break up data

Forum Attachments

break up data

calccrypto 12 Dec 2009 21:27

does anyone know of a way to break up data into blocks of arbitrary size, according to the input size and output size? i want to do it so that it can be done on the calc as well, so it cant be something wild. my main problem is that the input size could be 0 on the computer and 1 on the calc and the output size could be really big, or vice versa

---

Visit Calccrypto for info on crypto
KC2ZOF

Re: break up data

Sleight 13 Dec 2009 19:29

What exactly are you trying to do? I suppose it could be done, but you would need to explain exactly what you are trying to do. Are trying to involve a computer?

---

"Reality is that which, when you stop believing in it, doesn't go away."
-Philip K. Dick

Re: break up data

calccrypto 13 Dec 2009 21:13

im working on my hashing program on the calc and im writing it on the computer as well

on the calc, the max input i can use is 256 characters because my expansion function expands it to over the limit of the calc after 300 chars. its also very slow. i want to break it up and expand it to get the data to some size, operate on it, and then add it or something to a previous value

example:

say the calc can hold a 100000 char string and still run the program

my program will expand it to say, 1000000 chars, which the calc wont be able to handle

i want to break up the data so i run say 125 (or some arbitrary number generated in some way) chars at a time so that the calc will only have to save 99875 [without part of string being used] + (125 + 125) [part of string being worked on + the expanded part]

---

Visit Calccrypto for info on crypto
KC2ZOF

Last edited on 13 Dec 2009 21:15 by calccrypto Show more

Re: break up data

Sleight 13 Dec 2009 23:37

You seemed to have figured it out already…

Combine the sub( command with adding strings and the ability to archive/unarchive them, and you shouldn't have any problems.

---

"Reality is that which, when you stop believing in it, doesn't go away."
-Philip K. Dick

Re: break up data

calccrypto 14 Dec 2009 00:53

its not the commands i need help with. its how i should break and expand the data

---

Visit Calccrypto for info on crypto
KC2ZOF

Re: break up data

Sleight 15 Dec 2009 04:44

How do you intend to input the data? Just have the user type it in? If so, here is the basic outline of how I think it should be done: (In psuedocode)

Prompt length of input string
Repeat until length of input string is received
Input next 100 chars
Expand 100 chars
Add all previously archived strings to new one
Archive new longer string.
End

I don't see what the issue is…

---

"Reality is that which, when you stop believing in it, doesn't go away."
-Philip K. Dick

Re: break up data

calccrypto 15 Dec 2009 21:52

im just doing

input "Data:",str1

on the calc

my problem is that if i input a large amount of data, the commands will have to run through all of it every cycle. i wrote the algorithm to use lists to store data. if the list gets too big, it takes forever to run

if dim(list) = 999, and i do cumSum, mod, etc, it will have to run through each index in the list, which takes forever. on the other hand, if i break it up into blocks of 16 and operate on each of the blocks, it will run more times, but faster

is this really confusing?
my basic question is:

given a,b (integers ≥ 0, well, a might be 0, but b shouldn't be 0) and a string (str1) of arbitrary size, give me a way to 
split the string up in a somewhat random way that will allow the program to run efficiently

f(a,b)→c

if i did the math right:

sub(str1,1,c
sub(str1,c+1,c
sub(str1,2c+1,c

etc.

---

Visit Calccrypto for info on crypto
KC2ZOF

Last edited on 16 Dec 2009 04:13 by calccrypto Show more