Larger SysEx transfers get corrupted by incoming packets.
This changes the FIFOs not to overwrite their data. MIDI should not be
a transport that drops packets. A potentially blocking device is easier
to detect and handle than a device that silently corrupts the packet
stream at random overflows, especially when SysEx messages are involved.
This changes the internal buffering to the raw 4-byte messages. The
conversion of the messages to a byte-stream moved to the read/write
methods.
It adds a raw packet interface to send and retrieve the raw 4-byte
USB MIDI message:
static inline bool tud_midi_receive (uint8_t packet[4]);
static inline bool tud_midi_send (uint8_t const packet[4]);
MIDI USB packets carry virtual cable/wire/plug data in the packet header,
which cannot be exported in the byte-stream interface. The raw packet
interface allows to send and and receive the complete USB message.
Kay Sievers