diff options
Diffstat (limited to 'vendor/github.com/oschwald/maxminddb-golang/reader.go')
| -rw-r--r-- | vendor/github.com/oschwald/maxminddb-golang/reader.go | 259 |
1 files changed, 0 insertions, 259 deletions
diff --git a/vendor/github.com/oschwald/maxminddb-golang/reader.go b/vendor/github.com/oschwald/maxminddb-golang/reader.go deleted file mode 100644 index 97b9607..0000000 --- a/vendor/github.com/oschwald/maxminddb-golang/reader.go +++ /dev/null @@ -1,259 +0,0 @@ -package maxminddb - -import ( - "bytes" - "errors" - "fmt" - "net" - "reflect" -) - -const ( - // NotFound is returned by LookupOffset when a matched root record offset - // cannot be found. - NotFound = ^uintptr(0) - - dataSectionSeparatorSize = 16 -) - -var metadataStartMarker = []byte("\xAB\xCD\xEFMaxMind.com") - -// Reader holds the data corresponding to the MaxMind DB file. Its only public -// field is Metadata, which contains the metadata from the MaxMind DB file. -type Reader struct { - hasMappedFile bool - buffer []byte - decoder decoder - Metadata Metadata - ipv4Start uint -} - -// Metadata holds the metadata decoded from the MaxMind DB file. In particular -// in has the format version, the build time as Unix epoch time, the database -// type and description, the IP version supported, and a slice of the natural -// languages included. -type Metadata struct { - BinaryFormatMajorVersion uint `maxminddb:"binary_format_major_version"` - BinaryFormatMinorVersion uint `maxminddb:"binary_format_minor_version"` - BuildEpoch uint `maxminddb:"build_epoch"` - DatabaseType string `maxminddb:"database_type"` - Description map[string]string `maxminddb:"description"` - IPVersion uint `maxminddb:"ip_version"` - Languages []string `maxminddb:"languages"` - NodeCount uint `maxminddb:"node_count"` - RecordSize uint `maxminddb:"record_size"` -} - -// FromBytes takes a byte slice corresponding to a MaxMind DB file and returns -// a Reader structure or an error. -func FromBytes(buffer []byte) (*Reader, error) { - metadataStart := bytes.LastIndex(buffer, metadataStartMarker) - - if metadataStart == -1 { - return nil, newInvalidDatabaseError("error opening database: invalid MaxMind DB file") - } - - metadataStart += len(metadataStartMarker) - metadataDecoder := decoder{buffer[metadataStart:]} - - var metadata Metadata - - rvMetdata := reflect.ValueOf(&metadata) - _, err := metadataDecoder.decode(0, rvMetdata, 0) - if err != nil { - return nil, err - } - - searchTreeSize := metadata.NodeCount * metadata.RecordSize / 4 - dataSectionStart := searchTreeSize + dataSectionSeparatorSize - dataSectionEnd := uint(metadataStart - len(metadataStartMarker)) - if dataSectionStart > dataSectionEnd { - return nil, newInvalidDatabaseError("the MaxMind DB contains invalid metadata") - } - d := decoder{ - buffer[searchTreeSize+dataSectionSeparatorSize : metadataStart-len(metadataStartMarker)], - } - - reader := &Reader{ - buffer: buffer, - decoder: d, - Metadata: metadata, - ipv4Start: 0, - } - - reader.ipv4Start, err = reader.startNode() - - return reader, err -} - -func (r *Reader) startNode() (uint, error) { - if r.Metadata.IPVersion != 6 { - return 0, nil - } - - nodeCount := r.Metadata.NodeCount - - node := uint(0) - var err error - for i := 0; i < 96 && node < nodeCount; i++ { - node, err = r.readNode(node, 0) - if err != nil { - return 0, err - } - } - return node, err -} - -// Lookup takes an IP address as a net.IP structure and a pointer to the -// result value to Decode into. -func (r *Reader) Lookup(ipAddress net.IP, result interface{}) error { - if r.buffer == nil { - return errors.New("cannot call Lookup on a closed database") - } - pointer, err := r.lookupPointer(ipAddress) - if pointer == 0 || err != nil { - return err - } - return r.retrieveData(pointer, result) -} - -// LookupOffset maps an argument net.IP to a corresponding record offset in the -// database. NotFound is returned if no such record is found, and a record may -// otherwise be extracted by passing the returned offset to Decode. LookupOffset -// is an advanced API, which exists to provide clients with a means to cache -// previously-decoded records. -func (r *Reader) LookupOffset(ipAddress net.IP) (uintptr, error) { - if r.buffer == nil { - return 0, errors.New("cannot call LookupOffset on a closed database") - } - pointer, err := r.lookupPointer(ipAddress) - if pointer == 0 || err != nil { - return NotFound, err - } - return r.resolveDataPointer(pointer) -} - -// Decode the record at |offset| into |result|. The result value pointed to -// must be a data value that corresponds to a record in the database. This may -// include a struct representation of the data, a map capable of holding the -// data or an empty interface{} value. -// -// If result is a pointer to a struct, the struct need not include a field -// for every value that may be in the database. If a field is not present in -// the structure, the decoder will not decode that field, reducing the time -// required to decode the record. -// -// As a special case, a struct field of type uintptr will be used to capture -// the offset of the value. Decode may later be used to extract the stored -// value from the offset. MaxMind DBs are highly normalized: for example in -// the City database, all records of the same country will reference a -// single representative record for that country. This uintptr behavior allows -// clients to leverage this normalization in their own sub-record caching. -func (r *Reader) Decode(offset uintptr, result interface{}) error { - if r.buffer == nil { - return errors.New("cannot call Decode on a closed database") - } - return r.decode(offset, result) -} - -func (r *Reader) decode(offset uintptr, result interface{}) error { - rv := reflect.ValueOf(result) - if rv.Kind() != reflect.Ptr || rv.IsNil() { - return errors.New("result param must be a pointer") - } - - _, err := r.decoder.decode(uint(offset), reflect.ValueOf(result), 0) - return err -} - -func (r *Reader) lookupPointer(ipAddress net.IP) (uint, error) { - if ipAddress == nil { - return 0, errors.New("ipAddress passed to Lookup cannot be nil") - } - - ipV4Address := ipAddress.To4() - if ipV4Address != nil { - ipAddress = ipV4Address - } - if len(ipAddress) == 16 && r.Metadata.IPVersion == 4 { - return 0, fmt.Errorf("error looking up '%s': you attempted to look up an IPv6 address in an IPv4-only database", ipAddress.String()) - } - - return r.findAddressInTree(ipAddress) -} - -func (r *Reader) findAddressInTree(ipAddress net.IP) (uint, error) { - - bitCount := uint(len(ipAddress) * 8) - - var node uint - if bitCount == 32 { - node = r.ipv4Start - } - - nodeCount := r.Metadata.NodeCount - - for i := uint(0); i < bitCount && node < nodeCount; i++ { - bit := uint(1) & (uint(ipAddress[i>>3]) >> (7 - (i % 8))) - - var err error - node, err = r.readNode(node, bit) - if err != nil { - return 0, err - } - } - if node == nodeCount { - // Record is empty - return 0, nil - } else if node > nodeCount { - return node, nil - } - - return 0, newInvalidDatabaseError("invalid node in search tree") -} - -func (r *Reader) readNode(nodeNumber uint, index uint) (uint, error) { - RecordSize := r.Metadata.RecordSize - - baseOffset := nodeNumber * RecordSize / 4 - - var nodeBytes []byte - var prefix uint - switch RecordSize { - case 24: - offset := baseOffset + index*3 - nodeBytes = r.buffer[offset : offset+3] - case 28: - prefix = uint(r.buffer[baseOffset+3]) - if index != 0 { - prefix &= 0x0F - } else { - prefix = (0xF0 & prefix) >> 4 - } - offset := baseOffset + index*4 - nodeBytes = r.buffer[offset : offset+3] - case 32: - offset := baseOffset + index*4 - nodeBytes = r.buffer[offset : offset+4] - default: - return 0, newInvalidDatabaseError("unknown record size: %d", RecordSize) - } - return uintFromBytes(prefix, nodeBytes), nil -} - -func (r *Reader) retrieveData(pointer uint, result interface{}) error { - offset, err := r.resolveDataPointer(pointer) - if err != nil { - return err - } - return r.decode(offset, result) -} - -func (r *Reader) resolveDataPointer(pointer uint) (uintptr, error) { - var resolved = uintptr(pointer - r.Metadata.NodeCount - dataSectionSeparatorSize) - - if resolved > uintptr(len(r.buffer)) { - return 0, newInvalidDatabaseError("the MaxMind DB file's search tree is corrupt") - } - return resolved, nil -} |