Fix error_code() reporting errors in Data::BitStream instead of caller

lib/Data/BitStream/Base.pm

@@ -2,6 +2,7 @@ package Data::BitStream::Base;
 use strict;
 use warnings;
 use Carp;
+our @CARP_NOT;
 BEGIN {
   $Data::BitStream::Base::AUTHORITY = 'cpan:DANAJ';
   $Data::BitStream::Base::VERSION   = '0.08';
@@ -316,6 +317,7 @@ sub code_pos_is_set {
 sub error_off_stream {
   my $self = shift;
   my $skipping = shift;
+  local @CARP_NOT = (@CARP_NOT, ref($self));
 
   # Give the skip error only if we were not reading a code.
   if ( (defined $skipping) && (@{$self->_code_pos_array} == 0) ) {
@@ -329,6 +331,7 @@ sub error_off_stream {
 sub error_stream_mode {
   my $self = shift;
   my $type = shift;
+  local @CARP_NOT = (@CARP_NOT, ref($self));
   my $codename = $self->_code_restore_pos();
   $codename = " ($codename)" if $codename ne '';
 
@@ -351,6 +354,7 @@ sub error_code {
   my $self = shift;
   my $type = shift;
   my $text = shift;
+  local @CARP_NOT = (@CARP_NOT, ref($self));
   if ($type eq 'zeroval') {    # Implied text
     $type = 'value';
     $text = 'value must be >= 0';

lib/Data/BitStream/WordVec.pm

@@ -396,7 +396,19 @@ sub to_raw {
   my $self = shift;
   $self->write_close;
   my $rvec = $self->_vecref;
-  return $$rvec;
+  my $byte_count = int(($self->len + 7) / 8);
+  # $$rvec may have more or fewer zeroes than is appropriate based on
+  # optimizations
+  return $$rvec if length($$rvec) == $byte_count;
+  if (length($$rvec) > $byte_count) {
+	# return only the first $byte_count bytes 
+	return substr($$rvec, 0, $byte_count);
+  } else {
+	# a more complex case: there are some virtual '0' bits at the end
+	# we need to make them appear here
+	my $zeroes_needed = $byte_count - length($$rvec);
+	return $$rvec . ("\x00" x $zeroes_needed);
+  }
 }
 
 sub from_raw {

t/73-error-loc.t

@@ -0,0 +1,30 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+
+use Test::More tests => 5;
+use Test::Exception;
+
+use Moo::Role qw/apply_roles_to_object/;
+
+my $error_regex = qr/error-loc\.t/;
+
+require_ok 'Data::BitStream';
+
+my $dbs = Data::BitStream->new(mode => 'ro');
+
+throws_ok { $dbs->read($dbs->maxbits + 1) } $error_regex, 'read(maxbits + 1) should fail';
+note "Message: $@";
+throws_ok { $dbs->write(42, 8) } $error_regex, 'write to read-only should fail';
+note "Message: $@";
+throws_ok { $dbs->skip(-999999) } $error_regex, 'negative skip() should fail';
+note "Message: $@";
+
+# I'm not certain if this is the correct behavior, but a read() returns undef
+# if there are exactly zero bytes left in the stream
+$dbs = Data::BitStream->new();
+$dbs->from_raw("\x00");
+throws_ok { $dbs->read(32) } $error_regex, 'read past EOF should fail';
+note "Message: $@";
+
+done_testing;

t/74-to-raw.t

@@ -0,0 +1,31 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+
+use Test::More;
+
+use Moo::Role qw/apply_roles_to_object/;
+
+sub test_case(&);
+
+require_ok 'Data::BitStream';
+
+my $dbs;
+
+# write a single '1' bit; the result should be 1 byte long.
+test_case { $dbs->write(1, 1) };
+# write a single '1' bit; the result should be 1 byte long.
+test_case { $dbs->write(1, 0) };
+
+sub test_case(&) {
+	my ($sub) = @_;
+	$dbs = Data::BitStream->new();
+	$sub->($dbs);
+	my $bits = $dbs->len;
+	my $expected_length = int(($bits + 7) / 8);
+	my $raw_data = $dbs->to_raw();
+	my $actual_length = length($raw_data);
+	is($actual_length, $expected_length, "Expecting $bits bits to take $expected_length bytes");
+}
+
+done_testing;