youtubebeat/vendor/github.com/antchfx/xpath/operator.go

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2018-11-18 15:32:28 +01:00
package xpath
import (
"fmt"
"reflect"
"strconv"
)
// The XPath number operator function list.
// valueType is a return value type.
type valueType int
const (
booleanType valueType = iota
numberType
stringType
nodeSetType
)
func getValueType(i interface{}) valueType {
v := reflect.ValueOf(i)
switch v.Kind() {
case reflect.Float64:
return numberType
case reflect.String:
return stringType
case reflect.Bool:
return booleanType
default:
if _, ok := i.(query); ok {
return nodeSetType
}
}
panic(fmt.Errorf("xpath unknown value type: %v", v.Kind()))
}
type logical func(iterator, string, interface{}, interface{}) bool
var logicalFuncs = [][]logical{
{cmpBooleanBoolean, nil, nil, nil},
{nil, cmpNumericNumeric, cmpNumericString, cmpNumericNodeSet},
{nil, cmpStringNumeric, cmpStringString, cmpStringNodeSet},
{nil, cmpNodeSetNumeric, cmpNodeSetString, cmpNodeSetNodeSet},
}
// number vs number
func cmpNumberNumberF(op string, a, b float64) bool {
switch op {
case "=":
return a == b
case ">":
return a > b
case "<":
return a < b
case ">=":
return a >= b
case "<=":
return a <= b
case "!=":
return a != b
}
return false
}
// string vs string
func cmpStringStringF(op string, a, b string) bool {
switch op {
case "=":
return a == b
case ">":
return a > b
case "<":
return a < b
case ">=":
return a >= b
case "<=":
return a <= b
case "!=":
return a != b
}
return false
}
func cmpBooleanBooleanF(op string, a, b bool) bool {
switch op {
case "or":
return a || b
case "and":
return a && b
}
return false
}
func cmpNumericNumeric(t iterator, op string, m, n interface{}) bool {
a := m.(float64)
b := n.(float64)
return cmpNumberNumberF(op, a, b)
}
func cmpNumericString(t iterator, op string, m, n interface{}) bool {
a := m.(float64)
b := n.(string)
num, err := strconv.ParseFloat(b, 64)
if err != nil {
panic(err)
}
return cmpNumberNumberF(op, a, num)
}
func cmpNumericNodeSet(t iterator, op string, m, n interface{}) bool {
a := m.(float64)
b := n.(query)
for {
node := b.Select(t)
if node == nil {
break
}
num, err := strconv.ParseFloat(node.Value(), 64)
if err != nil {
panic(err)
}
if cmpNumberNumberF(op, a, num) {
return true
}
}
return false
}
func cmpNodeSetNumeric(t iterator, op string, m, n interface{}) bool {
a := m.(query)
b := n.(float64)
for {
node := a.Select(t)
if node == nil {
break
}
num, err := strconv.ParseFloat(node.Value(), 64)
if err != nil {
panic(err)
}
if cmpNumberNumberF(op, num, b) {
return true
}
}
return false
}
func cmpNodeSetString(t iterator, op string, m, n interface{}) bool {
a := m.(query)
b := n.(string)
for {
node := a.Select(t)
if node == nil {
break
}
if cmpStringStringF(op, b, node.Value()) {
return true
}
}
return false
}
func cmpNodeSetNodeSet(t iterator, op string, m, n interface{}) bool {
return false
}
func cmpStringNumeric(t iterator, op string, m, n interface{}) bool {
a := m.(string)
b := n.(float64)
num, err := strconv.ParseFloat(a, 64)
if err != nil {
panic(err)
}
return cmpNumberNumberF(op, b, num)
}
func cmpStringString(t iterator, op string, m, n interface{}) bool {
a := m.(string)
b := n.(string)
return cmpStringStringF(op, a, b)
}
func cmpStringNodeSet(t iterator, op string, m, n interface{}) bool {
a := m.(string)
b := n.(query)
for {
node := b.Select(t)
if node == nil {
break
}
if cmpStringStringF(op, a, node.Value()) {
return true
}
}
return false
}
func cmpBooleanBoolean(t iterator, op string, m, n interface{}) bool {
a := m.(bool)
b := n.(bool)
return cmpBooleanBooleanF(op, a, b)
}
// eqFunc is an `=` operator.
func eqFunc(t iterator, m, n interface{}) interface{} {
t1 := getValueType(m)
t2 := getValueType(n)
return logicalFuncs[t1][t2](t, "=", m, n)
}
// gtFunc is an `>` operator.
func gtFunc(t iterator, m, n interface{}) interface{} {
t1 := getValueType(m)
t2 := getValueType(n)
return logicalFuncs[t1][t2](t, ">", m, n)
}
// geFunc is an `>=` operator.
func geFunc(t iterator, m, n interface{}) interface{} {
t1 := getValueType(m)
t2 := getValueType(n)
return logicalFuncs[t1][t2](t, ">=", m, n)
}
// ltFunc is an `<` operator.
func ltFunc(t iterator, m, n interface{}) interface{} {
t1 := getValueType(m)
t2 := getValueType(n)
return logicalFuncs[t1][t2](t, "<", m, n)
}
// leFunc is an `<=` operator.
func leFunc(t iterator, m, n interface{}) interface{} {
t1 := getValueType(m)
t2 := getValueType(n)
return logicalFuncs[t1][t2](t, "<=", m, n)
}
// neFunc is an `!=` operator.
func neFunc(t iterator, m, n interface{}) interface{} {
t1 := getValueType(m)
t2 := getValueType(n)
return logicalFuncs[t1][t2](t, "!=", m, n)
}
// orFunc is an `or` operator.
var orFunc = func(t iterator, m, n interface{}) interface{} {
t1 := getValueType(m)
t2 := getValueType(n)
return logicalFuncs[t1][t2](t, "or", m, n)
}
func numericExpr(m, n interface{}, cb func(float64, float64) float64) float64 {
typ := reflect.TypeOf(float64(0))
a := reflect.ValueOf(m).Convert(typ)
b := reflect.ValueOf(n).Convert(typ)
return cb(a.Float(), b.Float())
}
// plusFunc is an `+` operator.
var plusFunc = func(m, n interface{}) interface{} {
return numericExpr(m, n, func(a, b float64) float64 {
return a + b
})
}
// minusFunc is an `-` operator.
var minusFunc = func(m, n interface{}) interface{} {
return numericExpr(m, n, func(a, b float64) float64 {
return a - b
})
}
// mulFunc is an `*` operator.
var mulFunc = func(m, n interface{}) interface{} {
return numericExpr(m, n, func(a, b float64) float64 {
return a * b
})
}
// divFunc is an `DIV` operator.
var divFunc = func(m, n interface{}) interface{} {
return numericExpr(m, n, func(a, b float64) float64 {
return a / b
})
}
// modFunc is an 'MOD' operator.
var modFunc = func(m, n interface{}) interface{} {
return numericExpr(m, n, func(a, b float64) float64 {
return float64(int(a) % int(b))
})
}