How to create a string buffer?

[RHL]

Hello all! :)
I would know how to you create a string buffer? for store any value :)
I have said about malloc, but I see complicated :/

in runtime :P
thanks :B

[dedndave]

for reasonably small buffers

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        .DATA?

Buffer  db 128 dup(?)
that method is good if you are going to continually re-use the buffer or if you need global scope

there are also numerous ways to allocate a temporary buffer on the stack
for example, inside a PROC...

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SomeFunction PROC

        LOCAL   Buffer[128]:BYTE
;
;

for larger buffers, there are LocalAlloc, GlobalAlloc, HeapAlloc, and VirtualAlloc functions
each function has a little different characteristics - pick the one that best suits your needs

for most buffers less than a few hundred Mbytes, i generally use HeapAlloc - it is simple and fast

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        INVOKE  GetProcessHeap
        mov     hHeap,eax
        INVOKE  HeapAlloc,eax,HEAP_ZERO_MEMORY,NumberOfBytes
        mov     hBlock,eax
;
;hBlock = address of heap block
;
;when done using the buffer, you must free it
;
        INVOKE  HeapFree,hHeap,NULL,hBlock

if you do not require that it be zero'ed, replace the "HEAP_ZERO_MEMORY" with "NULL"

[RHL]

thanks dedndave, the truth that I will use it in inline asm, and for that reason did not want to make a call to the API, for that be fast :B

[dedndave]

how large of a buffer do you need ?
is it temporary ?

[RHL]

I have the situation that, I cannot use the stack,API ( if posible)
The size I need to is 80-160 bytes and return the pointer of buffer , but this I can do, only I need a method :)

[dedndave]

well - if you cannot use the stack, then just put it in the .DATA? (or _BSS) section

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        .DATA?

Buffer  db 160 dup(?)

        .CODE

        mov     eax,offset Buffer

[RHL]

Sorry, but edit my first post x3
I need in runtime : P

[dedndave]

ok
you can't use a global allocation
can't use the stack
use HeapAlloc

you can initialize the hHeap value at the beginning of the program

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        INVOKE  GetProcessHeap
        mov     hHeap,eax

then use HeapAlloc and HeapFree inline

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        INVOKE  HeapAlloc,hHeap,HEAP_ZERO_MEMORY,NumberOfBytes
        mov     hBlock,eax
;
;
;
        INVOKE  HeapFree,hHeap,NULL,hBlock
it's quite fast, especially for a small buffer
even faster if you do not need it to be zero'ed

[RHL]

Ok very nice, dedndave thanks!  :U