Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win

x
?
Solved

Pointers inside pointers

Posted on 2000-02-16
3
Medium Priority
?
161 Views
Last Modified: 2010-04-04
 I have an app that uses an untyped pointer to a memory block up to >120MB. I want to divide it up into sub-blocks using other pointers, typed or untyped, which start at an arbitrary starting address (within the range of the original block), and have arbitrary sizes, (each of which will be less than the size of the original block).
  Damned if I know the solution.

Yours faithfully,
  HorridMan.
 
0
Comment
Question by:HorridMan
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
3 Comments
 
LVL 12

Expert Comment

by:rwilson032697
ID: 2530174
You can do it something like this:

var
  MainPtr : Pointer;
  HalfwayPtr : POinter;

GetMem(MainPtr, 120 * 1024 * 1024); // 120 Mb
HalfwayPtr := Pointer(Integer(MainPtr) + 60 * 1024 * 1024);

HalfwayPtr now points to the byte just after halfway (64Mb after MainPtr).

You can divide it any way you like...

Cheers,

Raymond.
0
 
LVL 12

Accepted Solution

by:
rwilson032697 earned 200 total points
ID: 2530176
Oops, meant that to be an answer
0
 
LVL 3

Expert Comment

by:sburck
ID: 2530179
For each memory block, assign a Tlist, which is an array of pointers.  Even better is a TStringList, where you can use the string portion of the list to put either a description of what your sub-pointer is pointing to, or a text version of the offset value (base pointer - sub pointer), so that if you need to save the memory block to disk, you can save the List as a text file, and then reload it and resurrect the pointers in the list from the text values.
0

Featured Post

What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In this tutorial I will show you how to use the Windows Speech API in Delphi. I will only cover basic functions such as text to speech and controlling the speed of the speech. SAPI Installation First you need to install the SAPI type library, th…
Creating an auto free TStringList The TStringList is a basic and frequently used object in Delphi. On many occasions, you may want to create a temporary list, process some items in the list and be done with the list. In such cases, you have to…
Are you ready to place your question in front of subject-matter experts for more timely responses? With the release of Priority Question, Premium Members, Team Accounts and Qualified Experts can now identify the emergent level of their issue, signal…
This lesson discusses how to use a Mainform + Subforms in Microsoft Access to find and enter data for payments on orders. The sample data comes from a custom shop that builds and sells movable storage structures that are delivered to your property. …
Suggested Courses

604 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question