151 lines
3 KiB
Go
151 lines
3 KiB
Go
package provider
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import (
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"context"
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"errors"
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"fmt"
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"github.com/evcc-io/evcc/util"
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)
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type calcProvider struct {
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add, mul, div []func() (float64, error)
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sign func() (float64, error)
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}
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func init() {
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registry.AddCtx("calc", NewCalcFromConfig)
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}
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// NewCalcFromConfig creates calc provider
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func NewCalcFromConfig(ctx context.Context, other map[string]interface{}) (Provider, error) {
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var cc struct {
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Add []Config
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Mul []Config
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Div []Config
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Sign *Config
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}
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if err := util.DecodeOther(other, &cc); err != nil {
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return nil, err
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}
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o := &calcProvider{}
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if i := min(len(cc.Add), 1) + min(len(cc.Mul), 1) + min(len(cc.Div), 1); i > 1 ||
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(len(cc.Add) > 0 && cc.Sign != nil) ||
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(len(cc.Mul) > 0 && cc.Sign != nil) ||
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(len(cc.Div) > 0 && cc.Sign != nil) {
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return nil, errors.New("can only have either add, mul, div or sign")
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}
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for idx, cc := range cc.Add {
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f, err := NewFloatGetterFromConfig(ctx, cc)
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if err != nil {
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return nil, fmt.Errorf("add[%d]: %w", idx, err)
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}
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o.add = append(o.add, f)
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}
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for idx, cc := range cc.Mul {
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f, err := NewFloatGetterFromConfig(ctx, cc)
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if err != nil {
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return nil, fmt.Errorf("mul[%d]: %w", idx, err)
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}
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o.mul = append(o.mul, f)
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}
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for idx, cc := range cc.Div {
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f, err := NewFloatGetterFromConfig(ctx, cc)
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if err != nil {
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return nil, fmt.Errorf("div[%d]: %w", idx, err)
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}
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o.div = append(o.div, f)
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}
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if cc.Sign != nil {
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f, err := NewFloatGetterFromConfig(ctx, *cc.Sign)
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if err != nil {
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return nil, fmt.Errorf("sign: %w", err)
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}
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o.sign = f
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}
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return o, nil
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}
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var _ IntProvider = (*calcProvider)(nil)
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func (o *calcProvider) IntGetter() (func() (int64, error), error) {
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return func() (int64, error) {
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f, err := o.floatGetter()
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return int64(f), err
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}, nil
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}
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var _ StringProvider = (*calcProvider)(nil)
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func (o *calcProvider) StringGetter() (func() (string, error), error) {
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return func() (string, error) {
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f, err := o.floatGetter()
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return fmt.Sprintf("%c", int(f)), err
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}, nil
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}
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var _ FloatProvider = (*calcProvider)(nil)
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func (o *calcProvider) FloatGetter() (func() (float64, error), error) {
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return o.floatGetter, nil
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}
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func (o *calcProvider) floatGetter() (float64, error) {
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var res float64
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switch {
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case len(o.mul) > 0:
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res = 1
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for idx, p := range o.mul {
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v, err := p()
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if err != nil {
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return 0, fmt.Errorf("mul[%d]: %w", idx, err)
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}
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res *= v
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}
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case len(o.add) > 0:
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for idx, p := range o.add {
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v, err := p()
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if err != nil {
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return 0, fmt.Errorf("add[%d]: %w", idx, err)
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}
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res += v
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}
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case len(o.div) > 0:
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for idx, p := range o.div {
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v, err := p()
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if err != nil {
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return 0, fmt.Errorf("div[%d]: %w", idx, err)
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}
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if idx == 0 {
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if v == 0 {
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break
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}
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res = v
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} else if v != 0 {
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res /= v
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} else if v == 0 {
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res = 0
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break
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}
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}
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default:
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v, err := o.sign()
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if err != nil {
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return 0, fmt.Errorf("sign: %w", err)
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}
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res = map[bool]float64{false: -1, true: 1}[v >= 0]
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}
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return res, nil
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}
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