Add SerdStatement

5 files changed, 115 insertions, 12 deletions

diff --git a/src/reader.c b/src/reader.c
index f6c5e056..351428fc 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -18,6 +18,8 @@
 
 #include "byte_source.h"
 #include "serd_internal.h"
+#include "stack.h"
+#include "statement.h"
 #include "system.h"
 #include "world.h"
 
@@ -121,8 +123,11 @@ emit_statement(SerdReader* reader, ReadContext ctx, SerdNode* o)
      (subject and predicate) were already zeroed by subsequent pushes. */
   serd_node_zero_pad(o);
 
-  const SerdStatus st = serd_sink_write(
-    reader->sink, *ctx.flags, ctx.subject, ctx.predicate, o, ctx.graph);
+  const SerdStatement statement = {{ctx.subject, ctx.predicate, o, ctx.graph},
+                                   &reader->source.cur};
+
+  const SerdStatus st =
+    serd_sink_write_statement(reader->sink, *ctx.flags, &statement);
 
   *ctx.flags &= SERD_ANON_CONT | SERD_LIST_CONT; // Preserve only cont flags
   return st;
diff --git a/src/sink.c b/src/sink.c
index b62af23a..6f8cc734 100644
--- a/src/sink.c
+++ b/src/sink.c
@@ -16,6 +16,8 @@
 
 #include "sink.h"
 
+#include "statement.h"
+
 #include "serd/serd.h"
 
 #include <stdlib.h>
@@ -86,6 +88,15 @@ serd_sink_write_prefix(const SerdSink* sink,
 }
 
 SerdStatus
+serd_sink_write_statement(const SerdSink*          sink,
+                          const SerdStatementFlags flags,
+                          const SerdStatement*     statement)
+{
+  return sink->statement ? sink->statement(sink->handle, flags, statement)
+                         : SERD_SUCCESS;
+}
+
+SerdStatus
 serd_sink_write(const SerdSink*          sink,
                 const SerdStatementFlags flags,
                 const SerdNode*          subject,
@@ -93,10 +104,8 @@ serd_sink_write(const SerdSink*          sink,
                 const SerdNode*          object,
                 const SerdNode*          graph)
 {
-  return sink->statement
-           ? sink->statement(
-               sink->handle, flags, graph, subject, predicate, object)
-           : SERD_SUCCESS;
+  const SerdStatement statement = {{subject, predicate, object, graph}, NULL};
+  return serd_sink_write_statement(sink, flags, &statement);
 }
 
 SerdStatus
diff --git a/src/statement.c b/src/statement.c
new file mode 100644
index 00000000..c9bac440
--- /dev/null
+++ b/src/statement.c
@@ -0,0 +1,53 @@
+/*
+  Copyright 2011-2020 David Robillard <d@drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include "statement.h"
+
+const SerdNode*
+serd_statement_node(const SerdStatement* statement, SerdField field)
+{
+  return statement->nodes[field];
+}
+
+const SerdNode*
+serd_statement_subject(const SerdStatement* statement)
+{
+  return statement->nodes[SERD_SUBJECT];
+}
+
+const SerdNode*
+serd_statement_predicate(const SerdStatement* statement)
+{
+  return statement->nodes[SERD_PREDICATE];
+}
+
+const SerdNode*
+serd_statement_object(const SerdStatement* statement)
+{
+  return statement->nodes[SERD_OBJECT];
+}
+
+const SerdNode*
+serd_statement_graph(const SerdStatement* statement)
+{
+  return statement->nodes[SERD_GRAPH];
+}
+
+const SerdCursor*
+serd_statement_cursor(const SerdStatement* statement)
+{
+  return statement->cursor;
+}
diff --git a/src/statement.h b/src/statement.h
new file mode 100644
index 00000000..a5baaa6a
--- /dev/null
+++ b/src/statement.h
@@ -0,0 +1,34 @@
+/*
+  Copyright 2011-2020 David Robillard <d@drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#ifndef SERD_STATEMENT_H
+#define SERD_STATEMENT_H
+
+#include "serd/serd.h"
+
+/**
+   Quad of nodes (a statement), or a quad pattern.
+
+   Nodes are ordered (S P O G).  The ID of the default graph is 0.
+*/
+typedef const SerdNode* SerdQuad[4];
+
+struct SerdStatementImpl {
+  SerdQuad    nodes;
+  SerdCursor* cursor;
+};
+
+#endif // SERD_STATEMENT_H
diff --git a/src/writer.c b/src/writer.c
index 8800282d..4160c09d 100644
--- a/src/writer.c
+++ b/src/writer.c
@@ -773,13 +773,15 @@ write_list_obj(SerdWriter*        writer,
 }
 
 static SerdStatus
-serd_writer_write_statement(SerdWriter*        writer,
-                            SerdStatementFlags flags,
-                            const SerdNode*    graph,
-                            const SerdNode*    subject,
-                            const SerdNode*    predicate,
-                            const SerdNode*    object)
+serd_writer_write_statement(SerdWriter*          writer,
+                            SerdStatementFlags   flags,
+                            const SerdStatement* statement)
 {
+  const SerdNode* const subject   = serd_statement_subject(statement);
+  const SerdNode* const predicate = serd_statement_predicate(statement);
+  const SerdNode* const object    = serd_statement_object(statement);
+  const SerdNode* const graph     = serd_statement_graph(statement);
+
   if (!is_resource(subject) || !is_resource(predicate) || !object) {
     return SERD_ERR_BAD_ARG;
   }