I mentioned a possible speed-up when 'unrolling' the regexp. Here's a small benchmark backing up that claim:

#!/usr/bin/perl

use strict;
use warnings;

use Benchmark 'cmpthese';

our $re1 = qr /"([^"\\]|\\.)*"/;
our $re2 = qr /"([^"\\]+|\\.)*"/;
our $re3 = qr /"[^"\\]*(\\.[^"\\]*)*"/;

chomp (our @data = <DATA>);
    
cmpthese -5  => {
    plain    => '/$re1/ for @data',
    unroll1  => '/$re2/ for @data',
    unroll2  => '/$re3/ for @data',
};

__DATA__
A "red" fish
A "red" fish and a "blue" fish
The book is called "A 5\" dwarf"
A backslash ("\\") and a forwardslash ("/")
No delimiters here at all.
[download]

The results:

           Rate   plain unroll1 unroll2
plain   50621/s      --    -20%    -38%
unroll1 63260/s     25%      --    -22%
unroll2 81507/s     61%     29%      --
[download]

Abigail