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, 7 insertions, 27 deletions

diff --git a/src/reader.c b/src/reader.c
index d89ea197..04c7f372 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -79,6 +79,13 @@ push_node_padded(SerdReader* const  reader,
                  const char* const  str,
                  const size_t       length)
 {
+  // 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));
 
@@ -95,12 +102,6 @@ push_node_padded(SerdReader* const  reader,
   char* buf = (char*)(node + 1);
   memcpy(buf, str, length + 1);
 
-#ifdef SERD_STACK_CHECK
-  reader->allocs = (SerdNode**)realloc(
-    reader->allocs, sizeof(reader->allocs) * (++reader->n_allocs));
-  reader->allocs[reader->n_allocs - 1] =
-    (SerdNode*)((char*)mem - reader->stack.buf);
-#endif
   return node;
 }
 
@@ -113,21 +114,6 @@ push_node(SerdReader* const  reader,
   return push_node_padded(reader, length, type, str, length);
 }
 
-SerdNode*
-pop_node(SerdReader* const reader, const SerdNode* const 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* const reader,
                const ReadContext ctx,
@@ -220,15 +206,9 @@ serd_reader_free(SerdReader* const reader)
     return;
   }
 
-  pop_node(reader, reader->rdf_nil);
-  pop_node(reader, reader->rdf_rest);
-  pop_node(reader, reader->rdf_first);
   serd_reader_finish(reader);
   serd_node_free(reader->default_graph);
 
-#ifdef SERD_STACK_CHECK
-  free(reader->allocs);
-#endif
   free(reader->stack.buf);
   free(reader->bprefix);
   free(reader);