From: Soeren Apel <redacted>
Date: Thu, 5 Nov 2015 18:14:46 +0000 (+0100)
Subject: StoreSession: Observe proper range order
X-Git-Tag: pulseview-0.3.0~48
X-Git-Url: https://sigrok.org/gitweb/?p=pulseview.git;a=commitdiff_plain;h=3e8a7cc6af5558a249c114b1609ececa2a381774

StoreSession: Observe proper range order

When I wrote the original solution I wanted min() and abs()
to take care of this issue. However, I forgot that abs()
works on a difference of two uint64_t, so this subtraction
will underflow if the range is in the wrong order.
Converting them to int64_t isn't a good solution, so I'm now
using an ordinary condition instead.
---

diff --git a/pv/storesession.cpp b/pv/storesession.cpp
index 5500292a..bdb0f279 100644
--- a/pv/storesession.cpp
+++ b/pv/storesession.cpp
@@ -149,8 +149,13 @@ bool StoreSession::start()
 		start_sample_ = 0;
 		sample_count_ = segment->get_sample_count();
 	} else {
-		start_sample_ = std::min(sample_range_.first, sample_range_.second);
-		sample_count_ = std::abs(sample_range_.second - sample_range_.first);
+		if (sample_range_.first > sample_range_.second) {
+			start_sample_ = sample_range_.second;
+			sample_count_ = sample_range_.first - sample_range_.second;
+		} else {
+			start_sample_ = sample_range_.first;
+			sample_count_ = sample_range_.second - sample_range_.first;
+		}
 	}
 
 	// Begin storing