Add support for more precision on buffer lengths; necessary for high bandwidth streams where 1 sec is too long.

Author: cboulay

include/lsl/common.h

@@ -150,6 +150,21 @@ typedef enum {
 	_lsl_error_code_maxval = 0x7f000000
 } lsl_error_code_t;
 
+/// Flags for outlet_ex and inlet_ex
+typedef enum {
+	/// Keep legacy behavior: max_buffered / max_buflen is in seconds; use asynch transfer.
+	transp_default = 0,
+
+	/// The supplied max_buf value is in samples.
+	transp_bufsize_samples = 1,
+
+	/// The supplied max_buf should be scaled by 0.001.
+	transp_bufsize_thousandths = 2,
+
+	// prevent compilers from assuming an instance fits in a single byte
+	_lsl_transport_options_maxval = 0x7f000000
+} lsl_transport_options_t;
+
 /// Return an explanation for the last error
 extern LIBLSL_C_API const char *lsl_last_error(void);
 

include/lsl/inlet.h

@@ -39,6 +39,11 @@
  * @return A newly created lsl_inlet handle or NULL in the event that an error occurred.
  */
 extern LIBLSL_C_API lsl_inlet lsl_create_inlet(lsl_streaminfo info, int32_t max_buflen, int32_t max_chunklen, int32_t recover);
+/** @copydoc lsl_create_inlet()
+ * @param flags An integer that is the result of bitwise OR'ing one or more options from
+* #lsl_transport_options_t together (e.g., #transp_bufsize_samples)
+ */
+extern LIBLSL_C_API lsl_inlet lsl_create_inlet_ex(lsl_streaminfo info, int32_t max_buflen, int32_t max_chunklen, int32_t recover, uint32_t flags);
 
 /**
 * Destructor.

include/lsl/outlet.h

@@ -34,6 +34,11 @@
  * @return A newly created lsl_outlet handle or NULL in the event that an error occurred.
  */
 extern LIBLSL_C_API lsl_outlet lsl_create_outlet(lsl_streaminfo info, int32_t chunk_size, int32_t max_buffered);
+/** @copydoc lsl_create_outlet()
+ * @param flags An integer that is the result of bitwise OR'ing one or more options from
+* #lsl_transport_options_t together (e.g., #transp_bufsize_samples|#transp_bufsize_thousandths)
+ */
+extern LIBLSL_C_API lsl_outlet lsl_create_outlet_ex(lsl_streaminfo info, int32_t chunk_size, int32_t max_buffered, uint32_t flags);
 
 /**
  * Destroy an outlet.

include/lsl_cpp.h

@@ -396,10 +396,10 @@ class stream_outlet {
 	 * @param max_buffered Optionally the maximum amount of data to buffer (in seconds if there is a
 	 * nominal sampling rate, otherwise x100 in samples). The default is 6 minutes of data.
 	 */
-	stream_outlet(const stream_info &info, int32_t chunk_size = 0, int32_t max_buffered = 360)
+	stream_outlet(const stream_info &info, int32_t chunk_size = 0, int32_t max_buffered = 360, uint32_t flags = transp_default)
 		: channel_count(info.channel_count()),
 		  sample_rate(info.nominal_srate()),
-		  obj(lsl_create_outlet(info.handle().get(), chunk_size, max_buffered), &lsl_destroy_outlet) {}
+		  obj(lsl_create_outlet_ex(info.handle().get(), chunk_size, max_buffered, flags), &lsl_destroy_outlet) {}
 
 	// ========================================
 	// === Pushing a sample into the outlet ===
@@ -900,9 +900,9 @@ class stream_inlet {
 	 * lsl::lost_error if the stream's source is lost (e.g., due to an app or computer crash).
 	 */
 	stream_inlet(const stream_info &info, int32_t max_buflen = 360, int32_t max_chunklen = 0,
-		bool recover = true)
+		bool recover = true, uint32_t flags = transp_default)
 		: channel_count(info.channel_count()),
-		  obj(lsl_create_inlet(info.handle().get(), max_buflen, max_chunklen, recover), &lsl_destroy_inlet) {}
+		  obj(lsl_create_inlet_ex(info.handle().get(), max_buflen, max_chunklen, recover, flags), &lsl_destroy_inlet) {}
 
 	/// Return a shared pointer to pass to C-API functions that aren't wrapped yet
 	///

src/lsl_inlet_c.cpp

@@ -14,11 +14,23 @@ extern "C" {
 
 using namespace lsl;
 
+LIBLSL_C_API lsl_inlet lsl_create_inlet_ex(
+	lsl_streaminfo info, int32_t max_buflen, int32_t max_chunklen, int32_t recover, uint32_t flags) {
+	int32_t buf_samples;
+	if (flags & transp_bufsize_samples)
+		buf_samples = max_buflen;
+	else if (info->nominal_srate() == LSL_IRREGULAR_RATE)
+		buf_samples = max_buflen * 100;
+	else
+		buf_samples = (int)(info->nominal_srate() * max_buflen);
+	if (flags & transp_bufsize_thousandths)
+		buf_samples /= 1000;
+	buf_samples = (buf_samples > 0) ? buf_samples : 1;
+	return create_object_noexcept<stream_inlet_impl>(*info, buf_samples, max_chunklen, recover != 0);
+}
 LIBLSL_C_API lsl_inlet lsl_create_inlet(
 	lsl_streaminfo info, int32_t max_buflen, int32_t max_chunklen, int32_t recover) {
-	return create_object_noexcept<stream_inlet_impl>(*info,
-		(info->nominal_srate() ? (int)(info->nominal_srate() * max_buflen) : max_buflen * 100) + 1,
-		max_chunklen, recover != 0);
+	return lsl_create_inlet_ex(info, max_buflen, max_chunklen, recover, transp_default);
 }
 
 LIBLSL_C_API void lsl_destroy_inlet(lsl_inlet in) {

src/lsl_outlet_c.cpp

@@ -15,12 +15,25 @@ extern "C" {
 using namespace lsl;
 
 // boilerplate wrapper code
+LIBLSL_C_API lsl_outlet lsl_create_outlet_ex(
+	lsl_streaminfo info, int32_t chunk_size, int32_t max_buffered, uint32_t flags) {
+	int32_t buf_samples;
+	if (flags & transp_bufsize_samples)
+		buf_samples = max_buffered;
+	else if (info->nominal_srate() == LSL_IRREGULAR_RATE)
+		buf_samples = max_buffered * 100;
+	else
+		buf_samples = info->nominal_srate() * max_buffered;
+	if (flags & transp_bufsize_thousandths)
+		buf_samples /= 1000;
+	buf_samples = (buf_samples > 0) ? buf_samples : 1;
+	return create_object_noexcept<stream_outlet_impl>(
+		*info, chunk_size, buf_samples);
+}
+
 LIBLSL_C_API lsl_outlet lsl_create_outlet(
 	lsl_streaminfo info, int32_t chunk_size, int32_t max_buffered) {
-	double buftime = info->nominal_srate();
-	if (buftime <= 0) buftime = 100;
-	return create_object_noexcept<stream_outlet_impl>(
-		*info, chunk_size, static_cast<int>(buftime * max_buffered));
+	return lsl_create_outlet_ex(info, chunk_size, max_buffered, transp_default);
 }
 
 LIBLSL_C_API void lsl_destroy_outlet(lsl_outlet out) {