Delphi Programming to convert 66-bit value (Hex) to Decimal

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Large numbers in Pascal (Delphi)

I am trying to convert a 66bit value to decimal.

I note that the largest data type in delphi in int64 which can only allow 64bit data. example of delphi code for such conversion is

result := strtoInt64('FFFFABCDEFF123456');

Please advice how to use delphi to this without returning out of range error.

Muda

Why not simply use strings to represent your arbitrary-length base-N integers? — Andreas Rejbrand, May 31 '11 at 15:06
voted to close. MPARITH seems like the right solution here too. — Warren P, May 31 '11 at 16:31
Pedantic point: Hex digits encode 4 binary bits per digit. So you can have a 64 bit, or a 68 bit hex value, but not a 66 bit value. — Warren P, May 31 '11 at 17:07
I think I'll skip Delphi 64-bits, and wait for Delphi 66-bit. — Wouter van Nifterick, May 31 '11 at 17:08
do you just want to convert to a string or do you want to perform other operations? — David Heffernan, May 31 '11 at 18:07
@warren your pedantry is unfounded. A 66 bit value can be written in hex in no more than 17 hex digits. — David Heffernan, May 31 '11 at 18:09
So someone would write a function that handles 68 bit values, and then, naturally 66 bit values would work too. So there's no such thing as "founded" and "unfounded" pedantry, there is merely pedantry, or not pedantry. As I have already been self-deprecating I see no purpose in your correction. — Warren P, Jun 01 '11 at 18:06

score 4 · Answer 1 · edited May 23 '17 at 12:10

4

Decimal in Delphi is called currency it uses 8 bytes = 64 bits.

You'll have to create your own type, see this article: http://www.delphi3000.com/articles/article_3772.asp
It describes how to create a 128bit integer.

Here's a bignum lib for Delphi: http://cc.embarcadero.com/item/27789
See also this question: Large numbers in Pascal (Delphi)

edited May 23 '17 at 12:10

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answered May 31 '11 at 15:04

Johan

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where does currency come in to integer arithmetic? – David Heffernan May 31 '11 at 18:04
@david, it's really an integer in disguise, and the OP asked about decimal, currency is the closed match to decimal. Compare decimal in database lingo. – Johan May 31 '11 at 18:25
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in this instance I understood OP to be using decimal to mean a base 10 integer. – David Heffernan May 31 '11 at 18:50

score 1 · Answer 2 · answered May 31 '11 at 17:31

If you can afford having some rounding errors, you can use the Extended type. That's an easy solution. I remember reading somewhere that it won't be supported in 64bit Delphi anymore though, so I personally wouldn't use it if it can be avoided.

Anyway, do you really want to do calculations on your number? Are you sure you don't just want to have an array (of bytes for example)? If that is the case, you should look at HexToBin().

Documentation: http://docwiki.embarcadero.com/VCL/en/Classes.HexToBin

Example where you can see it in use: http://docwiki.embarcadero.com/CodeExamples/en/HexEncoding_(Delphi)

Delphi Programming to convert 66-bit value (Hex) to Decimal

2 Answers2