MDEV-34177: Implements ST_PointFromGeoHash

The GIS function ST_PointFromGeoHash takes in input a geohash and
returns a point where the x is the longitude and the y is the latitude.
The latitude is returned as a numeric value in the interval [180, -180].
The longitude is returned as a numeric value in the interval [90, -90].
If the argument is NULL, the return value is NULL. If the argument is
invalid, an ER_GIS_INVALID_DATA is thrown.

Author: StefanoPetrilli <stefanop_1999@hotmail.it>
Co-authored-by: kevincheng2 <chengyf112@gmail.com>
Co-authored-by: Catalin Besleaga <catalin.besleaga@oracle.com>
Co-authored-by: Gleb Shchepa <gleb.shchepa@oracle.com>
Co-authored-by: Tatiana Azundris Nuernberg <tatjana.nuernberg@oracle.com>
Co-authored-by: Martin Hansson <martin.hansson@oracle.com>
Co-authored-by: Deepa Dixit <deepa.dixit@oracle.com>
Co-authored-by: Hans H Melby <hans.h.melby@oracle.com>
Co-authored-by: Jens Even Berg Blomsøy <jens.even.blomsoy@oracle.com>
Co-authored-by: Erlend Dahl <erlend.dahl@oracle.com>
Co-authored-by: Norvald H. Ryeng <norvald.ryeng@oracle.com>
Co-authored-by: BennyWang <benny.wang@oracle.com>
Co-authored-by: David.Zhao <david.zhao@oracle.com>
Co-authored-by: Erik Froseth <erik.froseth@oracle.com>

sql/item_geofunc.cc

@@ -3027,6 +3027,7 @@ bool Item_func_latlongfromgeohash::is_invalid_geohash_field(
     case MYSQL_TYPE_VARCHAR:
     case MYSQL_TYPE_LONG_BLOB:
     case MYSQL_TYPE_GEOMETRY:
+    case MYSQL_TYPE_STRING:
       return false;
     default:
       return true;
@@ -3034,6 +3035,7 @@ bool Item_func_latlongfromgeohash::is_invalid_geohash_field(
 }
 
 
+
 double Item_func_latlongfromgeohash::val_real()
 {
   null_value= 1;
@@ -3076,6 +3078,87 @@ double Item_func_latlongfromgeohash::val_real()
   return latitude;
 }
 
+
+bool Item_func_pointfromgeohash::is_invalid_SRID_field
+                                  (enum_field_types field_type)
+{
+  switch (field_type)
+  {
+    case MYSQL_TYPE_NULL:
+    case MYSQL_TYPE_LONG:
+    case MYSQL_TYPE_VARCHAR:
+    case MYSQL_TYPE_LONGLONG:
+      return false;
+    default:
+      return true;
+  }
+}
+
+
+String *Item_func_pointfromgeohash::val_str(String *str)
+{
+  DBUG_ASSERT(fixed());
+  null_value= 1;
+  String *input_value;
+  uint32 srid;
+
+  if (args[0]->null_value || args[1]->null_value)
+    return NULL;
+
+  if (is_invalid_SRID_field(args[1]->field_type()) ||
+      Item_func_latlongfromgeohash::is_invalid_geohash_field(
+        args[0]->field_type()
+      ))
+  {
+    my_error(ER_GIS_INVALID_DATA, MYF(0), "ST_PointFromGeoHash");
+    return NULL;
+  }
+
+  input_value= args[0]->val_str(&buf);
+  if (args[0]->null_value)
+  {
+    args[0]->null_value= 0;
+    return NULL;
+  }
+
+  if (input_value->length() == 0)
+  {
+    my_error(ER_WRONG_VALUE_FOR_TYPE, MYF(0), "geohash",
+            input_value->c_ptr_safe(), func_name());
+    return NULL;
+  }
+
+  srid= static_cast<uint32>(args[1]->val_uint());
+  if (args[1]->null_value)
+  {
+    my_error(ER_WRONG_VALUE_FOR_TYPE, MYF(0), "geohash",
+        input_value->c_ptr_safe(), func_name());
+    return NULL;
+  }
+
+  double latitude= 0.0, longitude= 0.0;
+  if (Item_func_latlongfromgeohash::decode_geohash(input_value, &latitude, &longitude)) {
+    my_error(ER_WRONG_VALUE_FOR_TYPE, MYF(0), "geohash",
+             input_value->c_ptr_safe(), func_name());
+    return NULL;
+  }
+
+  str->set_charset(&my_charset_bin);
+  str->length(0);
+  if (str->reserve(SRID_SIZE + WKB_HEADER_SIZE + POINT_DATA_SIZE))
+    return NULL;
+
+  str->q_append((uint32) srid);
+  str->q_append((char) Geometry::wkb_ndr);
+  str->q_append((uint32) Geometry::wkb_point);
+  str->q_append(longitude);
+  str->q_append(latitude);
+
+  null_value= 0;
+  return str;
+}
+
+
 String *Item_func_pointonsurface::val_str(String *str)
 {
   Gcalc_operation_transporter trn(&func, &collector);
@@ -3551,6 +3634,22 @@ class Create_func_longfromgeohash : public Create_func_arg1
 };
 
 
+class Create_func_pointfromgeohash : public Create_func_arg2
+{
+public:
+  Item *create_2_arg(THD *thd, Item *arg1, Item *arg2) override
+  {
+    return new (thd->mem_root) Item_func_pointfromgeohash(thd, arg1, arg2);
+  }
+
+  static Create_func_pointfromgeohash s_singleton;
+
+protected:
+  Create_func_pointfromgeohash() = default;
+  virtual ~Create_func_pointfromgeohash() = default;
+};
+
+
 class Create_func_endpoint : public Create_func_arg1
 {
 public:
@@ -4406,6 +4505,7 @@ Create_func_distance_sphere Create_func_distance_sphere::s_singleton;
 Create_func_geohash Create_func_geohash::s_singleton;
 Create_func_latfromgeohash Create_func_latfromgeohash ::s_singleton;
 Create_func_longfromgeohash Create_func_longfromgeohash ::s_singleton;
+Create_func_pointfromgeohash Create_func_pointfromgeohash ::s_singleton;
 Create_func_endpoint Create_func_endpoint::s_singleton;
 Create_func_envelope Create_func_envelope::s_singleton;
 Create_func_equals Create_func_equals::s_singleton;
@@ -4532,6 +4632,7 @@ static Native_func_registry func_array_geom[] =
   { { STRING_WITH_LEN("GEOHASH") }, GEOM_BUILDER(Create_func_geohash)},
   { { STRING_WITH_LEN("LATFROMGEOHASH") }, GEOM_BUILDER(Create_func_latfromgeohash)},
   { { STRING_WITH_LEN("LONGFROMGEOHASH") }, GEOM_BUILDER(Create_func_longfromgeohash)},
+  { { STRING_WITH_LEN("POINTFROMGEOHASH") }, GEOM_BUILDER(Create_func_pointfromgeohash)},
   { { STRING_WITH_LEN("SRID") }, GEOM_BUILDER(Create_func_srid)},
   { { STRING_WITH_LEN("ST_AREA") }, GEOM_BUILDER(Create_func_area)},
   { { STRING_WITH_LEN("STARTPOINT") }, GEOM_BUILDER(Create_func_startpoint)},
@@ -4616,6 +4717,7 @@ static Native_func_registry func_array_geom[] =
   { { STRING_WITH_LEN("ST_GEOHASH") }, GEOM_BUILDER(Create_func_geohash)},
   { { STRING_WITH_LEN("ST_LATFROMGEOHASH") }, GEOM_BUILDER(Create_func_latfromgeohash)},
   { { STRING_WITH_LEN("ST_LONGFROMGEOHASH") }, GEOM_BUILDER(Create_func_longfromgeohash)},
+  { { STRING_WITH_LEN("ST_POINTFROMGEOHASH") }, GEOM_BUILDER(Create_func_pointfromgeohash)},
   { { STRING_WITH_LEN("TOUCHES") }, GEOM_BUILDER(Create_func_touches)},
   { { STRING_WITH_LEN("WITHIN") }, GEOM_BUILDER(Create_func_within)},
   { { STRING_WITH_LEN("X") }, GEOM_BUILDER(Create_func_x)},

sql/item_geofunc.h

@@ -1262,13 +1262,13 @@ class Item_func_latlongfromgeohash : public Item_real_func {
   String buf;
   static const uint8_t geohash_alphabet[256];
   const bool decode_longitude;
-  static bool is_invalid_geohash_field(enum_field_types field_type);
 
  public:
   Item_func_latlongfromgeohash(THD *thd, Item *a, bool start_on_even_bit_arg)
       : Item_real_func(thd, a),
         decode_longitude(start_on_even_bit_arg) {}
   double val_real() override;
+  static bool is_invalid_geohash_field(const enum_field_types field_type);
   static bool decode_geohash(String *geohash, double *result_latitude,
                              double *result_longitude);
   static double round_latlongitude(double latlongitude, double error_range,
@@ -1306,6 +1306,26 @@ class Item_func_longfromgeohash: public Item_func_latlongfromgeohash
 };
 
 
+class Item_func_pointfromgeohash: public Item_geometry_func
+{
+private:
+  String buf;
+  static bool is_invalid_SRID_field(const enum_field_types field_type);
+
+public:
+  Item_func_pointfromgeohash(THD *thd, Item *a, Item *b)
+   :Item_geometry_func(thd, a, b) {}
+  LEX_CSTRING func_name_cstring() const override
+  {
+    static LEX_CSTRING name= {STRING_WITH_LEN("st_pointfromgeohash") };
+    return name;
+  }
+  String *val_str(String *) override;
+  Item *get_copy(THD *thd) override
+  { return get_item_copy<Item_func_pointfromgeohash>(thd, this); }
+};
+
+
 class Item_func_pointonsurface: public Item_geometry_func_args_geometry
 {
   String tmp_value;