From fdf5ef27fec1368a33801a98bbc5ed3556476979 Mon Sep 17 00:00:00 2001
From: Douglas Rumbaugh <dbr4@psu.edu>
Date: Mon, 8 May 2023 12:59:46 -0400
Subject: Began porting source files over from other repository

---
 include/util/base.h | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 include/util/base.h

(limited to 'include/util/base.h')

diff --git a/include/util/base.h b/include/util/base.h
new file mode 100644
index 0000000..1729687
--- /dev/null
+++ b/include/util/base.h
@@ -0,0 +1,73 @@
+/*
+ * include/util/base.h
+ *
+ * Copyright (C) 2023 Douglas Rumbaugh <drumbaugh@psu.edu> 
+ *                    Dong Xie <dongx@psu.edu>
+ *
+ * All rights reserved. Published under the Modified BSD License.
+ *
+ */
+#pragma once
+
+#include <cstdlib>
+#include <cstdint>
+#include <cstddef>
+#include <memory>
+
+namespace de {
+
+// The correct quantity for use in alignment of buffers to be
+// compatible with O_DIRECT
+const size_t SECTOR_SIZE = 512;
+
+// The standard sized block of data (in bytes) for use in IO 
+// operations.
+const size_t PAGE_SIZE = 4096;
+
+// The size of a cacheline, for alignment purposes.
+const size_t CACHELINE_SIZE = 64;
+
+// The largest representable PageNum. A given file cannot
+// have more pages than this.
+const size_t MAX_PAGE_COUNT = UINT32_MAX;
+
+// The largest representable FileId. The file manager cannot
+// manage more files than this.
+const size_t MAX_FILE_COUNT = UINT32_MAX;
+
+// The largest representable FrameId. No buffer can be defined with
+// more frames than this.
+const size_t MAX_FRAME_COUNT = UINT32_MAX;
+
+// The number of bytes of zeroes available in ZEROBUF. Will be
+// a multiple of the parm::PAGE_SIZE.
+constexpr size_t ZEROBUF_SIZE = 8 * PAGE_SIZE;
+
+// A large, preallocated, buffer of zeroes used for pre-allocation
+// of pages in a file.
+alignas(SECTOR_SIZE) const char ZEROBUF[ZEROBUF_SIZE] = {0};
+
+
+// alignment code taken from TacoDB (file: tdb_base.h)
+template<class T>
+constexpr T
+TYPEALIGN(uint64_t ALIGNVAL, T LEN) {
+    return (((uint64_t) (LEN) + ((ALIGNVAL) - 1)) & ~((uint64_t) ((ALIGNVAL) - 1)));
+}
+
+#define SHORTALIGN(LEN)         TYPEALIGN(2, (LEN))
+#define INTALIGN(LEN)           TYPEALIGN(4, (LEN))
+#define LONGALIGN(LEN)          TYPEALIGN(8, (LEN))
+#define DOUBLEALIGN(LEN)        TYPEALIGN(8, (LEN))
+#define MAXALIGN(LEN)           TYPEALIGN(8, (LEN))
+#define CACHELINEALIGN(LEN)     TYPEALIGN(CACHELINE_SIZE, (LEN))
+#define MAXALIGN_OF             8
+
+// Returns a pointer to the idx'th page contained within a multi-page
+// buffer. buffer must be page aligned, and idx must be less than the
+// number of pages within the buffer, or the result is undefined.
+static inline char *get_page(char *buffer, size_t idx) {
+    return buffer + (idx * PAGE_SIZE);
+}
+
+}
-- 
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