Array Descriptor

[DDastardly71]

Using ONLY the PEEK function, how would I be able to extract the information of the array descriptor and print each elements. This procedure should be able to print the elements of the array regardless if its 1, 2, or more dimensions.

Example:

DIM Array1$r(1 to 5)
Array1$r(1) = "orange"
Array1$r(2) = "apples"
Array1$r(3) = "pear"
Array1$r(4) = "pineapple"
Array1$r(5) = "orange"

Call PrintArray ( Array1$() )

DIM Array2$r(1 to 5, 1 to 25)
Array2$r(1, 1) = "orange"
.
.
.
Array2$r(5, 25) = "orange"

Call PrintArray ( Array2$() )


Sub PrintArray (Array$())

'-- print the elements regardless what the dimension of the array is

End Sub

[Anonymous]

Not quite sure why you would want to do that but you will probably want to use SADD(Array$(1)) to find the first memory address of the given element and then use PEEK a statement in a loop to get the string.

Code: Select all

DECLARE SUB PrintString (Addr AS INTEGER, NextAddr AS INTEGER)

DIM Array(3) AS STRING

Array(1) = "String 1"
Array(2) = "String 2"

CALL PrintString(SADD(dunno(1)), SADD(dunno(2)))

SUB PrintString (Addr AS INTEGER, NextAddr AS INTEGER)
    Position = Addr
    NewString$ = ""
    DO
        IF NextAddr = Position THEN EXIT DO
        NewString$ = NewString$ + CHR$(PEEK(Position))
        Position = Position + 1
        IF PEEK(Position) = 34 THEN EXIT DO
        IF PEEK(Position) = 46 THEN EXIT DO
        IF PEEK(Position) = 249 THEN EXIT DO
        IF PEEK(Position) < 32 THEN EXIT DO
        IF NextAddr = Position THEN EXIT DO
    LOOP
    PRINT NewString$
END SUB

If you are just trying to access arrays in a sub you could just use DIM SHARED

[DDastardly71]

Thanks for that reply but that won't work.

Even with fixed length string array you still have to set the correct segment before you can peek at the memory.

I know this is unorthodox way of doing it when I could easily just pass the array into the procedure. I wrote a user interface function in PDS for DOS where it will load a custom screen file that includes the screen image and the field definitions.

In this function I'm using a user define type field record and if there are notes fields, i would assign the segment/address of that array and assign it to the user defined element so that I only pass one record to the function.

Code: Select all

dim Fld(25) as FieldInfo
dim notes$(1 to 15)

Fld(5).NotesSegment = SSEG(notes$(1))
Fld(5).NotesAddress = SADD(notes$(1))

DO
  FormEdit Fld()
    .
    .
LOOP

I have no problem displaying the elements of a variable string array using NEAR string but FAR string is a bit more complex.

I'm using the Ethan Winer example in his book "BASIC Techniques & Utilities" where he uses the following array descriptor..i just cant seem to make it work.

Code: Select all

Offset  Size        Description
-------  -----        ----------------------------------------------------
  00     02   Address where array data begins

  00     02   Segment where that address resides

  04     02   Far heap descriptor, pointer

  06     02   Far heap descriptor, block size 

  08     01   Number of dimensions in the array

  09     01   Array type and storage method:
                Bit 0 set = far array
                Bit 1 set = huge (/ah) array
                Bit 6 set = static array
                Bit 7 set = string array

  0A     02   Adjusted Offset 

  0C     02   Length in bytes of each element

  0E     02   Number of elements in the last
              dimension (UBOUND - LBOUND + 1)

  10     02   First element number in that 
              dimension (LBOUND)

  12     02   Number of elements in the second
              from last dimension

  14     02   First element number in that
              dimension

    .    02   Repeat number of elements and
              first element number as necessary,
    .    02   through the first dimension