proj_trans_array(): make it transform all coordinates even when an error occurs

3 files changed, 71 insertions, 8 deletions

diff --git a/docs/source/development/reference/functions.rst b/docs/source/development/reference/functions.rst
index 5b559d55..08b3e669 100644
--- a/docs/source/development/reference/functions.rst
+++ b/docs/source/development/reference/functions.rst
@@ -368,13 +368,22 @@ Coordinate transformation
 
     Batch transform an array of :c:type:`PJ_COORD`.
 
+    Performs transformation on all points, even if errors occur on some points
+    (new to 8.0. Previous versions would exit early in case of failure on a given point)
+
+    Individual points that fail to transform will have their components set to
+    ``HUGE_VAL``
+
     :param P: Transformation object
     :type P: :c:type:`PJ` *
     :param `direction`: Transformation direction.
     :type `direction`: PJ_DIRECTION
     :param n: Number of coordinates in :c:data:`coord`
     :type n: `size_t`
-    :returns: `int` 0 if all observations are transformed without error, otherwise returns error number
+    :returns: `int` 0 if all observations are transformed without error, otherwise returns error number.
+              This error number will be a precise error number if all coordinates that fail to transform
+              for the same reason, or a generic error code if they fail for different
+              reasons.
 
 
 Error reporting
diff --git a/src/4D_api.cpp b/src/4D_api.cpp
index 612be716..556a8c2d 100644
--- a/src/4D_api.cpp
+++ b/src/4D_api.cpp
@@ -377,18 +377,43 @@ int proj_trans_array (PJ *P, PJ_DIRECTION direction, size_t n, PJ_COORD *coord)
 /******************************************************************************
     Batch transform an array of PJ_COORD.
 
+    Performs transformation on all points, even if errors occur on some points.
+
+    Individual points that fail to transform will have their components set to
+    HUGE_VAL
+
     Returns 0 if all coordinates are transformed without error, otherwise
-    returns error number.
+    returns a precise error number if all coordinates that fail to transform
+    for the same reason, or a generic error code if they fail for different
+    reasons.
 ******************************************************************************/
     size_t i;
+    int retErrno = 0;
+    bool hasSetRetErrno = false;
+    bool sameRetErrno = true;
 
     for (i = 0;  i < n;  i++) {
+        proj_context_errno_set(P->ctx, 0);
         coord[i] = proj_trans (P, direction, coord[i]);
-        if (proj_errno(P))
-            return proj_errno (P);
-    }
+        int thisErrno = proj_errno(P);
+        if( thisErrno != 0 )
+        {
+            if( !hasSetRetErrno )
+            {
+                retErrno = thisErrno;
+                hasSetRetErrno = true;
+            }
+            else if( sameRetErrno && retErrno != thisErrno )
+            {
+                sameRetErrno = false;
+                retErrno = PROJ_ERR_COORD_TRANSFM;
+            }
+        }
+   }
+
+   proj_context_errno_set(P->ctx, retErrno);
 
-   return 0;
+   return retErrno;
 }
 
 
diff --git a/test/unit/gie_self_tests.cpp b/test/unit/gie_self_tests.cpp
index 70e67dcc..4244766e 100644
--- a/test/unit/gie_self_tests.cpp
+++ b/test/unit/gie_self_tests.cpp
@@ -46,7 +46,7 @@ TEST(gie, cart_selftest) {
     PJ_CONTEXT *ctx;
     PJ *P;
     PJ_COORD a, b, obs[2];
-    PJ_COORD coord[2];
+    PJ_COORD coord[3];
 
     size_t n, sz;
     double dist, h, t;
@@ -200,7 +200,7 @@ TEST(gie, cart_selftest) {
 
     coord[0] = proj_coord(proj_torad(12), proj_torad(55), 45, 0);
     coord[1] = proj_coord(proj_torad(12), proj_torad(56), 50, 0);
-    ASSERT_FALSE(proj_trans_array(P, PJ_FWD, 2, coord));
+    ASSERT_EQ(proj_trans_array(P, PJ_FWD, 2, coord), 0);
 
     ASSERT_EQ(a.lpz.lam, coord[0].lpz.lam);
     ASSERT_EQ(a.lpz.phi, coord[0].lpz.phi);
@@ -209,6 +209,35 @@ TEST(gie, cart_selftest) {
     ASSERT_EQ(b.lpz.phi, coord[1].lpz.phi);
     ASSERT_EQ(b.lpz.z, coord[1].lpz.z);
 
+    /* test proj_trans_array () with two failed points for the same reason */
+
+    coord[0] =
+        proj_coord(proj_torad(12), proj_torad(95), 45, 0); // invalid latitude
+    coord[1] = proj_coord(proj_torad(12), proj_torad(56), 50, 0);
+    coord[2] =
+        proj_coord(proj_torad(12), proj_torad(95), 45, 0); // invalid latitude
+    ASSERT_EQ(proj_trans_array(P, PJ_FWD, 3, coord),
+              PROJ_ERR_COORD_TRANSFM_INVALID_COORD);
+
+    ASSERT_EQ(HUGE_VAL, coord[0].lpz.lam);
+    ASSERT_EQ(HUGE_VAL, coord[0].lpz.phi);
+    ASSERT_EQ(HUGE_VAL, coord[0].lpz.z);
+    ASSERT_EQ(b.lpz.lam, coord[1].lpz.lam);
+    ASSERT_EQ(b.lpz.phi, coord[1].lpz.phi);
+    ASSERT_EQ(b.lpz.z, coord[1].lpz.z);
+    ASSERT_EQ(HUGE_VAL, coord[2].lpz.lam);
+    ASSERT_EQ(HUGE_VAL, coord[2].lpz.phi);
+    ASSERT_EQ(HUGE_VAL, coord[2].lpz.z);
+
+    /* test proj_trans_array () with two failed points for different reasons */
+
+    coord[0] =
+        proj_coord(proj_torad(12), proj_torad(95), 45, 0); // invalid latitude
+    coord[1] =
+        proj_coord(proj_torad(105), proj_torad(0), 45,
+                   0); // in the equatorial axis, at 90° of the central meridian
+    ASSERT_EQ(proj_trans_array(P, PJ_FWD, 2, coord), PROJ_ERR_COORD_TRANSFM);
+
     /* Clean up  after proj_trans_* tests */
     proj_destroy(P);
 }