clojobuf-codec.decode — com.github.s-expresso/clojobuf-codec 0.1.6

Read protobuf's Tag-Len-Val or Tag-Val encoded data, where: (1) Tag is varint encoded containing wire-type (lowest 3-bits) packed with field number (2) Len is varint encoded containing number of bytes that Val occupy; only present of wire-type 2 (3) Val is varint encoded for wire-type 0, or a fixed length for wire-type 1 and 5, or N bytes (where N = Len) for wire-type 2

Wire-Type 0 VARINT int32, int64, uint32, uint64, sint32, sint64, bool, enum 1 I64 fixed64, sfixed64, double 2 LEN string, bytes, embedded messages, packed repeated fields 3 SGROUP group start (deprecated) 4 EGROUP group end (deprecated) 5 I32 fixed32, sfixed32, float Note SGROUP and EGROUP are not supported

For more info https://developers.google.com/protocol-buffers/docs/encoding

Decoding a protobuf encoded binary is a 2 steps process performed repeatedly: (1) call (read-tag rr) to get field-id and wire-type (2) look up field-id in your protobuf schema to determine field-type (A) field-type == primitive (a) not :bytes && wire-type 2 => (read-packed rr field-type) (b) all other cases => (read-pri rr field-type) (B) field-type == map<key-type, value-type> (a) value-type is msg => (read-kv-msg rr key-type) (b) value-type is enum => (read-kv-enum rr key-type) (c) value-type is primitive => (read-kv-pri rr key-type) (C) field-type == message => (read-len-coded-bytes rr) where rr is clojobuf-codec.io.reader.ByteReader reading the binary.

If look up of field-id fails, then sender is using a schema with additional fields. Use read-raw-wire to extract the value generically and continue.

If look up of field-id yields a field-type incompatible with the wire-type, then sender is using a schema that has breaking change. If you want to continue decoding, you must honour the wire-type and use read-raw-wire to preserve the correctness of Tag-(Len-)Value boundary.

read-len-coded-bytes clj/s

(read-len-coded-bytes reader)

Read the next value as varint N, and return the next N bytes as binary.

read-packed clj/s

(read-packed reader packed-type)

Read length encoded packed data return it as a vector. packed-type = :int32 | :int64 | :uint32 :uint64 | :sint32 | :sint64 | :bool | :enum :fixed32 | :sfixed32 | float | :fixed64 | :sfixed64 | double

read-pri clj/s

(read-pri reader field-type)

Read a single primitive value, where field-type = :int32 | :int64 | :uint32 :uint64 | :sint32 | :sint64 | :bool | :enum :fixed32 | :sfixed32 | :float | :fixed64 | :sfixed64 | :double | :string | :bytes

read-raw-wire clj/s

(read-raw-wire reader wire-type)

Read next value generically based on wire-type. This function is typically used iff the actual field type is unknown or incompatible with the wire-type. wire-type 0 => read as varint64, return as int64 wire-type 1 => read as sfixed64, return as int64 wire-type 2 => read as len-value, return as binary wire-type 5 => read as sfixed32, return as int32

read-tag clj/s

(read-tag reader)

Read the next value as varint and unpack it as [field-id wire-type] by assuming wire-type occupies lowest 3 bits. Returns [field-id wire-type].