Posts tagged BSD

TZDB 1.6, oh man!

It seems that changes keep piling up. I decided it is time to get these announcements out of my blog and into their own discussion group. No more TZDB release related news will be written on this blog.

Anyway, TZDB 1.6 1.7 introduces a better Delphi/FreePascal version detection and should work on Delphi 6 and FreePascal 2.0. Let me emphasize: should work ! (tested on Delphi 7). It’s a real pain to keep a project compatible with so many version of Delphi and FreePascal even for such a small project. Also, the embedded time zone database was upgraded to the latest version.

Grab the latest version here, and view the latest changes here.

TZDB 1.5, now with FreePascal support.

TZDB 1.5 was released today. If you are wondering where did 1.3 and 1.4 go … well, those were transitional releases. This version of TZDB is selectively dependent on Delphi features giving you the opportunity to actually compile TZDB on more versions of Delphi (should be compilable starting with 7th version) and even FreePascal 2.4.0 (I tested both the 32bit and 64bit versions).

Note: TZDB does not employ the “least common denominator” technique. If a certain feature is present in a Delphi or FreePascal version — it is used.

Grab the latest version here, and view the latest changes here.

TZDB 1.2, now with Delphi 2009 and 2010 support

TZDB 1.2 was released today. You can grab it here, and view the latest changes here.

The most notable changes are:

  • Latest tz database (2010m). Also removed a few less then useless time zones from the official distribution.
  • Bug fixes, and a new testing module that actually highlighted those bugs in the first place.
  • Support for Delphi 2009 and 2010. If compiled for these versions, TZDB provides some features of Delphi XE’s TTimeZone class (for API compatibility).

TZDB — new location

I have moved the TZDB to a new Google code project. There are two wiki pages explaining some basics and a download with the latest TZDB.


DeHL 0.8.3


I will be brief as usual — version 0.8.3 of DeHL is out. The downloads can be found on this page and changelog on this page. This release “fixes” some of the things I wanted fixed for a long time, so it seemed this is the perfect moment for this to happen. A new unit is introduced — DeHL.Tuples — which brings seven generic Tuple<…> types. I have also finished moving away from Integer and Cardinal to NativeInt and NativeUInt through all DeHL.

Breaking changes are:

  1. DeHL.Converter was renamed to DeHL.Conversion. This name change was done mostly to reflect the nature of the unit. It does not contain one simple class anymore. Now there is a fully featured conversion system.
  2. TBinaryTree<T> (in DeHL.Collections.BinaryTree) is no more. It was written way in the beginnings of the project and was buggy, incomplete and utterly useless.
  3. And the most visible and breaking of all changes is the removal of TKeyValuePair<TKey, TValue> (in DeHL.KeyValuePair). It was replaced with KVPair<TKey, TValue> (in DeHL.Tuples). The easiet way to get over this change is to find and replace all TKeyValuePair instances with KVPair and all DeHL.KeyValuePair uses with DeHL.Tuples.

Now, obviously an example using Tuples:

  SysUtils, DeHL.Tuples;

{ If you are lazy and do not wish to declare a new record type
  to be used as result. Use Tuple<..> do to that. }
function GiveMeSomeData(): Tuple<String, Integer, Integer>;
  { ... Do some processing ... }
  Result := Tuple.Create('Some data', 100, -99);

  LResult: Tuple<String, Integer, Integer>;
  { Obtain the result }
  LResult := GiveMeSomeData();

  { And write the results to the console }
  with LResult do
    WriteLn('Something was done with result: ', Value1, ', ', 
      Value2, ', ', Value3, '!');

The new conversion engine handles most of the possible conversions and also allows registering custom ones:


  { Declare some type that cannot be converted into integer directly.
    We're making up an "int". }
  TRecordInt = packed record
    FValueAsString: string;
    FSign: Boolean;

    constructor Create(const AInt: Integer);

{ TRecordInt }

constructor TRecordInt.Create(const AInt: Integer);
  { Decompose an int }
  FValueAsString := IntToStr(Abs(AInt));
  FSign := (AInt < 0);

  LInputList: TList<TRecordInt>;
  S: String;
  I: Integer;
  { Create a list of TRecordInt }
  LInputList := TList<TRecordInt>.Create();

  { Fill it with some random values (positive and negative) }
  for I := 0 to 10 do
    LInputList.Add(TRecordInt.Create(Random(MaxInt) - (MaxInt div 2)));

  { Now comes the interesting part ... register a custom converter
    from TRecordInt to Integer }
  TConverter<TRecordInt, Integer>.Method :=
    function(const AIn: TRecordInt; out AOut: Integer): Boolean
      { Convert the TRecordInt back to an integer }
      Result := TryStrToInt(AIn.FValueAsString, AOut);
      if Result and AIn.FSign then
        AOut := -AOut;

  { Now print the values to the console. Convert them from TRecordInt to
    Integer then to String }
  for S in LInputList.Op.Cast<Integer>.Op.Cast<String> do

TConverter is also smart enough to figure out that “type MyInt = type Integer” is actually equivalent to Integer. If there is no explicit custom conversion method registered for it the converter for the standard type will be selected is possible. In the worst case, when TConverter cannot convert directly between the given types, it falls back to Variant conversion (using TType.TryConvertToVariant and TType.TryConvertFromVariant) which all types registered with DeHL’s type system, if possible, should implement.

Well, that’s all for today,
Have Fun!

DeHL 0.7 is up


After a few months of no releases, I finally decided to throw one out — so here it is, DeHL 0.7. This release is adding three more collection, new types and fixes some internal limitations of the library.

For the people that never tried DeHL – it is a collection of types and classes that use (and even abuse) the newer generation Delphi compilers into obtaining some features that were impossible in the past releases.

The newly added collection classes are:

  • TPriorityQueue<TPriority, TValue> which implements the priority queue.
  • TDistinctMultiMap<TKey, TValue> that is similar to TMultiMap but uses sets instead of lists to store the values. This ensures that all values for a key are distinct. As usual 2 more flavors of this class exist – TSortedDistinctMultiMap<TKey, TValue> and TDoubleSortedDistinctMultiMap<TKey, TValue>.
  • TBidiMap<TKey, TValue> implements the concept of bi-directional map in which there is a bi-directional relation between keys and values (both are actually keys). TSortedBidiMap<TKey, TValue> and TDoubleSortedBidiMap<TKey, TValue> are the other two flavors of this class.
  • TStringList<T> and TWideStringList<T> collections are actually generic variants of the normal TStringList and TWideStringList (which are used as base classes).

Other enhancements include:

  • Singleton<T> class. Which can be used to access the same instance of a class across all application.
  • TWideCharSet (this was inspired on other implementations out there but use dynamic arrays to save memory and speed in certain circumstances).
  • TType speed and reliability increases.
  • A global files for all $IFDEF needs.
  • Types such as Nullable<T>, Scoped<T> and TKeyValuePair<TKey, TValue> now have their own type classes.

For a full list of changes see the changelog.

This release also makes use of some new improvements of the Delphi 2010 compiler (such as class constructors, or some fixed problems in the generics handling) which makes some features unavailable on Delphi 2009. I plan to keep Delphi 2009 supported for as long as possible, but many new planned features are not going to be available on that platform.

Have Fun!

Arbitrary precision integers

I have decided to extract the BigInteger and BigCardinal data types from DeHL and make a bundle with them separately. Someone may be interested in these types and not so much in DeHL. The attached unit should compile on D2007 and D2006 (not sure for earlier versions).

What can you learn:

  • Shows you how to develop “value types” with predictable states in Delphi using records, operator overloading and “managed types” (in this case a dynamic array).
  • How to develop a proxy class that plugs your type into the Variant manager.
  • Demonstrates how to use operator overloading (and I have overloaded a lot of operators there).
  • The reliance of the predictable state of the managed types to check whether a value is initialized or not.
  • Shows how the use an in-place BCD-izer algorithm that helps converting a big number into a string. It took me a quite some time and tweaking to come up with it so it may be interesting to someone.

Where can you use it:

  • Everywhere, except FOR loops of course.
  • The types are transparent and should be used the exact way as normal integer do.
  • Use it in applications that require very big integer values.
  • … you’ll come up with something else.

A small example of course:

  a, b: BigInteger;
  a := StrToBigInteger('8942374632463284632623837643468589' + 
  b := a * a;

… or as variants …

  a, b: Variant;
  a := StrToBigInteger('8942374632463284632623837643468589' + 
  b := a * a;

Final note: the code is tested since it’s a part of DeHL (in which I try to test everything I can) so it’s safe to use. BUT if you find any bugs, please drop me a line.

Finally! The code! You can find it here: Arbitrary precision Integers (1703)