static int updateUsbKeys (BrailleDisplay *brl) { while (1) { unsigned char packet[8]; { ssize_t result = gioReadData(brl->gioEndpoint, packet, sizeof(packet), 0); if (!result) return 1; if (result < 0) { if (errno == ENODEV) { /* Display was disconnected */ return 0; } logMessage(LOG_ERR, "USB read error: %s", strerror(errno)); keysInitialized = 0; return 1; } if (result < sizeof(packet)) { /* The display should only ever deliver packets of exactly 8 bytes */ logPartialPacket(packet, result); keysInitialized = 0; return 1; } logInputPacket(packet, result); } updateKeys(brl, packet); } }
int gioReadByte (GioEndpoint *endpoint, unsigned char *byte, int wait) { ssize_t result = gioReadData(endpoint, byte, 1, wait); if (result > 0) return 1; if (result == 0) errno = EAGAIN; return 0; }
static int readPacket (BrailleDisplay *brl, Packet *packet) { while (1) { int size = sizeof(PacketHeader); int hasPayload = 0; if (brl->data->inputCount >= sizeof(PacketHeader)) { if (brl->data->inputBuffer.packet.header.type & 0X80) { hasPayload = 1; size += brl->data->inputBuffer.packet.header.arg1 + 1; } } if (size <= brl->data->inputCount) { logInputPacket(brl->data->inputBuffer.bytes, size); if (hasPayload) { unsigned char checksum = 0; int index; for (index=0; index<size; index+=1) checksum -= brl->data->inputBuffer.bytes[index]; if (checksum) logMessage(LOG_WARNING, "Input packet checksum error."); } memcpy(packet, &brl->data->inputBuffer, size); memmove(&brl->data->inputBuffer.bytes[0], &brl->data->inputBuffer.bytes[size], brl->data->inputCount -= size); return size; } retry: { int count = gioReadData(brl->data->gioEndpoint, &brl->data->inputBuffer.bytes[brl->data->inputCount], size - brl->data->inputCount, 0); if (count < 1) { if (count == -1) { logSystemError("read"); } else if ((count == 0) && (brl->data->inputCount > 0)) { if (gioAwaitInput(brl->data->gioEndpoint, 1000)) goto retry; if (errno != EAGAIN) count = -1; logPartialPacket(brl->data->inputBuffer.bytes, brl->data->inputCount); brl->data->inputCount = 0; } return count; } brl->data->acknowledgementsMissing = 0; if (!brl->data->inputCount) { static const unsigned char packets[] = { PKT_ACK, PKT_NAK, PKT_KEY, PKT_EXTKEY, PKT_BUTTON, PKT_WHEEL, PKT_INFO }; int first; for (first=0; first<count; first+=1) if (memchr(packets, brl->data->inputBuffer.bytes[first], sizeof(packets))) break; if (first) { logDiscardedBytes(brl->data->inputBuffer.bytes, first); memmove(&brl->data->inputBuffer.bytes[0], &brl->data->inputBuffer.bytes[first], count-=first); } } brl->data->inputCount += count; } } }