Add serd_statement_matches()

4 files changed, 45 insertions, 0 deletions

diff --git a/include/serd/serd.h b/include/serd/serd.h
index 5d0f7290..cec77649 100644
--- a/include/serd/serd.h
+++ b/include/serd/serd.h
@@ -1177,6 +1177,20 @@ serd_statement_equals(const SerdStatement* SERD_NULLABLE a,
                       const SerdStatement* SERD_NULLABLE b);
 
 /**
+   Return true iff the statement matches the given pattern.
+
+   Nodes match if they are equivalent, or if one of them is NULL.  The
+   statement matches if every node matches.
+*/
+SERD_PURE_API
+bool
+serd_statement_matches(const SerdStatement* SERD_NONNULL statement,
+                       const SerdNode* SERD_NULLABLE     subject,
+                       const SerdNode* SERD_NULLABLE     predicate,
+                       const SerdNode* SERD_NULLABLE     object,
+                       const SerdNode* SERD_NULLABLE     graph);
+
+/**
    @}
    @defgroup serd_world World
    @{
diff --git a/src/node.h b/src/node.h
index 29164dc2..e064e96b 100644
--- a/src/node.h
+++ b/src/node.h
@@ -20,6 +20,7 @@
 #include "exess/exess.h"
 #include "serd/serd.h"
 
+#include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ -49,6 +50,13 @@ serd_node_string_i(const SerdNode* const SERD_NONNULL node)
   return (const char*)(node + 1);
 }
 
+static inline bool
+serd_node_pattern_match(const SerdNode* SERD_NULLABLE a,
+                        const SerdNode* SERD_NULLABLE b)
+{
+  return !a || !b || serd_node_equals(a, b);
+}
+
 SerdNode* SERD_ALLOCATED
 serd_node_malloc(size_t length, SerdNodeFlags flags, SerdNodeType type);
 
diff --git a/src/statement.c b/src/statement.c
index f3034566..d6571c6c 100644
--- a/src/statement.c
+++ b/src/statement.c
@@ -17,6 +17,7 @@
 #include "statement.h"
 
 #include "caret.h"
+#include "node.h"
 
 #include <assert.h>
 #include <stdbool.h>
@@ -132,3 +133,16 @@ serd_statement_equals(const SerdStatement* const a,
                      serd_node_equals(a->nodes[2], b->nodes[2]) &&
                      serd_node_equals(a->nodes[3], b->nodes[3])));
 }
+
+bool
+serd_statement_matches(const SerdStatement* const statement,
+                       const SerdNode* const      subject,
+                       const SerdNode* const      predicate,
+                       const SerdNode* const      object,
+                       const SerdNode* const      graph)
+{
+  return (serd_node_pattern_match(statement->nodes[0], subject) &&
+          serd_node_pattern_match(statement->nodes[1], predicate) &&
+          serd_node_pattern_match(statement->nodes[2], object) &&
+          serd_node_pattern_match(statement->nodes[3], graph));
+}
diff --git a/test/test_statement.c b/test/test_statement.c
index 6f92513f..45605dd1 100644
--- a/test/test_statement.c
+++ b/test/test_statement.c
@@ -84,6 +84,15 @@ test_fields(void)
   assert(serd_statement_graph(statement) == g);
   assert(serd_statement_caret(statement) != caret);
   assert(serd_caret_equals(serd_statement_caret(statement), caret));
+  assert(serd_statement_matches(statement, s, p, o, g));
+  assert(serd_statement_matches(statement, NULL, p, o, g));
+  assert(serd_statement_matches(statement, s, NULL, o, g));
+  assert(serd_statement_matches(statement, s, p, NULL, g));
+  assert(serd_statement_matches(statement, s, p, o, NULL));
+  assert(!serd_statement_matches(statement, o, NULL, NULL, NULL));
+  assert(!serd_statement_matches(statement, NULL, o, NULL, NULL));
+  assert(!serd_statement_matches(statement, NULL, NULL, s, NULL));
+  assert(!serd_statement_matches(statement, NULL, NULL, NULL, s));
 
   SerdStatement* const diff_s = serd_statement_new(o, p, o, g, caret);
   assert(!serd_statement_equals(statement, diff_s));