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git://sigrok.org/libserialport
synced 2023-08-10 21:13:24 +03:00
windows: Use an adaptively sized buffer for nonblocking writes.
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6bd6a8b520
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39df7833f7
@ -107,7 +107,8 @@ struct sp_port {
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OVERLAPPED read_ovl;
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OVERLAPPED wait_ovl;
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DWORD events;
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BYTE pending_byte;
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BYTE *write_buf;
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DWORD write_buf_size;
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BOOL writing;
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BOOL wait_running;
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#else
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47
serialport.c
47
serialport.c
@ -104,6 +104,8 @@ SP_API enum sp_return sp_get_port_by_name(const char *portname, struct sp_port *
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#ifdef _WIN32
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port->usb_path = NULL;
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port->hdl = INVALID_HANDLE_VALUE;
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port->write_buf = NULL;
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port->write_buf_size = 0;
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#else
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port->fd = -1;
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#endif
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@ -310,6 +312,8 @@ SP_API void sp_free_port(struct sp_port *port)
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#ifdef _WIN32
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if (port->usb_path)
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free(port->usb_path);
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if (port->write_buf)
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free(port->write_buf);
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#endif
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free(port);
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@ -643,6 +647,10 @@ SP_API enum sp_return sp_close(struct sp_port *port)
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CLOSE_OVERLAPPED(write_ovl);
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CLOSE_OVERLAPPED(wait_ovl);
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if (port->write_buf) {
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free(port->write_buf);
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port->write_buf = NULL;
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}
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#else
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/* Returns 0 upon success, -1 upon failure. */
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if (close(port->fd) == -1)
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@ -892,8 +900,7 @@ SP_API enum sp_return sp_nonblocking_write(struct sp_port *port,
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RETURN_INT(0);
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#ifdef _WIN32
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DWORD written = 0;
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BYTE *ptr = (BYTE *) buf;
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DWORD buf_bytes;
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/* Check whether previous write is complete. */
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if (port->writing) {
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@ -914,40 +921,26 @@ SP_API enum sp_return sp_nonblocking_write(struct sp_port *port,
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RETURN_FAIL("SetCommTimeouts() failed");
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}
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/*
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* Keep writing data until the OS has to actually start an async IO
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* for it. At that point we know the buffer is full.
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*/
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while (written < count) {
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/* Copy first byte of user buffer. */
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port->pending_byte = *ptr++;
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/* Copy data to our write buffer. */
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buf_bytes = min(port->write_buf_size, count);
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memcpy(port->write_buf, buf, buf_bytes);
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/* Start asynchronous write. */
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if (WriteFile(port->hdl, &port->pending_byte, 1, NULL, &port->write_ovl) == 0) {
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if (WriteFile(port->hdl, port->write_buf, buf_bytes, NULL, &port->write_ovl) == 0) {
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if (GetLastError() == ERROR_IO_PENDING) {
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if (HasOverlappedIoCompleted(&port->write_ovl)) {
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if ((port->writing = !HasOverlappedIoCompleted(&port->write_ovl)))
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DEBUG("Asynchronous write completed immediately");
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port->writing = 0;
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written++;
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continue;
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} else {
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else
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DEBUG("Asynchronous write running");
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port->writing = 1;
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RETURN_INT(++written);
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}
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} else {
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/* Actual failure of some kind. */
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RETURN_FAIL("WriteFile() failed");
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}
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} else {
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DEBUG("Single byte written immediately");
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written++;
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}
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}
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DEBUG("All bytes written immediately");
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RETURN_INT(written);
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RETURN_INT(buf_bytes);
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#else
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/* Returns the number of bytes written, or -1 upon failure. */
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ssize_t written = write(port->fd, buf, count);
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@ -1894,6 +1887,14 @@ static enum sp_return set_config(struct sp_port *port, struct port_data *data,
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if (i == NUM_STD_BAUDRATES)
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data->dcb.BaudRate = config->baudrate;
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/* Allocate write buffer for 50ms of data at baud rate. */
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port->write_buf_size = max(config->baudrate / (8 * 20), 1);
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port->write_buf = realloc(port->write_buf,
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port->write_buf_size);
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if (!port->write_buf)
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RETURN_ERROR(SP_ERR_MEM, "Allocating write buffer failed");
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}
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if (config->bits >= 0)
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