use readall, compatibility on 32bit systems

blockdiff_dump

@@ -5,21 +5,40 @@ use strict;
 use warnings;
 
 use Digest::MD5 qw(md5);
+use Errno;
 
 # file descriptors:
 #   0 < data file
 #   1 > patch data
 #   5 < old digest (optional)
 #   6 > new digest
 
+sub readall {
+    my ($fh, $buf, $len) = @_;
+    my $off = 0;
+    while ($off != $len) {
+	my $r = sysread($fh, $$buf, $len - $off, $off);
+	if ($r == 0) {
+	    return $off;
+	} elsif ($r == -1) {
+	    if ($! != Errno::EAGAIN) {
+		return $off || -1;
+	    }
+	} else {
+	    $off += $r;
+	}
+    }
+    return $off;
+}
+
 my $blocksize = $ENV{BLOCKSIZE} || 16384;
 
 # open files
 open my $new_digest_fp, '>&=', 6
     or die "cloud not open digest data output (fd:6):$!";
 my $orig_digest_fp;
 if (open $orig_digest_fp, '<&=', 5) {
-    sysread($orig_digest_fp, my $bsbin, 4) == 4
+    readall($orig_digest_fp, \my $bsbin, 4) == 4
         or die "old digest data is corrupt";
     $blocksize = unpack 'V', $bsbin;
 } else {
@@ -33,20 +52,20 @@ syswrite($new_digest_fp, pack('V', $blocksize)) == 4
     or die "failed to write digest data (fd:6):$!";
 
 for (my $offset = 0;
-     (my $rlen = sysread(STDIN, my $block, $blocksize)) != 0;
+     (my $rlen = readall(\*STDIN, \my $block, $blocksize)) != 0;
      $offset += $rlen) {
     die "failed to read data:$!"
         if $rlen == -1;
     my $digest = md5($block);
     my $orig_digest;
     if ($orig_digest_fp
-            && (sysread($orig_digest_fp, $orig_digest, length $digest)
+            && (readall($orig_digest_fp, \$orig_digest, length $digest)
                     == length $digest)
                 && $digest eq $orig_digest) {
         # no need to dump data
     } else {
         # dump data
-        (syswrite(STDOUT, pack('V2', $offset & 0xffffffff, $offset >> 32)) == 8
+        (syswrite(STDOUT, pack('V2', $offset % 2**32, $offset / 2**32)) == 8
              and syswrite(STDOUT, $block) == $rlen)
             or die "failed to write patch data (fd:1):$!";
     }

blockdiff_merge

@@ -44,7 +44,7 @@ while (readall(\*STDIN, \my $offbin, 8) == 8) {
         if $rlen <= 0;
     my $offset = do {
         my @o = unpack 'V2', $offbin;
-        $o[0] + $o[1] * (1<<32);
+        $o[0] + $o[1] * 2**32;
     };
     warn "writing at:$offset, size:$rlen" if $DEBUG;
     sysseek $fh, $offset, 0