func TestDecryptOAEP(t *testing.T) {
random := rand.Reader
sha1 := sha1.New()
n := new(big.Int)
d := new(big.Int)
for i, test := range testEncryptOAEPData {
n.SetString(test.modulus, 16)
d.SetString(test.d, 16)
private := new(PrivateKey)
private.PublicKey = PublicKey{n, test.e}
private.D = d
for j, message := range test.msgs {
out, err := DecryptOAEP(sha1, nil, private, message.out, nil)
if err != nil {
t.Errorf("#%d,%d error: %s", i, j, err)
} else if bytes.Compare(out, message.in) != 0 {
t.Errorf("#%d,%d bad result: %#v (want %#v)", i, j, out, message.in)
}
// Decrypt with blinding.
out, err = DecryptOAEP(sha1, random, private, message.out, nil)
if err != nil {
t.Errorf("#%d,%d (blind) error: %s", i, j, err)
} else if bytes.Compare(out, message.in) != 0 {
t.Errorf("#%d,%d (blind) bad result: %#v (want %#v)", i, j, out, message.in)
}
}
if testing.Short() {
break
}
}
}
// TODO: handle flonums, compnums, ratnums, etc
func _string_to_number(_str Obj, _radix Obj) Obj {
if is_immediate(_str) {
panic("bad type")
}
str := string((*_str).([]int))
radix := number_to_int(_radix)
switch {
case strings.HasPrefix(str, "#b"):
radix = 2
str = str[2:]
case strings.HasPrefix(str, "#o"):
radix = 8
str = str[2:]
case strings.HasPrefix(str, "#d"):
radix = 10
str = str[2:]
case strings.HasPrefix(str, "#x"):
radix = 16
str = str[2:]
}
var v big.Int
z, s := v.SetString(str, radix)
if !s {
return False
}
if z.Cmp(fixnum_max_Int) < 1 && z.Cmp(fixnum_min_Int) > -1 {
return Make_fixnum(int(z.Int64()))
}
return wrap(z)
}
func TestDecryptOAEP(t *testing.T) {
urandom, err := os.Open("/dev/urandom", os.O_RDONLY, 0)
if err != nil {
t.Errorf("Failed to open /dev/urandom")
}
sha1 := sha1.New()
n := new(big.Int)
d := new(big.Int)
for i, test := range testEncryptOAEPData {
n.SetString(test.modulus, 16)
d.SetString(test.d, 16)
private := PrivateKey{PublicKey{n, test.e}, d, nil, nil}
for j, message := range test.msgs {
out, err := DecryptOAEP(sha1, nil, &private, message.out, nil)
if err != nil {
t.Errorf("#%d,%d error: %s", i, j, err)
} else if bytes.Compare(out, message.in) != 0 {
t.Errorf("#%d,%d bad result: %#v (want %#v)", i, j, out, message.in)
}
// Decrypt with blinding.
out, err = DecryptOAEP(sha1, urandom, &private, message.out, nil)
if err != nil {
t.Errorf("#%d,%d (blind) error: %s", i, j, err)
} else if bytes.Compare(out, message.in) != 0 {
t.Errorf("#%d,%d (blind) bad result: %#v (want %#v)", i, j, out, message.in)
}
}
}
}
/**
* Store partial product result lines in the Calculator output lines.
*/
func (calc *Calculator) setPartialLines() {
var (
opDigits = calc.operands[1].String()
opLength = len(opDigits)
)
// From largest to smallest place values (i.e., last to first partial result
// lines)
for index, digit := range opDigits {
var (
placeValue big.Int
buffer bytes.Buffer
// Amount of right indentation this line has and also the position
// relative to the first partial result line (right after the first
// ruler)
offset = opLength - index - 1
)
placeValue.SetString(fmt.Sprintf("%c", digit), 10)
placeValue.Mul(&placeValue, &calc.operands[0])
// We're right-padding with spaces, but these will be stripped out later
buffer.WriteString(placeValue.String())
buffer.WriteString(strings.Repeat(" ", offset))
calc.lines[3+offset] = buffer.String()
}
}
// MakeConst makes an ideal constant from a literal
// token and the corresponding literal string.
func MakeConst(tok token.Token, lit string) Const {
switch tok {
case token.INT:
var x big.Int
_, ok := x.SetString(lit, 0)
assert(ok)
return Const{&x}
case token.FLOAT:
var y big.Rat
_, ok := y.SetString(lit)
assert(ok)
return Const{&y}
case token.IMAG:
assert(lit[len(lit)-1] == 'i')
var im big.Rat
_, ok := im.SetString(lit[0 : len(lit)-1])
assert(ok)
return Const{cmplx{big.NewRat(0, 1), &im}}
case token.CHAR:
assert(lit[0] == '\'' && lit[len(lit)-1] == '\'')
code, _, _, err := strconv.UnquoteChar(lit[1:len(lit)-1], '\'')
assert(err == nil)
return Const{big.NewInt(int64(code))}
case token.STRING:
s, err := strconv.Unquote(lit)
assert(err == nil)
return Const{s}
}
panic("unreachable")
}
func NewInteger(arg Any) *Integer {
var result big.Int
switch arg.(type) {
case int:
result.SetInt64(int64(arg.(int)))
case int64:
result.SetInt64(arg.(int64))
case uint64:
result.SetString(strconv.Uitoa64(arg.(uint64)), 0)
case string:
result.SetString(arg.(string), 0)
default:
panic(fmt.Sprintf("Can not convert %T to Integer", arg))
}
return (*Integer)(&result)
}
// NewCalculator constructs a new Calculator by reading test case data from
// input.
func NewCalculator(reader *bufio.Reader) *Calculator {
var total, diff big.Int
if line, err := reader.ReadString('\n'); err != nil {
panic(err)
} else {
total.SetString(line, 10)
}
if line, err := reader.ReadString('\n'); err != nil {
panic(err)
} else {
diff.SetString(line, 10)
}
return &Calculator{total: &total, diff: &diff}
}
func TestEncryptOAEP(t *testing.T) {
sha1 := sha1.New()
n := new(big.Int)
for i, test := range testEncryptOAEPData {
n.SetString(test.modulus, 16)
public := PublicKey{n, test.e}
for j, message := range test.msgs {
randomSource := bytes.NewBuffer(message.seed)
out, err := EncryptOAEP(sha1, randomSource, &public, message.in, nil)
if err != nil {
t.Errorf("#%d,%d error: %s", i, j, err)
}
if bytes.Compare(out, message.out) != 0 {
t.Errorf("#%d,%d bad result: %x (want %x)", i, j, out, message.out)
}
}
}
}
func bigFromString(s string) *big.Int {
ret := new(big.Int)
ret.SetString(s, 10)
return ret
}
func fromBase10(base10 string) *big.Int {
i := new(big.Int)
i.SetString(base10, 10)
return i
}
/**
* Find the next palindrome after the current number.
*/
func (factory *PalinFactory) Next() string {
var (
buffer bytes.Buffer
numberLen = len(factory.number)
oddLength = numberLen%2 > 0
// Greedily split the number into two halves. Greedily meaning for
// odd-length numbers, the middle digit belongs to both sides (e.g.,
// "987" splits into "98" and "87").
leftSide = factory.number[0 : (numberLen+1)/2]
rightSide = factory.number[numberLen/2:]
mirroredSide = Reverse(leftSide)
leftLength = len(leftSide)
)
// Before we create a palindrome, we can determine if the resulting
// palindrome will not be greater than the original number by mirroring the
// left side and comparing it to the right side.
//
// Using 123456 as an example, the palindrome will be 123321, which is less
// than 123456. If we mirror the left side, we get 321. The right side is
// 456. Since 321 <= 456, we know the palindrome will not be greater than
// the original number.
if !Greater(mirroredSide, rightSide) {
// Since it is not greater, we can increment the palindrome by
// incrementing the left side. This is essentially incrementing the
// middle digits of the palindrome, which results in the very next
// palindrome. Since we are also incrementing the left side, the
// resulting palindrome will also be greater than the original number.
leftSide = Increment(leftSide)
// One obvious optimization is to set leftSide here and then set it
// again in the next inner if {}, rather than calling leftValue.String()
// twice, but that seems to consistently be slower for some reason.
// If we introduced a new digit, this changes the evenness/oddness of
// the number, and we need to account for this when constructing the
// palindrome. Since we greedily split the number, going from odd to
// even means we need to drop a digit on the left.
//
// For example, the left side of 999 is "99". The left side of 1001 is
// "10". Notice both have two digits. However, if we increment "99"
// (as a left side), we get "100", so we need to divide by 10 to get the
// two digits that will be mirrored to form the palindrome 1001. This
// doesn't need to be done when going from odd to even, because the left
// side has one more digit (left side of 99 is "9", left side of 101 is
// "10").
if len(leftSide) != leftLength {
oddLength = !oddLength
if !oddLength {
var leftValue big.Int
leftValue.SetString(leftSide, 10)
leftValue.Div(&leftValue, big.NewInt(10))
leftSide = leftValue.String()
}
}
mirroredSide = Reverse(leftSide)
}
buffer.WriteString(leftSide)
// Mirror the left side onto the right to form a palindrome
if oddLength {
// When odd, the left and right sides "overlap" on the middle digit, so
// don't include in on the right
buffer.WriteString(mirroredSide[1:])
} else {
buffer.WriteString(mirroredSide)
}
return buffer.String()
}
func main() {
// integer
is := "1234"
fmt.Println("original: ", is)
i, err := strconv.Atoi(is)
if err != nil {
fmt.Println(err)
return
}
// assignment back to original variable shows result is the same type.
is = strconv.Itoa(i + 1)
fmt.Println("incremented:", is)
// error checking worthwhile
fmt.Println()
_, err = strconv.Atoi(" 1234") // whitespace not allowed
fmt.Println(err)
_, err = strconv.Atoi("12345678901")
fmt.Println(err)
_, err = strconv.Atoi("_1234")
fmt.Println(err)
_, err = strconv.Atof64("12.D34")
fmt.Println(err)
// float
fmt.Println()
fs := "12.34"
fmt.Println("original: ", fs)
f, err := strconv.Atof64(fs)
if err != nil {
fmt.Println(err)
return
}
// various options on Ftoa64 produce different formats. All are valid
// input to Atof64, so result format does not have to match original
// format. (Matching original format would take a lot of code.)
fs = strconv.Ftoa64(f+1, 'g', -1)
fmt.Println("incremented:", fs)
fs = strconv.Ftoa64(f+1, 'e', 4)
fmt.Println("what format?", fs)
// complex
// strconv package doesn't handle complex types, but fmt does.
// (fmt can be used on ints and floats too, but strconv is more efficient.)
fmt.Println()
cs := "(12+34i)"
fmt.Println("original: ", cs)
var c complex128
_, err = fmt.Sscan(cs, &c)
if err != nil {
fmt.Println(err)
return
}
cs = fmt.Sprint(c + 1)
fmt.Println("incremented:", cs)
// big integers have their own functions
fmt.Println()
bs := "170141183460469231731687303715884105728"
fmt.Println("original: ", bs)
var b, one big.Int
_, ok := b.SetString(bs, 10)
if !ok {
fmt.Println("big.SetString fail")
return
}
one.SetInt64(1)
bs = b.Add(&b, &one).String()
fmt.Println("incremented:", bs)
}