From: Fredrik Tolf <fredrik@dolda2000.com>
Date: Mon, 27 Jun 2022 12:45:14 +0000 (+0200)
Subject: bin: Added coding and decoding of floats.
X-Git-Url: http://www.dolda2000.com/gitweb/?p=coe.git;a=commitdiff_plain;h=e39561b7a9e74d39d061f8e153e48334a4facf3f

bin: Added coding and decoding of floats.
---

diff --git a/coe/bin.py b/coe/bin.py
index b9ee601..08e521e 100644
--- a/coe/bin.py
+++ b/coe/bin.py
@@ -1,3 +1,4 @@
+import io, math
 from . import data
 
 T_END = 0
@@ -70,6 +71,30 @@ class encoder(object):
         dst.write(text.encode("utf-8"))
         dst.write(b'\0')
 
+    @staticmethod
+    def writefloat(dst, x):
+        if x == 0.0:
+            mnt, exp = (0, 0)
+        elif math.isinf(x):
+            if x > 0:
+                mnt, exp = (0, 2)
+            else:
+                mnt, exp = (0, 3)
+        elif math.isnan(x):
+            mnt, exp = (0, 4)
+        else:
+            mnt, exp = math.frexp(x)
+            mnt *= 2
+            exp -= 1
+            while mnt != int(mnt):
+                mnt *= 2
+            mnt = int(mnt)
+        buf = bytearray()
+        buf.extend(encoder.encint(mnt))
+        buf.extend(encoder.encint(exp))
+        dst.write(encoder.encint(len(buf)))
+        dst.write(buf)
+
     def dumpseq(self, dst, seq):
         for v in seq:
             self.dump(dst, v)
@@ -103,6 +128,9 @@ class encoder(object):
             self.writetag(dst, T_BIT, 0, datum)
             dst.write(self.encint(len(datum)))
             dst.write(datum)
+        elif isinstance(datum, float):
+            self.writetag(dst, T_BIT, BIT_BFLOAT, datum)
+            self.writefloat(dst, datum)
         elif isinstance(datum, data.symbol):
             if datum.ns == "":
                 self.writetag(dst, T_STR, STR_SYM, datum)
@@ -265,10 +293,28 @@ class decoder(object):
             return self.addref(ret)
         elif pri == T_BIT:
             ln = self.loadint(fp)
-            ret = self.addref(fp.read(ln))
+            ret = fp.read(ln)
             if len(ret) < ln:
                 raise eoferror()
-            return ret
+            if sec == BIT_BFLOAT:
+                buf = io.BytesIO(ret)
+                mnt = self.loadint(buf)
+                exp = self.loadint(buf)
+                if mnt == 0:
+                    if exp == 0:
+                        return 0.0
+                    elif exp == 1:
+                        return -0.0
+                    elif exp == 2:
+                        return float("inf")
+                    elif exp == 3:
+                        return -float("inf")
+                    else:
+                        return float("nan")
+                else:
+                    ret = math.ldexp(mnt, exp - (mnt.bit_length() - 1))
+                return self.addref(ret)
+            return self.addref(ret)
         elif pri == T_NIL:
             if sec == NIL_TRUE:
                 return self.addref(True)