import {
dictionary,
tagGroups
} from './dictionary';
/**
* Immutable tag.
*/
export class Tag {
/**
* The tag group.
*
* @type {string}
*/
#group;
/**
* The tag element.
*
* @type {string}
*/
#element;
/**
* @param {string} group The tag group as '####'.
* @param {string} element The tag element as '####'.
*/
constructor(group, element) {
if (!group || typeof group === 'undefined') {
throw new Error('Cannot create tag with no group.');
}
if (group.length !== 4) {
throw new Error('Cannot create tag with badly sized group.');
}
if (!element || typeof element === 'undefined') {
throw new Error('Cannot create tag with no element.');
}
if (element.length !== 4) {
throw new Error('Cannot create tag with badly sized element.');
}
this.#group = group;
this.#element = element;
}
/**
* Get the tag group.
*
* @returns {string} The tag group.
*/
getGroup() {
return this.#group;
}
/**
* Get the tag element.
*
* @returns {string} The tag element.
*/
getElement() {
return this.#element;
}
/**
* Get as string representation of the tag: 'key: name'.
*
* @returns {string} A string representing the tag.
*/
toString() {
return this.getKey() + ': ' + this.getNameFromDictionary();
}
/**
* Check for Tag equality.
*
* @param {Tag} rhs The other tag to compare to.
* @returns {boolean} True if both tags are equal.
*/
equals(rhs) {
return rhs !== null &&
typeof rhs !== 'undefined' &&
this.#group === rhs.getGroup() &&
this.#element === rhs.getElement();
}
/**
* Get the group-element key used to store DICOM elements.
*
* @returns {string} The key as '########'.
*/
getKey() {
return this.#group + this.#element;
}
/**
* Get the group name as defined in TagGroups.
*
* @returns {string} The name.
*/
getGroupName() {
return tagGroups[this.#group];
}
/**
* Does this tag have a VR.
* Basically not the Item, ItemDelimitationItem nor
* SequenceDelimitationItem tags.
*
* @returns {boolean} True if this tag has a VR.
*/
isWithVR() {
return !(this.#group === 'FFFE' &&
(this.#element === 'E000' ||
this.#element === 'E00D' ||
this.#element === 'E0DD')
);
}
/**
* Is the tag group a private tag group ?
* see: http://dicom.nema.org/medical/dicom/2015a/output/html/part05.html#sect_7.8
*
* @returns {boolean} True if the tag group is private,
* ie if its group is an odd number.
*/
isPrivate() {
return parseInt(this.#group, 16) % 2 === 1;
}
/**
* Get the tag info from the dicom dictionary.
*
* @returns {Array|undefined} The info as [vr, multiplicity, name].
*/
getInfoFromDictionary() {
let info;
if (typeof dictionary[this.#group] !== 'undefined' &&
typeof dictionary[this.#group][this.#element] !==
'undefined') {
info = dictionary[this.#group][this.#element];
}
return info;
}
/**
* Get the tag Value Representation (VR) from the dicom dictionary.
*
* @returns {string|undefined} The VR.
*/
getVrFromDictionary() {
let vr;
const info = this.getInfoFromDictionary();
if (typeof info !== 'undefined') {
vr = info[0];
}
return vr;
}
/**
* Get the tag name from the dicom dictionary.
*
* @returns {string|undefined} The VR.
*/
getNameFromDictionary() {
let name;
const info = this.getInfoFromDictionary();
if (typeof info !== 'undefined') {
name = info[2];
}
return name;
}
} // Tag class
/**
* Tag compare function.
*
* @param {Tag} a The first tag.
* @param {Tag} b The second tag.
* @returns {number} The result of the tag comparison,
* positive for b before a, negative for a before b and
* zero to keep same order.
*/
export function tagCompareFunction(a, b) {
// first by group
let res = parseInt(a.getGroup(), 16) - parseInt(b.getGroup(), 16);
if (res === 0) {
// by element if same group
res = parseInt(a.getElement(), 16) - parseInt(b.getElement(), 16);
}
return res;
}
/**
* Split a group-element key used to store DICOM elements.
*
* @param {string} key The key in form "00280102" as generated by tag::getKey.
* @returns {Tag} The DICOM tag.
*/
export function getTagFromKey(key) {
if (!key || typeof key === 'undefined') {
throw new Error('Cannot create tag with no key.');
}
if (key.length !== 8) {
throw new Error('Cannot create tag with badly sized key.');
}
return new Tag(key.substring(0, 4), key.substring(4, 8));
}
/**
* Get the TransferSyntaxUID Tag.
*
* @returns {Tag} The tag.
*/
export function getTransferSyntaxUIDTag() {
return new Tag('0002', '0010');
}
/**
* Get the FileMetaInformationGroupLength Tag.
*
* @returns {Tag} The tag.
*/
export function getFileMetaInformationGroupLengthTag() {
return new Tag('0002', '0000');
}
/**
* Is the input tag the FileMetaInformationGroupLength Tag.
*
* @param {Tag} tag The tag to test.
* @returns {boolean} True if the asked tag.
*/
export function isFileMetaInformationGroupLengthTag(tag) {
return tag.equals(getFileMetaInformationGroupLengthTag());
}
/**
* Get the Item Tag.
*
* @returns {Tag} The tag.
*/
export function getItemTag() {
return new Tag('FFFE', 'E000');
}
/**
* Is the input tag the Item Tag.
*
* @param {Tag} tag The tag to test.
* @returns {boolean} True if the asked tag.
*/
export function isItemTag(tag) {
// faster than tag.equals(getItemTag());
return tag.getKey() === 'FFFEE000';
}
/**
* Get the ItemDelimitationItem Tag.
*
* @returns {Tag} The tag.
*/
export function getItemDelimitationItemTag() {
return new Tag('FFFE', 'E00D');
}
/**
* Is the input tag the ItemDelimitationItem Tag.
*
* @param {Tag} tag The tag to test.
* @returns {boolean} True if the asked tag.
*/
export function isItemDelimitationItemTag(tag) {
// faster than tag.equals(getItemDelimitationItemTag());
return tag.getKey() === 'FFFEE00D';
}
/**
* Get the SequenceDelimitationItem Tag.
*
* @returns {Tag} The tag.
*/
export function getSequenceDelimitationItemTag() {
return new Tag('FFFE', 'E0DD');
}
/**
* Is the input tag the SequenceDelimitationItem Tag.
*
* @param {Tag} tag The tag to test.
* @returns {boolean} True if the asked tag.
*/
export function isSequenceDelimitationItemTag(tag) {
// faster than tag.equals(getSequenceDelimitationItemTag());
return tag.getKey() === 'FFFEE0DD';
}
/**
* Get the PixelData Tag.
*
* @returns {Tag} The tag.
*/
export function getPixelDataTag() {
return new Tag('7FE0', '0010');
}
/**
* Is the input tag the PixelData Tag.
*
* @param {Tag} tag The tag to test.
* @returns {boolean} True if the asked tag.
*/
export function isPixelDataTag(tag) {
// faster than tag.equals(getPixelDataTag());
return tag.getKey() === '7FE00010';
}
/**
* Get a tag from the dictionary using a tag string name.
*
* @param {string} tagName The tag string name.
* @returns {Tag|undefined} The tag object or null if not found.
*/
export function getTagFromDictionary(tagName) {
if (typeof tagName === 'undefined' || tagName === null) {
return null;
}
let group = null;
let element = null;
const dict = dictionary;
const keys0 = Object.keys(dict);
let keys1 = null;
let foundTag = false;
// search through dictionary
for (let k0 = 0, lenK0 = keys0.length; k0 < lenK0; ++k0) {
group = keys0[k0];
keys1 = Object.keys(dict[group]);
for (let k1 = 0, lenK1 = keys1.length; k1 < lenK1; ++k1) {
element = keys1[k1];
if (dict[group][element][2] === tagName) {
foundTag = true;
break;
}
}
if (foundTag) {
break;
}
}
let tag;
if (foundTag) {
tag = new Tag(group, element);
}
return tag;
}