readTheHeader();
};
return dicomParser;
})(dicomParser);
/**
* Internal helper functions for parsing DICOM elements
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
function readDicomDataSetExplicitUndefinedLength(byteStream, warnings)
{
var elements = {};
while(byteStream.position < byteStream.byteArray.length)
{
var element = dicomParser.readDicomElementExplicit(byteStream, warnings);
elements[element.tag] = element;
// we hit an item delimiter tag, return the current offset to mark
// the end of this sequence item
if(element.tag === 'xfffee00d')
{
return new dicomParser.DataSet(byteStream.byteArrayParser, byteStream.byteArray, elements);
}
}
// eof encountered - log a warning and return what we have for the element
warnings.push('eof encountered before finding item delimiter tag while reading sequence item of undefined length');
return new dicomParser.DataSet(byteStream.byteArrayParser, byteStream.byteArray, elements);
}
function readSequenceItemExplicit(byteStream, warnings)
{
var item = dicomParser.readSequenceItem(byteStream);
if(item.length === 4294967295)
{
item.hadUndefinedLength = true;
item.dataSet = readDicomDataSetExplicitUndefinedLength(byteStream, warnings);
item.length = byteStream.position - item.dataOffset;
}
else
{
item.dataSet = new dicomParser.DataSet(byteStream.byteArrayParser, byteStream.byteArray, {});
dicomParser.parseDicomDataSetExplicit(item.dataSet, byteStream, byteStream.position + item.length);
}
return item;
}
function readSQElementUndefinedLengthExplicit(byteStream, element, warnings)
{
while((byteStream.position + 4) <= byteStream.byteArray.length)
{
// end reading this sequence if the next tag is the sequence delimitation item
var nextTag = dicomParser.readTag(byteStream);
byteStream.seek(-4);
if (nextTag === 'xfffee0dd') {
// set the correct length
element.length = byteStream.position - element.dataOffset;
byteStream.seek(8);
return element;
}
var item = readSequenceItemExplicit(byteStream, warnings);
element.items.push(item);
}
warnings.push('eof encountered before finding sequence delimitation tag while reading sequence of undefined length');
element.length = byteStream.position - element.dataOffset;
}
function readSQElementKnownLengthExplicit(byteStream, element, warnings)
{
var maxPosition = element.dataOffset + element.length;
while(byteStream.position < maxPosition)
{
var item = readSequenceItemExplicit(byteStream, warnings);
element.items.push(item);
}
}
dicomParser.readSequenceItemsExplicit = function(byteStream, element, warnings)
{
if(byteStream === undefined)
{
throw "dicomParser.readSequenceItemsExplicit: missing required parameter 'byteStream'";
}
if(element === undefined)
{
throw "dicomParser.readSequenceItemsExplicit: missing required parameter 'element'";
}
element.items = [];
if(element.length === 4294967295)
{
readSQElementUndefinedLengthExplicit(byteStream, element, warnings);
}
else
{
readSQElementKnownLengthExplicit(byteStream, element, warnings);
}
};
return dicomParser;
}(dicomParser));
/**
* Internal helper functions for parsing DICOM elements
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
function readDicomDataSetImplicitUndefinedLength(byteStream, vrCallback)
{
var elements = {};
while(byteStream.position < byteStream.byteArray.length)
{
var element = dicomParser.readDicomElementImplicit(byteStream, undefined, vrCallback);
elements[element.tag] = element;
// we hit an item delimiter tag, return the current offset to mark
// the end of this sequence item
if(element.tag === 'xfffee00d')
{
return new dicomParser.DataSet(byteStream.byteArrayParser, byteStream.byteArray, elements);
}
}
// eof encountered - log a warning and return what we have for the element
byteStream.warnings.push('eof encountered before finding sequence item delimiter in sequence item of undefined length');
return new dicomParser.DataSet(byteStream.byteArrayParser, byteStream.byteArray, elements);
}
function readSequenceItemImplicit(byteStream, vrCallback)
{
var item = dicomParser.readSequenceItem(byteStream);
if(item.length === 4294967295)
{
item.hadUndefinedLength = true;
item.dataSet = readDicomDataSetImplicitUndefinedLength(byteStream, vrCallback);
item.length = byteStream.position - item.dataOffset;
}
else
{
item.dataSet = new dicomParser.DataSet(byteStream.byteArrayParser, byteStream.byteArray, {});
dicomParser.parseDicomDataSetImplicit(item.dataSet, byteStream, byteStream.position + item.length, {vrCallback: vrCallback});
}
return item;
}
function readSQElementUndefinedLengthImplicit(byteStream, element, vrCallback)
{
while((byteStream.position + 4) <= byteStream.byteArray.length)
{
// end reading this sequence if the next tag is the sequence delimitation item
var nextTag = dicomParser.readTag(byteStream);
byteStream.seek(-4);
if (nextTag === 'xfffee0dd') {
// set the correct length
element.length = byteStream.position - element.dataOffset;
byteStream.seek(8);
return element;
}
var item = readSequenceItemImplicit(byteStream, vrCallback);
element.items.push(item);
}
byteStream.warnings.push('eof encountered before finding sequence delimiter in sequence of undefined length');
element.length = byteStream.byteArray.length - element.dataOffset;
}
function readSQElementKnownLengthImplicit(byteStream, element, vrCallback)
{
var maxPosition = element.dataOffset + element.length;
while(byteStream.position < maxPosition)
{
var item = readSequenceItemImplicit(byteStream, vrCallback);
element.items.push(item);
}
}
/**
* Reads sequence items for an element in an implicit little endian byte stream
* @param byteStream the implicit little endian byte stream
* @param element the element to read the sequence items for
* @param vrCallback an optional method that returns a VR string given a tag
*/
dicomParser.readSequenceItemsImplicit = function(byteStream, element, vrCallback)
{
if(byteStream === undefined)
{
throw "dicomParser.readSequenceItemsImplicit: missing required parameter 'byteStream'";
}
if(element === undefined)
{
throw "dicomParser.readSequenceItemsImplicit: missing required parameter 'element'";
}
element.items = [];
if(element.length === 4294967295)
{
readSQElementUndefinedLengthImplicit(byteStream, element, vrCallback);
}
else
{
readSQElementKnownLengthImplicit(byteStream, element, vrCallback);
}
};
return dicomParser;
}(dicomParser));
/**
* Internal helper functions for parsing DICOM elements
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
/**
* Reads the tag and length of a sequence item and returns them as an object with the following properties
* tag : string for the tag of this element in the format xggggeeee
* length: the number of bytes in this item or 4294967295 if undefined
* dataOffset: the offset into the byteStream of the data for this item
* @param byteStream the byte
* @returns {{tag: string, length: integer, dataOffset: integer}}
*/
dicomParser.readSequenceItem = function(byteStream)
{
if(byteStream === undefined)
{
throw "dicomParser.readSequenceItem: missing required parameter 'byteStream'";
}
var element = {
tag : dicomParser.readTag(byteStream),
length : byteStream.readUint32(),
dataOffset : byteStream.position
};
if (element.tag !== 'xfffee000') {
var startPosition = byteStream.position;
throw "dicomParser.readSequenceItem: item tag (FFFE,E000) not found at offset " + startPosition;
}
return element;
};
return dicomParser;
}(dicomParser));
/**
* Internal helper functions for parsing DICOM elements
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
/**
* Reads a tag (group number and element number) from a byteStream
* @param byteStream the byte stream to read from
* @returns {string} the tag in format xggggeeee where gggg is the lowercase hex value of the group number
* and eeee is the lower case hex value of the element number
*/
dicomParser.readTag = function(byteStream)
{
if(byteStream === undefined)
{
throw "dicomParser.readTag: missing required parameter 'byteStream'";
}
var groupNumber = byteStream.readUint16() * 256 * 256;
var elementNumber = byteStream.readUint16();
var tag = "x" + ('00000000' + (groupNumber + elementNumber).toString(16)).substr(-8);
return tag;
};
return dicomParser;
}(dicomParser));
/**
*
* Internal helper function to create a shared copy of a byteArray
*
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
/**
* Creates a view of the underlying byteArray. The view is of the same type as the byteArray (e.g.
* Uint8Array or Buffer) and shares the same underlying memory (changing one changes the other)
* @param byteArray the underlying byteArray (either Uint8Array or Buffer)
* @param byteOffset offset into the underlying byteArray to create the view of
* @param length number of bytes in the view
* @returns {object} Uint8Array or Buffer depending on the type of byteArray
*/
dicomParser.sharedCopy = function(byteArray, byteOffset, length) {
if (typeof Buffer !== 'undefined' && byteArray instanceof Buffer) {
return byteArray.slice(byteOffset, byteOffset + length);
}
else if(byteArray instanceof Uint8Array) {
return new Uint8Array(byteArray.buffer, byteArray.byteOffset + byteOffset, length);
} else {
throw 'dicomParser.from: unknown type for byteArray';
}
};
return dicomParser;
}(dicomParser));
/**
* Version
*/
var dicomParser = (function (dicomParser)
{
"use strict";
if(dicomParser === undefined)
{
dicomParser = {};
}
dicomParser.version = "1.5.0";
return dicomParser;
}(dicomParser));
return dicomParser;
}));
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