593 lines
12 KiB
Go
593 lines
12 KiB
Go
/*
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** Copyright 2022 Dolysis Consulting Limited
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**
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** Licensed under the Apache License, Version 2.0 (the "License");
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** you may not use this file except in compliance with the License.
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** You may obtain a copy of the License at
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**
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** http://www.apache.org/licenses/LICENSE-2.0
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**
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** Unless required by applicable law or agreed to in writing, software
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** distributed under the License is distributed on an "AS IS" BASIS,
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** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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** See the License for the specific language governing permissions and
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** limitations under the License.
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**
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** For changes see the git log
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*/
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package ipp
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import (
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"encoding/binary"
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"fmt"
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"io"
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)
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const (
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sizeInteger = int16(4)
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sizeBoolean = int16(1)
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)
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// AttributeEncoder encodes attribute to a io.Writer
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type AttributeEncoder struct {
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writer io.Writer
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}
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// NewAttributeEncoder returns a new encoder that writes to w
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func NewAttributeEncoder(w io.Writer) *AttributeEncoder {
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return &AttributeEncoder{w}
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}
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// Encode encodes a attribute and its value to a io.Writer
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// the tag is determined by the AttributeTagMapping map
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func (e *AttributeEncoder) Encode(attribute string, value interface{}) error {
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tag, ok := AttributeTagMapping[attribute]
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if !ok {
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return fmt.Errorf("cannot get tag of attribute %s", attribute)
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}
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switch value.(type) {
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case int:
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if tag != TagInteger && tag != TagEnum {
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return fmt.Errorf("tag for attribute %s does not match with value type", attribute)
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}
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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if err := e.encodeInteger(int32(value.(int))); err != nil {
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return err
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}
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case int16:
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if tag != TagInteger && tag != TagEnum {
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return fmt.Errorf("tag for attribute %s does not match with value type", attribute)
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}
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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if err := e.encodeInteger(int32(value.(int16))); err != nil {
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return err
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}
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case int8:
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if tag != TagInteger && tag != TagEnum {
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return fmt.Errorf("tag for attribute %s does not match with value type", attribute)
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}
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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if err := e.encodeInteger(int32(value.(int8))); err != nil {
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return err
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}
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case int32:
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if tag != TagInteger && tag != TagEnum {
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return fmt.Errorf("tag for attribute %s does not match with value type", attribute)
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}
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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if err := e.encodeInteger(value.(int32)); err != nil {
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return err
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}
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case int64:
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if tag != TagInteger && tag != TagEnum {
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return fmt.Errorf("tag for attribute %s does not match with value type", attribute)
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}
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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if err := e.encodeInteger(int32(value.(int64))); err != nil {
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return err
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}
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case []int:
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if tag != TagInteger && tag != TagEnum {
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return fmt.Errorf("tag for attribute %s does not match with value type", attribute)
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}
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for index, val := range value.([]int) {
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if index == 0 {
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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} else {
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if err := e.writeNullByte(); err != nil {
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return err
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}
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}
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if err := e.encodeInteger(int32(val)); err != nil {
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return err
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}
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}
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case []int16:
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if tag != TagInteger && tag != TagEnum {
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return fmt.Errorf("tag for attribute %s does not match with value type", attribute)
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}
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for index, val := range value.([]int16) {
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if index == 0 {
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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} else {
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if err := e.writeNullByte(); err != nil {
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return err
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}
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}
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if err := e.encodeInteger(int32(val)); err != nil {
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return err
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}
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}
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case []int8:
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if tag != TagInteger && tag != TagEnum {
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return fmt.Errorf("tag for attribute %s does not match with value type", attribute)
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}
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for index, val := range value.([]int8) {
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if index == 0 {
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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} else {
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if err := e.writeNullByte(); err != nil {
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return err
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}
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}
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if err := e.encodeInteger(int32(val)); err != nil {
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return err
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}
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}
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case []int32:
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if tag != TagInteger && tag != TagEnum {
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return fmt.Errorf("tag for attribute %s does not match with value type", attribute)
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}
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for index, val := range value.([]int32) {
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if index == 0 {
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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} else {
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if err := e.writeNullByte(); err != nil {
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return err
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}
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}
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if err := e.encodeInteger(val); err != nil {
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return err
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}
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}
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case []int64:
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if tag != TagInteger && tag != TagEnum {
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return fmt.Errorf("tag for attribute %s does not match with value type", attribute)
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}
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for index, val := range value.([]int64) {
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if index == 0 {
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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} else {
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if err := e.writeNullByte(); err != nil {
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return err
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}
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}
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if err := e.encodeInteger(int32(val)); err != nil {
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return err
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}
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}
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case bool:
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if tag != TagBoolean {
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return fmt.Errorf("tag for attribute %s does not match with value type", attribute)
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}
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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if err := e.encodeBoolean(value.(bool)); err != nil {
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return err
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}
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case []bool:
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if tag != TagBoolean {
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return fmt.Errorf("tag for attribute %s does not match with value type", attribute)
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}
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for index, val := range value.([]bool) {
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if index == 0 {
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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} else {
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if err := e.writeNullByte(); err != nil {
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return err
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}
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}
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if err := e.encodeBoolean(val); err != nil {
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return err
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}
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}
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case string:
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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if err := e.encodeString(value.(string)); err != nil {
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return err
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}
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case []string:
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for index, val := range value.([]string) {
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if err := e.encodeTag(tag); err != nil {
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return err
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}
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if index == 0 {
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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} else {
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if err := e.writeNullByte(); err != nil {
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return err
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}
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}
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if err := e.encodeString(val); err != nil {
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return err
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}
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}
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default:
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if tag != TagBeginCollection {
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return fmt.Errorf("type %T is not supported", value)
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}
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if err := e.encodeTag(TagBeginCollection); err != nil {
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return err
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}
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if err := e.encodeString(attribute); err != nil {
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return err
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}
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if err := e.writeNullByte(); err != nil {
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return err
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}
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for member, value := range value.(map[string]interface{}) {
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if err := e.encodeTag(TagMemberName); err != nil {
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return err
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}
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if err := e.writeNullByte(); err != nil {
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return err
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}
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if err := e.encodeString(member); err != nil {
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return err
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}
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if err := e.encodeTag(TagKeyword); err != nil {
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return err
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}
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if err := e.writeNullByte(); err != nil {
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return err
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}
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if err := e.encodeString(value.(string)); err != nil {
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return err
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}
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}
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if err := e.encodeTag(TagEndCollection); err != nil {
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return err
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}
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if err := e.writeNullByte(); err != nil {
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return err
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}
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if err := e.writeNullByte(); err != nil {
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return err
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}
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}
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return nil
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}
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func (e *AttributeEncoder) encodeString(s string) error {
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if err := binary.Write(e.writer, binary.BigEndian, int16(len(s))); err != nil {
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return err
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}
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_, err := e.writer.Write([]byte(s))
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return err
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}
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func (e *AttributeEncoder) encodeInteger(i int32) error {
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if err := binary.Write(e.writer, binary.BigEndian, sizeInteger); err != nil {
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return err
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}
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return binary.Write(e.writer, binary.BigEndian, i)
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}
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func (e *AttributeEncoder) encodeBoolean(b bool) error {
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if err := binary.Write(e.writer, binary.BigEndian, sizeBoolean); err != nil {
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return err
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}
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return binary.Write(e.writer, binary.BigEndian, b)
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}
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func (e *AttributeEncoder) encodeTag(t int8) error {
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return binary.Write(e.writer, binary.BigEndian, t)
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}
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func (e *AttributeEncoder) writeNullByte() error {
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return binary.Write(e.writer, binary.BigEndian, int16(0))
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}
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// Attribute defines an ipp attribute
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type Attribute struct {
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Tag int8
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Name string
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Value interface{}
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}
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// Resolution defines the resolution attribute
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type Resolution struct {
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Height int32
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Width int32
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Depth int8
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}
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// AttributeDecoder reads and decodes ipp from an input stream
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type AttributeDecoder struct {
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reader io.Reader
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}
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// NewAttributeDecoder returns a new decoder that reads from r
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func NewAttributeDecoder(r io.Reader) *AttributeDecoder {
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return &AttributeDecoder{r}
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}
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// Decode reads the next ipp attribute into a attribute struct. the type is identified by a tag passed as an argument
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func (d *AttributeDecoder) Decode(tag int8) (*Attribute, error) {
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attr := Attribute{Tag: tag}
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name, err := d.decodeString()
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if err != nil {
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return nil, err
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}
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attr.Name = name
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switch attr.Tag {
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case TagEnum, TagInteger:
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val, err := d.decodeInteger()
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if err != nil {
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return nil, err
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}
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attr.Value = val
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case TagBoolean:
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val, err := d.decodeBool()
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if err != nil {
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return nil, err
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}
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attr.Value = val
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case TagDate:
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val, err := d.decodeDate()
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if err != nil {
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return nil, err
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}
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attr.Value = val
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case TagRange:
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val, err := d.decodeRange()
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if err != nil {
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return nil, err
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}
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attr.Value = val
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case TagResolution:
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val, err := d.decodeResolution()
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if err != nil {
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return nil, err
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}
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attr.Value = val
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default:
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val, err := d.decodeString()
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if err != nil {
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return nil, err
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}
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attr.Value = val
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}
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return &attr, nil
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}
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func (d *AttributeDecoder) decodeBool() (b bool, err error) {
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if _, err = d.readValueLength(); err != nil {
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return
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}
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if err = binary.Read(d.reader, binary.BigEndian, &b); err != nil {
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return
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}
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return
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}
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func (d *AttributeDecoder) decodeInteger() (i int, err error) {
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if _, err = d.readValueLength(); err != nil {
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return
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}
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var reti int32
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if err = binary.Read(d.reader, binary.BigEndian, &reti); err != nil {
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return
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}
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return int(reti), nil
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}
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func (d *AttributeDecoder) decodeString() (string, error) {
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length, err := d.readValueLength()
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if err != nil {
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return "", err
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}
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if length == 0 {
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return "", nil
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}
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bs := make([]byte, length)
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if _, err := d.reader.Read(bs); err != nil {
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return "", nil
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}
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return string(bs), nil
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}
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func (d *AttributeDecoder) decodeDate() ([]int, error) {
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length, err := d.readValueLength()
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if err != nil {
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return nil, err
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}
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is := make([]int, length)
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var ti int8
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for i := int16(0); i < length; i++ {
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if err = binary.Read(d.reader, binary.BigEndian, &ti); err != nil {
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return nil, err
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}
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is[i] = int(ti)
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}
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return is, nil
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}
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func (d *AttributeDecoder) decodeRange() ([]int32, error) {
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length, err := d.readValueLength()
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if err != nil {
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return nil, err
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}
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// initialize range element count (c) and range slice (r)
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c := length / 4
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r := make([]int32, c)
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for i := int16(0); i < c; i++ {
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var ti int32
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if err = binary.Read(d.reader, binary.BigEndian, &ti); err != nil {
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return nil, err
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}
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r[i] = ti
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}
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return r, nil
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}
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func (d *AttributeDecoder) decodeResolution() (res Resolution, err error) {
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_, err = d.readValueLength()
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if err != nil {
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return
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}
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if err = binary.Read(d.reader, binary.BigEndian, &res.Height); err != nil {
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return
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}
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if err = binary.Read(d.reader, binary.BigEndian, &res.Width); err != nil {
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return
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}
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if err = binary.Read(d.reader, binary.BigEndian, &res.Depth); err != nil {
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return
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}
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return
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}
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func (d *AttributeDecoder) readValueLength() (length int16, err error) {
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err = binary.Read(d.reader, binary.BigEndian, &length)
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return
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}
|