1 files changed, 35 insertions, 0 deletions

diff --git a/examples/dte/history.h b/examples/dte/history.h
new file mode 100644
index 0000000..12073f5
--- /dev/null
+++ b/examples/dte/history.h
@@ -0,0 +1,35 @@
+#ifndef HISTORY_H
+#define HISTORY_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include "util/hashmap.h"
+#include "util/macros.h"
+
+typedef struct HistoryEntry {
+    struct HistoryEntry *next;
+    struct HistoryEntry *prev;
+    char *text;
+} HistoryEntry;
+
+// This is a HashMap with a doubly-linked list running through the
+// entries, in a way similar to the Java LinkedHashMap class. The
+// HashMap allows duplicates to be found and re-inserted at the end
+// of the list in O(1) time and the doubly-linked entries allow
+// ordered traversal.
+typedef struct {
+    char *filename;
+    HashMap entries;
+    HistoryEntry *first;
+    HistoryEntry *last;
+    size_t max_entries;
+} History;
+
+void history_add(History *history, const char *text);
+bool history_search_forward(const History *history, const HistoryEntry **pos, const char *text) WARN_UNUSED_RESULT;
+bool history_search_backward(const History *history, const HistoryEntry **pos, const char *text) WARN_UNUSED_RESULT;
+void history_load(History *history, char *filename);
+void history_save(const History *history);
+void history_free(History *history);
+
+#endif