#!/usr/bin/perl

use strict;
use warnings;

use File::Temp ();

#
# Unit tests of _downcopy function
#
# _downcopy($self, $data, $pos, $len)
# Write $data into a block of length $len at position $pos,
# moving everything in the block forwards to make room.
# Instead of writing the last length($data) bytes from the block
# (because there isn't room for them any longer) return them.

# Make a temp dir under the OS's normal temp directory for creating
# test files in. By using the OS's temp dir rather than the current
# directory, we increase the chances that the tests are run on a tmpfs
# file system or similar. This becomes important when the current
# directory is on a very slow USB drive for example, as this test file
# does lots of file creating, modifying and deleting.

my $tempdir = File::Temp::tempdir("Tie-File-XXXXXX",
                                    TMPDIR => 1, CLEANUP => 1);

print "1..718\n";

my $N = 1;
use Tie::File;
print "ok $N\n"; $N++;

$: = Tie::File::_default_recsep();

my @subtests = qw(x <x x> x><x <x> <x><x x><x> <x><x> <x><x><x> 0);
print "ok $N\n"; $N++;

# (3-144) These were generated by 'gentests.pl' to cover all possible cases
# (I hope)
# Legend:
#         x: data is entirely contained within one block
#        x>: data runs from the middle to the end of the block
#        <x: data runs from the start to the middle of the block
#       <x>: data occupies precisely one block
#      x><x: data overlaps one block boundary
#     <x><x: data runs from the start of one block into the middle of the next
#     x><x>: data runs from the middle of one block to the end of the next
#    <x><x>: data occupies two blocks exactly
# <x><x><x>: data occupies three blocks exactly
#         0: data is null
#
# For each possible alignment of the old and new data, we investigate
# up to three situations: old data is shorter, old and new data are the
# same length, and new data is shorter.
#
# try($pos, $old, $new) means to run a test where the data starts at 
# position $pos, the old data has length $old,
# and the new data has length $new.
try( 9659,  6635,  6691);  # old=x        , new=x        ; old < new
try( 8605,  2394,  2394);  # old=x        , new=x        ; old = new
try( 9768,  1361,   664);  # old=x        , new=x        ; old > new
try( 9955,  6429,  6429);  # old=x>       , new=x        ; old = new
try(10550,  5834,  4123);  # old=x>       , new=x        ; old > new
try(14580,  6158,   851);  # old=x><x     , new=x        ; old > new
try(13442, 11134,  1572);  # old=x><x>    , new=x        ; old > new
try( 8394,     0,  5742);  # old=0        , new=x        ; old < new
try( 8192,  2819,  6738);  # old=<x       , new=<x       ; old < new
try( 8192,   514,   514);  # old=<x       , new=<x       ; old = new
try( 8192,  2196,   858);  # old=<x       , new=<x       ; old > new
try( 8192,  8192,  8192);  # old=<x>      , new=<x       ; old = new
try( 8192,  8192,  1290);  # old=<x>      , new=<x       ; old > new
try( 8192, 10575,  6644);  # old=<x><x    , new=<x       ; old > new
try( 8192, 16384,  5616);  # old=<x><x>   , new=<x       ; old > new
try( 8192, 24576,  6253);  # old=<x><x><x>, new=<x       ; old > new
try( 8192,     0,  6870);  # old=0        , new=<x       ; old < new
try( 8478,  6259,  7906);  # old=x        , new=x>       ; old < new
try( 9965,  6419,  6419);  # old=x>       , new=x>       ; old = new
try(16059,  6102,   325);  # old=x><x     , new=x>       ; old > new
try( 9503, 15073,  6881);  # old=x><x>    , new=x>       ; old > new
try( 9759,     0,  6625);  # old=0        , new=x>       ; old < new
try( 8525,  2081,  8534);  # old=x        , new=x><x     ; old < new
try(15550,   834,  1428);  # old=x>       , new=x><x     ; old < new
try(14966,  1668,  3479);  # old=x><x     , new=x><x     ; old < new
try(16316,  1605,  1605);  # old=x><x     , new=x><x     ; old = new
try(16093,  4074,   993);  # old=x><x     , new=x><x     ; old > new
try(14739,  9837,  9837);  # old=x><x>    , new=x><x     ; old = new
try(14071, 10505,  7344);  # old=x><x>    , new=x><x     ; old > new
try(12602,     0,  8354);  # old=0        , new=x><x     ; old < new
try( 8192,  2767,  8192);  # old=<x       , new=<x>      ; old < new
try( 8192,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
try( 8192, 14817,  8192);  # old=<x><x    , new=<x>      ; old > new
try( 8192, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
try( 8192, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
try( 8192,     0,  8192);  # old=0        , new=<x>      ; old < new
try( 8192,  6532, 10882);  # old=<x       , new=<x><x    ; old < new
try( 8192,  8192, 16044);  # old=<x>      , new=<x><x    ; old < new
try( 8192,  9555, 11020);  # old=<x><x    , new=<x><x    ; old < new
try( 8192,  9001,  9001);  # old=<x><x    , new=<x><x    ; old = new
try( 8192, 11760, 10274);  # old=<x><x    , new=<x><x    ; old > new
try( 8192, 16384, 10781);  # old=<x><x>   , new=<x><x    ; old > new
try( 8192, 24576,  9284);  # old=<x><x><x>, new=<x><x    ; old > new
try( 8192,     0, 12488);  # old=0        , new=<x><x    ; old < new
try( 8222,  6385, 16354);  # old=x        , new=x><x>    ; old < new
try(13500,  2884, 11076);  # old=x>       , new=x><x>    ; old < new
try(14069,  4334, 10507);  # old=x><x     , new=x><x>    ; old < new
try(14761,  9815,  9815);  # old=x><x>    , new=x><x>    ; old = new
try(10469,     0, 14107);  # old=0        , new=x><x>    ; old < new
try( 8192,  4181, 16384);  # old=<x       , new=<x><x>   ; old < new
try( 8192,  8192, 16384);  # old=<x>      , new=<x><x>   ; old < new
try( 8192, 12087, 16384);  # old=<x><x    , new=<x><x>   ; old < new
try( 8192, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
try( 8192, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
try( 8192,     0, 16384);  # old=0        , new=<x><x>   ; old < new
try( 8192,  4968, 24576);  # old=<x       , new=<x><x><x>; old < new
try( 8192,  8192, 24576);  # old=<x>      , new=<x><x><x>; old < new
try( 8192, 14163, 24576);  # old=<x><x    , new=<x><x><x>; old < new
try( 8192, 16384, 24576);  # old=<x><x>   , new=<x><x><x>; old < new
try( 8192, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
try( 8192,     0, 24576);  # old=0        , new=<x><x><x>; old < new
try( 8771,   776,     0);  # old=x        , new=0        ; old > new
try( 8192,  2813,     0);  # old=<x       , new=0        ; old > new
try(13945,  2439,     0);  # old=x>       , new=0        ; old > new
try(14493,  6090,     0);  # old=x><x     , new=0        ; old > new
try( 8192,  8192,     0);  # old=<x>      , new=0        ; old > new
try( 8192, 10030,     0);  # old=<x><x    , new=0        ; old > new
try(14983,  9593,     0);  # old=x><x>    , new=0        ; old > new
try( 8192, 16384,     0);  # old=<x><x>   , new=0        ; old > new
try( 8192, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
try(10489,     0,     0);  # old=0        , new=0        ; old = new

# (142-223)
# These tests all take place at the start of the file
try(    0,   771,  1593);  # old=<x       , new=<x       ; old < new
try(    0,  4868,  4868);  # old=<x       , new=<x       ; old = new
try(    0,   147,   118);  # old=<x       , new=<x       ; old > new
try(    0,  8192,  8192);  # old=<x>      , new=<x       ; old = new
try(    0,  8192,  4574);  # old=<x>      , new=<x       ; old > new
try(    0, 11891,  1917);  # old=<x><x    , new=<x       ; old > new
try(    0, 16384,  5155);  # old=<x><x>   , new=<x       ; old > new
try(    0, 24576,  2953);  # old=<x><x><x>, new=<x       ; old > new
try(    0,     0,  1317);  # old=0        , new=<x       ; old < new
try(    0,  5609,  8192);  # old=<x       , new=<x>      ; old < new
try(    0,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
try(    0, 11083,  8192);  # old=<x><x    , new=<x>      ; old > new
try(    0, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
try(    0, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
try(    0,     0,  8192);  # old=0        , new=<x>      ; old < new
try(    0,  6265,  9991);  # old=<x       , new=<x><x    ; old < new
try(    0,  8192, 16119);  # old=<x>      , new=<x><x    ; old < new
try(    0, 10218, 11888);  # old=<x><x    , new=<x><x    ; old < new
try(    0, 14126, 14126);  # old=<x><x    , new=<x><x    ; old = new
try(    0, 12002,  9034);  # old=<x><x    , new=<x><x    ; old > new
try(    0, 16384, 13258);  # old=<x><x>   , new=<x><x    ; old > new
try(    0, 24576, 14367);  # old=<x><x><x>, new=<x><x    ; old > new
try(    0,     0, 10881);  # old=0        , new=<x><x    ; old < new
try(    0,  6448, 16384);  # old=<x       , new=<x><x>   ; old < new
try(    0,  8192, 16384);  # old=<x>      , new=<x><x>   ; old < new
try(    0, 15082, 16384);  # old=<x><x    , new=<x><x>   ; old < new
try(    0, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
try(    0, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
try(    0,     0, 16384);  # old=0        , new=<x><x>   ; old < new
try(    0,  2421, 24576);  # old=<x       , new=<x><x><x>; old < new
try(    0,  8192, 24576);  # old=<x>      , new=<x><x><x>; old < new
try(    0, 11655, 24576);  # old=<x><x    , new=<x><x><x>; old < new
try(    0, 16384, 24576);  # old=<x><x>   , new=<x><x><x>; old < new
try(    0, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
try(    0,     0, 24576);  # old=0        , new=<x><x><x>; old < new
try(    0,  6530,     0);  # old=<x       , new=0        ; old > new
try(    0,  8192,     0);  # old=<x>      , new=0        ; old > new
try(    0, 14707,     0);  # old=<x><x    , new=0        ; old > new
try(    0, 16384,     0);  # old=<x><x>   , new=0        ; old > new
try(    0, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
try(    0,     0,     0);  # old=0        , new=0        ; old = new

# (224-277)
# These tests all take place at the end of the file
my $FLEN = 40960;  # Force the file to be exactly 40960 bytes long
try(32768,  8192,  8192);  # old=<x>      , new=<x       ; old = new
try(32768,  8192,  4026);  # old=<x>      , new=<x       ; old > new
try(24576, 16384,  1917);  # old=<x><x>   , new=<x       ; old > new
try(16384, 24576,  3818);  # old=<x><x><x>, new=<x       ; old > new
try(40960,     0,  2779);  # old=0        , new=<x       ; old < new
try(32768,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
try(24576, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
try(16384, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
try(40960,     0,  8192);  # old=0        , new=<x>      ; old < new
try(32768,  8192, 10724);  # old=<x>      , new=<x><x    ; old < new
try(24576, 16384, 12221);  # old=<x><x>   , new=<x><x    ; old > new
try(16384, 24576, 15030);  # old=<x><x><x>, new=<x><x    ; old > new
try(40960,     0, 11752);  # old=0        , new=<x><x    ; old < new
try(32768,  8192, 16384);  # old=<x>      , new=<x><x>   ; old < new
try(24576, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
try(16384, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
try(40960,     0, 16384);  # old=0        , new=<x><x>   ; old < new
try(32768,  8192, 24576);  # old=<x>      , new=<x><x><x>; old < new
try(24576, 16384, 24576);  # old=<x><x>   , new=<x><x><x>; old < new
try(16384, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
try(40960,     0, 24576);  # old=0        , new=<x><x><x>; old < new
try(35973,  4987,     0);  # old=x>       , new=0        ; old > new
try(32768,  8192,     0);  # old=<x>      , new=0        ; old > new
try(29932, 11028,     0);  # old=x><x>    , new=0        ; old > new
try(24576, 16384,     0);  # old=<x><x>   , new=0        ; old > new
try(16384, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
try(40960,     0,     0);  # old=0        , new=0        ; old = new

# (278-357)
# These tests all take place at the end of the file
$FLEN = 42000;  # Force the file to be exactly 42000 bytes long
try(41275,   725,  4059);  # old=x        , new=x        ; old < new
try(41683,   317,   317);  # old=x        , new=x        ; old = new
try(41225,   775,   405);  # old=x        , new=x        ; old > new
try(35709,  6291,   284);  # old=x><x     , new=x        ; old > new
try(42000,     0,  2434);  # old=0        , new=x        ; old < new
try(40960,  1040,  1608);  # old=<x       , new=<x       ; old < new
try(40960,  1040,  1040);  # old=<x       , new=<x       ; old = new
try(40960,  1040,   378);  # old=<x       , new=<x       ; old > new
try(32768,  9232,  5604);  # old=<x><x    , new=<x       ; old > new
try(42000,     0,  6637);  # old=0        , new=<x       ; old < new
try(41022,   978,  8130);  # old=x        , new=x>       ; old < new
try(39994,  2006,   966);  # old=x><x     , new=x>       ; old > new
try(42000,     0,  7152);  # old=0        , new=x>       ; old < new
try(41613,   387, 10601);  # old=x        , new=x><x     ; old < new
try(38460,  3540,  3938);  # old=x><x     , new=x><x     ; old < new
try(36725,  5275,  5275);  # old=x><x     , new=x><x     ; old = new
try(37990,  4010,  3199);  # old=x><x     , new=x><x     ; old > new
try(42000,     0,  9189);  # old=0        , new=x><x     ; old < new
try(40960,  1040,  8192);  # old=<x       , new=<x>      ; old < new
try(32768,  9232,  8192);  # old=<x><x    , new=<x>      ; old > new
try(42000,     0,  8192);  # old=0        , new=<x>      ; old < new
try(40960,  1040, 11778);  # old=<x       , new=<x><x    ; old < new
try(32768,  9232, 13792);  # old=<x><x    , new=<x><x    ; old < new
try(32768,  9232,  9232);  # old=<x><x    , new=<x><x    ; old = new
try(32768,  9232,  8795);  # old=<x><x    , new=<x><x    ; old > new
try(42000,     0,  8578);  # old=0        , new=<x><x    ; old < new
try(41531,   469, 15813);  # old=x        , new=x><x>    ; old < new
try(39618,  2382,  9534);  # old=x><x     , new=x><x>    ; old < new
try(42000,     0, 15344);  # old=0        , new=x><x>    ; old < new
try(40960,  1040, 16384);  # old=<x       , new=<x><x>   ; old < new
try(32768,  9232, 16384);  # old=<x><x    , new=<x><x>   ; old < new
try(42000,     0, 16384);  # old=0        , new=<x><x>   ; old < new
try(40960,  1040, 24576);  # old=<x       , new=<x><x><x>; old < new
try(32768,  9232, 24576);  # old=<x><x    , new=<x><x><x>; old < new
try(42000,     0, 24576);  # old=0        , new=<x><x><x>; old < new
try(41500,   500,     0);  # old=x        , new=0        ; old > new
try(40960,  1040,     0);  # old=<x       , new=0        ; old > new
try(35272,  6728,     0);  # old=x><x     , new=0        ; old > new
try(32768,  9232,     0);  # old=<x><x    , new=0        ; old > new
try(42000,     0,     0);  # old=0        , new=0        ; old = new


sub try {
  my ($pos, $len, $newlen) = @_;
  try0($pos, $len, $newlen);
  # if len is undef, it implies 'to the end of the string'
  try0($pos, undef, $newlen);
}


sub try0 {
  my ($pos, $len, $newlen) = @_;

  my $line = (caller(1))[2];
  my $desc = sprintf "try(%5s, %5s, %5s) FLEN=%5s called from line %d",
                map { defined $_ ? $_ : 'undef' }
                    $pos, $len, $newlen, $FLEN, $line;

  my ($fh, $file) = File::Temp::tempfile("29-XXXXX", DIR => $tempdir);

  binmode $fh;

  # The record has exactly 17 characters.  This will help ensure that
  # even if _downcopy screws up, the data doesn't coincidentally
  # look good because the remainder accidentally lines up.
  my $d = substr("0123456789abcdef$:", -17);
  my $recs = defined($FLEN) ?
    int($FLEN/length($d))+1 : # enough to make up at least $FLEN
    int(8192*5/length($d))+1; # at least 5 blocks' worth
  my $oldfile = $d x $recs;
  my $flen = defined($FLEN) ? $FLEN : $recs * 17;
  substr($oldfile, $FLEN) = "" if defined $FLEN;  # truncate
  print $fh $oldfile;
  close $fh;

  die "wrong length!" unless -s $file == $flen;

  my $newdata = "-" x $newlen;
  my $expected = $oldfile;
  my $old = defined $len ? substr($expected, $pos, $len) 
                         : substr($expected, $pos);
  $old = "$newdata$old";
  my $x_retval;
  if (defined $len) {
    substr($expected, $pos, $len, substr($old, 0, $len, ""));
    $x_retval = $old;
  } else {
    substr($expected, $pos) = $old;
    $x_retval = "";
  }

  my $o = tie my @lines, 'Tie::File', $file or die $!;
  # allocate more time when are running tests in parallel
  my $alarm_time = $ENV{TEST_JOBS} || $ENV{HARNESS_OPTIONS} ? 20 : 10;
  local $SIG{ALRM} = sub { die "Alarm clock" };
  my $a_retval = eval { alarm($alarm_time) unless $^P; $o->_downcopy($newdata, $pos, $len) };
  my $err = $@;
  undef $o; untie @lines; alarm(0);
  if ($err) {
    if ($err =~ /^Alarm clock/) {
      print STDERR "# $0 Timeout after $alarm_time seconds at test $N - $desc\n";
      print "not ok $N - exp $desc TIMEOUT\n"; $N++;
      print "not ok $N - ret $desc TIMEOUT\n"; $N++;
      return;
    } else {
      $@ = $err;
      die;
    }
  }

  open F, '<', $file or die "Couldn't open file $file: $!";
  binmode F;
  my $actual;
  { local $/;
    $actual = <F>;
  }
  close F;

  my ($alen, $xlen) = (length $actual, length $expected);
  unless ($alen == $xlen) {
    my @ARGS = @_;
    for (@ARGS) { $_ = "UNDEF" unless defined }
    print "# try(@ARGS) expected file length $xlen, actual $alen!\n";
  }
  print $actual eq $expected ? "ok $N - exp $desc\n" : "not ok $N - exp $desc\n";
  $N++;
  print $a_retval eq $x_retval ? "ok $N - ret $desc\n" : "not ok $N - ret $desc\n";
  $N++;
}