Benchmark: timing 1000000 iterations of regex1, regex2, substr...
    regex1:  2 wallclock secs ( 2.76 usr +  0.00 sys =  2.76 CPU) @ 362318.84/s (n=1000000)
    regex2:  2 wallclock secs ( 2.44 usr +  0.00 sys =  2.44 CPU) @ 409836.07/s (n=1000000)
    substr:  1 wallclock secs ( 0.86 usr +  0.00 sys =  0.86 CPU) @ 1162790.70/s (n=1000000)

This is perl, v5.8.2 built for i686-linux