From c82c7e4e330ce5aa04c4f3b8e6f8de85e3e288e1 Mon Sep 17 00:00:00 2001
From: Jens Steinhauser <jens.steinhauser@gmail.com>
Date: Wed, 27 Aug 2014 11:12:40 +0200
Subject: [PATCH] Snapshot classes: Use vector instead of raw pointer

As a side-effect this turns a segfault (see bug #397) into a segfault
with a more usable message:

  terminate called after throwing an instance of 'std::bad_alloc'
    what():  std::bad_alloc
  Aborted (core dumped)
---
 pv/data/analogsnapshot.cpp | 10 +++++-----
 pv/data/logicsnapshot.cpp  |  8 ++++----
 pv/data/snapshot.cpp       |  8 +++-----
 pv/data/snapshot.h         |  3 ++-
 4 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/pv/data/analogsnapshot.cpp b/pv/data/analogsnapshot.cpp
index 9e9b5a0f..2a14d1ea 100644
--- a/pv/data/analogsnapshot.cpp
+++ b/pv/data/analogsnapshot.cpp
@@ -68,9 +68,9 @@ void AnalogSnapshot::append_interleaved_samples(const float *data,
 
 	lock_guard<recursive_mutex> lock(_mutex);
 
-	_data = realloc(_data, (_sample_count + sample_count) * sizeof(float));
+	_data.resize((_sample_count + sample_count) * sizeof(float));
 
-	float *dst = (float*)_data + _sample_count;
+	float *dst = (float*)_data.data() + _sample_count;
 	const float *dst_end = dst + sample_count;
 	while (dst != dst_end)
 	{
@@ -96,7 +96,7 @@ const float* AnalogSnapshot::get_samples(
 	lock_guard<recursive_mutex> lock(_mutex);
 
 	float *const data = new float[end_sample - start_sample];
-	memcpy(data, (float*)_data + start_sample, sizeof(float) *
+	memcpy(data, (float*)_data.data() + start_sample, sizeof(float) *
 		(end_sample - start_sample));
 	return data;
 }
@@ -156,9 +156,9 @@ void AnalogSnapshot::append_payload_to_envelope_levels()
 	dest_ptr = e0.samples + prev_length;
 
 	// Iterate through the samples to populate the first level mipmap
-	const float *const end_src_ptr = (float*)_data +
+	const float *const end_src_ptr = (float*)_data.data() +
 		e0.length * EnvelopeScaleFactor;
-	for (const float *src_ptr = (float*)_data +
+	for (const float *src_ptr = (float*)_data.data() +
 		prev_length * EnvelopeScaleFactor;
 		src_ptr < end_src_ptr; src_ptr += EnvelopeScaleFactor)
 	{
diff --git a/pv/data/logicsnapshot.cpp b/pv/data/logicsnapshot.cpp
index 3bd43c92..f1ff3c3c 100644
--- a/pv/data/logicsnapshot.cpp
+++ b/pv/data/logicsnapshot.cpp
@@ -162,7 +162,7 @@ void LogicSnapshot::get_samples(uint8_t *const data,
 	lock_guard<recursive_mutex> lock(_mutex);
 
 	const size_t size = (end_sample - start_sample) * _unit_size;
-	memcpy(data, (const uint8_t*)_data + start_sample * _unit_size, size);
+	memcpy(data, (const uint8_t*)_data.data() + start_sample * _unit_size, size);
 }
 
 void LogicSnapshot::reallocate_mipmap_level(MipMapLevel &m)
@@ -201,9 +201,9 @@ void LogicSnapshot::append_payload_to_mipmap()
 	dest_ptr = (uint8_t*)m0.data + prev_length * _unit_size;
 
 	// Iterate through the samples to populate the first level mipmap
-	const uint8_t *const end_src_ptr = (uint8_t*)_data +
+	const uint8_t *const end_src_ptr = (uint8_t*)_data.data() +
 		m0.length * _unit_size * MipMapScaleFactor;
-	for (src_ptr = (uint8_t*)_data +
+	for (src_ptr = (uint8_t*)_data.data() +
 		prev_length * _unit_size * MipMapScaleFactor;
 		src_ptr < end_src_ptr;)
 	{
@@ -266,7 +266,7 @@ uint64_t LogicSnapshot::get_sample(uint64_t index) const
 	assert(_data);
 	assert(index < _sample_count);
 
-	return unpack_sample((uint8_t*)_data + index * _unit_size);
+	return unpack_sample((uint8_t*)_data.data() + index * _unit_size);
 }
 
 void LogicSnapshot::get_subsampled_edges(
diff --git a/pv/data/snapshot.cpp b/pv/data/snapshot.cpp
index 2f3f0413..e8e285e7 100644
--- a/pv/data/snapshot.cpp
+++ b/pv/data/snapshot.cpp
@@ -31,7 +31,6 @@ namespace pv {
 namespace data {
 
 Snapshot::Snapshot(int unit_size) :
-	_data(NULL),
 	_sample_count(0),
 	_capacity(0),
 	_unit_size(unit_size)
@@ -43,7 +42,6 @@ Snapshot::Snapshot(int unit_size) :
 Snapshot::~Snapshot()
 {
 	lock_guard<recursive_mutex> lock(_mutex);
-	free(_data);
 }
 
 uint64_t Snapshot::get_sample_count() const
@@ -64,14 +62,14 @@ void Snapshot::set_capacity(const uint64_t new_capacity)
 	assert(_capacity >= _sample_count);
 	if (new_capacity > _capacity) {
 		_capacity = new_capacity;
-		_data = realloc(_data, (new_capacity * _unit_size) + sizeof(uint64_t));
+		_data.resize((new_capacity * _unit_size) + sizeof(uint64_t));
 	}
 }
 
 uint64_t Snapshot::capacity() const
 {
 	lock_guard<recursive_mutex> lock(_mutex);
-	return _capacity;
+	return _data.size();
 }
 
 void Snapshot::append_data(void *data, uint64_t samples)
@@ -86,7 +84,7 @@ void Snapshot::append_data(void *data, uint64_t samples)
 		set_capacity(_sample_count + samples);
 	}
 
-	memcpy((uint8_t*)_data + _sample_count * _unit_size,
+	memcpy((uint8_t*)_data.data() + _sample_count * _unit_size,
 		data, samples * _unit_size);
 	_sample_count += samples;
 }
diff --git a/pv/data/snapshot.h b/pv/data/snapshot.h
index 49916440..e4b9c0e8 100644
--- a/pv/data/snapshot.h
+++ b/pv/data/snapshot.h
@@ -25,6 +25,7 @@
 
 #include <thread>
 #include <mutex>
+#include <vector>
 
 namespace pv {
 namespace data {
@@ -72,7 +73,7 @@ protected:
 
 protected:
 	mutable std::recursive_mutex _mutex;
-	void *_data;
+	std::vector<uint8_t> _data;
 	uint64_t _sample_count;
 	uint64_t _capacity;
 	int _unit_size;
-- 
2.30.2