Verification of only valid ASCII Characters in Input Buffer 1

[jbs]

Given a null-terminated char array what is the most efficient method to validate that each byte contains a valid ASCII character (i.e. A-Z, 0-9, CR, LF, ..).

Curious as to opinions here...

thanks,

 

[cdraycott]

jbs,

Not sure how efficient but you could loop for all characters in the array and check for

__isascii

which returns a true for ascii char and false if not.

Hope this helps

 

[jbs]

Actually that sounds great. I hadn't heard of __isascii before and will try it out. Seems like that will require less lines of code than what I was thinking of....thanks for the time./j

 

[cpjust]

isascii() returns true for all characters between 0x00 & 0x7F (which includes a lot of non-printable characters).
You might be better off using isprint() which only returns true for chars 0x20 to 0x7E.

 

[cdraycott]

cpjust,

jbs mentioned that he wanted to see CR and LF so that is why i suggested __isascii

 

[cpjust]

Oops, missed that part. But it still depends on what kind of data he's trying to validate. If it's text data, then isascii() will let a lot of junk through. In that case you'd need to use both isprint() and isspace().

if ( isprint( c ) || isspace( c ) )
{
   ...
}