Pare down rawinsonde parser a bit (for now)

lib/xmet/rawins.py

@@ -1,5 +1,6 @@
 import io
 import re
+import enum
 import datetime
 
 from xmet.util     import each_chunk
@@ -12,17 +13,52 @@ CHUNK_STRIP_CHARS = "\x01\x03\x0a\x20"
 class RawinsReaderException(Exception):
     ...
 
+class RawinsSample():
+    def __init__(self):
+        self.surface:  bool  = False
+        self.height:   float = None
+        self.pressure: float = None
+        self.temp:     float = None
+        self.dewpoint: float = None
+
+class RawinsObs():
+    def __init__(self, kind: str):
+        self.kind = str
+        self.values: list[str] = list()
+
+    def read(self, value: str):
+        self.values.append(value)
+
 class RawinsChunk():
     def __init__(self,
                  wfo:     str,
                  product: str,
-                 station: str,
                  values:  list[str]):
         self.wfo     = wfo
         self.product = product
-        self.station = station
         self.values  = values
 
+    def is_obs_start(self, value: str) -> bool:
+        return value == 'TTAA' or value == 'TTBB' \
+            or value == 'TTCC' or value == 'TTDD' \
+            or value == 'PPAA' or value == 'PPBB' \
+            or value == 'PPCC' or value == 'PPDD'
+
+    def each_obs(self):
+        obs = None
+
+        for value in self.values:
+            if self.is_obs_start(value):
+                if obs is not None:
+                    yield obs
+
+                obs = RawinsObs(value)
+            elif obs is not None:
+                obs.read(value)
+
+        if obs is not None:
+            yield obs
+
 class RawinsReader():
     """
     A reader for the global `Current.rawins` file provided by UCAR:
@@ -37,8 +73,7 @@ class RawinsReader():
     def parse_chunk(self, text: str) -> RawinsChunk:
         meta = {
             'wfo':     None, # NWS forecast office
-            'product': None, # NWS product code
+            'product': None  # NWS product code
-            'station': None  # WMO rawinsonde station ID
         }
 
         line_index = 0
@@ -96,7 +131,6 @@ class RawinsReader():
 
         return RawinsChunk(meta['wfo'],
                            meta['product'],
-                           meta['station'],
                            values)
 
     def each_chunk(self) -> list[Sounding]: