#!/usr/bin/env perl
require 5.003;
use warnings;

# Global settings
# (The max_idx parameter is the only thing that needs to be changed when adding
#       support for a new major release.  If support for a prior major release
#       is added (like support for 1.4, etc), the min_sup_idx parameter will
#       need to be decremented.)

# Max. library "index" (0 = v1.0, 1 = 1.2, 2 = 1.4, 3 = 1.6, 4 = 1.8, 5 = 1.10, 6 = 1.12, 7 = 1.14, etc)
$max_idx = 7;

# Min. supported previous library version "index" (0 = v1.0, 1 = 1.2, etc)
$min_sup_idx = 3;

# Number of spaces to indent preprocessor commands inside ifdefs
$indent = 2;

#
# Copyright by The HDF Group.
# All rights reserved.
#
# This file is part of HDF5.  The full HDF5 copyright notice, including
# terms governing use, modification, and redistribution, is contained in
# the COPYING file, which can be found at the root of the source code
# distribution tree, or in https://www.hdfgroup.org/licenses.
# If you do not have access to either file, you may request a copy from
# help@hdfgroup.org.
#

# Create public symbol version headers
#
# Read in the public symbol version description text file and create the
# appropriate headers needed by the library.
#

##############################################################################
# Print the copyright into an open file
#
sub print_copyright ($) {
    my $fh = shift;

    print $fh "/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\n";
    print $fh " * Copyright by The HDF Group.                                               *\n";
    print $fh " * All rights reserved.                                                      *\n";
    print $fh " *                                                                           *\n";
    print $fh " * This file is part of HDF5.  The full HDF5 copyright notice, including     *\n";
    print $fh " * terms governing use, modification, and redistribution, is contained in    *\n";
    print $fh " * the COPYING file, which can be found at the root of the source code       *\n";
    print $fh " * distribution tree, or in https://www.hdfgroup.org/licenses.               *\n";
    print $fh " * If you do not have access to either file, you may request a copy from     *\n";
    print $fh " * help\@hdfgroup.org.                                                        *\n";
    print $fh " * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */\n";
}

##############################################################################
# Print the "do not change this file" warning
#
sub print_warning ($) {
    my $fh = shift;

    print $fh "\n/* Generated automatically by bin/make_vers -- do not edit */\n";
    print $fh "/* Add new versioned symbols to H5vers.txt file */\n\n";
}

##############################################################################
# Print start of ifdef's to prevent a file from being re-included
#
sub print_startprotect ($$) {
    my ($fh, $file) = @_;

    # Clip off the ".h" part of the name
    $file =~ s/(\w*)\.h/$1/;

    # Print the ifdef info
    print $fh "\n#ifndef ${file}_H\n";
    print $fh "#define ${file}_H\n";
}

##############################################################################
# Print check for conflicting version macro settings
#
sub print_checkoptions ($) {
    my $fh = shift;             # File handle for output file
    my $curr_idx;               # Current API version index

    # Print the option checking
    print $fh "\n\n/* Issue error if contradicting macros have been defined. */\n";
    print $fh "/* (Can't use an older (deprecated) API version if deprecated symbols have been disabled) */\n";

    # Print the #ifdef
    print $fh "#if (";
    for $curr_idx ($min_sup_idx .. ($max_idx - 1)) {
        print $fh "defined(H5_USE_1", ($curr_idx * 2), "_API)";
        if($curr_idx < ($max_idx - 1)) {
            print $fh " || ";
        }
    }
    print $fh ") && defined(H5_NO_DEPRECATED_SYMBOLS)\n";

    # Print the error for bad API version chosen
    print $fh ' ' x $indent, "#error \"Can't choose old API versions when deprecated APIs are disabled\"\n";

    # Print the #endif
    print $fh "#endif /* (";
    for $curr_idx ($min_sup_idx .. ($max_idx - 1)) {
        print $fh "defined(H5_USE_1", ($curr_idx * 2), "_API)";
        if($curr_idx < ($max_idx - 1)) {
            print $fh " || ";
        }
    }
    print $fh ") && defined(H5_NO_DEPRECATED_SYMBOLS) */\n";
}

##############################################################################
# Print "global" API version macro settings
#
sub print_globalapidefvers ($) {
    my $fh = shift;             # File handle for output file
    my $curr_idx;               # Current API version index

    # Print the descriptive comment
    print $fh "\n\n/* If a particular default \"global\" version of the library's interfaces is\n";
    print $fh " *      chosen, set the corresponding version macro for API symbols.\n";
    print $fh " *\n";
    print $fh " */\n";

    for $curr_idx ($min_sup_idx .. ($max_idx - 1)) {
        # Print API version ifdef
        print $fh "\n#if defined(H5_USE_1", ($curr_idx * 2), "_API_DEFAULT) && !defined(H5_USE_1", ($curr_idx * 2), "_API)\n";
        # Print API version definition
        print $fh " " x $indent, "#define H5_USE_1", ($curr_idx * 2), "_API 1\n";
        # Print API version endif
        print $fh "#endif /* H5_USE_1", ($curr_idx * 2), "_API_DEFAULT && !H5_USE_1", ($curr_idx * 2), "_API */\n";
    }
}

##############################################################################
# Print "global" API symbol version macro settings
#
sub print_globalapisymbolvers ($) {
    my $fh = shift;             # File handle for output file
    my $curr_idx;               # Current API version index

    # Print the descriptive comment
    print $fh "\n\n/* If a particular \"global\" version of the library's interfaces is chosen,\n";
    print $fh " *      set the versions for the API symbols affected.\n";
    print $fh " *\n";
    print $fh " * Note: If an application has already chosen a particular version for an\n";
    print $fh " *      API symbol, the individual API version macro takes priority.\n";
    print $fh " */\n";

    # Loop over supported older library APIs and define the appropriate macros
    for $curr_idx ($min_sup_idx .. ($max_idx - 1)) {
        # Print API version ifdef
        print $fh "\n#ifdef H5_USE_1", ($curr_idx * 2), "_API\n";

        # Print the version macro info for each function that is defined for
        # this API version
        print $fh "\n/*************/\n";
        print $fh "/* Functions */\n";
        print $fh "/*************/\n";
        for $name (sort keys %{$func_vers[$curr_idx]}) {
            print $fh "\n#if !defined(", $name, "_vers)\n";
            print $fh  " " x $indent, "#define ", $name, "_vers $func_vers[$curr_idx]{$name}\n";
            print $fh  "#endif /* !defined(", $name, "_vers) */\n";
        }

        # Print the version macro info for each typedef that is defined for
        # this API version
        print $fh "\n/************/\n";
        print $fh "/* Typedefs */\n";
        print $fh "/************/\n";
        for $name (sort keys %{$type_vers[$curr_idx]}) {
            print $fh "\n#if !defined(", $name, "_t_vers)\n";
            print $fh  " " x $indent, "#define ", $name, "_t_vers $type_vers[$curr_idx]{$name}\n";
            print $fh  "#endif /* !defined(", $name, "_t_vers) */\n";
        }

        # Print API version endif
        print $fh "\n#endif /* H5_USE_1", ($curr_idx * 2), "_API */\n";
    }
}

##############################################################################
# Print "default" API version macro settings
#
sub print_defaultapivers ($) {
    my $fh = shift;             # File handle for output file
    my $curr_name;              # Current API function

    # Print the descriptive comment
    print $fh "\n\n/* Choose the correct version of each API symbol, defaulting to the latest\n";
    print $fh " *      version of each.  The \"best\" name for API parameters/data structures\n";
    print $fh " *      that have changed definitions is also set.  An error is issued for\n";
    print $fh " *      specifying an invalid API version.\n";
    print $fh " */\n";

    # Loop over function names that are versioned and set up the version macros
    print $fh "\n/*************/\n";
    print $fh "/* Functions */\n";
    print $fh "/*************/\n";
    for $curr_name (sort keys %functions) {
        my $curr_vers_name;     # Name of version macro for current function
        my $curr_vers;          # Version of function
        my @param_list;         # Typedefs for the function parameters

        # Set up variables for later use
        $curr_vers_name = $curr_name . "_vers";
        $curr_vers = $functions{$curr_name};

        # Split up parameter info
        @param_list = split(/\s*,\s*/, $func_params{$curr_name});
#print "print_defaultapivers: param_list=(@param_list)\n";

        # Set up default/latest version name mapping
        print $fh "\n#if !defined($curr_vers_name) || $curr_vers_name == $curr_vers\n";
        print $fh " " x $indent, "#ifndef $curr_vers_name\n";
        print $fh " " x ($indent * 2), "#define $curr_vers_name $curr_vers\n";
        print $fh " " x $indent, "#endif /* $curr_vers_name */\n";
        print $fh " " x $indent, "#define $curr_name $curr_name$curr_vers\n";

        # Print function's dependent parameter types
        foreach(sort(@param_list)) {
            print $fh " " x $indent, "#define ${_}_t $_${curr_vers}_t\n";
        }

        # Loop to print earlier version name mappings
        $curr_vers--;
        while($curr_vers > 0) {
            print $fh "#elif $curr_vers_name == $curr_vers\n";
            print $fh " " x $indent, "#define $curr_name $curr_name$curr_vers\n";

            # Print function's dependent parameter types
            foreach(sort(@param_list)) {
                print $fh " " x $indent, "#define ${_}_t $_${curr_vers}_t\n";
            }

            $curr_vers--;
        }

        # Finish up with error for unknown version and endif
        print $fh "#else /* $curr_vers_name */\n";
        print $fh " " x $indent, "#error \"$curr_vers_name set to invalid value\"\n";
        print $fh "#endif /* $curr_vers_name */\n";
    }

    # Loop over typedefs that are versioned and set up the version macros
    print $fh "\n/************/\n";
    print $fh "/* Typedefs */\n";
    print $fh "/************/\n";
    for $curr_name (sort keys %typedefs) {
        my $curr_vers_name;     # Name of version macro for current function
        my $curr_vers;          # Version of function

        # Set up variables for later use
        $curr_vers_name = $curr_name . "_t_vers";
        $curr_vers = $typedefs{$curr_name};

        # Set up default/latest version name mapping
        print $fh "\n#if !defined($curr_vers_name) || $curr_vers_name == $curr_vers\n";
        print $fh " " x $indent, "#ifndef $curr_vers_name\n";
        print $fh " " x ($indent * 2), "#define $curr_vers_name $curr_vers\n";
        print $fh " " x $indent, "#endif /* $curr_vers_name */\n";
        print $fh " " x $indent, "#define ${curr_name}_t $curr_name${curr_vers}_t\n";

        # Loop to print earlier version name mappings
        $curr_vers--;
        while($curr_vers > 0) {
            print $fh "#elif $curr_vers_name == $curr_vers\n";
            print $fh " " x $indent, "#define ${curr_name}_t $curr_name${curr_vers}_t\n";
            $curr_vers--;
        }

        # Finish up with error for unknown version and endif
        print $fh "#else /* $curr_vers_name */\n";
        print $fh " " x $indent, "#error \"$curr_vers_name set to invalid value\"\n";
        print $fh "#endif /* $curr_vers_name */\n\n";
    }
}

##############################################################################
# Print end of ifdef's to prevent a file from being re-included
#
sub print_endprotect ($$) {
    my ($fh, $file) = @_;

    # Clip off the ".h" part of the name
    $file =~ s/(\w*)\.h/$1/;

    # Print the endif info
    print $fh "#endif /* ${file}_H */\n\n";
}

##############################################################################
# Parse a meaningful line (not a comment or blank line) into the appropriate
# data structure
#
sub parse_line ($) {
    my $line = shift;   # Get the line to parse

    # Parse API function lines
#print "line=$line\n";
    if($line =~ /^\s*FUNCTION:/ || $line =~ /^\s*TYPEDEF:/) {
        my $name;           # The name of the function
        my $params;         # Typedefs for function parameters
        my $vers;           # The version info for the function
        my @vers_list;      # Version info, as a list
        my @vers_nums;      # Version info, as a numeric list
        my $num_versions;   # Number of versions for function
        my %sym_versions;   # Versions for a symbol
        my $last_idx;       # The previous version index seen for a function
        my $last_vers;      # The previous version # seen for a function
        my $line_type;      # Type of line we are parsing

        # Determine the type of the line to parse
        if($line =~ /^\s*FUNCTION:/) {
            $line_type = 1;
            # Get the function's name & version info
            ($name, $params, $vers) = ($line =~ /^\s*FUNCTION:\s*(\w*);\s*(.*?)\s*;\s*(.*?)\s*$/);
#print "parse_line: name='$name', params='$params', vers='$vers'\n";
        }
        elsif($line =~ /^\s*TYPEDEF:/) {
            $line_type = 2;

            # Get the typedefs's name & version info
            ($name, $vers) = ($line =~ /^\s*TYPEDEF:\s*(\w*);\s*(.*?)\s*$/);
#print "parse_line: name='$name', vers='$vers'\n";
        }
#print "parse_line: line_type='$line_type'\n";


        # Check if the name already exists in the list of symbols
        if(exists($functions{$name}) || exists($typedefs{$name})) {
            die "duplicated symbol: $name";
        }

        # Check for no version info given
        if($vers eq "") {
            die "no version information: $name";
        }

        # Split up version info
        @vers_list = split(/\s*,\s*/, $vers);
#print "parse_line: vers_list=(@vers_list)\n";

        # Parse the version list into numbers, checking for invalid input
        foreach(@vers_list) {
            my $vers_idx;       # Index of version in array

            # Do some validation on the input
            # Note:  v111 is allowed because H5O functions were prematurely versioned
            #        in HDF5 1.10.  Because users were affected by this, the versioning
            #        was rescinded but the H5O version 2 functions were kept to be 
            #        called directly.  Now that the version macros are added in 1.12,
            #        along with a 3rd version of the H5O functions, the H5O function
            #        version for default api=v110 should be version 1 to work correctly
            #        with 1.10 applications that were using unversioned H5O functions,
            #        and the H5O function version should be version 3 for default api=v112 
            #        (the default api version for 1.12).  Allowing a v111 entry and 
            #        incrementing its index 13 lines below allows a version 2 that is
            #        never accessed via the H5O function macros.
            if(!( $_ =~ /v1[02468]/ || $_ =~ /v11[02468]/ ||  $_ =~ /v111/ )) {
                die "bad version information: $name";
            }
            if(exists($sym_versions{$_})) {
                die "duplicate version information: $name";
            }

            # Store the versions for the function in a local hash table, indexed by the version
            $sym_versions{$_}=$_;

#print "parse_line: _=$_\n";
            # Get the index of the version
            ($vers_idx) = ($_ =~ /v1(\d+)/);
            if($vers_idx == 11) {
                $vers_idx++;
            }
            $vers_idx /= 2;
#print "parse_line: vers_idx='$vers_idx'\n";
            push(@vers_nums, $vers_idx);
        }
#print "parse_line: vers_nums=(@vers_nums)\n";

        # Check for invalid version info given
        $last_idx = -1;
        $last_vers = 1;
        foreach(sort(@vers_nums)) {
#print "parse_line: _=$_ last_idx='$last_idx'\n";
            # Update intermediate versions of the library that included the API routine
            if($last_idx >= 0) {
#print "parse_line: name='$name'\n";
#print "parse_line: last_vers='$last_vers'\n";
#print "parse_line: last_idx='$last_idx'\n";

                # Add the function to the list of API routines available in
                # different versions of the library
                while($last_idx <= $_) {
                    if($line_type == 1) {
                        $func_vers[$last_idx]{$name} = $last_vers;
                    } elsif($line_type == 2) {
                        $type_vers[$last_idx]{$name} = $last_vers;
                    } else {
                        die "unknown line type: $line";
                    }
                    $last_idx++;
                }

                # Increment the version # of the function
                $last_vers++;
            }

            # Keep track of last version index seen
            $last_idx = $_;
        }

        # Finish updating versions of the library that included the API routine
        if($last_idx >= 0) {
#print "parse_line: max_idx='$max_idx'\n";

            # Add the function to the list of API routines available in
            # different versions of the library
            while($last_idx <= $max_idx) {
                if($line_type == 1) {
                    $func_vers[$last_idx]{$name} = $last_vers;
                } elsif($line_type == 2) {
                    $type_vers[$last_idx]{$name} = $last_vers;
                } else {
                    die "unknown line type: $line";
                }
                $last_idx++;
            }
        }

        # Store the number of symbol versions in a hash table, indexed by the name
        if($line_type == 1) {
            $functions{$name} = $#vers_list + 1;

            # Store the function's parameter types for later
            $func_params{$name} = $params;
        } elsif($line_type == 2) {
            $typedefs{$name} = $#vers_list + 1;
        } else {
            die "unknown line type: $line";
        }
    }
    # Unknown keyword
    else {
        die "unknown keyword: $line";
    }
}

##############################################################################
# Create the generated portion of the public header file
#
sub create_public ($) {
    my $prefix = shift;         # Get the prefix for the generated file
    my $file = "H5version.h";   # Name of file to generate
    my $name;                   # Name of function

    # Rename previous file
#    rename "${prefix}${file}", "${prefix}${file}~" or die "unable to make backup";

    # Open new header file
    open HEADER, ">${prefix}${file}" or die "unable to modify source";

    # Create file contents
    print_copyright(*HEADER);
    print_warning(*HEADER);
    print_startprotect(*HEADER, $file);
    print_globalapidefvers(*HEADER);
    print_checkoptions(*HEADER);
    print_globalapisymbolvers(*HEADER);
    print_defaultapivers(*HEADER);
    print_endprotect(*HEADER, $file);

    # Close header file
    close HEADER;
}

##############################################################################
# Read symbol version file (given as command-line argument) in and process it
# into internal data structures, then create header files.
#
for $file (@ARGV) {
    my $prefix;         # Local prefix for generated files

#print "file = '$file'\n";
    # Check for directory prefix on input file
    if($file =~ /\//) {
        ($prefix) = ($file =~ /(^.*\/)/);
    }
    else {
        $prefix = "";
    }
#print "prefix = '$prefix'\n";
    # Read in the entire file
    open SOURCE, $file or die "$file: $!\n";
    while ( defined ($line=<SOURCE>) ) {
        # Skip blank lines and those lines whose first character is a '#'
        if(!($line =~ /(^\s*#.*$)|(^\s*$)/)) {
            # Construct data structures for later printing
            parse_line($line);
        }
    }
    close SOURCE;

    # Create header files
    print "Generating 'H5version.h'\n";
    create_public($prefix);

#for $name (sort keys %functions) {
#    print "functions{$name} = $functions{$name}\n";
#}

#for $i (0 .. $#func_vers) {
#    my $vers_name;      # Name of indexed version
#    $vers_name = "v1." . ($i * 2);
#    print "$vers_name functions: ";
#    for $name (sort keys %{$func_vers[$i]}) {
#        print "$name$func_vers[$i]{$name} ";
#    }
#    print "\n";
#}

}