Re: get() and read() function from fstream
On Feb 5, 12:41 pm, ZikO <ze...@op.pl> wrote:
James Kanze wrote:
. char temp[5] = {0,0,0,0};
It's funny. Just missed last 0, the strange think is the
compiler did not warn that,
Not really. The standard says if there is an initializer,
anything left over without initialization is zero initialized.
So you can write things like:
int array[ 1000 ] = {} ;
and get the entire array initialized. And I certainly don't
want to have to write out 1000 0's just to avoid a warning.
(G++ does warn, and it gets on my nerves.)
however,
char temp[5];
works perfectly.
Only if it's static, or you do something to force the last byte
to 0. (Some compilers do zero the memory. Others do so only in
debugging mode.)
[...]
From what little information I've found, you need to do
something like:
unsigned long
readWaveInt(
std::istream& source )
{
unsigned long result = 0 ;
for ( int shift = 0 ; shift != 32 ; shift += 8 ) {
result |= source.get() << shift ;
}
return result ;
}
I like this idea. Probably will help me avoid many problems.
In the end, it's the only thing that works portably.
Since wave files were designed by Microsoft, for Intel based
processors, just reading the raw bytes into the int will work
under Windows. It won't work on the machine I usually work on,
nor on a lot of other machines.
If this code outputs "This is not a wave file", either
you've not successfully opened the file, or the first four
bytes aren't "RIFF" (or you're on a platform where the
native character encoding isn't an extension of ASCII, but
that's highly unlikely---I don't think you'd be reading wave
files on a mainframe).
The problem is very trivial ^^. strcmp() returns 0 if strings
are equal. Unfortunately, 0 means false in if() statement
which I didnt know. I was sue strcmp would return bool
true/false. This is another reason to stop using old <cstring>
I saw that. It's funny I didn't spot it myself, but in my
experience, the only people who use char[] and <string.h> are
ex-C hackers, who generally get these sort of things right, so I
didn't look too carefully.
--
James Kanze