#! perl -slw
use strict;
use Benchmark qw[timethese cmpthese];

our $s = q["string (12" or 1 foot or 1') into 6" MySQL varchar"];
our $t = q["string (12 or 1 foot or 1') into 6 MySQL varchar"];
our ($sub,$zwa);

my $tests = {
zwax0		=> q[ $zwa=$t; $zwa =~ s/(?<=.)"(?=.)/""/g; ],
subx0		=> q[ $sub=$t; substr($sub, 1, -1) =~ s/"/""/g; ],
zwax1		=> q[ $zwa=$s; $zwa =~ s/(?<=.)"(?=.)/""/g; ],
subx1		=> q[ $sub=$s; substr($sub, 1, -1) =~ s/"/""/g; ],
zwax4		=> q[ $zwa=$s x4; $zwa =~ s/(?<=.)"(?=.)/""/g; ],
subx4		=> q[ $sub=$s x4; substr($sub, 1, -1) =~ s/"/""/g; ],
zwax10		=> q[ $zwa=$s x10; $zwa =~ s/(?<=.)"(?=.)/""/g; ],
subx10		=> q[ $sub=$s x10; substr($sub, 1, -1) =~ s/"/""/g; ],
};

timethese( 2, $tests );
print 'Results same' if $zwa eq $sub;

cmpthese( 100000, $tests );
__DATA__
Results same
Benchmark: timing 100000 iterations of subx0, subx1, subx10, subx4, zwax0, zwax1, zwax10, zwax4 ...

     subx0:  1 wallclock secs ( 0.60 usr +  0.00 sys =  0.60 CPU) @ 166112.96/s (n=100000)
     subx1:  7 wallclock secs ( 5.71 usr +  0.00 sys =  5.71 CPU) @ 17516.20/s (n=100000)
    subx10: 25 wallclock secs (24.95 usr +  0.00 sys = 24.95 CPU) @ 4008.66/s (n=100000)
     subx4: 12 wallclock secs (12.77 usr +  0.00 sys = 12.77 CPU) @ 7832.08/s (n=100000)
     zwax0:  2 wallclock secs ( 1.34 usr +  0.00 sys =  1.34 CPU) @ 74515.65/s (n=100000)
     zwax1:  5 wallclock secs ( 4.64 usr +  0.00 sys =  4.64 CPU) @ 21570.32/s (n=100000)
    zwax10: 31 wallclock secs (30.02 usr +  0.00 sys = 30.02 CPU) @ 3330.67/s (n=100000)
     zwax4: 15 wallclock secs (13.69 usr +  0.00 sys = 13.69 CPU) @ 7304.60/s (n=100000)

           Rate zwax10 subx10  zwax4  subx4  subx1  zwax1  zwax0  subx0
zwax10   3331/s     --   -17%   -54%   -57%   -81%   -85%   -96%   -98%
subx10   4009/s    20%     --   -45%   -49%   -77%   -81%   -95%   -98%
zwax4    7305/s   119%    82%     --    -7%   -58%   -66%   -90%   -96%
subx4    7832/s   135%    95%     7%     --   -55%   -64%   -89%   -95%
subx1   17516/s   426%   337%   140%   124%     --   -19%   -76%   -89%
zwax1   21570/s   548%   438%   195%   175%    23%     --   -71%   -87%
zwax0   74516/s  2137%  1759%   920%   851%   325%   245%     --   -55%
subx0  166113/s  4887%  4044%  2174%  2021%   848%   670%   123%     --