#!/bin/sh
# -*- perl -*-
# Exercise head's --bytes=-N option.

: ${PERL=perl}
: ${srcdir=.}

$PERL -e 1 > /dev/null 2>&1 || {
  echo 1>&2 "$0: configure didn't find a usable version of Perl," \
    "so can't run this test"
  exit 77
}

exec $PERL -w -I$srcdir/.. -MFetish -- - <<\EOF
#/
require 5.003;
use strict;

(my $program_name = $0) =~ s|.*/||;

$ENV{PROG} = 'head';

# Turn off localization of executable's ouput.
@ENV{qw(LANGUAGE LANG LC_ALL)} = ('C') x 3;

# This should match the definition in head.c.
my $READ_BUFSIZE = 4096;

my @Tests =
  (
   # Elide the exact size of the file.
   ['elide-b1', "--bytes=-2", {IN=>"a\n"}, {OUT=>''}],
   # Elide more than the size of the file.
   ['elide-b2', "--bytes=-2", {IN=>"a"},   {OUT=>''}],
   # Leave just one byte.
   ['elide-b3', "--bytes=-2", {IN=>"abc"}, {OUT=>'a'}],
   # Make it so the elided bytes straddle the end of the first
   # $READ_BUFSIZE block.
   ['elide-b4', "--bytes=-2",
    {IN=> 'a' x ($READ_BUFSIZE-3) . "\nbcd"},
    {OUT=>'a' x ($READ_BUFSIZE-3) . "\nb"}],
   # Make it so the elided bytes straddle the end of the 2nd
   # $READ_BUFSIZE block.
   ['elide-b5', "--bytes=-2",
    {IN=> 'a' x (2 * $READ_BUFSIZE - 2) . 'bcd'},
    {OUT=>'a' x (2 * $READ_BUFSIZE - 2) . 'b'}],

   ['elide-l0', "--lines=-1", {IN=>''}, {OUT=>''}],
   ['elide-l1', "--lines=-1", {IN=>"a\n"}, {OUT=>''}],
   ['elide-l2', "--lines=-1", {IN=>"a"}, {OUT=>''}],
   ['elide-l3', "--lines=-1", {IN=>"a\nb"}, {OUT=>"a\n"}],
   ['elide-l4', "--lines=-1", {IN=>"a\nb\n"}, {OUT=>"a\n"}],
  );

if ($ENV{RUN_EXPENSIVE_TESTS})
  {
    # Brute force: use all combinations of file sizes [0..20] and
    # number of bytes to elide [0..20].  For better coverage, recompile
    # head with -DHEAD_TAIL_PIPE_READ_BUFSIZE=4 and
    # -DHEAD_TAIL_PIPE_BYTECOUNT_THRESHOLD=8
    my $s = "abcdefghijklmnopqrst";
    for my $file_size (0..20)
      {
	for my $n_elide (0..20)
	  {
	    my $input = substr $s, 0, $file_size;
	    my $out_len = $n_elide < $file_size ? $file_size - $n_elide : 0;
	    my $output = substr $input, 0, $out_len;
	    my $t = ["elideb$file_size-$n_elide", "--bytes=-$n_elide",
		     {IN=>$input}, {OUT=>$output}];
	    push @Tests, $t;
	    my @u = @$t;
	    # Insert the --presume-input-pipe option.
	    $u[0] .= 'p';
	    $u[1] .= ' --presume-input-pipe';
	    push @Tests, \@u;
	  }
      }

    $s =~ s/(.)/$1\n/g;
    for my $file_size (0..20)
      {
	for my $n_elide (0..20)
	  {
	    my $input = substr $s, 0, 2 * $file_size;
	    my $out_len = $n_elide < $file_size ? $file_size - $n_elide : 0;
	    my $output = substr $input, 0, 2 * $out_len;
	    my $t = ["elidel$file_size-$n_elide", "--lines=-$n_elide",
		     {IN=>$input}, {OUT=>$output}];
	    push @Tests, $t;
	    my @u = @$t;
	    # Insert the --presume-input-pipe option.
	    $u[0] .= 'p';
	    $u[1] .= ' --presume-input-pipe';
	    push @Tests, \@u;
	  }
      }
  }

my $save_temps = $ENV{DEBUG};
my $verbose = $ENV{VERBOSE};

my $prog = $ENV{PROG} || die "$0: \$PROG not specified in environment\n";
my $fail = run_tests ($program_name, $prog, \@Tests, $save_temps, $verbose);
exit $fail;
EOF
