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/*
* 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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