Merge pull request #15 from codex-storage/integers-to-field

integers to field elements

poseidon2.nim

@@ -8,5 +8,6 @@ export sponge
 export compress
 export merkle
 export toBytes
+export toF
 export elements
 export types

poseidon2/io.nim

@@ -1,6 +1,7 @@
 import ./types
 import constantine/math/arithmetic
 import constantine/math/io/io_bigints
+import constantine/math/io/io_fields
 import constantine/math/config/curves
 
 export curves
@@ -35,3 +36,10 @@ iterator elements*(bytes: openArray[byte], _: type F): F =
   let finalChunk = bytes[chunkStart..<bytes.len] & endMarker
   let finalElement = F.fromOpenArray(finalChunk)
   yield finalElement
+
+# Remark: since `fromInt()` does not work at compile time, this doesn't either
+func toF*(a: SomeInteger | SomeUnsignedInt) : F =
+  when a is SomeInteger:
+    fromInt(result, a)
+  else:
+    fromUInt(result, a)

poseidon2/types.nim

@@ -18,12 +18,6 @@ func getZero*() : F =
   setZero(z)
   return z
 
-# Remark: since `fromInt()` does not work at compile time, this doesn't either
-func toF*(a: int) : F =
-  var y : F
-  y.fromInt(a)
-  return y
-
 #-------------------------------------------------------------------------------
 
 const zero* : F = getZero()

tests/poseidon2/testCompress.nim

@@ -1,6 +1,6 @@
 import std/unittest
 import constantine/math/arithmetic
-import poseidon2/types
+import poseidon2/io
 import poseidon2/permutation
 import poseidon2/compress
 

tests/poseidon2/testIo.nim

@@ -1,6 +1,7 @@
 import std/unittest
 import std/sequtils
 import constantine/math/io/io_bigints
+import constantine/math/io/io_fields
 import constantine/math/arithmetic
 import poseidon2/types
 import poseidon2/io
@@ -54,3 +55,29 @@ suite "conversion to/from bytes":
     var expected: array[32, byte]
     marshal(expected, element.toBig(), littleEndian)
     check element.toBytes() == expected
+
+suite "conversion from integers":
+
+  test "converts unsigned integers to a field element":
+
+    proc checkConversion[I](integer: I) =
+      var expected: F
+      fromUint(expected, integer)
+      check bool(integer.toF == expected)
+
+    checkConversion(0x11'u8)
+    checkConversion(0x1122'u16)
+    checkConversion(0x11223344'u32)
+    checkConversion(0x1122334455667788'u64)
+
+  test "converts signed integers to a field element":
+
+    proc checkConversion[I](integer: I) =
+      var expected: F
+      fromInt(expected, integer)
+      check bool(integer.toF == expected)
+
+    checkConversion(0x11'i8)
+    checkConversion(0x1122'i16)
+    checkConversion(0x11223344'i32)
+    checkConversion(0x1122334455667788'i64)

tests/poseidon2/testPermutation.nim

@@ -3,9 +3,9 @@ import std/unittest
 import constantine/math/arithmetic
 import constantine/math/io/io_fields
 import constantine/math/io/io_bigints
-import constantine/math/config/curves
 
 import poseidon2/types
+import poseidon2/io
 import poseidon2/permutation
 
 suite "permutation":

tests/poseidon2/testSponge.nim

@@ -5,6 +5,7 @@ import constantine/math/io/io_fields
 import constantine/math/arithmetic
 
 import poseidon2/types
+import poseidon2/io
 import poseidon2
 
 #-------------------------------------------------------------------------------