118 lines
2.6 KiB
Go
118 lines
2.6 KiB
Go
package amf
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import (
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"errors"
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"encoding/binary"
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"math"
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)
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type AMFObj map[interface{}]interface{}
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func DecodeAMF(data *[]byte) (AMFObj, error) {
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var byte_idx uint32
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var root_obj_idx int
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amf_root_obj := make(AMFObj)
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for {
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top_level_obj, err := read_next(data, &byte_idx)
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if err != nil {
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return amf_root_obj, err
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}
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amf_root_obj[root_obj_idx] = top_level_obj
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root_obj_idx += 1
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if byte_idx == uint32(len(*data)) {
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break
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}
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}
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return amf_root_obj, nil
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}
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func read_bytes(data *[]byte, byte_idx *uint32, n uint32) ([]byte, error) {
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if int(*byte_idx + n) > len(*data) {
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return make([]byte, 0), errors.New("Read goes past end")
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}
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read_slice := (*data)[*byte_idx:*byte_idx + n]
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*byte_idx += n
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return read_slice, nil
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}
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func read_number(data *[]byte, byte_idx *uint32) (float64, error) {
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float_bytes, err := read_bytes(data, byte_idx, 8)
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if err != nil {
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return 0.0, err
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}
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return math.Float64frombits(binary.BigEndian.Uint64(float_bytes)), nil
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}
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func read_bool(data *[]byte, byte_idx *uint32) (bool, error) {
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bool_byte, err := read_bytes(data, byte_idx, 1)
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if err != nil {
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return false, err
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}
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if bool_byte[0] > 1 {
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return false, errors.New("bool byte must be 0 or 1")
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}
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return bool_byte[0] != 0, nil
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}
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func read_string(data *[]byte, byte_idx *uint32) (string, error) {
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string_len, err := read_bytes(data, byte_idx, 2)
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if err != nil {
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return "", err
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}
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string_bytes, err := read_bytes(data, byte_idx, uint32(binary.BigEndian.Uint16(string_len)))
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if err != nil {
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return "", err
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}
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return string(string_bytes), err
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}
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func read_object(data *[]byte, byte_idx *uint32) (AMFObj, error) {
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root_obj := make(AMFObj)
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for {
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key, err := read_string(data, byte_idx)
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if err != nil {
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return root_obj, err
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}
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if key == "" {
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if end_byte, err := read_bytes(data, byte_idx, 1); err != nil {
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return root_obj, err
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} else if end_byte[0] != 9 {
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return root_obj, errors.New("Object should end but didnt")
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}
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return root_obj, nil
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}
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val, err := read_next(data, byte_idx)
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if err != nil {
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return root_obj, err
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}
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root_obj[key] = val
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}
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}
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func read_next(data *[]byte, byte_idx *uint32) (interface{}, error) {
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data_type, err := read_bytes(data, byte_idx, 1)
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var next_obj interface{}
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if err != nil {
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return nil, err
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}
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switch data_type[0] {
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case 0:
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next_obj, err = read_number(data, byte_idx)
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case 1:
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next_obj, err = read_bool(data, byte_idx)
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case 2:
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next_obj, err = read_string(data, byte_idx)
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case 3:
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next_obj, err = read_object(data, byte_idx)
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default:
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return nil, errors.New("Unhandled data type")
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}
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if err != nil {
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return nil, err
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}
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return next_obj, nil
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}
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