• Sean L. Palmer (18/18) Nov 19 2001 Often in C I want the compiler to generate a simple hash of a string or
• Walter (8/26) Nov 19 2001 While the compiler could do such, it does not fold constants computed by

"Sean L. Palmer" <spalmer iname.com> writes:

Often in C I want the compiler to generate a simple hash of a string or
something at compile time... this is very troublesome as the compiler hardly
ever does it all at compile time.  For instance:

Will the D compiler (with optimizations enabled) generate the same code for
this snippet:

{
  static const char[] str = "123";
  int checksum = 0;
  for (int i = 0; i < str.length; ++i)
    checksum += str[i];
}

as it would make for this snippet? :

{
  int checksum = '1' + '2' + '3';
}

It should, since everything involved in the first snippet is compile-time
constants.

Sean

"Walter" <walter digitalmars.com> writes:

While the compiler could do such, it does not fold constants computed by
loops. If you need them computed at compile time, what I'd do is write a
program that generated the strings and their hashes, wrote out a module, and
then compile that module.

"Sean L. Palmer" <spalmer iname.com> wrote in message
news:9tainn$1gb7$1 digitaldaemon.com...
 Often in C I want the compiler to generate a simple hash of a string or
 something at compile time... this is very troublesome as the compiler

hardly
 ever does it all at compile time.  For instance:

 Will the D compiler (with optimizations enabled) generate the same code

for
 this snippet:

 {
   static const char[] str = "123";
   int checksum = 0;
   for (int i = 0; i < str.length; ++i)
     checksum += str[i];
 }

 as it would make for this snippet? :

 {
   int checksum = '1' + '2' + '3';
 }

 It should, since everything involved in the first snippet is compile-time
 constants.

 Sean