O2 - some basic questions

[ReneMiner]

A couple of questions, hopefully someone has an answer to one or another.

I think it's possible to run a few different O2-scripts from within one tB-script - at least I hope so. All examples I've studied use only one script once.

So the first question would be: Is there any limit?

When do I have to terminate an O2-script?

And I want to know if it's possible to pass the source-string "src" also as a pointer from tB. Instead

O2_Basic src

it would be great if it were possible to pass the pointer of - for example some dictionary-bucket so I could 'feed' O2 just by passing some dictionary-keyname alike this:

O2_BasicAt StrPtr(src)
'...
O2_BasicAt Peek(Dword, Dictionary_Exists(my02DrawingDict, "mandelbrot"))
O2_BasicAt Peek(Dword, Dictionary_Exists(my02DrawingDict, "pyramids"))

O2_BasicAt Peek(Dword, Dictionary_Exists(my02CollisionDict, "face2face"))
O2_BasicAt Peek(Dword, Dictionary_Exists(my02CollisionDict, "face2point"))
'...
O2_BasicAt myStrPtr ' whereever - as long as valid stringpointer
' over the top:
O2_BasicAt myPtr, SizeInBytes ' so could use Heap or any other memory to store different scripts

is there such method? Only clue I have is thinBasic_keywords.ini which lists:

O2_ASM
O2_ASMO
O2_ASMO_FILE
O2_ASM_FILE
O2_BASIC *
O2_BUF
O2_ERROR
O2_EVAL *
O2_EXEC
O2_GET
O2_LEN
O2_LINK
O2_PREP *
O2_PUT
O2_VIEW
O2_VIEW_FILE
OXYGEN_EVAL - suppose, has been replaced with O2_Eval ?

* = no documentation found

...or would it be better to have all those example functions in the code above (drawing, collision) in one big O2-script that stays permanently "alive" as long as my tB-script runs?

[ReneMiner]

How to Peek something from memory using oxygen?

Uses "oxygen", "console"
Alias Memory_Get As Get$
Alias Long As FunctionPtr

FunctionPtr P_O2End, P_GetPtr


If Not run_O2() Then  
  PrintL "error within O2-script - can not run this"
  PrintL O2_ERROR
  WaitKey
  Stop
EndIf

Declare Sub finish() At P_O2End
Declare Function GetPtr(ByVal String, Optional ByVal Long, Optional ByVal Long) As DWord At P_GetPtr

' some testing:
Long foo = 123
DWord myPtr = GetPtr("foo")
 
PrintL "foo = " + CVL(Get$(myPtr, SizeOf(Long)))

Dim dog(123) As Byte
dog(42) = 42  

myPtr = GetPtr("dog", 42, SizeOf(Byte))
Dim olk(77) As Double
olk(33) = CVBYT(Get$(myPtr, SizeOf(Byte))) + 0.125

PrintL "olk(33) = " + CVD(Get$(GetPtr("olk", 33, SizeOf(Double)), SizeOf(Double)))

String test = "I am an important string"
myPtr = GetPtr("test")
PrintL "memory found:" + Get$(myPtr, Peek(DWord, myPtr - 4))

WaitKey
finish()

'----------------------------------------------
Function run_O2() As Boolean

Local src As String = "
  #basic
  include "thincore.inc" 
  
  Function GetPtr(Byval sName as String, Optional ByVal Index as Long, Optional Byval lSize as Long) As Dword link #P_GetPtr
    Long MainType, SubType, IsArray, DataPtr, nElements
    
    thinBasic_VariableGetInfoEX(sName, MainType, SubType, IsArray, DataPtr, nElements)
    If Index > 0 And Index <= nElements then
      If MainType = 30 Then ' string
        Function = *( DataPtr + (Index - 1) * 4) 
      Else
        Function =  DataPtr + (Index - 1) * lSize    
      EndIf
    Else
      If MainType = 30 Then ' string
         Function = *DataPtr 
      Else
        Function = DataPtr    
      EndIf
    EndIf                      
  End Function
  
  
  '------------------------------------------
  Sub finish() link #P_O2End
    terminate
  End Sub     
"


  O2_BASIC src
  If O2_ERROR <> "" Then Return FALSE
  O2_EXEC
  
  Function = TRUE
  
End Function

Edit:Script corrected - returns pointers now for any thinBasic-variable-name passed as string

[Charles Pegge]

Peeking longs and dwords can be done using the '*' pointer operator

sys dat,adr
string s="12345678"


adr=strptr s
print hex *(adr+4) 'result 38373635

For more structured peeking, use an array overlay at...

string s="12345678"


long d at (strptr s)
print hex d[2] 'result 38373635


byte b at (strptr s)
print hex b[5] 'result 35

[ReneMiner]

thanks. the idea to use an overlay came to me already but I think it's good to know some "GetDataAt-method" as *
"sys" some alias for 'Dword' to store pointers?

PS. instead of reposting the correct script now I just changed the one above

[Charles Pegge]

Sys is a signed integer that is safe to use as a pointer. When compiling 64 bit binaries, it becomes 64 bits wide, whereas long, dword and int remain 32 bit integers.

[ReneMiner]

ah, ok. there seems something not to work as I wish it would... I repost the changed script here - the line which makes it crash is commented (line-number 42) - oh what coincidence... perhaps I have made something wrong in line 61 with that * ?

Problem seems to be that the pointers of a string-array are not there where I thought they would be. Straight in a row of Dwords starting at DataPtr...

Uses "oxygen", "console"

Alias Long As FunctionPtr

FunctionPtr P_O2End, P_GetPtr


If Not run_O2() Then  
  PrintL "error within O2-script - can not run this"
  PrintL O2_ERROR
  WaitKey
  Stop
EndIf

Declare Sub finish() At P_O2End
Declare Function GetPtr(ByVal String, Optional ByVal Long, Optional ByVal Long) As DWord At P_GetPtr

' some testing:
Long foo = 123
DWord myPtr = GetPtr("foo")
 
PrintL "foo = " + CVL(Memory_Get(myPtr, SizeOf(Long)))

Dim dog(123) As Byte
dog(42) = 42  

myPtr = GetPtr("dog", 42, SizeOf(Byte))
Dim olk(77) As Double
olk(33) = CVBYT(Memory_Get(myPtr, SizeOf(Byte))) + 0.125

PrintL "olk(33) = " + CVD(Memory_Get(GetPtr("olk", 33, SizeOf(Double)), SizeOf(Double)))

String test = "I am an important string"
myPtr = GetPtr("test")
PrintL "memory found:" 
PrintL Memory_Get(myPtr, Peek(DWord, myPtr - 4))  

Dim s2(5) As String = "wrong", "wrong", "right", "wrong", "wrong"

myPtr = GetPtr("s2", 3)
PrintL "memory found:" 
' This crashes >>> PrintL Memory_Get(myPtr, Peek(DWord, myPtr - 4))

WaitKey
finish()

'----------------------------------------------
Function run_O2() As Boolean

Local src As String = "
  #basic
  include "thincore.inc" 
  
  Function GetPtr(Byval sName as String, Optional ByVal Index as Long, Optional Byval lSize as Long) As Dword link #P_GetPtr
    long MainType, SubType, IsArray, DataPtr, nElements
    
    thinBasic_VariableGetInfoEX(sName, MainType, SubType, IsArray, DataPtr, nElements)
    If Index > 0 And Index <= nElements then
      If MainType = 30 Then ' string 
    '   print "String Array Check"
        Function = *(DataPtr + (Index-1) * SizeOf(Dword))  
      Else
        Function = DataPtr + (Index - 1) * lSize    
      EndIf
    Else
      If MainType = 30 Then ' string
        Function = *DataPtr 
      Else
        Function = DataPtr    
      EndIf
    EndIf                      
  End Function
  
  
  '------------------------------------------
  Sub finish() link #P_O2End
    terminate
  End Sub     
"


  O2_BASIC src
  If O2_ERROR <> "" Then Return FALSE
  O2_EXEC
  
  Function = TRUE
  
End Function

and I still don't know how I could place some dword-array [nElements] at DataPtr - anyhow I try - error
dword sPtrs[nElements] at DataPtr - error invalid constant autodim,
the method in line 61 is not correct - I tested the result from thinBasic where I can find the Stringpointers in order as awaited and it returns wrong values.

[zlatkoAB]

anyhow I try - error

heh it looks that you trying to use wrong variable type but is not clear to me
because code is mix of oxygen & thinBasic...
Do you can use oxygen only code?

[ReneMiner]

...Do you can use oxygen only code?

Sorry - I wouldn't know how - even after downloading oxygen-basic now...
Problem is, I get on string-arrays the first elements pointer returned correct from O2 if I use just

Function = DataPtr

(line 61)

and peek the desired Index from thinBaisc side correct like

correctStrPtr = Peek(Dword, GetPtr("myvar",1) + (Index-1) * SizeOf(Dword))

but

Function = *( DataPtr + (Index-1) * SizeOf(Dword) )

does not return the expected value. Maybe I've misunderstood the use of * ?

[zlatkoAB]

Rene
I am confused with what you trying to do ...
what a heck is sizeOf(dWord) - i am not sure but i think that is not posible
get size of reserved variable type as is DWORD...

You say that you have oxygen - then try first directly in oxygen then if work
properly tray in thinBasic...
And what is not clear to you when you use Oxygen?

[ReneMiner]

I'm trying to use oxygen to manipulate thinBasic-variables.

SizeOf(Dword) should return the size of one element of variable type dword - can replace with 4 but won't help

Imagine a data-bound listview, that shall for example display a phone numbers list. The user tells the listview once: Hey, data for that list to find in an array-variable named "Phonelist", in first column display content of Phonelist().Name, in second column fill in the numbers found at PhoneList().Numbers. So no matter what user does with this array thereafter- the list "knows" always what and how much to display and where to find it - even if pointers change - when list gets drawn it "knows" what it has to fill in.So therefor I need a method to not just receive the correct pointers but also one to change dynamic strings without "loosing and orphaning" their pointers so my list becomes editable