Cool, thanks for the testing.
On Thu, Jul 2, 2009 at 9:19 AM, Lorenz Quack<d...@amberfisharts.com> wrote: > Ok, so here goes my analysis of the failures in ColorTypeTest: > In src/color.c line 1435 (and some following lines) we bit shift each color > component and stuff them > in an unsigned long. Maybe this should be into a uint32 instead? > I think the problem arises when we bitshift the r value and r is >127 > My guess is that C converts r to an integer during the bitshift and not to > an unsigned int so > if r > 127 the integer (r is shifted by 24) overflows and becomes negative > (note that the internal > bit representation of the int has not changed) but when we store this > (negative) integer into a > long it remains negative so the first bits get filled up with "1"s. > I see different solutions to this and cant decide which is the _correct_ one > so I'll just present them > instead: > 1) don't save the combined color in an unsigned long. use a unsigned int > instead. > This should work as long as r, g, b, a are UInt8 and aren't shifted more > than 24 > 2) explicitly cast the r value to be unsigned > 3) cast the r value to be (unsigned) long > > furthermore I think in the we should compare tmp to UINT_MAX in line 1438, > 1476 and 1492. > even though I haven't put much thought into this at least then the tests > don't fail. >
