1 files changed, 721 insertions, 0 deletions
diff --git a/vendor/github.com/oschwald/maxminddb-golang/decoder.go b/vendor/github.com/oschwald/maxminddb-golang/decoder.go
new file mode 100644
index 0000000..6e4d7e5
--- /dev/null
+++ b/vendor/github.com/oschwald/maxminddb-golang/decoder.go
@@ -0,0 +1,721 @@
+package maxminddb
+
+import (
+	"encoding/binary"
+	"math"
+	"math/big"
+	"reflect"
+	"sync"
+)
+
+type decoder struct {
+	buffer []byte
+}
+
+type dataType int
+
+const (
+	_Extended dataType = iota
+	_Pointer
+	_String
+	_Float64
+	_Bytes
+	_Uint16
+	_Uint32
+	_Map
+	_Int32
+	_Uint64
+	_Uint128
+	_Slice
+	_Container
+	_Marker
+	_Bool
+	_Float32
+)
+
+const (
+	// This is the value used in libmaxminddb
+	maximumDataStructureDepth = 512
+)
+
+func (d *decoder) decode(offset uint, result reflect.Value, depth int) (uint, error) {
+	if depth > maximumDataStructureDepth {
+		return 0, newInvalidDatabaseError("exceeded maximum data structure depth; database is likely corrupt")
+	}
+	typeNum, size, newOffset, err := d.decodeCtrlData(offset)
+	if err != nil {
+		return 0, err
+	}
+
+	if typeNum != _Pointer && result.Kind() == reflect.Uintptr {
+		result.Set(reflect.ValueOf(uintptr(offset)))
+		return d.nextValueOffset(offset, 1)
+	}
+	return d.decodeFromType(typeNum, size, newOffset, result, depth+1)
+}
+
+func (d *decoder) decodeCtrlData(offset uint) (dataType, uint, uint, error) {
+	newOffset := offset + 1
+	if offset >= uint(len(d.buffer)) {
+		return 0, 0, 0, newOffsetError()
+	}
+	ctrlByte := d.buffer[offset]
+
+	typeNum := dataType(ctrlByte >> 5)
+	if typeNum == _Extended {
+		if newOffset >= uint(len(d.buffer)) {
+			return 0, 0, 0, newOffsetError()
+		}
+		typeNum = dataType(d.buffer[newOffset] + 7)
+		newOffset++
+	}
+
+	var size uint
+	size, newOffset, err := d.sizeFromCtrlByte(ctrlByte, newOffset, typeNum)
+	return typeNum, size, newOffset, err
+}
+
+func (d *decoder) sizeFromCtrlByte(ctrlByte byte, offset uint, typeNum dataType) (uint, uint, error) {
+	size := uint(ctrlByte & 0x1f)
+	if typeNum == _Extended {
+		return size, offset, nil
+	}
+
+	var bytesToRead uint
+	if size < 29 {
+		return size, offset, nil
+	}
+
+	bytesToRead = size - 28
+	newOffset := offset + bytesToRead
+	if newOffset > uint(len(d.buffer)) {
+		return 0, 0, newOffsetError()
+	}
+	if size == 29 {
+		return 29 + uint(d.buffer[offset]), offset + 1, nil
+	}
+
+	sizeBytes := d.buffer[offset:newOffset]
+
+	switch {
+	case size == 30:
+		size = 285 + uintFromBytes(0, sizeBytes)
+	case size > 30:
+		size = uintFromBytes(0, sizeBytes) + 65821
+	}
+	return size, newOffset, nil
+}
+
+func (d *decoder) decodeFromType(
+	dtype dataType,
+	size uint,
+	offset uint,
+	result reflect.Value,
+	depth int,
+) (uint, error) {
+	result = d.indirect(result)
+
+	// For these types, size has a special meaning
+	switch dtype {
+	case _Bool:
+		return d.unmarshalBool(size, offset, result)
+	case _Map:
+		return d.unmarshalMap(size, offset, result, depth)
+	case _Pointer:
+		return d.unmarshalPointer(size, offset, result, depth)
+	case _Slice:
+		return d.unmarshalSlice(size, offset, result, depth)
+	}
+
+	// For the remaining types, size is the byte size
+	if offset+size > uint(len(d.buffer)) {
+		return 0, newOffsetError()
+	}
+	switch dtype {
+	case _Bytes:
+		return d.unmarshalBytes(size, offset, result)
+	case _Float32:
+		return d.unmarshalFloat32(size, offset, result)
+	case _Float64:
+		return d.unmarshalFloat64(size, offset, result)
+	case _Int32:
+		return d.unmarshalInt32(size, offset, result)
+	case _String:
+		return d.unmarshalString(size, offset, result)
+	case _Uint16:
+		return d.unmarshalUint(size, offset, result, 16)
+	case _Uint32:
+		return d.unmarshalUint(size, offset, result, 32)
+	case _Uint64:
+		return d.unmarshalUint(size, offset, result, 64)
+	case _Uint128:
+		return d.unmarshalUint128(size, offset, result)
+	default:
+		return 0, newInvalidDatabaseError("unknown type: %d", dtype)
+	}
+}
+
+func (d *decoder) unmarshalBool(size uint, offset uint, result reflect.Value) (uint, error) {
+	if size > 1 {
+		return 0, newInvalidDatabaseError("the MaxMind DB file's data section contains bad data (bool size of %v)", size)
+	}
+	value, newOffset, err := d.decodeBool(size, offset)
+	if err != nil {
+		return 0, err
+	}
+	switch result.Kind() {
+	case reflect.Bool:
+		result.SetBool(value)
+		return newOffset, nil
+	case reflect.Interface:
+		if result.NumMethod() == 0 {
+			result.Set(reflect.ValueOf(value))
+			return newOffset, nil
+		}
+	}
+	return newOffset, newUnmarshalTypeError(value, result.Type())
+}
+
+// indirect follows pointers and create values as necessary. This is
+// heavily based on encoding/json as my original version had a subtle
+// bug. This method should be considered to be licensed under
+// https://golang.org/LICENSE
+func (d *decoder) indirect(result reflect.Value) reflect.Value {
+	for {
+		// Load value from interface, but only if the result will be
+		// usefully addressable.
+		if result.Kind() == reflect.Interface && !result.IsNil() {
+			e := result.Elem()
+			if e.Kind() == reflect.Ptr && !e.IsNil() {
+				result = e
+				continue
+			}
+		}
+
+		if result.Kind() != reflect.Ptr {
+			break
+		}
+
+		if result.IsNil() {
+			result.Set(reflect.New(result.Type().Elem()))
+		}
+		result = result.Elem()
+	}
+	return result
+}
+
+var sliceType = reflect.TypeOf([]byte{})
+
+func (d *decoder) unmarshalBytes(size uint, offset uint, result reflect.Value) (uint, error) {
+	value, newOffset, err := d.decodeBytes(size, offset)
+	if err != nil {
+		return 0, err
+	}
+	switch result.Kind() {
+	case reflect.Slice:
+		if result.Type() == sliceType {
+			result.SetBytes(value)
+			return newOffset, nil
+		}
+	case reflect.Interface:
+		if result.NumMethod() == 0 {
+			result.Set(reflect.ValueOf(value))
+			return newOffset, nil
+		}
+	}
+	return newOffset, newUnmarshalTypeError(value, result.Type())
+}
+
+func (d *decoder) unmarshalFloat32(size uint, offset uint, result reflect.Value) (uint, error) {
+	if size != 4 {
+		return 0, newInvalidDatabaseError("the MaxMind DB file's data section contains bad data (float32 size of %v)", size)
+	}
+	value, newOffset, err := d.decodeFloat32(size, offset)
+	if err != nil {
+		return 0, err
+	}
+
+	switch result.Kind() {
+	case reflect.Float32, reflect.Float64:
+		result.SetFloat(float64(value))
+		return newOffset, nil
+	case reflect.Interface:
+		if result.NumMethod() == 0 {
+			result.Set(reflect.ValueOf(value))
+			return newOffset, nil
+		}
+	}
+	return newOffset, newUnmarshalTypeError(value, result.Type())
+}
+
+func (d *decoder) unmarshalFloat64(size uint, offset uint, result reflect.Value) (uint, error) {
+
+	if size != 8 {
+		return 0, newInvalidDatabaseError("the MaxMind DB file's data section contains bad data (float 64 size of %v)", size)
+	}
+	value, newOffset, err := d.decodeFloat64(size, offset)
+	if err != nil {
+		return 0, err
+	}
+	switch result.Kind() {
+	case reflect.Float32, reflect.Float64:
+		if result.OverflowFloat(value) {
+			return 0, newUnmarshalTypeError(value, result.Type())
+		}
+		result.SetFloat(value)
+		return newOffset, nil
+	case reflect.Interface:
+		if result.NumMethod() == 0 {
+			result.Set(reflect.ValueOf(value))
+			return newOffset, nil
+		}
+	}
+	return newOffset, newUnmarshalTypeError(value, result.Type())
+}
+
+func (d *decoder) unmarshalInt32(size uint, offset uint, result reflect.Value) (uint, error) {
+	if size > 4 {
+		return 0, newInvalidDatabaseError("the MaxMind DB file's data section contains bad data (int32 size of %v)", size)
+	}
+	value, newOffset, err := d.decodeInt(size, offset)
+	if err != nil {
+		return 0, err
+	}
+
+	switch result.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		n := int64(value)
+		if !result.OverflowInt(n) {
+			result.SetInt(n)
+			return newOffset, nil
+		}
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		n := uint64(value)
+		if !result.OverflowUint(n) {
+			result.SetUint(n)
+			return newOffset, nil
+		}
+	case reflect.Interface:
+		if result.NumMethod() == 0 {
+			result.Set(reflect.ValueOf(value))
+			return newOffset, nil
+		}
+	}
+	return newOffset, newUnmarshalTypeError(value, result.Type())
+}
+
+func (d *decoder) unmarshalMap(
+	size uint,
+	offset uint,
+	result reflect.Value,
+	depth int,
+) (uint, error) {
+	result = d.indirect(result)
+	switch result.Kind() {
+	default:
+		return 0, newUnmarshalTypeError("map", result.Type())
+	case reflect.Struct:
+		return d.decodeStruct(size, offset, result, depth)
+	case reflect.Map:
+		return d.decodeMap(size, offset, result, depth)
+	case reflect.Interface:
+		if result.NumMethod() == 0 {
+			rv := reflect.ValueOf(make(map[string]interface{}, size))
+			newOffset, err := d.decodeMap(size, offset, rv, depth)
+			result.Set(rv)
+			return newOffset, err
+		}
+		return 0, newUnmarshalTypeError("map", result.Type())
+	}
+}
+
+func (d *decoder) unmarshalPointer(size uint, offset uint, result reflect.Value, depth int) (uint, error) {
+	pointer, newOffset, err := d.decodePointer(size, offset)
+	if err != nil {
+		return 0, err
+	}
+	_, err = d.decode(pointer, result, depth)
+	return newOffset, err
+}
+
+func (d *decoder) unmarshalSlice(
+	size uint,
+	offset uint,
+	result reflect.Value,
+	depth int,
+) (uint, error) {
+	switch result.Kind() {
+	case reflect.Slice:
+		return d.decodeSlice(size, offset, result, depth)
+	case reflect.Interface:
+		if result.NumMethod() == 0 {
+			a := []interface{}{}
+			rv := reflect.ValueOf(&a).Elem()
+			newOffset, err := d.decodeSlice(size, offset, rv, depth)
+			result.Set(rv)
+			return newOffset, err
+		}
+	}
+	return 0, newUnmarshalTypeError("array", result.Type())
+}
+
+func (d *decoder) unmarshalString(size uint, offset uint, result reflect.Value) (uint, error) {
+	value, newOffset, err := d.decodeString(size, offset)
+
+	if err != nil {
+		return 0, err
+	}
+	switch result.Kind() {
+	case reflect.String:
+		result.SetString(value)
+		return newOffset, nil
+	case reflect.Interface:
+		if result.NumMethod() == 0 {
+			result.Set(reflect.ValueOf(value))
+			return newOffset, nil
+		}
+	}
+	return newOffset, newUnmarshalTypeError(value, result.Type())
+
+}
+
+func (d *decoder) unmarshalUint(size uint, offset uint, result reflect.Value, uintType uint) (uint, error) {
+	if size > uintType/8 {
+		return 0, newInvalidDatabaseError("the MaxMind DB file's data section contains bad data (uint%v size of %v)", uintType, size)
+	}
+
+	value, newOffset, err := d.decodeUint(size, offset)
+	if err != nil {
+		return 0, err
+	}
+
+	switch result.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		n := int64(value)
+		if !result.OverflowInt(n) {
+			result.SetInt(n)
+			return newOffset, nil
+		}
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		if !result.OverflowUint(value) {
+			result.SetUint(value)
+			return newOffset, nil
+		}
+	case reflect.Interface:
+		if result.NumMethod() == 0 {
+			result.Set(reflect.ValueOf(value))
+			return newOffset, nil
+		}
+	}
+	return newOffset, newUnmarshalTypeError(value, result.Type())
+}
+
+var bigIntType = reflect.TypeOf(big.Int{})
+
+func (d *decoder) unmarshalUint128(size uint, offset uint, result reflect.Value) (uint, error) {
+	if size > 16 {
+		return 0, newInvalidDatabaseError("the MaxMind DB file's data section contains bad data (uint128 size of %v)", size)
+	}
+	value, newOffset, err := d.decodeUint128(size, offset)
+	if err != nil {
+		return 0, err
+	}
+
+	switch result.Kind() {
+	case reflect.Struct:
+		if result.Type() == bigIntType {
+			result.Set(reflect.ValueOf(*value))
+			return newOffset, nil
+		}
+	case reflect.Interface:
+		if result.NumMethod() == 0 {
+			result.Set(reflect.ValueOf(value))
+			return newOffset, nil
+		}
+	}
+	return newOffset, newUnmarshalTypeError(value, result.Type())
+}
+
+func (d *decoder) decodeBool(size uint, offset uint) (bool, uint, error) {
+	return size != 0, offset, nil
+}
+
+func (d *decoder) decodeBytes(size uint, offset uint) ([]byte, uint, error) {
+	newOffset := offset + size
+	bytes := make([]byte, size)
+	copy(bytes, d.buffer[offset:newOffset])
+	return bytes, newOffset, nil
+}
+
+func (d *decoder) decodeFloat64(size uint, offset uint) (float64, uint, error) {
+	newOffset := offset + size
+	bits := binary.BigEndian.Uint64(d.buffer[offset:newOffset])
+	return math.Float64frombits(bits), newOffset, nil
+}
+
+func (d *decoder) decodeFloat32(size uint, offset uint) (float32, uint, error) {
+	newOffset := offset + size
+	bits := binary.BigEndian.Uint32(d.buffer[offset:newOffset])
+	return math.Float32frombits(bits), newOffset, nil
+}
+
+func (d *decoder) decodeInt(size uint, offset uint) (int, uint, error) {
+	newOffset := offset + size
+	var val int32
+	for _, b := range d.buffer[offset:newOffset] {
+		val = (val << 8) | int32(b)
+	}
+	return int(val), newOffset, nil
+}
+
+func (d *decoder) decodeMap(
+	size uint,
+	offset uint,
+	result reflect.Value,
+	depth int,
+) (uint, error) {
+	if result.IsNil() {
+		result.Set(reflect.MakeMap(result.Type()))
+	}
+
+	for i := uint(0); i < size; i++ {
+		var key []byte
+		var err error
+		key, offset, err = d.decodeKey(offset)
+
+		if err != nil {
+			return 0, err
+		}
+
+		value := reflect.New(result.Type().Elem())
+		offset, err = d.decode(offset, value, depth)
+		if err != nil {
+			return 0, err
+		}
+		result.SetMapIndex(reflect.ValueOf(string(key)), value.Elem())
+	}
+	return offset, nil
+}
+
+func (d *decoder) decodePointer(
+	size uint,
+	offset uint,
+) (uint, uint, error) {
+	pointerSize := ((size >> 3) & 0x3) + 1
+	newOffset := offset + pointerSize
+	if newOffset > uint(len(d.buffer)) {
+		return 0, 0, newOffsetError()
+	}
+	pointerBytes := d.buffer[offset:newOffset]
+	var prefix uint
+	if pointerSize == 4 {
+		prefix = 0
+	} else {
+		prefix = uint(size & 0x7)
+	}
+	unpacked := uintFromBytes(prefix, pointerBytes)
+
+	var pointerValueOffset uint
+	switch pointerSize {
+	case 1:
+		pointerValueOffset = 0
+	case 2:
+		pointerValueOffset = 2048
+	case 3:
+		pointerValueOffset = 526336
+	case 4:
+		pointerValueOffset = 0
+	}
+
+	pointer := unpacked + pointerValueOffset
+
+	return pointer, newOffset, nil
+}
+
+func (d *decoder) decodeSlice(
+	size uint,
+	offset uint,
+	result reflect.Value,
+	depth int,
+) (uint, error) {
+	result.Set(reflect.MakeSlice(result.Type(), int(size), int(size)))
+	for i := 0; i < int(size); i++ {
+		var err error
+		offset, err = d.decode(offset, result.Index(i), depth)
+		if err != nil {
+			return 0, err
+		}
+	}
+	return offset, nil
+}
+
+func (d *decoder) decodeString(size uint, offset uint) (string, uint, error) {
+	newOffset := offset + size
+	return string(d.buffer[offset:newOffset]), newOffset, nil
+}
+
+type fieldsType struct {
+	namedFields     map[string]int
+	anonymousFields []int
+}
+
+var (
+	fieldMap   = map[reflect.Type]*fieldsType{}
+	fieldMapMu sync.RWMutex
+)
+
+func (d *decoder) decodeStruct(
+	size uint,
+	offset uint,
+	result reflect.Value,
+	depth int,
+) (uint, error) {
+	resultType := result.Type()
+
+	fieldMapMu.RLock()
+	fields, ok := fieldMap[resultType]
+	fieldMapMu.RUnlock()
+	if !ok {
+		numFields := resultType.NumField()
+		namedFields := make(map[string]int, numFields)
+		var anonymous []int
+		for i := 0; i < numFields; i++ {
+			field := resultType.Field(i)
+
+			fieldName := field.Name
+			if tag := field.Tag.Get("maxminddb"); tag != "" {
+				if tag == "-" {
+					continue
+				}
+				fieldName = tag
+			}
+			if field.Anonymous {
+				anonymous = append(anonymous, i)
+				continue
+			}
+			namedFields[fieldName] = i
+		}
+		fieldMapMu.Lock()
+		fields = &fieldsType{namedFields, anonymous}
+		fieldMap[resultType] = fields
+		fieldMapMu.Unlock()
+	}
+
+	// This fills in embedded structs
+	for _, i := range fields.anonymousFields {
+		_, err := d.unmarshalMap(size, offset, result.Field(i), depth)
+		if err != nil {
+			return 0, err
+		}
+	}
+
+	// This handles named fields
+	for i := uint(0); i < size; i++ {
+		var (
+			err error
+			key []byte
+		)
+		key, offset, err = d.decodeKey(offset)
+		if err != nil {
+			return 0, err
+		}
+		// The string() does not create a copy due to this compiler
+		// optimization: https://github.com/golang/go/issues/3512
+		j, ok := fields.namedFields[string(key)]
+		if !ok {
+			offset, err = d.nextValueOffset(offset, 1)
+			if err != nil {
+				return 0, err
+			}
+			continue
+		}
+
+		offset, err = d.decode(offset, result.Field(j), depth)
+		if err != nil {
+			return 0, err
+		}
+	}
+	return offset, nil
+}
+
+func (d *decoder) decodeUint(size uint, offset uint) (uint64, uint, error) {
+	newOffset := offset + size
+	bytes := d.buffer[offset:newOffset]
+
+	var val uint64
+	for _, b := range bytes {
+		val = (val << 8) | uint64(b)
+	}
+	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 uint, uintBytes []byte) uint {
+	val := prefix
+	for _, b := range uintBytes {
+		val = (val << 8) | uint(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, err := d.decodeCtrlData(offset)
+	if err != nil {
+		return nil, 0, err
+	}
+	if typeNum == _Pointer {
+		pointer, ptrOffset, err := d.decodePointer(size, dataOffset)
+		if err != nil {
+			return nil, 0, err
+		}
+		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
+	if newOffset > uint(len(d.buffer)) {
+		return nil, 0, newOffsetError()
+	}
+	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, error) {
+	if numberToSkip == 0 {
+		return offset, nil
+	}
+	typeNum, size, offset, err := d.decodeCtrlData(offset)
+	if err != nil {
+		return 0, err
+	}
+	switch typeNum {
+	case _Pointer:
+		_, offset, err = d.decodePointer(size, offset)
+		if err != nil {
+			return 0, err
+		}
+	case _Map:
+		numberToSkip += 2 * size
+	case _Slice:
+		numberToSkip += size
+	case _Bool:
+	default:
+		offset += size
+	}
+	return d.nextValueOffset(offset, numberToSkip-1)
+}