update cmakelists

.gitignore

@@ -1,5 +1,6 @@
 .env
 build/
+build*/
 .DS_Store
 config.json
 .vscode

CMakeLists.txt

@@ -246,7 +246,9 @@ else()
             hammy_append_supported_c_flags(HAMMY_ANALYZER_FLAGS
                 -fanalyzer-verbosity=${ANALYZER_VERBOSITY}
                 -fanalyzer
-            )
+		--param=analyzer-checker=taint
+            	--Wanalyzer-too-complex
+	    )
         endif()
     elseif(CMAKE_C_COMPILER_ID MATCHES "Clang")
         # Clang-only diagnostics. Clang has no in-compiler equivalent of
@@ -413,6 +415,8 @@ else()
         OUTPUT "${CONCORD_INSTALL_SCRIPT}"
         @ONLY
         CONTENT [[
+cmake_policy(SET CMP0057 NEW)
+
 file(MAKE_DIRECTORY "@CONCORD_INCLUDE_DIR@/concord" "@CONCORD_PREFIX@/lib")
 
 # Upstream flattens all three header directories into one include/concord. Check
@@ -594,6 +598,11 @@ target_include_directories(hammy SYSTEM PRIVATE
 # warning set and no second copy under third_party/ is needed.
 
 target_link_libraries(hammy PRIVATE concord::concord SQLite::SQLite3)
+
+if (NOT MSVC)
+    target_link_libraries(hammy PRIVATE m)
+endif()
+
 if(HAMMY_CONCORD_EXTERNAL)
     add_dependencies(hammy ${HAMMY_CONCORD_EXTERNAL})
 endif()

README.md

@@ -4,6 +4,15 @@ A Discord Bot for Ham/Amateur Radio
 Fun fact: The logo of Hammy is a function! It is: f(x) = e^(-x^2)sin(9x)
 
 ## Features
+Current features:
+- /freq <frequency (MHz)> [country (default: US)] - Show the band, segment and who can transmit (for that country).
+- /abbr <abbreviation> - Convert Abbreviation to Meaning and Context of Meaning.
+- /q <q-code> - Convert Q-Code to Question/Answer.
+- /phonetic <text> - Convert Text to Phonetics (useful for callsigns); If text is under 12 characters, also shows pronunciaction.
+- /morse <text> - Convert Text to Morse Code.
+- /dxcc <callsign> [grid (maidenhead locator)] - Show the DXCC Entity of a Callsign.
+- /ping - Ping the Bot.
+
 Currently in-development, many features planned!
 
 ## Architecture

include/hammy/commands.h

@@ -0,0 +1,16 @@
+// commands.h
+#ifndef HAMMY_COMMANDS_H
+#define HAMMY_COMMANDS_H
+
+#include <concord/discord.h>
+#include <hammy/types.h>
+
+void hammy_cmd_ping(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb);      // Ping
+void hammy_cmd_morse(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb);     // Text -> Morse
+void hammy_cmd_freq(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb);      // Frequency lookup
+void hammy_cmd_q(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb);         // Q-Code lookup
+void hammy_cmd_abbr(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb);      // Abbreviation lookup
+void hammy_cmd_phonetic(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb);  // Callsign -> Phonetics
+void hammy_cmd_dxcc(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb);      // Callsign + Grid -> DXCC
+
+#endif

include/hammy/embeds.h

@@ -8,11 +8,11 @@
 static inline bool hammy_embeds_genericerror(struct discord *client, struct discord_embed *out) {
     if (!out || !client) { return false; }
 
-    static struct discord_embed_footer footer = { .text = "Hammy Bot" };
+    static struct discord_embed_footer footer = { .text = (char*)"Hammy Bot" };
 
     out[0] = (struct discord_embed){
-        .title = "An Error Occurred",
+        .title = (char*)"An Error Occurred",
-        .description = "An error occurred while processing your request.",
+        .description = (char*)"An error occurred while processing your request.",
         .color = 0xFF0000,
         .timestamp = discord_timestamp(client),
         .footer = &footer,
@@ -26,8 +26,8 @@ static inline bool hammy_embeds_genericerror(struct discord *client, struct disc
 static inline bool hammy_embeds_customerror(struct discord *client,
                                             struct discord_embed *out,
                                             struct discord_embed_fields *fieldsOut,
-                                            char *title,
+                                            const char *title,
-                                            char *description,
+                                            const char *description,
                                             struct discord_embed_field *fields,
                                             int fieldCount)
 {
@@ -35,7 +35,7 @@ static inline bool hammy_embeds_customerror(struct discord *client,
     if (fieldCount < 0 || (fieldCount > 0 && !fields)) { return false; }
     if (fieldCount > 0 && !fieldsOut) { return false; }
 
-    static struct discord_embed_footer footer = { .text = "Hammy Bot" };
+    static struct discord_embed_footer footer = { .text = (char*)"Hammy Bot" };
 
     if (fieldCount > 0) {
         *fieldsOut = (struct discord_embed_fields){
@@ -45,8 +45,8 @@ static inline bool hammy_embeds_customerror(struct discord *client,
     }
 
     out[0] = (struct discord_embed){
-        .title = title,
+        .title = (char*)title,
-        .description = description,
+        .description = (char*)description,
         .color = 0xFF0000,
         .timestamp = discord_timestamp(client),
         .footer = &footer,
@@ -61,8 +61,8 @@ static inline bool hammy_embeds_customerror(struct discord *client,
 static inline bool hammy_embeds_customembed(struct discord *client,
                                               struct discord_embed *out,
                                               struct discord_embed_fields *fieldsOut,
-                                              char *title,
+                                              const char *title,
-                                              char *description,
+                                              const char *description,
                                               struct discord_embed_field *fields,
                                               int fieldCount,
                                               int color)
@@ -71,7 +71,7 @@ static inline bool hammy_embeds_customembed(struct discord *client,
     if (fieldCount < 0 || (fieldCount > 0 && !fields)) { return false; }
     if (fieldCount > 0 && !fieldsOut) { return false; }
 
-    static struct discord_embed_footer footer = { .text = "Hammy Bot" };
+    static struct discord_embed_footer footer = { .text = (char*)"Hammy Bot" };
 
     if (fieldCount > 0) {
         *fieldsOut = (struct discord_embed_fields){
@@ -81,8 +81,8 @@ static inline bool hammy_embeds_customembed(struct discord *client,
     }
 
     out[0] = (struct discord_embed){
-        .title = title,
+        .title = (char*)title,
-        .description = description,
+        .description = (char*)description,
         .color = color,
         .timestamp = discord_timestamp(client),
         .footer = &footer,

include/hammy/geo.h

@@ -0,0 +1,43 @@
+#ifndef HAMMY_GEO_H
+#define HAMMY_GEO_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+// Maidenhead locators and great-circle maths. No dependencies beyond libm, no
+// state, no database - safe to call from any thread.
+//
+// Lives in its own module rather than utils.h because /grid, /beacon and /sat
+// will all want it, and mixing coordinate maths in with string helpers makes
+// both harder to find.
+
+// 8 characters plus NUL. Longer locators exist in theory; nothing uses them.
+#define HAMMY_GRID_MAX 9
+
+// Writes a Maidenhead locator for the given coordinates. precision must be
+// 2 (field), 4 (square), 6 (subsquare) or 8 (extended square); 6 is what people
+// quote. Returns false on out-of-range coordinates, bad precision, or too small
+// a buffer.
+bool hammy_grid_from_latlon(double lat, double lon, int precision, char* out, size_t cap);
+
+// Parses a 2, 4, 6 or 8 character locator. Case-insensitive, ignores embedded
+// whitespace, rejects anything longer rather than truncating it.
+//
+// Returns the CENTER of the square, not its south-west corner: using the corner
+// biases every distance by up to half a square, which at 4-character precision
+// is about 60 km.
+bool hammy_grid_to_latlon(const char* grid, double* outLat, double* outLon);
+
+// Haversine distance in km and initial bearing in degrees true. Either output
+// pointer may be NULL.
+void hammy_great_circle(double lat1, double lon1, double lat2, double lon2,
+                        double* outDistKm, double* outBearingDeg);
+
+// The other way round the planet.
+double hammy_long_path_km(double shortPathKm);
+double hammy_reciprocal_bearing(double bearingDeg);
+
+// 16-point compass abbreviation ("NNE"). Points at static storage.
+const char* hammy_compass_point(double bearingDeg);
+
+#endif

include/hammy/refdb.h

@@ -111,7 +111,7 @@ struct hammy_freq_t {
     int64_t bandHighHz;
  
     // The frequency sits exactly on a band or segment boundary. Worth saying
-    // out loud: a signal of any width centred there straddles both sides.
+    // out loud: a signal of any width centerd there straddles both sides.
     bool atBandEdge;
     bool atSegmentEdge;
  

sqlite/03-bands.sql

@@ -86,7 +86,7 @@ SELECT v.band_id, 'US', lc.id, v.low_hz, v.high_hz, v.modes, v.max_power_w, v.no
  WHERE lc.country = 'US' AND lc.rank >= 30;
 
 -- 60m: five discrete channels, General and above. Stored as channel-width
--- ranges; the USB dial frequency is the channel centre minus 1.5 kHz.
+-- ranges; the USB dial frequency is the channel center minus 1.5 kHz.
 INSERT INTO band_segments (band_id, country, class_id, low_hz, high_hz, modes, max_power_w, notes)
 SELECT 5, 'US', lc.id, v.low_hz, v.high_hz, 'CW,DATA,PHONE', NULL, v.notes
   FROM license_classes lc

src/commands/abbr.c

@@ -4,6 +4,7 @@
 #include <string.h>
 
 #include <hammy/command.h>
+#include <hammy/commands.h>
 #include <hammy/job.h>
 #include <hammy/refdb.h>
 #include <hammy/utils.h>
@@ -31,7 +32,7 @@ void hammy_cmd_abbr(const hammy_job_t* job, struct discord* client, hammy_refdb_
         return;
     }
 
-    hammy_to_uppercase(abbr);
+    hammy_to_uppercase((char*)abbr);
     
     snprintf(body, sizeof(body), "Abbreviation: `%s`\nMeaning: `%s`\nUsage Context: `%s`", abbr, (str ? str : "Not Specified"), (context ? context : "Not Specified"));
 

src/commands/dxcc.c

@@ -0,0 +1,191 @@
+#include <concord/discord.h>
+#include <inttypes.h>
+#include <math.h>
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+
+#include <hammy/command.h>
+#include <hammy/commands.h>
+#include <hammy/geo.h>
+#include <hammy/job.h>
+#include <hammy/refdb.h>
+#include <hammy/utils.h>
+
+#define HAMMY_DXCC_BODY_MAX 2048
+#define HAMMY_DXCC_TITLE_MAX 128
+
+// Formats a signed decimal degree as "38.90 N" / "77.04 W".
+static void hammy_dxcc_fmt_coord(double value, bool isLatitude, char* out, size_t cap) {
+    char hemi = isLatitude ? (value >= 0.0 ? 'N' : 'S')
+                           : (value >= 0.0 ? 'E' : 'W');
+
+    snprintf(out, cap, "%.2f %c", fabs(value), hemi);
+}
+
+// Formats a UTC offset as "UTC+9", "UTC-5", "UTC+5:30". cty.dat carries half
+// hour offsets for a handful of entities, so the fractional case is real.
+static void hammy_dxcc_fmt_offset(double offset, char* out, size_t cap) {
+    int totalMinutes = (int)lround(offset * 60.0);
+    char sign = totalMinutes < 0 ? '-' : '+';
+
+    if (totalMinutes < 0) { totalMinutes = -totalMinutes; }
+
+    int hours = totalMinutes / 60;
+    int minutes = totalMinutes % 60;
+
+    if (minutes) {
+        snprintf(out, cap, "UTC%c%d:%02d", sign, hours, minutes);
+    } else {
+        snprintf(out, cap, "UTC%c%d", sign, hours);
+    }
+}
+
+// Wall-clock time at the entity. cty.dat gives STANDARD offsets with no notion
+// of summer time, so this can be an hour out for part of the year. Said so in
+// the output rather than quietly presenting it as exact.
+static void hammy_dxcc_fmt_local_time(double offset, char* out, size_t cap) {
+    time_t now = time(NULL);
+
+    if (now == (time_t)-1) {
+        snprintf(out, cap, "unknown");
+        return;
+    }
+
+    time_t shifted = now + (time_t)lround(offset * 3600.0);
+    struct tm tmBuf;
+
+    // gmtime_r rather than gmtime: instant commands run on the gateway thread
+    // and deferred ones on a worker, and gmtime's static buffer is shared.
+    if (!gmtime_r(&shifted, &tmBuf)) {
+        snprintf(out, cap, "unknown");
+        return;
+    }
+
+    snprintf(out, cap, "%02d:%02d", tmBuf.tm_hour, tmBuf.tm_min);
+}
+
+// Instant command: runs on the gateway thread, sends a fresh response.
+void hammy_cmd_dxcc(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb) {
+    if (!refdb) {
+        hammy_job_respond(job, client, "Error", "Reference data is unavailable. Please try again later.", true);
+        return;
+    }
+
+    const char* callsign = hammy_job_get_arg(job, "callsign");
+    if (!callsign || !*callsign) {
+        hammy_job_respond(job, client, "Error", "No callsign provided for lookup.", true);
+        return;
+    }
+
+    hammy_dxcc_t entity;
+    if (!hammy_refdb_dxcc(refdb, callsign, &entity)) {
+        char body[HAMMY_DXCC_BODY_MAX];
+
+        snprintf(body, sizeof(body),
+                 "No DXCC entity matches `%s`.\n\n"
+                 "Prefixes are matched longest-first, so this usually means a typo "
+                 "or a prefix that has never been allocated.", callsign);
+
+        hammy_job_respond(job, client, "Entity Not Found!", body, true);
+        return;
+    }
+
+    char gridStr[HAMMY_GRID_MAX] = "unknown";
+    bool haveEntityGrid = hammy_grid_from_latlon(entity.latitude, entity.longitude, 6,
+                                                 gridStr, sizeof(gridStr));
+
+    char latStr[24];
+    char lonStr[24];
+    hammy_dxcc_fmt_coord(entity.latitude, true, latStr, sizeof(latStr));
+    hammy_dxcc_fmt_coord(entity.longitude, false, lonStr, sizeof(lonStr));
+
+    char offsetStr[24];
+    char timeStr[16];
+    hammy_dxcc_fmt_offset(entity.utcOffset, offsetStr, sizeof(offsetStr));
+    hammy_dxcc_fmt_local_time(entity.utcOffset, timeStr, sizeof(timeStr));
+
+    char title[HAMMY_DXCC_TITLE_MAX];
+    char upperCallsign[HAMMY_CALLSIGN_MAX];
+    snprintf(upperCallsign, sizeof(upperCallsign), "%s", callsign);
+    hammy_to_uppercase(upperCallsign);
+    snprintf(title, sizeof(title), "%s - %s", upperCallsign, entity.name);
+
+    char body[HAMMY_DXCC_BODY_MAX];
+    int len = 0;
+
+    len += snprintf(body + len, sizeof(body) - (size_t)len,
+                    "Entity: `%s` (DXCC `%d`)\n"
+                    "Continent: `%s`  CQ zone: `%d`  ITU zone: `%d`\n",
+                    entity.name, entity.entityId, entity.continent,
+                    entity.cqZone, entity.ituZone);
+
+    if (haveEntityGrid) {
+        len += snprintf(body + len, sizeof(body) - (size_t)len,
+                        "Location: `%s` (%s, %s)\n", gridStr, latStr, lonStr);
+    } else {
+        len += snprintf(body + len, sizeof(body) - (size_t)len,
+                        "Location: %s, %s\n", latStr, lonStr);
+    }
+
+    len += snprintf(body + len, sizeof(body) - (size_t)len,
+                    "Local time: `%s` (`%s`, standard time)\n", timeStr, offsetStr);
+
+    // Saying WHICH rule matched matters more than it looks. An exact hit means
+    // cty.dat carries a whole-callsign override, and a short prefix hit on a
+    // long callsign is a hint that the entity guess may be loose.
+    if (entity.exact) {
+        len += snprintf(body + len, sizeof(body) - (size_t)len,
+                        "Matched: exact callsign rule `%s`\n", entity.matchedPrefix);
+    } else {
+        len += snprintf(body + len, sizeof(body) - (size_t)len,
+                        "Matched: prefix `%s`\n", entity.matchedPrefix);
+    }
+
+    // Optional second argument: the asker's own locator, which turns this from
+    // trivia into something you can point an antenna with.
+    const char* fromGrid = hammy_job_get_arg(job, "grid");
+
+    if (fromGrid && *fromGrid) {
+        double fromLat = 0.0;
+        double fromLon = 0.0;
+
+        if (!hammy_grid_to_latlon(fromGrid, &fromLat, &fromLon)) {
+            len += snprintf(body + len, sizeof(body) - (size_t)len,
+                            "\nCould not read `%s` as a Maidenhead locator. "
+                            "Try something like `JN76` or `JN76gb`.\n", fromGrid);
+        } else {
+            double distKm = 0.0;
+            double bearing = 0.0;
+            hammy_great_circle(fromLat, fromLon, entity.latitude, entity.longitude,
+                               &distKm, &bearing);
+
+            double longKm = hammy_long_path_km(distKm);
+            double longBearing = hammy_reciprocal_bearing(bearing);
+
+            char fromNorm[HAMMY_GRID_MAX];
+            if (!hammy_grid_from_latlon(fromLat, fromLon, 6, fromNorm, sizeof(fromNorm))) {
+                snprintf(fromNorm, sizeof(fromNorm), "%s", fromGrid);
+            }
+
+            len += snprintf(body + len, sizeof(body) - (size_t)len,
+                            "\n**From %s**\n"
+                            "Short path: `%.0f km` (`%.0f mi`) bearing `%.0f` (%s)\n"
+                            "Long path: `%.0f km` bearing `%.0f` (%s)\n",
+                            fromNorm,
+                            distKm, distKm * 0.621371, bearing, hammy_compass_point(bearing),
+                            longKm, longBearing, hammy_compass_point(longBearing));
+        }
+    }
+
+    // The entity coordinates are a nominal center for the whole entity, not the
+    // station's own position. For the US that is a point in Washington DC, so a
+    // bearing to a California station will be well off. Worth admitting.
+    len += snprintf(body + len, sizeof(body) - (size_t)len,
+                    "\n-# Coordinates are the entity's nominal center, not the "
+                    "station's actual location.");
+
+    (void)len;
+
+    hammy_job_respond(job, client, title, body, false);
+}

src/commands/freq.c

@@ -7,6 +7,7 @@
 #include <stdarg.h>
 
 #include <hammy/command.h>
+#include <hammy/commands.h>
 #include <hammy/job.h>
 #include <hammy/refdb.h>
 
@@ -29,7 +30,10 @@ static void sb_addf(hammy_sb_t* sb, const char* fmt, ...) {
  
     va_list ap;
     va_start(ap, fmt);
+    #pragma clang diagnostic push
+    #pragma clang diagnostic ignored "-Wformat-nonliteral"
     int n = vsnprintf(sb->buf + sb->len, sb->cap - sb->len, fmt, ap);
+    #pragma clang diagnostic pop
     va_end(ap);
  
     if (n < 0) {
@@ -191,9 +195,9 @@ void hammy_cmd_freq(const hammy_job_t* job, struct discord* client, hammy_refdb_
 
     // Boundary warnings
     if (r.atBandEdge) {
-        sb_addf(&sb, "\n> This is exactly the band edge. A signal of any width centred here extends outside the band.\n");
+        sb_addf(&sb, "\n> This is exactly the band edge. A signal of any width centerd here extends outside the band.\n");
     } else if (r.atSegmentEdge) {
-        sb_addf(&sb, "\n> This is exactly a segment boundary, so a signal centred here straddles both sides.\n");
+        sb_addf(&sb, "\n> This is exactly a segment boundary, so a signal centerd here straddles both sides.\n");
     }
  
     if (sb.overflow) {

src/commands/morse.c

@@ -4,6 +4,7 @@
 #include <string.h>
 
 #include <hammy/command.h>
+#include <hammy/commands.h>
 #include <hammy/job.h>
 #include <hammy/refdb.h>
 
@@ -28,7 +29,7 @@
 // invalid JSON.
 static bool morse_append(char* buf, size_t cap, size_t* len, bool gap, const char* token) {
     size_t n = strlen(token);
-    size_t need = (*len > 0 ? 1 : 0) + (gap ? 2 : 0) + n;
+    size_t need = (*len > 0 ? 1u : 0u) + (gap ? 2u : 0u) + n;
 
     if (*len + need + 1 > cap) { return false; }
 

src/commands/phonetic.c

@@ -4,6 +4,7 @@
 #include <string.h>
 
 #include <hammy/command.h>
+#include <hammy/commands.h>
 #include <hammy/job.h>
 #include <hammy/refdb.h>
 #include <hammy/utils.h>
@@ -29,7 +30,7 @@
 // invalid JSON.
 static bool phonetic_append(char* buf, size_t cap, size_t* len, bool gap, const char* token) {
     size_t n = strlen(token);
-    size_t need = (*len > 0 ? 1 : 0) + (gap ? 2 : 0) + n;
+    size_t need = (*len > 0 ? 1u : 0u) + (gap ? 2u : 0u) + n;
 
     if (*len + need + 1 > cap) { return false; }
 
@@ -129,7 +130,7 @@ void hammy_cmd_phonetic(const hammy_job_t* job, struct discord* client, hammy_re
         memcpy(pronunciation + pronunciationLen, HAMMY_PHONETIC_TRUNCATED, sizeof(HAMMY_PHONETIC_TRUNCATED));
     }
 
-    hammy_to_uppercase(text);
+    hammy_to_uppercase((char*)text);
 
     // Reply with the phonetic words and how each of them is spoken.
     char body[sizeof(phonetic) + sizeof(pronunciation) + 48];

src/commands/ping.c

@@ -3,6 +3,7 @@
 #include <stdio.h>
 
 #include <hammy/command.h>
+#include <hammy/commands.h>
 #include <hammy/job.h>
 
 // Discord epoch, for turning a snowflake back into a wall-clock time.

src/commands/q.c

@@ -4,6 +4,7 @@
 #include <string.h>
 
 #include <hammy/command.h>
+#include <hammy/commands.h>
 #include <hammy/job.h>
 #include <hammy/refdb.h>
 #include <hammy/utils.h>
@@ -31,7 +32,7 @@ void hammy_cmd_q(const hammy_job_t* job, struct discord* client, hammy_refdb_t*
         return;
     }
 
-    hammy_to_uppercase(qcode);
+    hammy_to_uppercase((char*)qcode);
     
     snprintf(body, sizeof(body), "Q-Code: `%s`\nQuestion: `%s`\nAnswer: `%s`", qcode, (questionStr ? questionStr : "Not Specified"), (answerStr ? answerStr : "Not Specified"));
 

src/hammy/bot.c

@@ -52,7 +52,7 @@ static void hammy_bot_on_interaction(struct discord* client, const struct discor
             code = discord_create_interaction_response(client, event->id, event->token, &params, NULL);
         } else {
             params.data = &(struct discord_interaction_callback_data){
-                .content = "I don't know that command!"
+                .content = (char*)"I don't know that command!"
             };
 
             code = discord_create_interaction_response(client, event->id, event->token, &params, NULL);

src/hammy/command.c

@@ -2,21 +2,16 @@
 #include <string.h>
 
 #include <hammy/command.h>
+#include <hammy/commands.h> // Table
 
 // Handlers live in src/hammy/commands/. Declared here rather than in a header
 // so adding a command touches exactly two places: its own .c file and this
 // table.
-void hammy_cmd_ping(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb);      // Ping
-void hammy_cmd_morse(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb);     // Text -> Morse
-void hammy_cmd_freq(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb);      // Frequency lookup
-void hammy_cmd_q(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb);         // Q-Code lookup
-void hammy_cmd_abbr(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb);      // Abbreviation lookup
-void hammy_cmd_phonetic(const hammy_job_t* job, struct discord* client, hammy_refdb_t* refdb);  // Callsign -> Phonetics
 
 // TODO: Temporary - move to a proper options system; e.g. a vector of heap-allocated options or something. For now, just point at static storage.
 static struct discord_application_command_option morse_opts[] = {
-    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = "text",
+    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = (char*)"text",
-      .description = "Text to convert to Morse code", .required = true },
+      .description = (char*)"Text to convert to Morse code", .required = true },
 };
 
 static struct discord_application_command_options morse_opts_struct = {
@@ -25,10 +20,10 @@ static struct discord_application_command_options morse_opts_struct = {
 };
 
 static struct discord_application_command_option freq_opts[] = {
-    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = "frequency",
+    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = (char*)"frequency",
-      .description = "Frequency in MHz", .required = true },
+      .description = (char*)"Frequency in MHz", .required = true },
-    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = "country",
+    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = (char*)"country",
-       .description = "Country code to look up (e.g. US) - Defaults to US if none specified.", .required = false },
+       .description = (char*)"Country code to look up (e.g. US) - Defaults to US if none specified.", .required = false },
 };
 
 static struct discord_application_command_options freq_opts_struct = {
@@ -37,8 +32,8 @@ static struct discord_application_command_options freq_opts_struct = {
 };
 
 static struct discord_application_command_option q_opts[] = {
-    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = "q-code",
+    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = (char*)"q-code",
-      .description = "Q-Code to convert to Question/Answer", .required = true },
+      .description = (char*)"Q-Code to convert to Question/Answer", .required = true },
 };
 
 static struct discord_application_command_options q_opts_struct = {
@@ -47,8 +42,8 @@ static struct discord_application_command_options q_opts_struct = {
 };
 
 static struct discord_application_command_option abbr_opts[] = {
-    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = "abbreviation",
+    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = (char*)"abbreviation",
-      .description = "Abbreviation to convert to Meaning", .required = true },
+      .description = (char*)"Abbreviation to convert to Meaning", .required = true },
 };
 
 static struct discord_application_command_options abbr_opts_struct = {
@@ -57,8 +52,8 @@ static struct discord_application_command_options abbr_opts_struct = {
 };
 
 static struct discord_application_command_option phonetic_opts[] = {
-    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = "text",
+    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = (char*)"text",
-      .description = "Text to convert to Phonetics", .required = true },
+      .description = (char*)"Text to convert to Phonetics", .required = true },
 };
 
 static struct discord_application_command_options phonetic_opts_struct = {
@@ -66,6 +61,15 @@ static struct discord_application_command_options phonetic_opts_struct = {
     .array = phonetic_opts
 };
 
+static struct discord_application_command_option dxcc_opts[] = {
+    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = (char*)"callsign",
+      .description = (char*)"Callsign or prefix to look up", .required = true },
+    { .type = DISCORD_APPLICATION_OPTION_STRING, .name = (char*)"grid",
+      .description = (char*)"Your Maidenhead locator, for distance and bearing", .required = false },
+};
+
+static struct discord_application_command_options dxcc_opts_struct = { .size = 2, .array = dxcc_opts };
+
 // The command table. Pure data - no allocation, no lifetime, no destructor.
 // Copying an entry into the bot's vector is a plain struct copy, and the vector
 // may be created with a NULL destructor hook.
@@ -77,6 +81,7 @@ static const hammy_command_t hammy_builtin_commands[] = {
     { "freq", "Band, segment and who can transmit", &freq_opts_struct, &hammy_cmd_freq, true },
     { "q", "Convert Q-Code to the corresponding question and answer", &q_opts_struct, &hammy_cmd_q, true },
     { "phonetic", "Convert Text to Phonetics", &phonetic_opts_struct, &hammy_cmd_phonetic, true },
+    { "dxcc", "Look up the DXCC entity for a callsign", &dxcc_opts_struct, &hammy_cmd_dxcc, true },
     { "abbr", "Convert Abbreviation to Meaning and Context", &abbr_opts_struct, &hammy_cmd_abbr, true }
 
     // Tier 0 commands go here as they land. All pure computation, so instant:

src/hammy/geo.c

@@ -0,0 +1,197 @@
+#include <ctype.h>
+#include <math.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <string.h>
+
+#include <hammy/geo.h>
+
+// M_PI is POSIX, not C99, so it is absent under -std=c99 without _GNU_SOURCE.
+// Defining it here keeps the build strict and portable.
+#define HAMMY_PI 3.14159265358979323846
+
+// IUGG mean Earth radius. Any of the common radii agree to well within the
+// error a 6-character grid square already carries.
+#define HAMMY_EARTH_RADIUS_KM 6371.0088
+#define HAMMY_EARTH_CIRCUM_KM (2.0 * HAMMY_PI * HAMMY_EARTH_RADIUS_KM)
+
+static double deg_to_rad(double deg) { return deg * HAMMY_PI / 180.0; }
+static double rad_to_deg(double rad) { return rad * 180.0 / HAMMY_PI; }
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wbad-function-cast" // suppresses the dumb floor() cast to int warning
+bool hammy_grid_from_latlon(double lat, double lon, int precision, char* out, size_t cap) {
+    if (!out || cap < 3) { return false; }
+    if (lat < -90.0 || lat > 90.0 || lon < -180.0 || lon > 180.0) { return false; }
+    if (precision != 2 && precision != 4 && precision != 6 && precision != 8) { return false; }
+    if (cap < (size_t)precision + 1) { return false; }
+
+    // Shift into the all-positive space the locator system is defined over.
+    double lonA = lon + 180.0;
+    double latA = lat + 90.0;
+
+    // Clamp the poles and the antimeridian so floor() cannot walk off the end
+    // of the field letters at exactly +90 / +180.
+    if (lonA >= 360.0) { lonA = 359.999999; }
+    if (latA >= 180.0) { latA = 179.999999; }
+
+    int i = 0;
+
+    int f1 = (int)floor(lonA / 20.0);
+    int f2 = (int)floor(latA / 10.0);
+    out[i++] = (char)('A' + f1);
+    out[i++] = (char)('A' + f2);
+
+    double remLon = lonA - f1 * 20.0;
+    double remLat = latA - f2 * 10.0;
+
+    if (precision >= 4) {
+        int s1 = (int)floor(remLon / 2.0);
+        int s2 = (int)floor(remLat / 1.0);
+        out[i++] = (char)('0' + s1);
+        out[i++] = (char)('0' + s2);
+
+        remLon -= s1 * 2.0;
+        remLat -= s2 * 1.0;
+    }
+
+    if (precision >= 6) {
+        // A square is 2 deg of longitude by 1 deg of latitude, divided 24 ways.
+        int ss1 = (int)floor(remLon / (2.0 / 24.0));
+        int ss2 = (int)floor(remLat / (1.0 / 24.0));
+        if (ss1 > 23) { ss1 = 23; }
+        if (ss2 > 23) { ss2 = 23; }
+        out[i++] = (char)('a' + ss1);
+        out[i++] = (char)('a' + ss2);
+
+        remLon -= ss1 * (2.0 / 24.0);
+        remLat -= ss2 * (1.0 / 24.0);
+    }
+
+    if (precision >= 8) {
+        int e1 = (int)floor(remLon / (2.0 / 240.0));
+        int e2 = (int)floor(remLat / (1.0 / 240.0));
+        if (e1 > 9) { e1 = 9; }
+        if (e2 > 9) { e2 = 9; }
+        out[i++] = (char)('0' + e1);
+        out[i++] = (char)('0' + e2);
+    }
+
+    out[i] = '\0';
+
+    return true;
+}
+
+bool hammy_grid_to_latlon(const char* grid, double* outLat, double* outLon) {
+    if (!grid || !outLat || !outLon) { return false; }
+
+    char g[HAMMY_GRID_MAX];
+    size_t n = 0;
+
+    for (size_t i = 0; grid[i]; i++) {
+        if (isspace((unsigned char)grid[i])) { continue; }
+
+        // Reject rather than truncate. Silently clipping "IO91wm12345" to
+        // "IO91wm12" would hand back a plausible-looking position for input the
+        // user clearly got wrong.
+        if (n + 1 >= sizeof(g)) { return false; }
+
+        g[n++] = grid[i];
+    }
+    g[n] = '\0';
+
+    // Locators come in even-length pairs; 2, 4, 6 and 8 are the useful ones.
+    if (n != 2 && n != 4 && n != 6 && n != 8) { return false; }
+
+    int f1 = toupper((unsigned char)g[0]) - 'A';
+    int f2 = toupper((unsigned char)g[1]) - 'A';
+    if (f1 < 0 || f1 > 17 || f2 < 0 || f2 > 17) { return false; }
+
+    double lon = f1 * 20.0;
+    double lat = f2 * 10.0;
+    double lonSize = 20.0;
+    double latSize = 10.0;
+
+    if (n >= 4) {
+        if (!isdigit((unsigned char)g[2]) || !isdigit((unsigned char)g[3])) { return false; }
+        lon += (g[2] - '0') * 2.0;
+        lat += (g[3] - '0') * 1.0;
+        lonSize = 2.0;
+        latSize = 1.0;
+    }
+
+    if (n >= 6) {
+        int s1 = tolower((unsigned char)g[4]) - 'a';
+        int s2 = tolower((unsigned char)g[5]) - 'a';
+        if (s1 < 0 || s1 > 23 || s2 < 0 || s2 > 23) { return false; }
+        lon += s1 * (2.0 / 24.0);
+        lat += s2 * (1.0 / 24.0);
+        lonSize = 2.0 / 24.0;
+        latSize = 1.0 / 24.0;
+    }
+
+    if (n >= 8) {
+        if (!isdigit((unsigned char)g[6]) || !isdigit((unsigned char)g[7])) { return false; }
+        lon += (g[6] - '0') * (2.0 / 240.0);
+        lat += (g[7] - '0') * (1.0 / 240.0);
+        lonSize = 2.0 / 240.0;
+        latSize = 1.0 / 240.0;
+    }
+
+    // Report the CENTER of the square, not its south-west corner. Using the
+    // corner biases every distance by up to half a square, which at 4-character
+    // precision is about 60 km.
+    *outLon = lon + lonSize / 2.0 - 180.0;
+    *outLat = lat + latSize / 2.0 - 90.0;
+
+    return true;
+}
+
+void hammy_great_circle(double lat1, double lon1, double lat2, double lon2,
+                        double* outDistKm, double* outBearingDeg) {
+    double p1 = deg_to_rad(lat1);
+    double p2 = deg_to_rad(lat2);
+    double dp = p2 - p1;
+    double dl = deg_to_rad(lon2 - lon1);
+
+    if (outDistKm) {
+        // Haversine. The spherical law of cosines is shorter but loses precision
+        // for short distances, which is exactly the "how far to the next town"
+        // case people try first.
+        double a = sin(dp / 2.0) * sin(dp / 2.0)
+                 + cos(p1) * cos(p2) * sin(dl / 2.0) * sin(dl / 2.0);
+        if (a > 1.0) { a = 1.0; }
+
+        *outDistKm = 2.0 * HAMMY_EARTH_RADIUS_KM * asin(sqrt(a));
+    }
+
+    if (outBearingDeg) {
+        double y = sin(dl) * cos(p2);
+        double x = cos(p1) * sin(p2) - sin(p1) * cos(p2) * cos(dl);
+        double b = rad_to_deg(atan2(y, x));
+
+        *outBearingDeg = fmod(b + 360.0, 360.0);
+    }
+}
+
+double hammy_long_path_km(double shortPathKm) {
+    return HAMMY_EARTH_CIRCUM_KM - shortPathKm;
+}
+
+double hammy_reciprocal_bearing(double bearingDeg) {
+    return fmod(bearingDeg + 180.0, 360.0);
+}
+
+const char* hammy_compass_point(double bearingDeg) {
+    static const char* POINTS[16] = {
+        "N", "NNE", "NE", "ENE", "E", "ESE", "SE", "SSE",
+        "S", "SSW", "SW", "WSW", "W", "WNW", "NW", "NNW"
+    };
+
+    double b = fmod(bearingDeg + 360.0, 360.0);
+    int idx = (int)floor((b + 11.25) / 22.5) % 16;
+
+    return POINTS[idx];
+}
+
+#pragma clang diagnostic pop

src/hammy/pool.c

@@ -192,4 +192,4 @@ void hammy_pool_stats(hammy_pool_t* pool, size_t* outQueued, size_t* outBusy) {
     if (outBusy) { *outBusy = pool->busy; }
     if (outQueued) { *outQueued = pool->count; }
     pthread_mutex_unlock(&pool->lock);
-}
+}

src/hammy/refdb.c

@@ -196,6 +196,8 @@ static bool prepare(sqlite3* h, const char* sql, sqlite3_stmt** out) {
     return true;
 }
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wjump-misses-init" // suppresses the "jumped initialization of varaible" warning, has no effect here
 hammy_refdb_t* hammy_refdb_open(const char* path) {
     if (!path) { return NULL; }
 
@@ -272,6 +274,7 @@ fail:
     hammy_refdb_close(&db);
     return NULL;
 }
+#pragma GCC diagnostic pop
 
 bool hammy_refdb_close(hammy_refdb_t** db) {
     if (!db || !(*db)) { return false; }
@@ -818,7 +821,7 @@ bool hammy_refdb_freq(hammy_refdb_t* db, int64_t freqHz, const char* country,
     sqlite3_reset(st);
  
     // Sitting exactly on a segment boundary is worth flagging: a signal of any
-    // width centred there straddles both sides.
+    // width centerd there straddles both sides.
     st = db->stFreqSegEdge;
     sqlite3_reset(st);
     sqlite3_clear_bindings(st);

src/hammy/utils.c

@@ -2,12 +2,12 @@
 
 void hammy_to_uppercase(char* str) {
     for (size_t i = 0; str[i] != '\0'; i++) {
-        str[i] = toupper((unsigned char)str[i]);
+        str[i] = (char)toupper((unsigned char)str[i]);
     }
 }
 
 void hammy_to_lowercase(char* str) {
     for (size_t i = 0; str[i] != '\0'; i++) {
-        str[i] = tolower((unsigned char)str[i]);
+        str[i] = (char)tolower((unsigned char)str[i]);
     }
 }