Hi All,
I'm having a problem reading numbers from some raw data I need to
read. The data encodes numbers in little-endian format. I am defining
a category on NSData to accomplish this.
- (NSNumber *)interpretAsSingleNumber {
NSMutableString *hexString = [NSMutableString string];
unsigned char *bytes = [self bytes];
for (int i = [self length] - 1; i > -1; i --) {
[hexString appendFormat:@"%02X", bytes[i]];
}
[hexString insertString:@"0x" atIndex:0];
unsigned int result;
[[NSScanner scannerWithString:hexString] scanHexInt:&result];
return [NSNumber numberWithInt:result];
}
The problem here is that NSScanner can only scan 32-bit integers. The
numbers in the data I'm trying to read can be either 8 or 16 bits. I'm
given the information as to exactly what range in the data represents
a certain number, so I could see whether it is one or two bytes long,
but how can I accomplish getting an int from this data that IS the
length of the data.
In other words, I might read one piece of data that is one byte: <FE>.
I would want this to be read as -2. However, the current method would
make the string "0xFE", then scan it to 0x000000FE, which is
completely different.
I might then read a piece of data that is two bytes: <01 80> (little
endian). This needs to be read as -32,767. However, the current method
gives 0x00008001.
Any hints as to how I might accomplish this? Thanks!
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