I'm trying to read in just the first part of a .png file to peek
at it's width and height without loading in the whole file. I'm
using FreeImage for reading the whole file but since it doesn't
have a function to let me peek at the image size before loading
it all in I'm rolling my own.
I've gotten as a far as reading in the first 16 bytes which
includes an 8 byte signature, then the length and type of the
first chunk:
struct Header {
ubyte[8] signature;
uint length;
char[4] type;
}
union Un {
Header h;
ubyte[16] u;
}
auto f = File(path, "r");
foreach (ubyte[] buffer; f.byChunk(16)){
Un fff;
fff.u = buffer[0..16];
writeln(fff.h);
break;
}
It prints out:
Header([137, 80, 78, 71, 13, 10, 26, 10], 218103808, "IHDR")
The signature is correct, the type is correct, but the value I
get for length should be 13, not 218103808. So I'm guessing my
ubytes are in the wrong order in the uint... how should I put
them around the correct way so that my code won't break on
another machine with different endianness?
