Create class SHPC

The motivation is to manage an SHPC directory without opening first
all the files inside. The class allows to open files dynamically and
remember already opened files.

Common/util_eddies.py

@@ -4,6 +4,82 @@ from os import path
 import numpy as np
 import sys
 
+class SHPC_class:
+    def __init__(self, SHPC_dir, def_orient):
+        """def_orient, for default orientation, is used to define d_init and
+        n_dates. Since we are going to open files, we might as
+        well ask the user which orientation will be useful.
+
+        """
+
+        self.dir = SHPC_dir
+        self.def_orient = def_orient
+        fname = path.join(SHPC_dir, "n_slices.txt")
+        with open(fname) as f: self.n_slices = int(f.read())
+        self._readers = [{"Anticyclones": {}, "Cyclones": {}}
+                        for i in range(self.n_slices)]
+
+        for i_slice, reader in enumerate(self._readers):
+            my_shapefile = path.join(SHPC_dir, f"Slice_{i_slice}", def_orient,
+                                     "extremum")
+            reader[def_orient]["extremum"] = shapefile.Reader(my_shapefile)
+
+        self.d_init = [reader[def_orient]["extremum"].record(0).date
+                       for reader in self._readers]
+        self._n_dates = np.zeros(self.n_slices, dtype = int)
+        self._ishape_last = [{"Anticyclones": None, "Cyclones": None}
+                             for i in range(self.n_slices)]
+        self._n_shapes = [{"Anticyclones": 0, "Cyclones": 0}
+                         for i in range(self.n_slices)]
+
+    def get_n_dates(self, i_slice):
+        if self._n_dates[i_slice] == 0:
+            # Find out the number of dates in the slice:
+            if self._ishape_last[i_slice]["Anticyclones"] is not None:
+                self._n_dates[i_slice] \
+                    = self._ishape_last[i_slice]["Anticyclones"].size
+            elif self._ishape_last[i_slice]["Cyclones"] is not None:
+                self._n_dates[i_slice] \
+                    = self._ishape_last[i_slice]["Cyclones"].size
+            else:
+                self._n_dates[i_slice] = self.get_ishape_last(i_slice).size
+
+        return self._n_dates[i_slice]
+
+    def get_ishape_last(self, i_slice, orientation = None):
+        if orientation is None: orientation = self.def_orient
+
+        if self._ishape_last[i_slice][orientation] is None:
+            fname = path.join(self.dir, f"Slice_{i_slice}", orientation,
+                              "ishape_last.txt")
+            print("Reading", fname, "...")
+            self._ishape_last[i_slice][orientation] \
+                = np.loadtxt(fname, dtype = int, ndmin = 1)
+
+        return self._ishape_last[i_slice][orientation]
+
+    def get_reader(self, i_slice, layer, orientation = None):
+        if orientation is None: orientation = self.def_orient
+
+        if layer not in self._readers[i_slice][orientation]:
+            my_shapefile = path.join(self.dir, f"Slice_{i_slice}", orientation,
+                                     layer)
+            print("Opening", my_shapefile, "...")
+            self._readers[i_slice][orientation][layer] \
+                = shapefile.Reader(my_shapefile)
+
+        return self._readers[i_slice][orientation][layer]
+
+    def get_n_shapes(self, i_slice, orientation = None):
+        if orientation is None: orientation = self.def_orient
+
+        if self._n_shapes[i_slice][orientation] == 0:
+            reader = self.get_reader(i_slice, layer = "extremum",
+                                     orientation = orientation)
+            self._n_shapes[i_slice][orientation] = len(reader)
+
+        return self._n_shapes[i_slice][orientation]
+
 def comp_ishape(handler, date, eddy_index):
     """Compute the location in the shapefiles. handler should be a
     dictionary returned by open_shpc.