From 9243700f938656936ac57a19c030fef1aaa0ebc0 Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Wed, 13 Jan 2021 23:47:44 +0100
Subject: 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.
---
 src/reader.c | 28 ++++++++--------------------
 1 file changed, 8 insertions(+), 20 deletions(-)

(limited to 'src/reader.c')

diff --git a/src/reader.c b/src/reader.c
index 1693ef64..24240de8 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -75,6 +75,13 @@ push_node_padded(SerdReader*  reader,
                  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));
 
@@ -93,8 +100,7 @@ push_node_padded(SerdReader*  reader,
 #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);
+  reader->allocs[reader->n_allocs - 1] = node;
 #endif
   return node;
 }
@@ -108,21 +114,6 @@ push_node(SerdReader*  reader,
   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)
 {
@@ -199,9 +190,6 @@ 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_reader_finish(reader);
   serd_node_free(reader->default_graph);
 
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