X-Git-Url: https://sigrok.org/gitweb/?p=pulseview.git;a=blobdiff_plain;f=pv%2Fdata%2Fsegment.cpp;h=88015c3639860597accf8bf23eb21ed98d499e53;hp=f635fc387a59dc4156273ca0dd4d88602ca35a27;hb=c063290ac7189bdd15221450f598504f43286b43;hpb=26a883ede0bcf68d087eda5dd2082890d36c7aef

diff --git a/pv/data/segment.cpp b/pv/data/segment.cpp
index f635fc38..88015c36 100644
--- a/pv/data/segment.cpp
+++ b/pv/data/segment.cpp
@@ -20,32 +20,33 @@
 
 #include "segment.hpp"
 
-#include <assert.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include <vector>
+#include <cassert>
+#include <cstdlib>
+#include <cstring>
 
 using std::lock_guard;
+using std::min;
 using std::recursive_mutex;
-using std::vector;
 
 namespace pv {
 namespace data {
 
+const uint64_t Segment::MaxChunkSize = 10*1024*1024;  /* 10MiB */
+
 Segment::Segment(uint64_t samplerate, unsigned int unit_size) :
 	sample_count_(0),
 	start_time_(0),
 	samplerate_(samplerate),
-	unit_size_(unit_size)
+	unit_size_(unit_size),
+	iterator_count_(0),
+	mem_optimization_requested_(false)
 {
 	lock_guard<recursive_mutex> lock(mutex_);
 	assert(unit_size_ > 0);
 
 	// Determine the number of samples we can fit in one chunk
 	// without exceeding MaxChunkSize
-	chunk_size_ = std::min(MaxChunkSize,
-		(MaxChunkSize / unit_size_) * unit_size_);
+	chunk_size_ = min(MaxChunkSize, (MaxChunkSize / unit_size_) * unit_size_);
 
 	// Create the initial chunk
 	current_chunk_ = new uint8_t[chunk_size_];
@@ -88,6 +89,27 @@ unsigned int Segment::unit_size() const
 	return unit_size_;
 }
 
+void Segment::free_unused_memory()
+{
+	lock_guard<recursive_mutex> lock(mutex_);
+
+	// Do not mess with the data chunks if we have iterators pointing at them
+	if (iterator_count_ > 0) {
+		mem_optimization_requested_ = true;
+		return;
+	}
+
+	// No more data will come in, so re-create the last chunk accordingly
+	uint8_t* resized_chunk = new uint8_t[used_samples_ * unit_size_];
+	memcpy(resized_chunk, current_chunk_, used_samples_ * unit_size_);
+
+	delete[] current_chunk_;
+	current_chunk_ = resized_chunk;
+
+	data_chunks_.pop_back();
+	data_chunks_.push_back(resized_chunk);
+}
+
 void Segment::append_single_sample(void *data)
 {
 	lock_guard<recursive_mutex> lock(mutex_);
@@ -95,8 +117,7 @@ void Segment::append_single_sample(void *data)
 	// There will always be space for at least one sample in
 	// the current chunk, so we do not need to test for space
 
-	memcpy(current_chunk_ + (used_samples_ * unit_size_),
-		data, unit_size_);
+	memcpy(current_chunk_ + (used_samples_ * unit_size_), data, unit_size_);
 	used_samples_++;
 	unused_samples_--;
 
@@ -164,7 +185,7 @@ uint8_t* Segment::get_raw_samples(uint64_t start, uint64_t count) const
 	while (count > 0) {
 		const uint8_t* chunk = data_chunks_[chunk_num];
 
-		uint64_t copy_size = std::min(count * unit_size_,
+		uint64_t copy_size = min(count * unit_size_,
 			chunk_size_ - chunk_offs);
 
 		memcpy(dest_ptr, chunk + chunk_offs, copy_size);
@@ -179,12 +200,14 @@ uint8_t* Segment::get_raw_samples(uint64_t start, uint64_t count) const
 	return dest;
 }
 
-SegmentRawDataIterator* Segment::begin_raw_sample_iteration(uint64_t start) const
+SegmentRawDataIterator* Segment::begin_raw_sample_iteration(uint64_t start)
 {
 	SegmentRawDataIterator* it = new SegmentRawDataIterator;
 
 	assert(start < sample_count_);
 
+	iterator_count_++;
+
 	it->sample_index = start;
 	it->chunk_num = (start * unit_size_) / chunk_size_;
 	it->chunk_offs = (start * unit_size_) % chunk_size_;
@@ -194,18 +217,16 @@ SegmentRawDataIterator* Segment::begin_raw_sample_iteration(uint64_t start) cons
 	return it;
 }
 
-void Segment::continue_raw_sample_iteration(SegmentRawDataIterator* it, uint64_t increase) const
+void Segment::continue_raw_sample_iteration(SegmentRawDataIterator* it, uint64_t increase)
 {
 	lock_guard<recursive_mutex> lock(mutex_);
 
+	// Fail gracefully if we are asked to deliver data we don't have
 	if (it->sample_index > sample_count_)
-	{
-		// Fail gracefully if we are asked to deliver data we don't have
 		return;
-	} else {
-		it->sample_index += increase;
-		it->chunk_offs += (increase * unit_size_);
-	}
+
+	it->sample_index += increase;
+	it->chunk_offs += (increase * unit_size_);
 
 	if (it->chunk_offs > (chunk_size_ - 1)) {
 		it->chunk_num++;
@@ -216,11 +237,17 @@ void Segment::continue_raw_sample_iteration(SegmentRawDataIterator* it, uint64_t
 	it->value = it->chunk + it->chunk_offs;
 }
 
-void Segment::end_raw_sample_iteration(SegmentRawDataIterator* it) const
+void Segment::end_raw_sample_iteration(SegmentRawDataIterator* it)
 {
 	delete it;
-}
 
+	iterator_count_--;
+
+	if ((iterator_count_ == 0) && mem_optimization_requested_) {
+		mem_optimization_requested_ = false;
+		free_unused_memory();
+	}
+}
 
 } // namespace data
 } // namespace pv