mirror of
https://github.com/octoleo/syncthing.git
synced 2024-12-24 20:00:26 +00:00
621 lines
16 KiB
Go
621 lines
16 KiB
Go
package maxminddb
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import (
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"encoding/binary"
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"math"
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"math/big"
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"reflect"
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"sync"
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)
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type decoder struct {
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buffer []byte
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}
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type dataType int
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const (
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_Extended dataType = iota
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_Pointer
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_String
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_Float64
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_Bytes
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_Uint16
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_Uint32
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_Map
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_Int32
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_Uint64
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_Uint128
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_Slice
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_Container
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_Marker
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_Bool
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_Float32
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)
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func (d *decoder) decode(offset uint, result reflect.Value) (uint, error) {
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typeNum, size, newOffset := d.decodeCtrlData(offset)
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if typeNum != _Pointer && result.Kind() == reflect.Uintptr {
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result.Set(reflect.ValueOf(uintptr(offset)))
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return d.nextValueOffset(offset, 1), nil
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}
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return d.decodeFromType(typeNum, size, newOffset, result)
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}
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func (d *decoder) decodeCtrlData(offset uint) (dataType, uint, uint) {
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newOffset := offset + 1
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ctrlByte := d.buffer[offset]
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typeNum := dataType(ctrlByte >> 5)
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if typeNum == _Extended {
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typeNum = dataType(d.buffer[newOffset] + 7)
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newOffset++
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}
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var size uint
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size, newOffset = d.sizeFromCtrlByte(ctrlByte, newOffset, typeNum)
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return typeNum, size, newOffset
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}
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func (d *decoder) sizeFromCtrlByte(ctrlByte byte, offset uint, typeNum dataType) (uint, uint) {
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size := uint(ctrlByte & 0x1f)
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if typeNum == _Extended {
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return size, offset
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}
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var bytesToRead uint
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if size > 28 {
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bytesToRead = size - 28
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}
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newOffset := offset + bytesToRead
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sizeBytes := d.buffer[offset:newOffset]
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switch {
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case size == 29:
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size = 29 + uint(sizeBytes[0])
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case size == 30:
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size = 285 + uint(uintFromBytes(0, sizeBytes))
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case size > 30:
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size = uint(uintFromBytes(0, sizeBytes)) + 65821
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}
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return size, newOffset
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}
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func (d *decoder) decodeFromType(dtype dataType, size uint, offset uint, result reflect.Value) (uint, error) {
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result = d.indirect(result)
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switch dtype {
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case _Bool:
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return d.unmarshalBool(size, offset, result)
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case _Bytes:
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return d.unmarshalBytes(size, offset, result)
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case _Float32:
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return d.unmarshalFloat32(size, offset, result)
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case _Float64:
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return d.unmarshalFloat64(size, offset, result)
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case _Int32:
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return d.unmarshalInt32(size, offset, result)
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case _Map:
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return d.unmarshalMap(size, offset, result)
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case _Pointer:
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return d.unmarshalPointer(size, offset, result)
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case _Slice:
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return d.unmarshalSlice(size, offset, result)
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case _String:
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return d.unmarshalString(size, offset, result)
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case _Uint16:
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return d.unmarshalUint(size, offset, result, 16)
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case _Uint32:
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return d.unmarshalUint(size, offset, result, 32)
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case _Uint64:
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return d.unmarshalUint(size, offset, result, 64)
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case _Uint128:
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return d.unmarshalUint128(size, offset, result)
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default:
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return 0, newInvalidDatabaseError("unknown type: %d", dtype)
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}
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}
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func (d *decoder) unmarshalBool(size uint, offset uint, result reflect.Value) (uint, error) {
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if size > 1 {
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return 0, newInvalidDatabaseError("the MaxMind DB file's data section contains bad data (bool size of %v)", size)
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}
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value, newOffset, err := d.decodeBool(size, offset)
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if err != nil {
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return 0, err
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}
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switch result.Kind() {
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case reflect.Bool:
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result.SetBool(value)
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return newOffset, nil
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case reflect.Interface:
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if result.NumMethod() == 0 {
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result.Set(reflect.ValueOf(value))
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return newOffset, nil
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}
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}
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return newOffset, newUnmarshalTypeError(value, result.Type())
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}
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// indirect follows pointers and create values as necessary. This is
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// heavily based on encoding/json as my original version had a subtle
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// bug. This method should be considered to be licensed under
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// https://golang.org/LICENSE
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func (d *decoder) indirect(result reflect.Value) reflect.Value {
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for {
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// Load value from interface, but only if the result will be
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// usefully addressable.
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if result.Kind() == reflect.Interface && !result.IsNil() {
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e := result.Elem()
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if e.Kind() == reflect.Ptr && !e.IsNil() {
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result = e
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continue
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}
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}
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if result.Kind() != reflect.Ptr {
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break
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}
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if result.IsNil() {
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result.Set(reflect.New(result.Type().Elem()))
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}
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result = result.Elem()
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}
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return result
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}
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func (d *decoder) unmarshalBytes(size uint, offset uint, result reflect.Value) (uint, error) {
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value, newOffset, err := d.decodeBytes(size, offset)
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if err != nil {
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return 0, err
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}
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switch result.Kind() {
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case reflect.Slice:
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result.SetBytes(value)
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return newOffset, nil
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case reflect.Interface:
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if result.NumMethod() == 0 {
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result.Set(reflect.ValueOf(value))
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return newOffset, nil
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}
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}
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return newOffset, newUnmarshalTypeError(value, result.Type())
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}
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func (d *decoder) unmarshalFloat32(size uint, offset uint, result reflect.Value) (uint, error) {
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if size != 4 {
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return 0, newInvalidDatabaseError("the MaxMind DB file's data section contains bad data (float32 size of %v)", size)
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}
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value, newOffset, err := d.decodeFloat32(size, offset)
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if err != nil {
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return 0, err
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}
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switch result.Kind() {
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case reflect.Float32, reflect.Float64:
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result.SetFloat(float64(value))
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return newOffset, nil
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case reflect.Interface:
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if result.NumMethod() == 0 {
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result.Set(reflect.ValueOf(value))
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return newOffset, nil
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}
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}
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return newOffset, newUnmarshalTypeError(value, result.Type())
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}
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func (d *decoder) unmarshalFloat64(size uint, offset uint, result reflect.Value) (uint, error) {
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if size != 8 {
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return 0, newInvalidDatabaseError("the MaxMind DB file's data section contains bad data (float 64 size of %v)", size)
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}
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value, newOffset, err := d.decodeFloat64(size, offset)
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if err != nil {
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return 0, err
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}
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switch result.Kind() {
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case reflect.Float32, reflect.Float64:
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if result.OverflowFloat(value) {
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return 0, newUnmarshalTypeError(value, result.Type())
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}
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result.SetFloat(value)
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return newOffset, nil
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case reflect.Interface:
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if result.NumMethod() == 0 {
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result.Set(reflect.ValueOf(value))
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return newOffset, nil
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}
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}
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return newOffset, newUnmarshalTypeError(value, result.Type())
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}
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func (d *decoder) unmarshalInt32(size uint, offset uint, result reflect.Value) (uint, error) {
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if size > 4 {
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return 0, newInvalidDatabaseError("the MaxMind DB file's data section contains bad data (int32 size of %v)", size)
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}
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value, newOffset, err := d.decodeInt(size, offset)
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if err != nil {
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return 0, err
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}
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switch result.Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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n := int64(value)
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if !result.OverflowInt(n) {
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result.SetInt(n)
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return newOffset, nil
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}
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
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n := uint64(value)
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if !result.OverflowUint(n) {
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result.SetUint(n)
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return newOffset, nil
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}
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case reflect.Interface:
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if result.NumMethod() == 0 {
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result.Set(reflect.ValueOf(value))
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return newOffset, nil
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}
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}
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return newOffset, newUnmarshalTypeError(value, result.Type())
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}
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func (d *decoder) unmarshalMap(size uint, offset uint, result reflect.Value) (uint, error) {
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result = d.indirect(result)
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switch result.Kind() {
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default:
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return 0, newUnmarshalTypeError("map", result.Type())
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case reflect.Struct:
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return d.decodeStruct(size, offset, result)
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case reflect.Map:
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return d.decodeMap(size, offset, result)
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case reflect.Interface:
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if result.NumMethod() == 0 {
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rv := reflect.ValueOf(make(map[string]interface{}, size))
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newOffset, err := d.decodeMap(size, offset, rv)
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result.Set(rv)
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return newOffset, err
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}
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return 0, newUnmarshalTypeError("map", result.Type())
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}
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}
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func (d *decoder) unmarshalPointer(size uint, offset uint, result reflect.Value) (uint, error) {
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pointer, newOffset := d.decodePointer(size, offset)
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_, err := d.decode(pointer, result)
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return newOffset, err
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}
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func (d *decoder) unmarshalSlice(size uint, offset uint, result reflect.Value) (uint, error) {
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switch result.Kind() {
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case reflect.Slice:
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return d.decodeSlice(size, offset, result)
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case reflect.Interface:
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if result.NumMethod() == 0 {
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a := []interface{}{}
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rv := reflect.ValueOf(&a).Elem()
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newOffset, err := d.decodeSlice(size, offset, rv)
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result.Set(rv)
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return newOffset, err
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}
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}
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return 0, newUnmarshalTypeError("array", result.Type())
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}
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func (d *decoder) unmarshalString(size uint, offset uint, result reflect.Value) (uint, error) {
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value, newOffset, err := d.decodeString(size, offset)
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if err != nil {
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return 0, err
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}
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switch result.Kind() {
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case reflect.String:
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result.SetString(value)
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return newOffset, nil
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case reflect.Interface:
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if result.NumMethod() == 0 {
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result.Set(reflect.ValueOf(value))
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return newOffset, nil
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}
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}
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return newOffset, newUnmarshalTypeError(value, result.Type())
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}
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func (d *decoder) unmarshalUint(size uint, offset uint, result reflect.Value, uintType uint) (uint, error) {
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if size > uintType/8 {
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return 0, newInvalidDatabaseError("the MaxMind DB file's data section contains bad data (uint%v size of %v)", uintType, size)
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}
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value, newOffset, err := d.decodeUint(size, offset)
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if err != nil {
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return 0, err
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}
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switch result.Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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n := int64(value)
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if !result.OverflowInt(n) {
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result.SetInt(n)
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return newOffset, nil
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}
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
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if !result.OverflowUint(value) {
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result.SetUint(value)
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return newOffset, nil
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}
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case reflect.Interface:
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if result.NumMethod() == 0 {
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result.Set(reflect.ValueOf(value))
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return newOffset, nil
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}
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}
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return newOffset, newUnmarshalTypeError(value, result.Type())
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}
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func (d *decoder) unmarshalUint128(size uint, offset uint, result reflect.Value) (uint, error) {
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if size > 16 {
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return 0, newInvalidDatabaseError("the MaxMind DB file's data section contains bad data (uint128 size of %v)", size)
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}
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value, newOffset, err := d.decodeUint128(size, offset)
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if err != nil {
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return 0, err
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}
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switch result.Kind() {
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case reflect.Struct:
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result.Set(reflect.ValueOf(*value))
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return newOffset, nil
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case reflect.Interface:
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if result.NumMethod() == 0 {
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result.Set(reflect.ValueOf(value))
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return newOffset, nil
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}
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}
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return newOffset, newUnmarshalTypeError(value, result.Type())
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}
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func (d *decoder) decodeBool(size uint, offset uint) (bool, uint, error) {
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return size != 0, offset, nil
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}
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func (d *decoder) decodeBytes(size uint, offset uint) ([]byte, uint, error) {
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newOffset := offset + size
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bytes := make([]byte, size)
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copy(bytes, d.buffer[offset:newOffset])
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return bytes, newOffset, nil
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}
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func (d *decoder) decodeFloat64(size uint, offset uint) (float64, uint, error) {
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newOffset := offset + size
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bits := binary.BigEndian.Uint64(d.buffer[offset:newOffset])
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return math.Float64frombits(bits), newOffset, nil
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}
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func (d *decoder) decodeFloat32(size uint, offset uint) (float32, uint, error) {
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newOffset := offset + size
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bits := binary.BigEndian.Uint32(d.buffer[offset:newOffset])
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return math.Float32frombits(bits), newOffset, nil
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}
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func (d *decoder) decodeInt(size uint, offset uint) (int, uint, error) {
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newOffset := offset + size
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var val int32
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for _, b := range d.buffer[offset:newOffset] {
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val = (val << 8) | int32(b)
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}
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return int(val), newOffset, nil
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}
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func (d *decoder) decodeMap(size uint, offset uint, result reflect.Value) (uint, error) {
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if result.IsNil() {
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result.Set(reflect.MakeMap(result.Type()))
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}
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for i := uint(0); i < size; i++ {
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var key []byte
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var err error
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key, offset, err = d.decodeKey(offset)
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|
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if err != nil {
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return 0, err
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}
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value := reflect.New(result.Type().Elem())
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offset, err = d.decode(offset, value)
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if err != nil {
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return 0, err
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}
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result.SetMapIndex(reflect.ValueOf(string(key)), value.Elem())
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}
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return offset, nil
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}
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|
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func (d *decoder) decodePointer(size uint, offset uint) (uint, uint) {
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pointerSize := ((size >> 3) & 0x3) + 1
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newOffset := offset + pointerSize
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pointerBytes := d.buffer[offset:newOffset]
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var prefix uint64
|
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if pointerSize == 4 {
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prefix = 0
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} else {
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prefix = uint64(size & 0x7)
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}
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unpacked := uint(uintFromBytes(prefix, pointerBytes))
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|
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var pointerValueOffset uint
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switch pointerSize {
|
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case 1:
|
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pointerValueOffset = 0
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case 2:
|
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pointerValueOffset = 2048
|
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case 3:
|
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pointerValueOffset = 526336
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case 4:
|
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pointerValueOffset = 0
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}
|
|
|
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pointer := unpacked + pointerValueOffset
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|
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return pointer, newOffset
|
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}
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|
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func (d *decoder) decodeSlice(size uint, offset uint, result reflect.Value) (uint, error) {
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result.Set(reflect.MakeSlice(result.Type(), int(size), int(size)))
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for i := 0; i < int(size); i++ {
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var err error
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offset, err = d.decode(offset, result.Index(i))
|
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if err != nil {
|
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return 0, err
|
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}
|
|
}
|
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return offset, nil
|
|
}
|
|
|
|
func (d *decoder) decodeString(size uint, offset uint) (string, uint, error) {
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newOffset := offset + size
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return string(d.buffer[offset:newOffset]), newOffset, nil
|
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}
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|
|
|
type fieldsType struct {
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namedFields map[string]int
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anonymousFields []int
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}
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|
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var (
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fieldMap = map[reflect.Type]*fieldsType{}
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fieldMapMu sync.RWMutex
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)
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|
|
func (d *decoder) decodeStruct(size uint, offset uint, result reflect.Value) (uint, error) {
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resultType := result.Type()
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|
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fieldMapMu.RLock()
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fields, ok := fieldMap[resultType]
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fieldMapMu.RUnlock()
|
|
if !ok {
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numFields := resultType.NumField()
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namedFields := make(map[string]int, numFields)
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var anonymous []int
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for i := 0; i < numFields; i++ {
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field := resultType.Field(i)
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fieldName := field.Name
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if tag := field.Tag.Get("maxminddb"); tag != "" {
|
|
if tag == "-" {
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continue
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}
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fieldName = tag
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}
|
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if field.Anonymous {
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anonymous = append(anonymous, i)
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continue
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}
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namedFields[fieldName] = i
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}
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fieldMapMu.Lock()
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fields = &fieldsType{namedFields, anonymous}
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fieldMap[resultType] = fields
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fieldMapMu.Unlock()
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}
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|
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// This fills in embedded structs
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for i := range fields.anonymousFields {
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_, err := d.unmarshalMap(size, offset, result.Field(i))
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if err != nil {
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return 0, err
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}
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}
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|
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// This handles named fields
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for i := uint(0); i < size; i++ {
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var (
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err error
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key []byte
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)
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key, offset, err = d.decodeKey(offset)
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if err != nil {
|
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return 0, err
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}
|
|
// The string() does not create a copy due to this compiler
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|
// optimization: https://github.com/golang/go/issues/3512
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j, ok := fields.namedFields[string(key)]
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if !ok {
|
|
offset = d.nextValueOffset(offset, 1)
|
|
continue
|
|
}
|
|
|
|
offset, err = d.decode(offset, result.Field(j))
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
}
|
|
return offset, nil
|
|
}
|
|
|
|
func (d *decoder) decodeUint(size uint, offset uint) (uint64, uint, error) {
|
|
newOffset := offset + size
|
|
val := uintFromBytes(0, d.buffer[offset:newOffset])
|
|
|
|
return val, newOffset, nil
|
|
}
|
|
|
|
func (d *decoder) decodeUint128(size uint, offset uint) (*big.Int, uint, error) {
|
|
newOffset := offset + size
|
|
val := new(big.Int)
|
|
val.SetBytes(d.buffer[offset:newOffset])
|
|
|
|
return val, newOffset, nil
|
|
}
|
|
|
|
func uintFromBytes(prefix uint64, uintBytes []byte) uint64 {
|
|
val := prefix
|
|
for _, b := range uintBytes {
|
|
val = (val << 8) | uint64(b)
|
|
}
|
|
return val
|
|
}
|
|
|
|
// decodeKey decodes a map key into []byte slice. We use a []byte so that we
|
|
// can take advantage of https://github.com/golang/go/issues/3512 to avoid
|
|
// copying the bytes when decoding a struct. Previously, we achieved this by
|
|
// using unsafe.
|
|
func (d *decoder) decodeKey(offset uint) ([]byte, uint, error) {
|
|
typeNum, size, dataOffset := d.decodeCtrlData(offset)
|
|
if typeNum == _Pointer {
|
|
pointer, ptrOffset := d.decodePointer(size, dataOffset)
|
|
key, _, err := d.decodeKey(pointer)
|
|
return key, ptrOffset, err
|
|
}
|
|
if typeNum != _String {
|
|
return nil, 0, newInvalidDatabaseError("unexpected type when decoding string: %v", typeNum)
|
|
}
|
|
newOffset := dataOffset + size
|
|
return d.buffer[dataOffset:newOffset], newOffset, nil
|
|
}
|
|
|
|
// This function is used to skip ahead to the next value without decoding
|
|
// the one at the offset passed in. The size bits have different meanings for
|
|
// different data types
|
|
func (d *decoder) nextValueOffset(offset uint, numberToSkip uint) uint {
|
|
if numberToSkip == 0 {
|
|
return offset
|
|
}
|
|
typeNum, size, offset := d.decodeCtrlData(offset)
|
|
switch typeNum {
|
|
case _Pointer:
|
|
_, offset = d.decodePointer(size, offset)
|
|
case _Map:
|
|
numberToSkip += 2 * size
|
|
case _Slice:
|
|
numberToSkip += size
|
|
case _Bool:
|
|
default:
|
|
offset += size
|
|
}
|
|
return d.nextValueOffset(offset, numberToSkip-1)
|
|
}
|