fix(gds): float values in decompiled GDA scripts are now displayed ro…

…unded to the lowest number of decimal points that still produces identical byte data.

formats/gds/gda.py

@@ -18,6 +18,7 @@
     GDSConditionToken
 )
 
+from utils import round_perfect
 
 def read_gda(data: str, path: Optional[str] = None) -> GDSProgram:
     pass
@@ -101,7 +102,7 @@ def write_simple(ctx: WriterContext, cmd: GDSInvocation):
             ctx.write(str(val))
         elif arg in GDSValue.float:
             val: float = arg()
-            ctx.write(str(val))
+            ctx.write(str(round_perfect(val)))
         elif arg in GDSValue.str or arg in GDSValue.longstr:
             val: str = arg()
             if param.type == "longstr":

utils.py

@@ -2,6 +2,7 @@
 from contextlib import contextmanager, suppress
 from typing import (Any, Callable, Generic, Mapping, TypeVar, Union,
                     get_origin, get_type_hints)
+import struct
 
 
 def cli_file_pairs(
@@ -207,3 +208,16 @@ class NestedBreakException(Exception):
         pass
     with suppress(NestedBreakException):
         yield NestedBreakException
+
+def round_places(x: float, places: int=0) -> float:
+    return round(x * (10**places)) / (10**places)
+
+def round_perfect(x: float) -> float:
+    for i in range(1, 8):
+        y = round_places(x, i)
+        # If the rounded form is equivalent in bits to the full version,
+        # just use this simpler rounded version.
+        if struct.unpack("<f", struct.pack("<f", y))[0] == x:
+            return y
+    # We couldn't round without loss of information
+    return x