#!perl -w
use 5.015;
use strict;
use warnings;
use Unicode::UCD qw(prop_invlist prop_invmap);
require 'regen/regen_lib.pl';

# This program outputs charclass_invlists.h, which contains various inversion
# lists in the form of C arrays that are to be used as-is for inversion lists.
# Thus, the lists it contains are essentially pre-compiled, and need only a
# light-weight fast wrapper to make them usable at run-time.

# As such, this code knows about the internal structure of these lists, and
# any change made to that has to be done here as well.  A random number stored
# in the headers is used to minimize the possibility of things getting
# out-of-sync, or the wrong data structure being passed.  Currently that
# random number is:
my $VERSION_DATA_STRUCTURE_TYPE = 148565664;

my $out_fh = open_new('charclass_invlists.h', '>',
		      {style => '*', by => $0,
                      from => "Unicode::UCD"});

print $out_fh "/* See the generating file for comments */\n\n";

my %include_in_ext_re = ( NonL1_Perl_Non_Final_Folds => 1 );

sub output_invlist ($$) {
    my $name = shift;
    my $invlist = shift;     # Reference to inversion list array

    die "No inversion list for $name" unless defined $invlist
                                             && ref $invlist eq 'ARRAY'
                                             && @$invlist;

    # Output the inversion list $invlist using the name $name for it.
    # It is output in the exact internal form for inversion lists.

    # Is the last element of the header 0, or 1 ?
    my $zero_or_one = 0;
    if ($invlist->[0] != 0) {
        unshift @$invlist, 0;
        $zero_or_one = 1;
    }
    my $count = @$invlist;

    print $out_fh "\n#ifndef PERL_IN_XSUB_RE\n" unless exists $include_in_ext_re{$name};
    print $out_fh "\nstatic const UV ${name}_invlist[] = {\n";

    print $out_fh "\t$count,\t/* Number of elements */\n";
    print $out_fh "\t$VERSION_DATA_STRUCTURE_TYPE, /* Version and data structure type */\n";
    print $out_fh "\t", $zero_or_one,
                  ",\t/* 0 if the list starts at 0;",
                  "\n\t\t   1 if it starts at the element beyond 0 */\n";

    # The main body are the UVs passed in to this routine.  Do the final
    # element separately
    for my $i (0 .. @$invlist - 1 - 1) {
        print $out_fh "\t$invlist->[$i],\n";
    }

    # The final element does not have a trailing comma, as C can't handle it.
    print $out_fh "\t$invlist->[-1]\n";

    print $out_fh "};\n";
    print $out_fh "\n#endif\n" unless exists $include_in_ext_re{$name};

}

sub mk_invlist_from_cp_list {

    # Returns an inversion list constructed from the sorted input array of
    # code points

    my $list_ref = shift;

    # Initialize to just the first element
    my @invlist = ( $list_ref->[0], $list_ref->[0] + 1);

    # For each succeeding element, if it extends the previous range, adjust
    # up, otherwise add it.
    for my $i (1 .. @$list_ref - 1) {
        if ($invlist[-1] == $list_ref->[$i]) {
            $invlist[-1]++;
        }
        else {
            push @invlist, $list_ref->[$i], $list_ref->[$i] + 1;
        }
    }
    return @invlist;
}

# Read in the Case Folding rules, and construct arrays of code points for the
# properties we need.
my ($cp_ref, $folds_ref, $format) = prop_invmap("Case_Folding");
die "Could not find inversion map for Case_Folding" unless defined $format;
die "Incorrect format '$format' for Case_Folding inversion map"
                                                    unless $format eq 'al';
my @has_multi_char_fold;
my @is_non_final_fold;

for my $i (0 .. @$folds_ref - 1) {
    next unless ref $folds_ref->[$i];   # Skip single-char folds
    push @has_multi_char_fold, $cp_ref->[$i];

    # Add to the non-finals list each code point that is in a non-final
    # position
    for my $j (0 .. @{$folds_ref->[$i]} - 2) {
        push @is_non_final_fold, $folds_ref->[$i][$j]
                unless grep { $folds_ref->[$i][$j] == $_ } @is_non_final_fold;
    }
}

sub _Perl_Non_Final_Folds {
    @is_non_final_fold = sort { $a <=> $b } @is_non_final_fold;
    return mk_invlist_from_cp_list(\@is_non_final_fold);
}

sub UpperLatin1 {
    my @upper_latin1;
    for my $i (0 .. 255) {  # Complicated because of EBCDIC
        push @upper_latin1, $i if chr($i) =~ /[[:^ascii:]]/;
    }
    return mk_invlist_from_cp_list(\@upper_latin1);
}

output_invlist("Latin1", [ 0, 256 ]);
output_invlist("AboveLatin1", [ 256 ]);

# We construct lists for all the POSIX and backslash sequence character
# classes in two forms:
#   1) ones which match only in the ASCII range
#   2) ones which match either in the Latin1 range, or the entire Unicode range
#
# These get compiled in, and hence affect the memory footprint of every Perl
# program, even those not using Unicode.  To minimize the size, currently
# the Latin1 version is generated for the beyond ASCII range except for those
# lists that are quite small for the entire range, such as for \s, which is 22
# UVs long plus 4 UVs (currently) for the header.
#
# To save even more memory, the ASCII versions could be derived from the
# larger ones at runtime, saving some memory (minus the expense of the machine
# instructions to do so), but these are all small anyway, so their total is
# about 100 UVs.
#
# In the list of properties below that get generated, the L1 prefix is a fake
# property that means just the Latin1 range of the full property (whose name
# has an X prefix instead of L1).
#
# An initial & means to use the subroutine from this file instead of an
# official inversion list.

for my $prop (qw(
                ASCII
                Cased
		VertSpace
                XPerlSpace
                XPosixAlnum
                XPosixAlpha
                XPosixBlank
                XPosixCntrl
                XPosixDigit
                XPosixGraph
                XPosixLower
                XPosixPrint
                XPosixPunct
                XPosixSpace
                XPosixUpper
                XPosixWord
                XPosixXDigit
                _Perl_Any_Folds
                &NonL1_Perl_Non_Final_Folds
                _Perl_Folds_To_Multi_Char
                &UpperLatin1
                _Perl_IDStart
                _Perl_IDCont
    )
) {

    # For the Latin1 properties, we change to use the eXtended version of the
    # base property, then go through the result and get rid of everything not
    # in Latin1 (above 255).  Actually, we retain the element for the range
    # that crosses the 255/256 boundary if it is one that matches the
    # property.  For example, in the Word property, there is a range of code
    # points that start at U+00F8 and goes through U+02C1.  Instead of
    # artificially cutting that off at 256 because 256 is the first code point
    # above Latin1, we let the range go to its natural ending.  That gives us
    # extra information with no added space taken.  But if the range that
    # crosses the boundary is one that doesn't match the property, we don't
    # start a new range above 255, as that could be construed as going to
    # infinity.  For example, the Upper property doesn't include the character
    # at 255, but does include the one at 256.  We don't include the 256 one.
    my $prop_name = $prop;
    my $is_local_sub = $prop_name =~ s/^&//;
    my $lookup_prop = $prop_name;
    my $l1_only = ($lookup_prop =~ s/^L1Posix/XPosix/ or $lookup_prop =~ s/^L1//);
    my $nonl1_only = 0;
    $nonl1_only = $lookup_prop =~ s/^NonL1// unless $l1_only;

    my @invlist;
    if ($is_local_sub) {
        @invlist = eval $lookup_prop;
    }
    else {
        @invlist = prop_invlist($lookup_prop, '_perl_core_internal_ok');
    }
    die "Could not find inversion list for '$lookup_prop'" unless @invlist;

    if ($l1_only) {
        for my $i (0 .. @invlist - 1 - 1) {
            if ($invlist[$i] > 255) {

                # In an inversion list, even-numbered elements give the code
                # points that begin ranges that match the property;
                # odd-numbered give ones that begin ranges that don't match.
                # If $i is odd, we are at the first code point above 255 that
                # doesn't match, which means the range it is ending does
                # match, and crosses the 255/256 boundary.  We want to include
                # this ending point, so increment $i, so the splice below
                # includes it.  Conversely, if $i is even, it is the first
                # code point above 255 that matches, which means there was no
                # matching range that crossed the boundary, and we don't want
                # to include this code point, so splice before it.
                $i++ if $i % 2 != 0;

                # Remove everything past this.
                splice @invlist, $i;
                last;
            }
        }
    }
    elsif ($nonl1_only) {
        my $found_nonl1 = 0;
        for my $i (0 .. @invlist - 1 - 1) {
            next if $invlist[$i] < 256;

            # Here, we have the first element in the array that indicates an
            # element above Latin1.  Get rid of all previous ones.
            splice @invlist, 0, $i;

            # If this one's index is not divisible by 2, it means that this
            # element is inverting away from being in the list, which means
            # all code points from 256 to this one are in this list.
            unshift @invlist, 256 if $i % 2 != 0;
            $found_nonl1 = 1;
            last;
        }
        die "No non-Latin1 code points in $lookup_prop" unless $found_nonl1;
    }

    output_invlist($prop_name, \@invlist);
}

read_only_bottom_close_and_rename($out_fh)