QPID-8453: fix boundary test between map8 and map32 encodings for AMQP 1.0 messages

Author: Cliff Jansen

src/qpid/amqp/MapEncoder.cpp

@@ -116,9 +116,11 @@ void MapEncoder::handleString(const CharSequence& key, const CharSequence& value
 
 void MapEncoder::writeMetaData(size_t size, size_t count, const Descriptor* d)
 {
-    if (count > 255 || size > 255) {
+
+    if (count > 255 || (size+1) > 255) {
         writeMap32MetaData((uint32_t) size, (uint32_t) count, d);
     } else {
+        /* can use more compact format */
         writeMap8MetaData((uint8_t) size, (uint8_t) count, d);
     }
 }

src/qpid/amqp/MapSizeCalculator.cpp

@@ -139,7 +139,7 @@ size_t MapSizeCalculator::getTotalSizeRequired(const Descriptor* d) const
     size_t result(size);
     if (d) result += d->getSize();
     result += 1/*typecode*/;
-    if (count * 2 > 255 || size > 255) {
+    if (count * 2 > 255 || (size+1) > 255) {
         result += 4/*size*/ + 4/*count*/;
     } else {
         result += 1/*size*/ + 1/*count*/;