terraform/internal/lang/funcs/number.go

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package funcs
import (
"math"
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"math/big"
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"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/function"
"github.com/zclconf/go-cty/cty/gocty"
)
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// LogFunc contructs a function that returns the logarithm of a given number in a given base.
var LogFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "num",
Type: cty.Number,
},
{
Name: "base",
Type: cty.Number,
},
},
Type: function.StaticReturnType(cty.Number),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
var num float64
if err := gocty.FromCtyValue(args[0], &num); err != nil {
return cty.UnknownVal(cty.String), err
}
var base float64
if err := gocty.FromCtyValue(args[1], &base); err != nil {
return cty.UnknownVal(cty.String), err
}
return cty.NumberFloatVal(math.Log(num) / math.Log(base)), nil
},
})
// PowFunc contructs a function that returns the logarithm of a given number in a given base.
var PowFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "num",
Type: cty.Number,
},
{
Name: "power",
Type: cty.Number,
},
},
Type: function.StaticReturnType(cty.Number),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
var num float64
if err := gocty.FromCtyValue(args[0], &num); err != nil {
return cty.UnknownVal(cty.String), err
}
var power float64
if err := gocty.FromCtyValue(args[1], &power); err != nil {
return cty.UnknownVal(cty.String), err
}
return cty.NumberFloatVal(math.Pow(num, power)), nil
},
})
// SignumFunc contructs a function that returns the closest whole number greater
// than or equal to the given value.
var SignumFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "num",
Type: cty.Number,
},
},
Type: function.StaticReturnType(cty.Number),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
var num int
if err := gocty.FromCtyValue(args[0], &num); err != nil {
return cty.UnknownVal(cty.String), err
}
switch {
case num < 0:
return cty.NumberIntVal(-1), nil
case num > 0:
return cty.NumberIntVal(+1), nil
default:
return cty.NumberIntVal(0), nil
}
},
})
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// ParseIntFunc contructs a function that parses a string argument and returns an integer of the specified base.
var ParseIntFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "number",
Type: cty.DynamicPseudoType,
AllowMarked: true,
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},
{
Name: "base",
Type: cty.Number,
AllowMarked: true,
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},
},
Type: func(args []cty.Value) (cty.Type, error) {
if !args[0].Type().Equals(cty.String) {
return cty.Number, function.NewArgErrorf(0, "first argument must be a string, not %s", args[0].Type().FriendlyName())
}
return cty.Number, nil
},
Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
var numstr string
var base int
var err error
numArg, numMarks := args[0].Unmark()
if err = gocty.FromCtyValue(numArg, &numstr); err != nil {
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return cty.UnknownVal(cty.String), function.NewArgError(0, err)
}
baseArg, baseMarks := args[1].Unmark()
if err = gocty.FromCtyValue(baseArg, &base); err != nil {
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return cty.UnknownVal(cty.Number), function.NewArgError(1, err)
}
if base < 2 || base > 62 {
return cty.UnknownVal(cty.Number), function.NewArgErrorf(
1,
"base must be a whole number between 2 and 62 inclusive",
)
}
num, ok := (&big.Int{}).SetString(numstr, base)
if !ok {
return cty.UnknownVal(cty.Number), function.NewArgErrorf(
0,
"cannot parse %s as a base %s integer",
redactIfSensitive(numstr, numMarks),
redactIfSensitive(base, baseMarks),
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)
}
parsedNum := cty.NumberVal((&big.Float{}).SetInt(num)).WithMarks(numMarks, baseMarks)
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return parsedNum, nil
},
})
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// Log returns returns the logarithm of a given number in a given base.
func Log(num, base cty.Value) (cty.Value, error) {
return LogFunc.Call([]cty.Value{num, base})
}
// Pow returns the logarithm of a given number in a given base.
func Pow(num, power cty.Value) (cty.Value, error) {
return PowFunc.Call([]cty.Value{num, power})
}
// Signum determines the sign of a number, returning a number between -1 and
// 1 to represent the sign.
func Signum(num cty.Value) (cty.Value, error) {
return SignumFunc.Call([]cty.Value{num})
}
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// ParseInt parses a string argument and returns an integer of the specified base.
func ParseInt(num cty.Value, base cty.Value) (cty.Value, error) {
return ParseIntFunc.Call([]cty.Value{num, base})
}