DCMTree_Utils::UIDGenerator Class Reference

Class to generate unique ids, valid to be used in a DICOM environment. More...

#include <DCMTree_UIDGenerator.h>

Static Public Member Functions
static void	initialize (const std::string &iso_root_uid=std::string(), const std::string &replacementMac=std::string())
	Function to be called exactly once before any other function is called.
static void	initialize (std::string iso_root_uid, std::string systemtype, std::string softwaretype, std::string replacementMac=std::string())
	Overload to keep old code working, systemtype and softwaretype are not used any more.
static std::string	uid ()
	create a new uid
static bool	isInitialized ()
	return true if class is initialized
static void	setMaxCounterPerSecond (int value)
	This method allows to overwrite how many uids can be created per second.
static int	getMaxCounterPerSecond ()
	Get the used max counter per seconds.
static std::string	hashUID (const std::string &uid)
	Get a uid that is basically a hash of the argument uid (with an appropriate prefix).

Detailed Description

Class to generate unique ids, valid to be used in a DICOM environment.

The created UIDs have the following form: 'iso_root_uid'.'mac of the system'.'process id'.'seconds since epoch'.'counter'

The uids are unique even in a multi-threaded environment The mac of the system has to be unique of course.

Known problem of the implementation: If an application is started multiple times in the same second AND gets the same process id again, it is possible to get the same UID again.

The implementation allows the time of the computer to be changed to the past and will adapt the time to not reuse timestamps that were already used.

Definition at line 40 of file DCMTree_UIDGenerator.h.

Member Function Documentation

getMaxCounterPerSecond()

static int DCMTree_Utils::UIDGenerator::getMaxCounterPerSecond ( )

static

Get the used max counter per seconds.

hashUID()

static std::string DCMTree_Utils::UIDGenerator::hashUID ( const std::string & uid )

static

Get a uid that is basically a hash of the argument uid (with an appropriate prefix).

The same

The input can be basically be any string, since SHA1 is applied on the bytes, so you can also append/prepend a "salt" value to the input uid if required.

The prefix is the iso_root_uid given in the initialize function (or DCMTree_MeVis_UidPrefix if omitted), plus DCMTree_MeVis_UidHashedUid from the file DCMTree_MeVisDicomTags.h.

The result is filled up up to the allowed limit of 64 characters with digits from the hash value of input uid. For the default prefix this represents about 112 bits from the hash value.

initialize() [1/2]

static void DCMTree_Utils::UIDGenerator::initialize ( const std::string & iso_root_uid = std::string(), const std::string & replacementMac = std::string() )

static

Function to be called exactly once before any other function is called.

This function sets some predefined values, especially the _prefix part of the UIDs up to the 'process id'

Parameters

iso_root_uid	specifies the iso root id without a trailing dot. If the string is empty, the DCMTree_MeVis_UidPrefix uid is used.
replacementMac	optional parameter. If a replacementMac is provided it will be used in the _prefix; otherwise the MAC adress is determined with the getMac() function. A replacementMac is especially useful if the getMac() cannot guarantee to return a unique MAC which could be the case if VMWare is installed (which installs its own virtual adapters)

initialize() [2/2]

static void DCMTree_Utils::UIDGenerator::initialize ( std::string iso_root_uid, std::string systemtype, std::string softwaretype, std::string replacementMac = std::string() )

static

Overload to keep old code working, systemtype and softwaretype are not used any more.

isInitialized()

static bool DCMTree_Utils::UIDGenerator::isInitialized ( )

static

return true if class is initialized

setMaxCounterPerSecond()

static void DCMTree_Utils::UIDGenerator::setMaxCounterPerSecond ( int value )

static

This method allows to overwrite how many uids can be created per second.

This should mainly be used for testing purposes. Also resets counter to 0.

uid()

static std::string DCMTree_Utils::UIDGenerator::uid ( )

static

create a new uid

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The documentation for this class was generated from the following file:

• MeVis/Foundation/Sources/DicomTree/MLDicomTree/DCMTree_UIDGenerator.h