Re: NSData dataWithBytes:Length: all 00
Chase Meadors wrote:
I have the following code, which is a category on NSData. It is always
called on especially designated NSData objects with four bytes.
- (NSData *)resolve {
unsigned char *buf = [self bytes];
const unsigned char *newBytes[4] = { (buf[3] - 0x08), buf[2],
buf[1], buf[0] };
You've declared an array of pointers to bytes, not an array of bytes.
Take out that asterisk.
for (int i = 0; i < 4; i ++) {
NSLog(@"%02X", newBytes[i]);
}
NSData *ret = [NSData dataWithBytes:newBytes length:4];
return ret;
}
The for statement logging the individual bytes is exactly as expected.
However, the new data object ret is <>. I couldn't really find
an answer on google, probably because it's a simple answer I'm missing,
so I asked here. Thanks for any help.
___
--
James W. Walker, Innoventive Software LLC
Re: NSData dataWithBytes:Length: all 00
On Tue, Jul 21, 2009 at 3:38 PM, Chase Meadors wrote:
> I have the following code, which is a category on NSData. It is always
> called on especially designated NSData objects with four bytes.
>
> - (NSData *)resolve {
>
> unsigned char *buf = [self bytes];
>
> const unsigned char *newBytes[4] = { (buf[3] - 0x08), buf[2], buf[1],
> buf[0] };
When I compile this line, I get all kinds of warnings. Do you? And if
you do, why are you ignoring them? The warning helps point to what is
wrong.
You've allocated an array of four POINTERS, when what you want is an
array of four UNSIGNED CHARACTERS. So it should be:
const unsigned char newBytes[4] = { (buf[3] - 0x08), buf[2], buf[1], buf[0] };
> for (int i = 0; i < 4; i ++) {
> NSLog(@"%02X", newBytes[i]);
> }
>
> NSData *ret = [NSData dataWithBytes:newBytes length:4];
> return ret;
>
> }
___
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NSData dataWithBytes:Length: all 00
I have the following code, which is a category on NSData. It is always
called on especially designated NSData objects with four bytes.
- (NSData *)resolve {
unsigned char *buf = [self bytes];
const unsigned char *newBytes[4] = { (buf[3] - 0x08), buf[2], buf[1],
buf[0] };
for (int i = 0; i < 4; i ++) {
NSLog(@"%02X", newBytes[i]);
}
NSData *ret = [NSData dataWithBytes:newBytes length:4];
return ret;
}
The for statement logging the individual bytes is exactly as expected.
However, the new data object ret is <>. I couldn't really find
an answer on google, probably because it's a simple answer I'm
missing, so I asked here. Thanks for any help.
___
Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)
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Contact the moderators at cocoa-dev-admins(at)lists.apple.com
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This email sent to arch...@mail-archive.com
