Equality checks for structures

.github/workflows/test.yml

@@ -93,8 +93,10 @@ jobs:
           distro: ${{ matrix.distro }}
           install: |
             apt-get update -q -y
-            apt-get install -q -y make gcc gfortran
-          run: make test
+            apt-get install -q -y make gcc g++ gfortran
+          run: |
+            export ENABLE_CPP=1
+            make test
 
   test-macos:
     name: Test on MacOS

CHANGELOG.md

@@ -9,16 +9,27 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 
 ## [Unreleased]
 
-Upcoming maintenance release, possibly around 1 August 2026.
+Upcoming feature release, possibly around 1 August 2026.
 
 ### Added
 
  - #316: Spherical offset positions along a grat circle in specified direction and distance, based on the __astropy__
    `offset_by()` function. Added `novas_offset_by()`, `novas_equ_offset_by()` functions; and `Equatorial::offset()`, 
    `Ecliptic::offset()`, `Galactic::offset()`, and `Horizontal::offset()` methods. (thanks to aleberti)
 
+ - #318: New functions to check for effective equality of data structures, within typical tolerances of the library.
+   The functions are in `cmp.c`, and have names `novas_equals_[...]()`.
+
+ - #318: `CatalogEntry`, `OrbitalSystem`, `Orbital`, `Source`, `Observer`, and `Frame` now have `equals()` methods
+   as well as overridden `==` and `!=` operators, thanks to the new C99 comparison functions.
+
 ### Changed
 
+ - #317: Avoid `memcmp()` in testing structs for equality, using new comparison functions instead.
+
+ - #318: `Vector::equals()` to use the new `novas_equals_vector()` for consitent implementation between the C99 and 
+   C++ APIs.
+
  - Improved CMake installation of examples (no unintended files, C++ examples only if `ENABLE_CPP` option is used). 
 
  - Adjust C++ testing precision on tests that can trip up, depending on the platform.
@@ -32,6 +43,7 @@ Upcoming maintenance release, possibly around 1 August 2026.
  - `examples/Makefile` to work standalone, without `config.mk`.
 
  - Fix wrong argument types in error traces of `Source` and `Ecliptic` (found by CodeQL).
+
 
 
 ## [1.6.0] - 2026-04-27

config.mk

@@ -170,7 +170,7 @@ endif
 SOURCES = target.c observer.c earth.c equator.c system.c transform.c cio.c \
           orbital.c spectral.c grav.c nutation.c timescale.c frames.c place.c \
           calendar.c refract.c naif.c parse.c util.c planets.c itrf.c \
-          ephemeris.c solsys3.c solsys-ephem.c moon.c
+          ephemeris.c solsys3.c solsys-ephem.c moon.c cmp.c
 
 # Generate a list of object (obj/*.o) files from the input sources
 OBJECTS := $(addprefix $(OBJ)/,$(subst .c,.o,$(SOURCES)))

include/novas.h

@@ -3384,7 +3384,7 @@ int novas_icrs_to_sys(const double *in, double jd_tdb, enum novas_accuracy accur
 int novas_sys_to_icrs(enum novas_reference_system sys, const double *in, double jd_tdb, enum novas_accuracy accuracy, double *out);
 
 
-// ---------------------- Added in 1.6.0 -------------------------
+// ---------------------- Added in 1.7.0 -------------------------
 
 // in util.c
 /// @c_util
@@ -3393,6 +3393,44 @@ int novas_offset_by(double lon, double lat, double direction, double distance, d
 /// @c_util
 int novas_equ_offset_by(double ra, double dec, double direction, double distance, double *restrict out_ra, double *restrict out_dec);
 
+// in cmp.c
+/// @c_util
+int novas_equals_vector(const double *a, const double *b, double tol);
+
+/// @c_time
+int novas_equals_timespec(const novas_timespec *a, const novas_timespec *b);
+
+/// @c_observer
+int novas_equals_on_surface(const on_surface *a, const on_surface *b);
+
+/// @c_observer
+int novas_equals_near_earth(const in_space *a, const in_space *b);
+
+/// @c_observer
+int novas_equals_ssb_posvel(const in_space *a, const in_space *b);
+
+/// @c_observer
+int novas_equals_observer(const observer *a, const observer *b);
+
+/// @c_source
+int novas_equals_cat_entry(const cat_entry *a, const cat_entry *b);
+
+/// @c_source
+int novas_equals_orbsys(const novas_orbital_system *a, const novas_orbital_system *b);
+
+/// @c_source
+int novas_equals_orbital(const novas_orbital *a, const novas_orbital *b);
+
+/// @c_source
+int novas_equals_object(const object *a, const object *b);
+
+/// @c_apparent
+int novas_equals_sky_pos(const sky_pos *a, const sky_pos *b);
+
+int novas_equals_planet_bundle(const novas_planet_bundle *a, const novas_planet_bundle *b);
+
+/// @c_frame
+int novas_equals_frame(const novas_frame *a, const novas_frame *b);
 
 // <================= END of SuperNOVAS API =====================>
 

include/supernovas.h

@@ -1483,6 +1483,12 @@ class Observer : public Validating {
 
   virtual bool is_geocentric() const;
 
+  virtual bool equals(const Observer& other) const;
+
+  bool operator==(const Observer& other) const;
+
+  bool operator!=(const Observer& other) const;
+
   /// @ingroup frame
   Frame frame_at(const Time& time, enum novas_accuracy accuracy = NOVAS_FULL_ACCURACY) const;
 
@@ -1547,6 +1553,8 @@ class GeodeticObserver : public Observer {
 
   bool is_geodetic() const override;
 
+  bool equals(const Observer& other) const override;
+
   Site site() const;
 
   Velocity itrs_velocity() const;
@@ -1932,6 +1940,12 @@ class Frame : public Validating {
 
   Frame& operator=(const Frame& frame);
 
+  bool equals(const Frame& other) const;
+
+  bool operator==(const Frame& other) const;
+
+  bool operator!=(const Frame& other) const;
+
   const novas_frame* _novas_frame() const;
 
   enum novas_accuracy accuracy() const;
@@ -1997,6 +2011,12 @@ class Source : public Validating {
 
   enum novas_object_type type() const;
 
+  bool equals(const Source& other) const;
+
+  bool operator==(const Source &other) const;
+
+  bool operator!=(const Source &other) const;
+
   /// @ingroup apparent
   Apparent apparent_in(const Frame &frame) const;
 
@@ -2054,7 +2074,7 @@ class Source : public Validating {
 class CatalogEntry : public Validating {
 private:
   cat_entry _entry = {};   ///< stored catalog entry
-  Equinox _sys;                   ///< stored catalog system
+  Equinox _sys;            ///< stored catalog system
 
   void validate(const char *loc);
 
@@ -2069,6 +2089,12 @@ class CatalogEntry : public Validating {
 
   const cat_entry* _cat_entry() const;
 
+  bool equals(const CatalogEntry& other) const;
+
+  bool operator==(const CatalogEntry& other) const;
+
+  bool operator!=(const CatalogEntry& other) const;
+
   const Equinox& system() const;
 
   std::string name() const;
@@ -2291,6 +2317,12 @@ class OrbitalSystem : public Validating {
 public:
   const novas_orbital_system * _novas_orbital_system() const;
 
+  bool equals(const OrbitalSystem& other) const;
+
+  bool operator==(const OrbitalSystem& other) const;
+
+  bool operator!=(const OrbitalSystem& other) const;
+
   Planet center() const;
 
   Angle obliquity() const;
@@ -2361,6 +2393,12 @@ class Orbital : public Validating {
   static Orbital from_mean_motion(const OrbitalSystem& system, const Time& ref_time, const Coordinate& semi_major, const Angle& mean_anomaly,
           double rad_per_s);
 
+  bool equals(const Orbital& other) const;
+
+  bool operator==(const Orbital& other) const;
+
+  bool operator!=(const Orbital& other) const;
+
   const novas_orbital * _novas_orbital() const;
 
   OrbitalSystem system() const;

src/CMakeLists.txt

@@ -33,6 +33,7 @@ set(SUPERNOVAS_CORE_SOURCES
     solsys3.c
     solsys-ephem.c
     moon.c
+    cmp.c
 )