Add some mechanical hexid->registration conversions.

public_html/gmap.html

@@ -16,6 +16,7 @@
 		<script type="text/javascript" src="config.js"></script>
 		<script type="text/javascript" src="markers.js"></script>
 		<script type="text/javascript" src="dbloader.js"></script>
+		<script type="text/javascript" src="registrations.js"></script>
 		<script type="text/javascript" src="planeObject.js"></script>
 		<script type="text/javascript" src="formatter.js"></script>
 		<script type="text/javascript" src="flags.js"></script>

public_html/planeObject.js

@@ -44,9 +44,12 @@ function PlaneObject(icao) {
         this.markerStyleKey = null;
         this.markerSvgKey = null;
 
-        // request metadata
+        // start from a computed registration, let the DB override it
-        this.registration = null;
+        // if it has something else.
+        this.registration = registration_from_hexid(this.icao);
         this.icaotype = null;
+
+        // request metadata
         getAircraftData(this.icao).done(function(data) {
                 if ("r" in data) {
                         this.registration = data.r;

public_html/registrations.js

@@ -0,0 +1,310 @@
+// Various reverse-engineered versions of the allocation algorithms
+// used by different countries to allocate 24-bit ICAO addresses based
+// on the aircraft registration.
+//
+// These were worked out by looking at the allocation patterns and
+// working backwards to an algorithm that generates that pattern,
+// spot-checking aircraft to see if it worked.
+// YMMV.
+
+registration_from_hexid = (function () {
+        // hide the guts in a closure
+
+        var limited_alphabet = "ABCDEFGHJKLMNPQRSTUVWXYZ"; // 24 chars; no I, O
+        var full_alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";  // 26 chars
+
+        // handles 3-letter suffixes assigned with a regular pattern
+        //
+        // start: first hexid of range
+        // s1: major stride (interval between different first letters)
+        // s2: minor stride (interval between different second letters)
+        // prefix: the registration prefix
+        //
+        // optionally:
+        //   alphabet: the alphabet to use (defaults full_alphabet)
+        //   first: the suffix to use at the start of the range (default: AAA)
+        //   last: the last valid suffix in the range (default: ZZZ)
+
+        var stride_mappings = [
+                { start: 0x008011, s1: 26*26, s2: 26, prefix: "ZS-" },
+
+                { start: 0x390000, s1: 1024, s2:  32, prefix: "F-G" },
+                { start: 0x398000, s1: 1024, s2:  32, prefix: "F-H" },
+
+                { start: 0x3C4421, s1: 1024,  s2: 32, prefix: "D-A", first: 'AAA', last: 'OZZ' },
+                { start: 0x3C0001, s1: 26*26, s2: 26, prefix: "D-A", first: 'PAA', last: 'ZZZ' },
+                { start: 0x3C8421, s1: 1024,  s2: 32, prefix: "D-B", first: 'AAA', last: 'OZZ' },
+                { start: 0x3C2001, s1: 26*26, s2: 26, prefix: "D-B", first: 'PAA', last: 'ZZZ' },
+                { start: 0x3CC000, s1: 26*26, s2: 26, prefix: "D-C" },
+                { start: 0x3D04A8, s1: 26*26, s2: 26, prefix: "D-E" },
+                { start: 0x3D4950, s1: 26*26, s2: 26, prefix: "D-F" },
+                { start: 0x3D8DF8, s1: 26*26, s2: 26, prefix: "D-G" },
+                { start: 0x3DD2A0, s1: 26*26, s2: 26, prefix: "D-H" },
+                { start: 0x3E1748, s1: 26*26, s2: 26, prefix: "D-I" },
+
+                { start: 0x448421, s1: 1024,  s2: 32, prefix: "OO-" },
+                { start: 0x458421, s1: 1024,  s2: 32, prefix: "OY-" },
+                { start: 0x460000, s1: 26*26, s2: 26, prefix: "OH-" },
+                { start: 0x468421, s1: 1024,  s2: 32, prefix: "SX-" },
+                { start: 0x490421, s1: 1024,  s2: 32, prefix: "CS-" },
+                { start: 0x4A0421, s1: 1024,  s2: 32, prefix: "YR-" },
+                { start: 0x4B8421, s1: 1024,  s2: 32, prefix: "TC-" },
+                { start: 0x740421, s1: 1024,  s2: 32, prefix: "JY-" },
+                { start: 0x760421, s1: 1024,  s2: 32, prefix: "AP-" },
+                { start: 0x768421, s1: 1024,  s2: 32, prefix: "9V-" },
+                { start: 0x778421, s1: 1024,  s2: 32, prefix: "YK-" },
+                { start: 0xC00001, s1: 26*26, s2: 26, prefix: "C-F" },
+                { start: 0xC044A9, s1: 26*26, s2: 26, prefix: "C-G" },
+                { start: 0xE01041, s1: 4096,  s2: 64, prefix: "LV-" }
+        ];
+
+        // numeric registrations
+        //  start: start hexid in range
+        //  first: first numeric registration
+        //  count: number of numeric registrations
+        //  template: registration template, trailing characters are replaced with the numeric registration
+        var numeric_mappings = [
+                { start: 0x140000, first: 0,    count: 100000, template: "RA0000" },
+                { start: 0x0B03E8, first: 1000, count: 1000,   template: "CUT0000" }
+        ];
+
+        // fill in some derived data
+        for (var i = 0; i < stride_mappings.length; ++i) {
+                var mapping = stride_mappings[i];
+
+                if (!mapping.alphabet) {
+                        mapping.alphabet = full_alphabet;
+                }
+
+                if (mapping.first) {
+                        var c1 = mapping.alphabet.indexOf(mapping.first.charAt(0));
+                        var c2 = mapping.alphabet.indexOf(mapping.first.charAt(1));
+                        var c3 = mapping.alphabet.indexOf(mapping.first.charAt(2));
+                        mapping.offset = c1 * mapping.s1 + c2 * mapping.s2 + c3;
+                } else {
+                        mapping.offset = 0;
+                }
+
+                if (mapping.last) {
+                        var c1 = mapping.alphabet.indexOf(mapping.last.charAt(0));
+                        var c2 = mapping.alphabet.indexOf(mapping.last.charAt(1));
+                        var c3 = mapping.alphabet.indexOf(mapping.last.charAt(2));
+                        mapping.end = mapping.start - mapping.offset +
+                                c1 * mapping.s1 +
+                                c2 * mapping.s2 +
+                                c3 - mapping.offset;
+                } else {
+                        mapping.end = mapping.start - mapping.offset +
+                                (mapping.alphabet.length - 1) * mapping.s1 +
+                                (mapping.alphabet.length - 1) * mapping.s2 +
+                                (mapping.alphabet.length - 1);
+                }
+        }
+
+        for (var i = 0; i < numeric_mappings.length; ++i) {
+                numeric_mappings[i].end = numeric_mappings[i].start + numeric_mappings[i].count - 1;
+        }
+
+        function lookup(hexid) {
+                var hexid = +("0x" + hexid);
+
+                reg = n_reg(hexid);
+                if (reg)
+                        return reg;
+
+                reg = ja_reg(hexid);
+                if (reg)
+                        return reg;
+
+                reg = hl_reg(hexid);
+                if (reg)
+                        return reg;
+
+                reg = numeric_reg(hexid);
+                if (reg)
+                        return reg;
+
+                reg = stride_reg(hexid);
+                if (reg)
+                        return reg;
+
+                return null;
+        }
+
+        function stride_reg(hexid) {
+                // try the mappings in stride_mappings
+                var i;
+                for (i = 0; i < stride_mappings.length; ++i) {
+                        var mapping = stride_mappings[i];
+                        if (hexid < mapping.start || hexid > mapping.end)
+                                continue;
+
+                        var offset = hexid - mapping.start + mapping.offset;
+
+                        var i1 = Math.floor(offset / mapping.s1);
+                        offset = offset % mapping.s1;
+                        var i2 = Math.floor(offset / mapping.s2);
+                        offset = offset % mapping.s2;
+                        var i3 = offset;
+
+                        if (i1 < 0 || i1 >= mapping.alphabet.length ||
+                            i2 < 0 || i2 >= mapping.alphabet.length ||
+                            i3 < 0 || i3 >= mapping.alphabet.length)
+                                continue;
+
+                        return mapping.prefix + mapping.alphabet.charAt(i1) + mapping.alphabet.charAt(i2) + mapping.alphabet.charAt(i3);
+                }
+
+                // nothing
+                return null;
+        }
+
+        function numeric_reg(hexid) {
+                // try the mappings in numeric_mappings
+                var i;
+                for (i = 0; i < numeric_mappings.length; ++i) {
+                        var mapping = numeric_mappings[i];
+                        if (hexid < mapping.start || hexid > mapping.end)
+                                continue;
+
+                        var reg = (hexid - mapping.start + mapping.first) + "";
+                        return mapping.template.substring(0, mapping.template.length - reg.length) + reg;
+                }
+        }
+
+        //
+        // US N-numbers
+        //
+
+        function n_letters(rem) {
+                if (rem == 0)
+                        return "";
+
+                --rem;
+                return limited_alphabet.charAt(Math.floor(rem / 25)) + n_letter(rem % 25);
+        }
+
+        function n_letter(rem) {
+                if (rem == 0)
+                        return "";
+
+                --rem;
+                return limited_alphabet.charAt(rem);
+        }
+
+        function n_reg(hexid) {
+                var offset = hexid - 0xA00001;
+                if (offset < 0 || offset >= 915399) {
+                        return null;
+                }
+
+                var digit1 = Math.floor(offset / 101711) + 1;
+                var reg = "N" + digit1;
+                offset = offset % 101711;
+                if (offset <= 600) {
+                        // Na, NaA .. NaZ, NaAA .. NaZZ
+                        return reg + n_letters(offset);
+                }
+
+                // Na0* .. Na9*
+                offset -= 601;
+
+                var digit2 = Math.floor(offset / 10111);
+                reg += digit2;
+                offset = offset % 10111;
+
+                if (offset <= 600) {
+                        // Nab, NabA..NabZ, NabAA..NabZZ
+                        return reg + n_letters(offset);
+                }
+
+                // Nab0* .. Nab9*
+                offset -= 601;
+
+                var digit3 = Math.floor(offset / 951);
+                reg += digit3;
+                offset = offset % 951;
+
+                if (offset <= 600) {
+                        // Nabc, NabcA .. NabcZ, NabcAA .. NabcZZ
+                        return reg + n_letters(offset);
+                }
+
+                // Nabc0* .. Nabc9*
+                offset -= 601;
+
+                var digit4 = Math.floor(offset / 35);
+                reg += digit4.toFixed(0);
+                offset = offset % 35;
+
+                if (offset <= 24) {
+                        // Nabcd, NabcdA .. NabcdZ
+                        return reg + n_letter(offset);
+                }
+
+                // Nabcd0 .. Nabcd9
+                offset -= 25;
+                return reg + offset.toFixed(0);
+        }
+
+        // South Korea
+        function hl_reg(hexid) {
+                if (hexid >= 0x71BA00 && hexid <= 0x71bf99) {
+                        return "HL" + (hexid - 0x71BA00 + 0x7200).toString(16);
+                }
+
+                if (hexid >= 0x71C000 && hexid <= 0x71C099) {
+                        return "HL" + (hexid - 0x71C000 + 0x8000).toString(16);
+                }
+
+                if (hexid >= 0x71C200 && hexid <= 0x71C299) {
+                        return "HL" + (hexid - 0x71C200 + 0x8200).toString(16);
+                }
+
+                return null;
+        }
+
+        // Japan
+        function ja_reg(hexid) {
+                var offset = hexid - 0x840000;
+                if (offset < 0 || offset >= 229840)
+                        return null;
+
+                var reg = "JA";
+
+                var digit1 = Math.floor(offset / 22984);
+                if (digit1 < 0 || digit1 > 9)
+                        return null;
+                reg += digit1;
+                offset = offset % 22984;
+
+                var digit2 = Math.floor(offset / 916);
+                if (digit2 < 0 || digit2 > 9)
+                        return null;
+                reg += digit2;
+                offset = offset % 916;
+
+                if (offset < 340) {
+                        // 3rd is a digit, 4th is a digit or letter
+                        var digit3 = Math.floor(offset / 34);
+                        reg += digit3;
+                        offset = offset % 34;
+
+                        if (offset < 10) {
+                                // 4th is a digit
+                                return reg + offset;
+                        }
+
+                        // 4th is a letter
+                        offset -= 10;
+                        return reg + limited_alphabet.charAt(offset);
+                }
+
+                // 3rd and 4th are letters
+                offset -= 340;
+                var letter3 = Math.floor(offset / 24);
+                return reg + limited_alphabet.charAt(letter3) + limited_alphabet.charAt(offset % 24);
+        }
+
+        return lookup;
+})();