Simplify stack management by popping in bulk at higher levels

Since all memory used by the reader is POD in the stack, there is no benefit to
forcing code to explicitly pop everything pushed to the stack, since any
function can record an offset and pop back down to it regardless of what its
callers pushed if it knows that it does not need those items.

1 files changed, 8 insertions, 19 deletions

diff --git a/src/reader.c b/src/reader.c
index bb71be83..c3e2e268 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -71,6 +71,13 @@ SerdNode*
 push_node_padded(SerdReader* reader, size_t maxlen,
                  SerdType type, const char* str, size_t n_bytes)
 {
+	// Push a null byte to ensure the previous node was null terminated
+	char* terminator = (char*)serd_stack_push(&reader->stack, 1);
+	if (!terminator) {
+		return NULL;
+	}
+	*terminator = 0;
+
 	void* mem = serd_stack_push_aligned(
 		&reader->stack, sizeof(SerdNode) + maxlen + 1, sizeof(SerdNode));
 
@@ -89,7 +96,7 @@ push_node_padded(SerdReader* reader, size_t maxlen,
 #ifdef SERD_STACK_CHECK
 	reader->allocs = (Ref*)realloc(
 		reader->allocs, sizeof(reader->allocs) * (++reader->n_allocs));
-	reader->allocs[reader->n_allocs - 1] = (mem - reader->stack.buf);
+	reader->allocs[reader->n_allocs - 1] = node;
 #endif
 	return node;
 }
@@ -100,21 +107,6 @@ push_node(SerdReader* reader, SerdType type, const char* str, size_t n_bytes)
 	return push_node_padded(reader, n_bytes, type, str, n_bytes);
 }
 
-SerdNode*
-pop_node(SerdReader* reader, const SerdNode* node)
-{
-	if (node && node != reader->rdf_first && node != reader->rdf_rest
-	    && node != reader->rdf_nil) {
-#ifdef SERD_STACK_CHECK
-		SERD_STACK_ASSERT_TOP(reader, node);
-		--reader->n_allocs;
-#endif
-		char* const top = reader->stack.buf + reader->stack.size;
-		serd_stack_pop_aligned(&reader->stack, (size_t)(top - (char*)node));
-	}
-	return NULL;
-}
-
 SerdStatus
 emit_statement(SerdReader* reader, ReadContext ctx, SerdNode* o)
 {
@@ -193,9 +185,6 @@ serd_reader_free(SerdReader* reader)
 		return;
 	}
 
-	pop_node(reader, reader->rdf_nil);
-	pop_node(reader, reader->rdf_rest);
-	pop_node(reader, reader->rdf_first);
 	serd_node_free(reader->default_graph);
 
 #ifdef SERD_STACK_CHECK