Refactor Storable::read_magic to avoid 4 arg substr.

This makes it fractionally shorter, and restores all compatibility with 5.004

diff --git a/dist/Storable/Storable.pm b/dist/Storable/Storable.pm
index e762a3b..8368928 100644 (file)
--- a/dist/Storable/Storable.pm
+++ b/dist/Storable/Storable.pm
@@ -151,14 +151,14 @@ sub read_magic {
        $net_order = 0;
     }
     else {
-       $net_order = ord(substr($buf, 0, 1, ""));
-       my $major = $net_order >> 1;
+       $buf =~ s/(.)//s;
+       my $major = (ord $1) >> 1;
        return undef if $major > 4; # sanity (assuming we never go that high)
        $info{major} = $major;
-       $net_order &= 0x01;
+       $net_order = (ord $1) & 0x01;
        if ($major > 1) {
-           return undef unless length($buf);
-           my $minor = ord(substr($buf, 0, 1, ""));
+           return undef unless $buf =~ s/(.)//s;
+           my $minor = ord $1;
            $info{minor} = $minor;
            $info{version} = "$major.$minor";
            $info{version_nv} = sprintf "%d.%03d", $major, $minor;
@@ -171,17 +171,16 @@ sub read_magic {
     $info{netorder} = $net_order;
 
     unless ($net_order) {
-       return undef unless length($buf);
-       my $len = ord(substr($buf, 0, 1, ""));
+       return undef unless $buf =~ s/(.)//s;
+       my $len = ord $1;
        return undef unless length($buf) >= $len;
        return undef unless $len == 4 || $len == 8;  # sanity
-       $info{byteorder} = substr($buf, 0, $len, "");
-       $info{intsize} = ord(substr($buf, 0, 1, ""));
-       $info{longsize} = ord(substr($buf, 0, 1, ""));
-       $info{ptrsize} = ord(substr($buf, 0, 1, ""));
+       @info{qw(byteorder intsize longsize ptrsize)}
+           = unpack "a${len}CCC", $buf;
+       (substr $buf, 0, $len + 3) = '';
        if ($info{version_nv} >= 2.002) {
-           return undef unless length($buf);
-           $info{nvsize} = ord(substr($buf, 0, 1, ""));
+           return undef unless $buf =~ s/(.)//s;
+           $info{nvsize} = ord $1;
        }
     }
     $info{hdrsize} = $buflen - length($buf);