Implement LEBS2OSP and LEOS2BSP

sapling_utils.py

@@ -16,3 +16,23 @@ def leos2ip(S):
 # This should be equivalent to LEBS2OSP(I2LEBSP(l, x))
 def i2leosp(l, x):
     return x.to_bytes(cldiv(l, 8), byteorder='little')
+
+def ledna(bits):
+    ret = 0
+    for b in bits[::-1]:
+        ret = ret * 2
+        if b:
+            ret += 1
+    return ret
+
+def lebs2osp(bits):
+    l = len(bits)
+    bits = bits + [0] * (8 * cldiv(l, 8) - l)
+    return bytes([ledna(bits[i:i + 8]) for i in range(0, len(bits), 8)])
+
+def leos2bsp(buf):
+    return sum([[(c >> i) & 1 for i in range(8)] for c in buf], [])
+
+
+assert i2leosp(5, 7) == lebs2osp(i2lebsp(5, 7))
+assert i2leosp(32, 1234567890) == lebs2osp(i2lebsp(32, 1234567890))