From 4fd757a03c592bf049361bd6259f3ffc978cfc5b Mon Sep 17 00:00:00 2001
From: arnaucube <root@arnaucube.com>
Date: Mon, 8 Mar 2021 14:17:16 +0100
Subject: [PATCH] Fix NewFloat40Floor helper method

---
 common/float40.go      | 22 +++++++++++-----------
 common/float40_test.go | 39 ++++++++++++++++++++++++++-------------
 2 files changed, 37 insertions(+), 24 deletions(-)

diff --git a/common/float40.go b/common/float40.go
index 432824a..92744b6 100644
--- a/common/float40.go
+++ b/common/float40.go
@@ -81,9 +81,9 @@ func (f40 Float40) BigInt() (*big.Int, error) {
 	return r, nil
 }
 
-// newFloat40ME takes a *big.Int integer and returns the m (mantissa) & e
-// (exponent) from the Float40 representation
-func newFloat40ME(f *big.Int) (*big.Int, *big.Int) {
+// NewFloat40 encodes a *big.Int integer as a Float40, returning error in case
+// of loss during the encoding.
+func NewFloat40(f *big.Int) (Float40, error) {
 	m := f
 	e := big.NewInt(0)
 	zero := big.NewInt(0)
@@ -92,13 +92,6 @@ func newFloat40ME(f *big.Int) (*big.Int, *big.Int) {
 		m = new(big.Int).Div(m, ten)
 		e = new(big.Int).Add(e, big.NewInt(1))
 	}
-	return m, e
-}
-
-// NewFloat40 encodes a *big.Int integer as a Float40, returning error in case
-// of loss during the encoding.
-func NewFloat40(f *big.Int) (Float40, error) {
-	m, e := newFloat40ME(f)
 	if e.Int64() > 31 {
 		return 0, tracerr.Wrap(ErrFloat40E31)
 	}
@@ -116,7 +109,14 @@ func NewFloat40(f *big.Int) (Float40, error) {
 // hermez-node, it's a helper for external usage to generate valid Float40
 // values.
 func NewFloat40Floor(f *big.Int) (Float40, error) {
-	m, e := newFloat40ME(f)
+	m := f
+	e := big.NewInt(0)
+	// zero := big.NewInt(0)
+	ten := big.NewInt(10)
+	for m.Cmp(thres) >= 0 {
+		m = new(big.Int).Div(m, ten)
+		e = new(big.Int).Add(e, big.NewInt(1))
+	}
 	if e.Int64() > 31 {
 		return 0, tracerr.Wrap(ErrFloat40E31)
 	}
diff --git a/common/float40_test.go b/common/float40_test.go
index 0089332..9378d6a 100644
--- a/common/float40_test.go
+++ b/common/float40_test.go
@@ -1,6 +1,7 @@
 package common
 
 import (
+	"fmt"
 	"math/big"
 	"testing"
 
@@ -61,20 +62,28 @@ func TestExpectError(t *testing.T) {
 }
 
 func TestNewFloat40Floor(t *testing.T) {
-	testVector := map[string][]uint64{
+	testVector := map[string][]string{
 		// []int contains [Float40 value, Flot40 Floor value], when
 		// Float40 value is expected to be 0, is because is expected to
 		// be an error
-		"9922334455000000000000000000000000000000":   {1040714485495, 1040714485495},
-		"9922334455000000000000000000000000000001":   {0, 6846188881046405121},
-		"9922334454999999999999999999999999999999":   {0, 6846188881046405119},
-		"42949672950000000000000000000000000000000":  {1069446856703, 1069446856703},
-		"99223344556573838487575":                    {0, 16754928163869896727},
-		"992233445500000000000000000000000000000000": {0, 0},
-		"343597383670000000000000000000000000000000": {1099511627775, 1099511627775},
-		"343597383680000000000000000000000000000000": {0, 1099511627776},
-		"343597383690000000000000000000000000000000": {0, 1099511627777},
-		"343597383700000000000000000000000000000000": {0, 0},
+		"9922334455000000000000000000000000000000": {
+			"1040714485495", "1040714485495", "9922334455000000000000000000000000000000"},
+		"9922334455000000000000000000000000000001": { // Floor [2] will be same as prev line
+			"0", "1040714485495", "9922334455000000000000000000000000000000"},
+		"9922334454999999999999999999999999999999": {
+			"0", "1040714485494", "9922334454000000000000000000000000000000"},
+		"42949672950000000000000000000000000000000": {
+			"1069446856703", "1069446856703", "42949672950000000000000000000000000000000"},
+		"99223344556573838487575": {
+			"0", "456598933239", "99223344550000000000000"},
+		"992233445500000000000000000000000000000000": {
+			"0", "0", "0"}, // e>31, returns 0, err
+		"343597383670000000000000000000000000000000": {
+			"1099511627775", "1099511627775", "343597383670000000000000000000000000000000"},
+		"343597383680000000000000000000000000000000": {
+			"0", "0", "0"}, // e>31, returns 0, err
+		"1157073197879933027": {
+			"0", "286448638922", "1157073197800000000"},
 	}
 	for test := range testVector {
 		bi, ok := new(big.Int).SetString(test, 10)
@@ -85,7 +94,7 @@ func TestNewFloat40Floor(t *testing.T) {
 		} else {
 			assert.NoError(t, err)
 		}
-		assert.Equal(t, testVector[test][0], uint64(f40))
+		assert.Equal(t, testVector[test][0], fmt.Sprint(uint64(f40)))
 
 		f40, err = NewFloat40Floor(bi)
 		if f40 == 0 {
@@ -93,7 +102,11 @@ func TestNewFloat40Floor(t *testing.T) {
 		} else {
 			assert.NoError(t, err)
 		}
-		assert.Equal(t, testVector[test][1], uint64(f40))
+		assert.Equal(t, testVector[test][1], fmt.Sprint(uint64(f40)))
+
+		bi2, err := f40.BigInt()
+		require.NoError(t, err)
+		assert.Equal(t, fmt.Sprint(testVector[test][2]), bi2.String())
 	}
 }