How remove the warning "large integer implicitly truncated" for sqlite/unicode support?

Question

I use the solution of http://ioannis.mpsounds.net/2007/12/19/sqlite-native-unicode-like-support/ for my POS App for the iPhone, and work great.

However, as say in the comments:

For instance, sqlite_unicode.c line 1861 contains integral constants greater than 0xffff but are declared as unsigned short. I wonder how I should cope with that.

I'm fixing all the warnings in my project and this is the last one. The code is this:

static unsigned short unicode_unacc_data198[] = { 0x8B8A, 0x8D08, 0x8F38, 0x9072, 0x9199, 0x9276, 0x967C, 0x96E3, 0x9756, 0x97DB, 0x97FF, 0x980B, 0x983B, 0x9B12, 0x9F9C, 0x2284A, 0x22844, 0x233D5, 0x3B9D, 0x4018, 0x4039, 0x25249, 0x25CD0, 0x27ED3, 0x9F43, 0x9F8E, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF };

I don't know about this hex stuff, so what to do? I don't get a error, not know if this could cause one in the future...

Answer 1

Yes, 0x2284A is indeed larger than 0xFFFF, which is the largest a 16-bit unsigned integer can contain.(*)

This is a lookup table for mapping characters with diacritical marks to basic unaccented characters. For some reason, a few mappings are defined that point to characters outside the ‘Basic Multilingual Plane’ of Unicode characters that fit in 16 bits.

U+2284A and the others above are highly obscure extended Chinese characters. I'm not sure why a character in the BMP would refer to such a character as its base unaccented version. Maybe it's an error in the source data used to generate the tables, or maybe it's just another weird quirk of the Chinese writing system. Either way, it's extremely unlikely you'll ever need that mapping. So just change all the five-digit hex codes in this array to be 0xFFFF instead (which seems to be what the code is using to signify ‘no mapping’).

(*: in theory a short could be more than 16 bits, but in reality it isn't going to be. If it were it looks like this code would totally fall over anyway, as it's freely mixing short with u16 pointers.)