std_strtof.go

// Code generated by __generator__/interpreter.go at once

package builtin

import (
	"regexp"
	"strconv"
	"strings"

	"github.com/ysugimoto/falco/interpreter/context"
	"github.com/ysugimoto/falco/interpreter/function/errors"
	"github.com/ysugimoto/falco/interpreter/value"
)

const Std_strtof_Name = "std.strtof"

var Std_strtof_ArgumentTypes = []value.Type{value.StringType, value.IntegerType}

func Std_strtof_Validate(args []value.Value) error {
	if len(args) != 2 {
		return errors.ArgumentNotEnough(Std_strtof_Name, 2, args)
	}
	for i := range args {
		if args[i].Type() != Std_strtof_ArgumentTypes[i] {
			return errors.TypeMismatch(Std_strtof_Name, i+1, Std_strtof_ArgumentTypes[i], args[i].Type())
		}
	}
	return nil
}

func Std_strtof_Decimal(s string) (value.Value, error) {
	f, err := strconv.ParseFloat(s, 64)
	if err != nil {
		return value.Null, errors.New(Std_strtof_Name, "Failed to parse string to decimal float: %s", s)
	}
	return &value.Float{Value: f}, nil
}

var hexMantissaSuffix = regexp.MustCompile(`p[+-][0-9]+$`)

func Std_strtof_Hex(s string) (value.Value, error) {
	// To convert hex float string correctly in Golang, mantissa suffix is needed
	if !hexMantissaSuffix.MatchString(s) {
		s += "p0"
	}
	f, err := strconv.ParseFloat(s, 64)
	if err != nil {
		return value.Null, errors.New(Std_strtof_Name, "Failed to parse string to hex float: %s", s)
	}
	return &value.Float{Value: f}, nil
}

// Fastly built-in function implementation of std.strtof
// Arguments may be:
// - STRING, INTEGER
// Reference: https://developer.fastly.com/reference/vcl/functions/strings/std-strtof/
func Std_strtof(ctx *context.Context, args ...value.Value) (value.Value, error) {
	// Argument validations
	if err := Std_strtof_Validate(args); err != nil {
		return value.Null, err
	}

	s := value.Unwrap[*value.String](args[0]).Value
	base := value.Unwrap[*value.Integer](args[1]).Value

	switch base {
	case 0:
		if strings.HasPrefix(s, "0x") {
			return Std_strtof_Hex(s)
		}
		return Std_strtof_Decimal(s)
	case 10:
		if strings.HasPrefix(s, "0x") {
			ctx.FastlyError = &value.String{Value: "EPARSENUM"}
			return value.Null, errors.New(Std_strtof_Name, "string must not have 0x prefix of when base number is 10")
		}
		return Std_strtof_Decimal(s)
	case 16:
		if !strings.HasPrefix(s, "0x") {
			ctx.FastlyError = &value.String{Value: "EPARSENUM"}
			return value.Null, errors.New(Std_strtof_Name, "string must have 0x prefix of when base number is 16")
		}
		return Std_strtof_Hex(s)
	default:
		ctx.FastlyError = &value.String{Value: "EPARSENUM"}
		return value.Null, errors.New(Std_strtof_Name, "Base number accepts only 0, 10 and 16")
	}
}