DecodeSignal: Fix race condition

diff --git a/pv/data/decodesignal.cpp b/pv/data/decodesignal.cpp
index f7fe004c0f45afb01ca137a36b81c133ba1f0612..cb16ecb8fc47b5fc567d3f8102e19dcd2756a7f7 100644 (file)
--- a/pv/data/decodesignal.cpp
+++ b/pv/data/decodesignal.cpp
@@ -567,7 +567,7 @@ void DecodeSignal::get_binary_data_chunks_merged(uint32_t segment_id,
 
                // Determine overall size before copying to resize dest vector only once
                uint64_t size = 0;
-               int matches = 0;
+               uint64_t matches = 0;
                for (const DecodeBinaryData& d : segment->binary_data)
                        if ((d.sample >= start_sample) && (d.sample < end_sample)) {
                                size += d.data.size();
@@ -575,11 +575,17 @@ void DecodeSignal::get_binary_data_chunks_merged(uint32_t segment_id,
                        }
                dest->resize(size);
 
-               uint64_t index = 0;
+               uint64_t offset = 0;
+               uint64_t matches2 = 0;
                for (const DecodeBinaryData& d : segment->binary_data)
                        if ((d.sample >= start_sample) && (d.sample < end_sample)) {
-                               memcpy(dest->data() + index, d.data.data(), d.data.size());
-                               index += d.data.size();
+                               memcpy(dest->data() + offset, d.data.data(), d.data.size());
+                               offset += d.data.size();
+                               matches2++;
+
+                               // Make sure we don't overwrite memory if the array grew in the meanwhile
+                               if (matches2 == matches)
+                                       break;
                        }
        } catch (out_of_range&) {
                // Do nothing