1 files changed, 63 insertions, 0 deletions
diff --git a/src/H5FDonion_history.h b/src/H5FDonion_history.h
new file mode 100644
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+++ b/src/H5FDonion_history.h
@@ -0,0 +1,63 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the COPYING file, which can be found at the root of the source code       *
+ * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
+ * If you do not have access to either file, you may request a copy from     *
+ * help@hdfgroup.org.                                                        *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Onion Virtual File Driver (VFD)
+ *
+ * Purpose:     Interface for the onion file's history
+ */
+
+#ifndef H5FDonion_history_H
+#define H5FDonion_history_H
+
+/* Number of bytes to encode fixed-size components */
+#define H5FD_ONION_ENCODED_SIZE_HISTORY 20
+
+#define H5FD_ONION_HISTORY_SIGNATURE    "OWHS"
+#define H5FD_ONION_HISTORY_VERSION_CURR 1
+
+/* In-memory representation of the on-store revision record.
+ * Used in the history.
+ */
+typedef struct H5FD_onion_record_loc_t {
+    haddr_t  phys_addr;
+    hsize_t  record_size;
+    uint32_t checksum;
+} H5FD_onion_record_loc_t;
+
+/* In-memory representation of the on-store history record/summary.
+ */
+typedef struct H5FD_onion_history_t {
+    uint8_t                  version;
+    uint64_t                 n_revisions;
+    H5FD_onion_record_loc_t *record_locs;
+    uint32_t                 checksum;
+} H5FD_onion_history_t;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+H5_DLL herr_t H5FD__onion_ingest_history(H5FD_onion_history_t *history_out, H5FD_t *raw_file, haddr_t addr,
+                                         haddr_t size);
+
+H5_DLL uint64_t H5FD__onion_write_history(H5FD_onion_history_t *history, H5FD_t *file, haddr_t off_start,
+                                          haddr_t filesize_curr);
+
+H5_DLL size_t H5FD__onion_history_decode(unsigned char *buf, H5FD_onion_history_t *history);
+H5_DLL size_t H5FD__onion_history_encode(H5FD_onion_history_t *history, unsigned char *buf,
+                                         uint32_t *checksum);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* H5FDonion_history_H */