1 files changed, 47 insertions, 0 deletions
diff --git a/src/libdisfluid/disfluid-cache-group.h b/src/libdisfluid/disfluid-cache-group.h
index 6f6b386..b0a94af 100644
--- a/src/libdisfluid/disfluid-cache-group.h
+++ b/src/libdisfluid/disfluid-cache-group.h
@@ -13,6 +13,9 @@ MAYBE_UNUSED static int
 ao_cache_group_push (int fd, size_t *offset,
 		     size_t n_entries, const size_t *entry_offsets);
 
+MAYBE_UNUSED static int
+ao_cache_group_invalidate (int fd, size_t offset, size_t *invalidated_offset);
+
 # include "disfluid-append-only-file.h"
 # include "safe-alloc.h"
 
@@ -127,4 +130,48 @@ ao_cache_group_push (int fd,
   return ao_file_push_data (fd, header_desc, offset);
 }
 
+MAYBE_UNUSED static int
+ao_cache_group_invalidate (int fd, size_t offset, size_t *invalidated_offset)
+{
+  size_t n_entries = 42;
+  size_t *offsets = NULL;
+  int error = ao_cache_group_read (fd, offset, &n_entries, &offsets);
+  if (error != 0)
+    {
+      FREE (offsets);
+      return -1;
+    }
+  bool changed = false;
+  for (size_t i = 0; i < n_entries; i++)
+    {
+      size_t old_offset = offsets[i];
+      size_t new_offset = 42;
+      if (ao_cache_entry_invalidate (fd, old_offset, &new_offset) < 0)
+	{
+	  FREE (offsets);
+	  return -1;
+	}
+      if (old_offset != new_offset)
+	{
+	  changed = true;
+	}
+      offsets[i] = new_offset;
+    }
+  if (changed)
+    {
+      if (ao_cache_group_push (fd, invalidated_offset, n_entries, offsets) <
+	  0)
+	{
+	  FREE (offsets);
+	  return -1;
+	}
+    }
+  else
+    {
+      *invalidated_offset = offset;
+    }
+  FREE (offsets);
+  return 0;
+}
+
 #endif /* DISFLUID_DISFLUID_CACHE_GROUP_INCLUDED */