Replace seek/read with mmap.

1 files changed, 12 insertions, 19 deletions

diff --git a/cgi-bin/find.cgi b/cgi-bin/find.cgi
index 4091c7a..9a4bd34 100644
--- a/cgi-bin/find.cgi
+++ b/cgi-bin/find.cgi
@@ -2,6 +2,7 @@
 
 use strict;
 use warnings;
+use Sys::Mmap;
 use Storable qw(retrieve);
 use Encode qw(decode_utf8 encode_utf8);
 use URI::Escape qw(uri_unescape);
@@ -75,6 +76,11 @@ if (-f $sa_file && -f $cp_file) {
     binmode($fh_sa);
     binmode($fh_cp);
 
+    # Memory map files
+    my ($sa_mapped, $cp_mapped);
+    mmap($sa_mapped, 0, PROT_READ, MAP_SHARED, $fh_sa) or die "Could not map SA: $!";
+    mmap($cp_mapped, 0, PROT_READ, MAP_SHARED, $fh_cp) or die "Could not map Corpus: $!";
+
     my $file_map = retrieve($map_file);
     my $total_suffixes = (-s $sa_file) / 4;
 
@@ -84,12 +90,8 @@ if (-f $sa_file && -f $cp_file) {
 
     while ($low <= $high) {
         my $mid = int(($low + $high) / 2);
-        seek($fh_sa, $mid * 4, 0);
-        read($fh_sa, my $bin_off, 4);
-        my $off = unpack("L", $bin_off);
-        seek($fh_cp, $off, 0);
-        read($fh_cp, my $text, $query_len);
-        
+        my $off = unpack("L", substr($sa_mapped, $mid * 4, 4));
+        my $text = substr($cp_mapped, $off, $query_len);
         my $cmp = $text cmp $query;
         if ($cmp >= 0) {
             $first_hit = $mid if $cmp == 0;
@@ -107,12 +109,8 @@ if (-f $sa_file && -f $cp_file) {
         # Find right boundary
         while ($low <= $high) {
             my $mid = int(($low + $high) / 2);
-            seek($fh_sa, $mid * 4, 0);
-            read($fh_sa, my $bin_off, 4);
-            my $off = unpack("L", $bin_off);
-            seek($fh_cp, $off, 0);
-            read($fh_cp, my $text, $query_len);
-            
+            my $off = unpack("L", substr($sa_mapped, $mid * 4, 4));
+            my $text = substr($cp_mapped, $off, $query_len);
             if (($text cmp $query) <= 0) {
                 $last_hit = $mid if $text eq $query;
                 $low = $mid + 1;
@@ -123,10 +121,7 @@ if (-f $sa_file && -f $cp_file) {
 
         my %seen;
         for my $i ($first_hit .. $last_hit) {
-            seek($fh_sa, $i * 4, 0);
-            read($fh_sa, my $bin_off, 4);
-            my $offset = unpack("L", $bin_off);
-
+            my $offset = unpack("L", substr($sa_mapped, $i * 4, 4));
             foreach my $m (@$file_map) {
                 if ($offset >= $m->{start} && $offset < $m->{end}) {
                     if (!$seen{$m->{path}}++) {
@@ -134,9 +129,7 @@ if (-f $sa_file && -f $cp_file) {
                         my $snip_start = ($offset - 30 < $m->{start}) ? $m->{start} : $offset - 30;
                         my $max_len = $m->{end} - $snip_start;
                         my $read_len = ($max_len > 120) ? 120 : $max_len;
-                        seek($fh_cp, $snip_start, 0);
-                        read($fh_cp, my $raw_snip, $read_len);
-                        
+                        my $raw_snip = substr($cp_mapped, $snip_start, $read_len);
                         my $snippet = decode_utf8($raw_snip, Encode::FB_QUIET) // $raw_snip;
                         $snippet =~ s/\s+/ /g; # Normalize whitespace