vikunja-api/vendor/honnef.co/go/tools/staticcheck/vrp/int.go

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2018-12-31 02:18:41 +01:00
package vrp
import (
"fmt"
"go/token"
"go/types"
"math/big"
"honnef.co/go/tools/ssa"
)
type Zs []Z
func (zs Zs) Len() int {
return len(zs)
}
func (zs Zs) Less(i int, j int) bool {
return zs[i].Cmp(zs[j]) == -1
}
func (zs Zs) Swap(i int, j int) {
zs[i], zs[j] = zs[j], zs[i]
}
type Z struct {
infinity int8
integer *big.Int
}
func NewZ(n int64) Z {
return NewBigZ(big.NewInt(n))
}
func NewBigZ(n *big.Int) Z {
return Z{integer: n}
}
func (z1 Z) Infinite() bool {
return z1.infinity != 0
}
func (z1 Z) Add(z2 Z) Z {
if z2.Sign() == -1 {
return z1.Sub(z2.Negate())
}
if z1 == NInfinity {
return NInfinity
}
if z1 == PInfinity {
return PInfinity
}
if z2 == PInfinity {
return PInfinity
}
if !z1.Infinite() && !z2.Infinite() {
n := &big.Int{}
n.Add(z1.integer, z2.integer)
return NewBigZ(n)
}
panic(fmt.Sprintf("%s + %s is not defined", z1, z2))
}
func (z1 Z) Sub(z2 Z) Z {
if z2.Sign() == -1 {
return z1.Add(z2.Negate())
}
if !z1.Infinite() && !z2.Infinite() {
n := &big.Int{}
n.Sub(z1.integer, z2.integer)
return NewBigZ(n)
}
if z1 != PInfinity && z2 == PInfinity {
return NInfinity
}
if z1.Infinite() && !z2.Infinite() {
return Z{infinity: z1.infinity}
}
if z1 == PInfinity && z2 == PInfinity {
return PInfinity
}
panic(fmt.Sprintf("%s - %s is not defined", z1, z2))
}
func (z1 Z) Mul(z2 Z) Z {
if (z1.integer != nil && z1.integer.Sign() == 0) ||
(z2.integer != nil && z2.integer.Sign() == 0) {
return NewBigZ(&big.Int{})
}
if z1.infinity != 0 || z2.infinity != 0 {
return Z{infinity: int8(z1.Sign() * z2.Sign())}
}
n := &big.Int{}
n.Mul(z1.integer, z2.integer)
return NewBigZ(n)
}
func (z1 Z) Negate() Z {
if z1.infinity == 1 {
return NInfinity
}
if z1.infinity == -1 {
return PInfinity
}
n := &big.Int{}
n.Neg(z1.integer)
return NewBigZ(n)
}
func (z1 Z) Sign() int {
if z1.infinity != 0 {
return int(z1.infinity)
}
return z1.integer.Sign()
}
func (z1 Z) String() string {
if z1 == NInfinity {
return "-∞"
}
if z1 == PInfinity {
return "∞"
}
return fmt.Sprintf("%d", z1.integer)
}
func (z1 Z) Cmp(z2 Z) int {
if z1.infinity == z2.infinity && z1.infinity != 0 {
return 0
}
if z1 == PInfinity {
return 1
}
if z1 == NInfinity {
return -1
}
if z2 == NInfinity {
return 1
}
if z2 == PInfinity {
return -1
}
return z1.integer.Cmp(z2.integer)
}
func MaxZ(zs ...Z) Z {
if len(zs) == 0 {
panic("Max called with no arguments")
}
if len(zs) == 1 {
return zs[0]
}
ret := zs[0]
for _, z := range zs[1:] {
if z.Cmp(ret) == 1 {
ret = z
}
}
return ret
}
func MinZ(zs ...Z) Z {
if len(zs) == 0 {
panic("Min called with no arguments")
}
if len(zs) == 1 {
return zs[0]
}
ret := zs[0]
for _, z := range zs[1:] {
if z.Cmp(ret) == -1 {
ret = z
}
}
return ret
}
var NInfinity = Z{infinity: -1}
var PInfinity = Z{infinity: 1}
var EmptyIntInterval = IntInterval{true, PInfinity, NInfinity}
func InfinityFor(v ssa.Value) IntInterval {
if b, ok := v.Type().Underlying().(*types.Basic); ok {
if (b.Info() & types.IsUnsigned) != 0 {
return NewIntInterval(NewZ(0), PInfinity)
}
}
return NewIntInterval(NInfinity, PInfinity)
}
type IntInterval struct {
known bool
Lower Z
Upper Z
}
func NewIntInterval(l, u Z) IntInterval {
if u.Cmp(l) == -1 {
return EmptyIntInterval
}
return IntInterval{known: true, Lower: l, Upper: u}
}
func (i IntInterval) IsKnown() bool {
return i.known
}
func (i IntInterval) Empty() bool {
return i.Lower == PInfinity && i.Upper == NInfinity
}
func (i IntInterval) IsMaxRange() bool {
return i.Lower == NInfinity && i.Upper == PInfinity
}
func (i1 IntInterval) Intersection(i2 IntInterval) IntInterval {
if !i1.IsKnown() {
return i2
}
if !i2.IsKnown() {
return i1
}
if i1.Empty() || i2.Empty() {
return EmptyIntInterval
}
i3 := NewIntInterval(MaxZ(i1.Lower, i2.Lower), MinZ(i1.Upper, i2.Upper))
if i3.Lower.Cmp(i3.Upper) == 1 {
return EmptyIntInterval
}
return i3
}
func (i1 IntInterval) Union(other Range) Range {
i2, ok := other.(IntInterval)
if !ok {
i2 = EmptyIntInterval
}
if i1.Empty() || !i1.IsKnown() {
return i2
}
if i2.Empty() || !i2.IsKnown() {
return i1
}
return NewIntInterval(MinZ(i1.Lower, i2.Lower), MaxZ(i1.Upper, i2.Upper))
}
func (i1 IntInterval) Add(i2 IntInterval) IntInterval {
if i1.Empty() || i2.Empty() {
return EmptyIntInterval
}
l1, u1, l2, u2 := i1.Lower, i1.Upper, i2.Lower, i2.Upper
return NewIntInterval(l1.Add(l2), u1.Add(u2))
}
func (i1 IntInterval) Sub(i2 IntInterval) IntInterval {
if i1.Empty() || i2.Empty() {
return EmptyIntInterval
}
l1, u1, l2, u2 := i1.Lower, i1.Upper, i2.Lower, i2.Upper
return NewIntInterval(l1.Sub(u2), u1.Sub(l2))
}
func (i1 IntInterval) Mul(i2 IntInterval) IntInterval {
if i1.Empty() || i2.Empty() {
return EmptyIntInterval
}
x1, x2 := i1.Lower, i1.Upper
y1, y2 := i2.Lower, i2.Upper
return NewIntInterval(
MinZ(x1.Mul(y1), x1.Mul(y2), x2.Mul(y1), x2.Mul(y2)),
MaxZ(x1.Mul(y1), x1.Mul(y2), x2.Mul(y1), x2.Mul(y2)),
)
}
func (i1 IntInterval) String() string {
if !i1.IsKnown() {
return "[⊥, ⊥]"
}
if i1.Empty() {
return "{}"
}
return fmt.Sprintf("[%s, %s]", i1.Lower, i1.Upper)
}
type IntArithmeticConstraint struct {
aConstraint
A ssa.Value
B ssa.Value
Op token.Token
Fn func(IntInterval, IntInterval) IntInterval
}
type IntAddConstraint struct{ *IntArithmeticConstraint }
type IntSubConstraint struct{ *IntArithmeticConstraint }
type IntMulConstraint struct{ *IntArithmeticConstraint }
type IntConversionConstraint struct {
aConstraint
X ssa.Value
}
type IntIntersectionConstraint struct {
aConstraint
ranges Ranges
A ssa.Value
B ssa.Value
Op token.Token
I IntInterval
resolved bool
}
type IntIntervalConstraint struct {
aConstraint
I IntInterval
}
func NewIntArithmeticConstraint(a, b, y ssa.Value, op token.Token, fn func(IntInterval, IntInterval) IntInterval) *IntArithmeticConstraint {
return &IntArithmeticConstraint{NewConstraint(y), a, b, op, fn}
}
func NewIntAddConstraint(a, b, y ssa.Value) Constraint {
return &IntAddConstraint{NewIntArithmeticConstraint(a, b, y, token.ADD, IntInterval.Add)}
}
func NewIntSubConstraint(a, b, y ssa.Value) Constraint {
return &IntSubConstraint{NewIntArithmeticConstraint(a, b, y, token.SUB, IntInterval.Sub)}
}
func NewIntMulConstraint(a, b, y ssa.Value) Constraint {
return &IntMulConstraint{NewIntArithmeticConstraint(a, b, y, token.MUL, IntInterval.Mul)}
}
func NewIntConversionConstraint(x, y ssa.Value) Constraint {
return &IntConversionConstraint{NewConstraint(y), x}
}
func NewIntIntersectionConstraint(a, b ssa.Value, op token.Token, ranges Ranges, y ssa.Value) Constraint {
return &IntIntersectionConstraint{
aConstraint: NewConstraint(y),
ranges: ranges,
A: a,
B: b,
Op: op,
}
}
func NewIntIntervalConstraint(i IntInterval, y ssa.Value) Constraint {
return &IntIntervalConstraint{NewConstraint(y), i}
}
func (c *IntArithmeticConstraint) Operands() []ssa.Value { return []ssa.Value{c.A, c.B} }
func (c *IntConversionConstraint) Operands() []ssa.Value { return []ssa.Value{c.X} }
func (c *IntIntersectionConstraint) Operands() []ssa.Value { return []ssa.Value{c.A} }
func (s *IntIntervalConstraint) Operands() []ssa.Value { return nil }
func (c *IntArithmeticConstraint) String() string {
return fmt.Sprintf("%s = %s %s %s", c.Y().Name(), c.A.Name(), c.Op, c.B.Name())
}
func (c *IntConversionConstraint) String() string {
return fmt.Sprintf("%s = %s(%s)", c.Y().Name(), c.Y().Type(), c.X.Name())
}
func (c *IntIntersectionConstraint) String() string {
return fmt.Sprintf("%s = %s %s %s (%t branch)", c.Y().Name(), c.A.Name(), c.Op, c.B.Name(), c.Y().(*ssa.Sigma).Branch)
}
func (c *IntIntervalConstraint) String() string { return fmt.Sprintf("%s = %s", c.Y().Name(), c.I) }
func (c *IntArithmeticConstraint) Eval(g *Graph) Range {
i1, i2 := g.Range(c.A).(IntInterval), g.Range(c.B).(IntInterval)
if !i1.IsKnown() || !i2.IsKnown() {
return IntInterval{}
}
return c.Fn(i1, i2)
}
func (c *IntConversionConstraint) Eval(g *Graph) Range {
s := &types.StdSizes{
// XXX is it okay to assume the largest word size, or do we
// need to be platform specific?
WordSize: 8,
MaxAlign: 1,
}
fromI := g.Range(c.X).(IntInterval)
toI := g.Range(c.Y()).(IntInterval)
fromT := c.X.Type().Underlying().(*types.Basic)
toT := c.Y().Type().Underlying().(*types.Basic)
fromB := s.Sizeof(c.X.Type())
toB := s.Sizeof(c.Y().Type())
if !fromI.IsKnown() {
return toI
}
if !toI.IsKnown() {
return fromI
}
// uint<N> -> sint/uint<M>, M > N: [max(0, l1), min(2**N-1, u2)]
if (fromT.Info()&types.IsUnsigned != 0) &&
toB > fromB {
n := big.NewInt(1)
n.Lsh(n, uint(fromB*8))
n.Sub(n, big.NewInt(1))
return NewIntInterval(
MaxZ(NewZ(0), fromI.Lower),
MinZ(NewBigZ(n), toI.Upper),
)
}
// sint<N> -> sint<M>, M > N; [max(-∞, l1), min(2**N-1, u2)]
if (fromT.Info()&types.IsUnsigned == 0) &&
(toT.Info()&types.IsUnsigned == 0) &&
toB > fromB {
n := big.NewInt(1)
n.Lsh(n, uint(fromB*8))
n.Sub(n, big.NewInt(1))
return NewIntInterval(
MaxZ(NInfinity, fromI.Lower),
MinZ(NewBigZ(n), toI.Upper),
)
}
return fromI
}
func (c *IntIntersectionConstraint) Eval(g *Graph) Range {
xi := g.Range(c.A).(IntInterval)
if !xi.IsKnown() {
return c.I
}
return xi.Intersection(c.I)
}
func (c *IntIntervalConstraint) Eval(*Graph) Range { return c.I }
func (c *IntIntersectionConstraint) Futures() []ssa.Value {
return []ssa.Value{c.B}
}
func (c *IntIntersectionConstraint) Resolve() {
r, ok := c.ranges[c.B].(IntInterval)
if !ok {
c.I = InfinityFor(c.Y())
return
}
switch c.Op {
case token.EQL:
c.I = r
case token.GTR:
c.I = NewIntInterval(r.Lower.Add(NewZ(1)), PInfinity)
case token.GEQ:
c.I = NewIntInterval(r.Lower, PInfinity)
case token.LSS:
// TODO(dh): do we need 0 instead of NInfinity for uints?
c.I = NewIntInterval(NInfinity, r.Upper.Sub(NewZ(1)))
case token.LEQ:
c.I = NewIntInterval(NInfinity, r.Upper)
case token.NEQ:
c.I = InfinityFor(c.Y())
default:
panic("unsupported op " + c.Op.String())
}
}
func (c *IntIntersectionConstraint) IsKnown() bool {
return c.I.IsKnown()
}
func (c *IntIntersectionConstraint) MarkUnresolved() {
c.resolved = false
}
func (c *IntIntersectionConstraint) MarkResolved() {
c.resolved = true
}
func (c *IntIntersectionConstraint) IsResolved() bool {
return c.resolved
}