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;
}
}
}
