From: Joel Holdsworth <redacted>
Date: Fri, 15 Mar 2013 18:28:28 +0000 (+0000)
Subject: Analog buffer sharing crash by memcpying for the AnanlogSignal::paint
X-Git-Tag: pulseview-0.1.0~82
X-Git-Url: https://sigrok.org/gitaction?a=commitdiff_plain;h=d37583678256450d7eb646213d0b9e170a427933;p=pulseview.git

Analog buffer sharing crash by memcpying for the AnanlogSignal::paint
---

diff --git a/pv/data/analogsnapshot.cpp b/pv/data/analogsnapshot.cpp
index 2bcb99f3..1658a04c 100644
--- a/pv/data/analogsnapshot.cpp
+++ b/pv/data/analogsnapshot.cpp
@@ -49,9 +49,21 @@ void AnalogSnapshot::append_payload(
 	append_data(analog.data, analog.num_samples);
 }
 
-const float* AnalogSnapshot::get_samples() const
+const float* AnalogSnapshot::get_samples(
+	int64_t start_sample, int64_t end_sample) const
 {
-	return (const float*)_data;
+	assert(start_sample >= 0);
+	assert(start_sample < (int64_t)_sample_count);
+	assert(end_sample >= 0);
+	assert(end_sample < (int64_t)_sample_count);
+	assert(start_sample <= end_sample);
+
+	lock_guard<recursive_mutex> lock(_mutex);
+
+	float *const data = new float[end_sample - start_sample];
+	memcpy(data, (float*)_data + start_sample, sizeof(float) *
+		(end_sample - start_sample));
+	return data;
 }
 
 } // namespace data
diff --git a/pv/data/analogsnapshot.h b/pv/data/analogsnapshot.h
index 9ca08f1e..a4539184 100644
--- a/pv/data/analogsnapshot.h
+++ b/pv/data/analogsnapshot.h
@@ -36,7 +36,8 @@ public:
 
 	void append_payload(const sr_datafeed_analog &analog);
 
-	const float* get_samples() const;
+	const float* get_samples(int64_t start_sample,
+		int64_t end_sample) const;
 };
 
 } // namespace data
diff --git a/pv/view/analogsignal.cpp b/pv/view/analogsignal.cpp
index 209512b5..a6f032b5 100644
--- a/pv/view/analogsignal.cpp
+++ b/pv/view/analogsignal.cpp
@@ -68,18 +68,21 @@ void AnalogSignal::paint(QPainter &p, int y, int left, int right, double scale,
 		(int64_t)0), last_sample);
 	const int64_t end_sample = min(max((int64_t)ceil(end),
 		(int64_t)0), last_sample);
+	const int64_t sample_count = end_sample - start_sample;
 
-	const float* samples = snapshot->get_samples();
+	const float* samples = snapshot->get_samples(
+		start_sample, end_sample);
 	assert(samples);
 
-	QPointF *points = new QPointF[end_sample - start_sample];
+	QPointF *points = new QPointF[sample_count];
 	QPointF *point = points;
 
 	for (int64_t sample = start_sample;
 		sample != end_sample; sample++) {
 		const float x = (sample / samples_per_pixel -
 			pixels_offset) + left;
-		*point++ = QPointF(x, samples[sample] + y);
+		*point++ = QPointF(x,
+			samples[sample - start_sample] + y);
 	}
 
 	p.setPen(_colour);