[Tutor] using while loop for read process memory

[Michael C]

Sorry Alan, Steve, everyone

Can you take a look of this please?



Here is my question about the memory:

So I have a base address of a chunk of memory from it's size, from
VirtualQueryEx
(if you dont use windows, it's ok, it's not about how u get these values,
because I think
the base concept is the same)

start = mbi.BaseAddress
finish = mbi.RegionSize

So at this time, I use while and this is how it looks like

while index < finish:
   # access the memory here:
   while memory function( index)
   # then index += 1, for the inner loop

## this line complete the outer while loop
index += mbi.RegionSize


so Why did I put down index += 1  ?

That's because what I think about the memory looks like this
(short)(int)(double)(int)(int)(int)(double)  and so on,

since I can't predict which address is the beginning of a double, the only
way
to deal with that is to use increment by 1.

Now, from what I have been reading, it seems there is a better way to do it,
for instance, a for loop.

for(start,finish, 8)

why 8? because double begins at exact 0 or multiple of 8 bytes, right?

On Thu, Oct 12, 2017 at 6:54 PM, Michael C <mysecretrobotfactory at gmail.com>
wrote:

> Here is my question about the memory:
>
> So I have a base address of a chunk of memory from it's size, from
> VirtualQueryEx
> (if you dont use windows, it's ok, it's not about how u get these values,
> because I think
> the base concept is the same)
>
> start = mbi.BaseAddress
> finish = mbi.RegionSize
>
> So at this time, I use while and this is how it looks like
>
> while index < finish:
>    # access the memory here:
>    while memory function( index)
>    # then index += 1, for the inner loop
>
> ## this line complete the outer while loop
> index += mbi.RegionSize
>
>
> so Why did I put down index += 1  ?
>
> That's because what I think about the memory looks like this
> (short)(int)(double)(int)(int)(int)(double)  and so on,
>
> since I can't predict which address is the beginning of a double, the only
> way
> to deal with that is to use increment by 1.
>
> Now, from what I have been reading, it seems there is a better way to do
> it,
> for instance, a for loop.
>
> for(start,finish, 8)
>
> why 8? because double begins at exact 0 or multiple of 8 bytes, right?
>
>
>
> On Sun, Oct 8, 2017 at 4:46 PM, Alan Gauld via Tutor <tutor at python.org>
> wrote:
>
>> On 08/10/17 20:18, Michael C wrote:
>> > This is the red part
>> >   index = current_address
>> >         end = current_address + mbi.RegionSize
>> >
>> >         while index < end:
>> >             if ReadProcessMemory(Process, index, ctypes.byref(buffer), \
>> >                                  ctypes.sizeof(buffer),
>> > ctypes.byref(nread)):
>> >                 ## value comparison to be implemented.
>> >                 pass
>> >             else:
>> >                     raise ctypes.WinError(ctypes.get_last_error())
>> >
>> >             index += 1
>>
>> I haven't been following this closely so may be way off here,
>> but does this mean you are incrementing the memory address
>> by 1? If so you are only increasing the pointer by 1 byte
>> but you are, presumably, reading multiple bytes at a time
>> (the size of the buffer presumably).
>>
>> Do you perhaps need to treat the buffer as a byte array
>> and use something like the struct module to decode it?
>> (assuming you know what you are reading...?)
>>
>> But I may be way off, I'm just going on a cursory look.
>>
>> --
>> Alan G
>> Author of the Learn to Program web site
>> http://www.alan-g.me.uk/
>> http://www.amazon.com/author/alan_gauld
>> Follow my photo-blog on Flickr at:
>> http://www.flickr.com/photos/alangauldphotos
>>
>>
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>
>