Signed Size

Int (i.e. signed) as type for *.size()

• Because mixing signed and unsigned integer (e.g. “signed - unsigned”) and even calculating “unsigned - unsigned” is difficult to handle.
  • Problem in C/C++: aUInt - 1 >= 0 is always true (even if aUInt is 0)
• When working with sizes, calculating the difference is common; Then you are limited to Int/SSize/PtrDiff (i.e. signed integer) anyway.
• Anyone who needs more than 2GB of data in a single “byte array”, should please use a 64 bit platform.
• For bounds checking, the two comparisons x >= 0 and x < width may very well be reduced to a single UInt(x) < width by the compiler in an optimization step.
• Then types Size and SSize/PtrDiff are not necessary anymore, so two/three types less.
  • We simply use Int instead.
  • UInt is used in rare cases (i.e. hardware registers, masks, flags), surely not for sizes.
• See also Going Native 2012, Day 2, Interactive Panel: Ask Us Anything
  • 42:41 - 45:28
    • Bjarne Stroustrup and Herb Sutter recommend using signed integer.
  • 1:02:51 - 1:03:14
    • Herb Sutter and Chandler Carruth about unsigned size_t in the C++ STL containers: “They are wrong”, “We are sorry”