Preallocate memory before samples are received.

[pulseview.git] / pv / data / analogsnapshot.cpp

diff --git a/pv/data/analogsnapshot.cpp b/pv/data/analogsnapshot.cpp
index 4907d7954a186af7c6d7b5f0c2c8447714edc32a..4d4f5d67b8866b4d29aa754c595cf15c2cdd235b 100644 (file)
--- a/pv/data/analogsnapshot.cpp
+++ b/pv/data/analogsnapshot.cpp
@@ -47,9 +47,11 @@ const float AnalogSnapshot::LogEnvelopeScaleFactor =
        logf(EnvelopeScaleFactor);
 const uint64_t AnalogSnapshot::EnvelopeDataUnit = 64*1024;     // bytes
 
-AnalogSnapshot::AnalogSnapshot() :
+AnalogSnapshot::AnalogSnapshot(const uint64_t expected_num_samples) :
        Snapshot(sizeof(float))
 {
+       set_capacity(expected_num_samples);
+
        lock_guard<recursive_mutex> lock(_mutex);
        memset(_envelope_levels, 0, sizeof(_envelope_levels));
 }