fixed_array algo and test piece.

[hutch--]

I thought someone may like this, its a single memory allocation that stores both the array of pointer and the data stored in the same block of memory. Its plussed are that its fast to get going and maintains 4 byte alignment for each array member, its minuses are it has no bounds checking and does not store the member count.

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IF 0  ; ¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
                      Build this template with "CONSOLE ASSEMBLE AND LINK"
ENDIF ; ¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤

    include \masm32\include\masm32rt.inc

    fixed_array PROTO :DWORD,:DWORD

    .code

start:
   
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    call main
    inkey
    exit

; ¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤

main proc

    LOCAL hArr  :DWORD
    LOCAL acnt  :DWORD

    push ebx
    push esi
    push edi

    mov acnt, 8192
    mov hArr, rv(fixed_array,acnt,12)

    mov esi, hArr
    xor edi, edi
    xor ebx, ebx
  ; --------------------------------------------
  ; write ascending hex strings to array members
  ; --------------------------------------------
  @@:
    fn szCopy,uhex$(ebx),[esi]      ; write string to address in ESI
    add esi, 4                      ; set address to next pointer
    add ebx, 1                      ; increment number counter
    add edi, 1                      ; increment loop counter
    cmp edi, acnt                   ; compare it to array count
    jl @B                           ; jump back if lower

    mov esi, hArr
    xor edi, edi
  ; ---------------------------------
  ; display the ascending hex strings
  ; ---------------------------------
  @@:
    print [esi],13,10
    add esi, 4
    add edi, 1
    cmp edi, acnt
    jl @B

    invoke GlobalFree,hArr          ; deallocate memory allocated in the "fixed_array" algo

    pop edi
    pop esi
    pop ebx

    ret

main endp

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OPTION PROLOGUE:NONE
OPTION EPILOGUE:NONE

    align 16

fixed_array proc cnt:DWORD,blen:DWORD

  ; allocate a zero filled array with pointers to members
  ; at the front and member storage after the pointers
  ; array member storage aligned to a minimum of 4 bytes

  ; when the array is no longer required the memory should be
  ; de-allocated using the GlobalFree() API function call

  ; virtues (1) fast allocation of zero filled fixed array with aligned members
  ;         (2) single memory allocation for both pointers and data storage
  ; vices   (1) no bounds check to member length
  ;         (2) array count is not stored in the array

  ; the pointer array and the data storage is layed out with this logic

  ;  ----------------------------------------------------------------
  ;  | ptr1 | ptr2 | ptr3 |    data1    |    data2    |    data3    |  etc ....
  ;  ----------------------------------------------------------------

  ; each pointer occupies 4 bytes, each data storage is
  ; the nominated size rounded up to a 4 byte boundary.

    push esi
    push edi

    mov edi, [esp+16]

    add edi, 3                      ; align blen up to next 4 byte boundary
    and edi, -4

    mov esi, [esp+12]
    add esi, esi                    ; mul cnt by 4
    add esi, esi                    ; store pointer array length in ESI
   
    mov ecx, [esp+12]               ; calculate length required
    mov eax, edi
    imul ecx                        ; multiply cnt by blen to get data storage size
    add eax, esi                    ; add pointer array length

    push eax
    push GMEM_FIXED or GMEM_ZEROINIT    ; allocate fixed memory
    call GlobalAlloc

    mov edx, eax                    ; store memory address in EDX
    mov ecx, eax
    add ecx, esi                    ; add the length of the pointer array to ECX

    mov esi, [esp+12]

  align 4
  @@:
  REPEAT 3
    mov [eax], ecx                  ; write each data storage member to pointer array
    add eax, 4                      ; next pointer
    add ecx, edi                    ; add blen for next data storage
    sub esi, 1
    jz @F
  ENDM

    mov [eax], ecx                  ; write each data storage member to pointer array
    add eax, 4                      ; next pointer
    add ecx, edi                    ; add blen for next data storage
    sub esi, 1
    jnz @B

  @@:

    mov eax, edx                    ; return the memory start address

    pop edi
    pop esi

    ret 8

fixed_array endp

OPTION PROLOGUE:PrologueDef
OPTION EPILOGUE:EpilogueDef

; ¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤

end start


[frktons]

Thanks Steve.

I really like these examples of yours.
They always make me learn something interesting.

Frank