How to get two bytes form a buffer?

[cylin]

Dear all,

From now on, I just can get a byte twice.
Then decode this two bytes.

for example,
buffer is a unsigned char array.

value=(*buffer)<<8;
value+=*(buffer+1);

Is there any fast way to do that?

Regards,
cylin.

 

[Sebastian \Psy\ Messerschmidt]

Dear all,

From now on, I just can get a byte twice.
Then decode this two bytes.

for example,
buffer is a unsigned char array.

value=(*buffer)<<8;
value+=*(buffer+1);

thats how I did it.
but alternatives could be:

memcpy(&value,buffer,2);

or some fancy casting:

value = *((unsigned int*)&(buffer))
respective; value=*(unsigned int*)(buffer);


but I'm not sure if uint has two bytes size, see it for yourself


hth psy

 

[Sean Kenwrick]

"Sebastian "Psy" Messerschmidt"

Dear all,

From now on, I just can get a byte twice.
Then decode this two bytes.

for example,
buffer is a unsigned char array.

value=(*buffer)<<8;
value+=*(buffer+1);

thats how I did it.
but alternatives could be:

memcpy(&value,buffer,2);

or some fancy casting:

value = *((unsigned int*)&(buffer))
respective; value=*(unsigned int*)(buffer);


but I'm not sure if uint has two bytes size, see it for yourself


hth psy

value=*(short *) buffer;

Sean

 

[Thomas Matthews]

Dear all,

From now on, I just can get a byte twice.
Then decode this two bytes.

for example,
buffer is a unsigned char array.

value=(*buffer)<<8;
value+=*(buffer+1);

thats how I did it.
but alternatives could be:

memcpy(&value,buffer,2);

or some fancy casting:

value = *((unsigned int*)&(buffer))
respective; value=*(unsigned int*)(buffer);


but I'm not sure if uint has two bytes size, see it for yourself


hth psy

if (sizeof(short) == 2)
{

value=*(short *) buffer; }


Sean

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[Jack Klein]

Dear all,

From now on, I just can get a byte twice.
Then decode this two bytes.

for example,
buffer is a unsigned char array.

value=(*buffer)<<8;
value+=*(buffer+1);


thats how I did it.
but alternatives could be:

memcpy(&value,buffer,2);

or some fancy casting:

value = *((unsigned int*)&(buffer))
respective; value=*(unsigned int*)(buffer);


but I'm not sure if uint has two bytes size, see it for yourself


hth psy

if (sizeof(short) == 2)

....and it the short is big-endian.

{
}

--
Jack Klein
Home: http://JK-Technology.Com
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[cylin]

But my buffer is 4k bytes length,
and there are lot of such values in this buffer.
It's not only in *(buffer) and *(buffer+1) but also everywhere.

memcpy only can handle the first n bytes in the buffer.

Thanks all to reply.

Regards,
cylin.

"Jack Klein" <[email protected]>
???????:[email protected]...

Dear all,

From now on, I just can get a byte twice.
Then decode this two bytes.

for example,
buffer is a unsigned char array.

value=(*buffer)<<8;
value+=*(buffer+1);


thats how I did it.
but alternatives could be:

memcpy(&value,buffer,2);

or some fancy casting:

value = *((unsigned int*)&(buffer))
respective; value=*(unsigned int*)(buffer);


but I'm not sure if uint has two bytes size, see it for yourself


hth psy

if (sizeof(short) == 2)

....and it the short is big-endian.

{
}

--
Jack Klein
Home: http://JK-Technology.Com
FAQs for
comp.lang.c http://www.eskimo.com/~scs/C-faq/top.html
comp.lang.c++ http://www.parashift.com/c++-faq-lite/
alt.comp.lang.learn.c-c++ ftp://snurse-l.org/pub/acllc-c++/faq