mach0data.h

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/** @file include/mach0data.h
 Utilities for converting data from the database file
 to the machine format.
 
 Created 11/28/1995 Heikki Tuuri
 ***********************************************************************/
 
#ifndef mach0data_h
#define mach0data_h
 
#include "mtr0types.h"
#include "univ.i"
 
#ifdef UNIV_HOTBACKUP
#include "ut0byte.h"
#endif /* UNIV_HOTBACKUP */
 
/* The data and all fields are always stored in a database file
in the same format: ascii, big-endian, ... .
All data in the files MUST be accessed using the functions in this
module. */
 
/** The following function is used to store data in one byte.
@param[in]      b       pointer to byte where to store
@param[in]      n       One byte integer to be stored, >= 0, < 256 */
static inline void mach_write_to_1(byte *b, ulint n);
 
/** The following function is used to fetch data from one byte.
@param[in]      b       pointer to a byte to read
@return ulint integer, >= 0, < 256 */
[[nodiscard]] static inline uint8_t mach_read_from_1(const byte *b);
 
/** The following function is used to store data in two consecutive bytes. We
store the most significant byte to the lower address.
@param[in]      b       pointer to 2 bytes where to store
@param[in]      n       2-byte integer to be stored, >= 0, < 64k */
static inline void mach_write_to_2(byte *b, ulint n);
 
/** The following function is used to fetch data from 2 consecutive
bytes. The most significant byte is at the lowest address.
@param[in]      b       pointer to 2 bytes where to store
@return 2-byte integer, >= 0, < 64k */
[[nodiscard]] static inline uint16_t mach_read_from_2(const byte *b);
 
/** The following function is used to convert a 16-bit data item to the
canonical format, for fast bytewise equality test against memory.
@param[in]  n   integer in machine-dependent format
@return 16-bit integer in canonical format */
static inline uint16_t mach_encode_2(ulint n);
 
/** The following function is used to convert a 16-bit data item from the
canonical format, for fast bytewise equality test against memory.
@param[in]  n   16-bit integer in canonical format
@return integer in machine-dependent format */
static inline ulint mach_decode_2(uint16 n);
 
/** The following function is used to store data in 3 consecutive
bytes. We store the most significant byte to the lowest address.
@param[in]      b       pointer to 3 bytes where to store
@param[in]      n       3 byte integer to be stored */
static inline void mach_write_to_3(byte *b, ulint n);
 
/** The following function is used to fetch data from 3 consecutive
bytes. The most significant byte is at the lowest address.
@param[in]      b       pointer to 3 bytes to read
@return 32 bit integer */
[[nodiscard]] static inline uint32_t mach_read_from_3(const byte *b);
 
/** The following function is used to store data in 4 consecutive
bytes. We store the most significant byte to the lowest address.
@param[in]      b       pointer to 4 bytes where to store
@param[in]      n       4 byte integer to be stored */
static inline void mach_write_to_4(byte *b, ulint n);
 
/** The following function is used to fetch data from 4 consecutive
bytes. The most significant byte is at the lowest address.
@param[in]      b       pointer to 4 bytes to read
@return 32 bit integer */
[[nodiscard]] static inline uint32_t mach_read_from_4(const byte *b);
 
/** Write a ulint in a compressed form (1..5 bytes).
@param[in]      b       pointer to memory where to store
@param[in]      n       ulint integer to be stored
@return stored size in bytes */
static inline ulint mach_write_compressed(byte *b, ulint n);
 
/** Return the size of an ulint when written in the compressed form.
@param[in]      n       ulint integer to be stored
@return compressed size in bytes */
static inline uint32_t mach_get_compressed_size(ulint n);
 
/** Read a 32-bit integer in a compressed form.
@param[in,out]  b       pointer to memory where to read;
advanced by the number of bytes consumed
@return unsigned value */
static inline uint32_t mach_read_next_compressed(const byte **b);
 
/** The following function is used to store data in 6 consecutive
bytes. We store the most significant byte to the lowest address.
@param[in]      b       pointer to 6 bytes where to store
@param[in]      id      48-bit integer to write */
static inline void mach_write_to_6(byte *b, uint64_t id);
 
/** The following function is used to fetch data from 6 consecutive
bytes. The most significant byte is at the lowest address.
@param[in]      b       pointer to 6 bytes to read
@return 48-bit integer */
[[nodiscard]] static inline uint64_t mach_read_from_6(const byte *b);
 
/** The following function is used to store data in 7 consecutive
bytes. We store the most significant byte to the lowest address.
@param[in]      b       pointer to 7 bytes where to store
@param[in]      n       56-bit integer */
static inline void mach_write_to_7(byte *b, uint64_t n);
 
/** The following function is used to fetch data from 7 consecutive
bytes. The most significant byte is at the lowest address.
@param[in]      b       pointer to 7 bytes to read
@return 56-bit integer */
[[nodiscard]] static inline uint64_t mach_read_from_7(const byte *b);
 
/** The following function is used to store data in 8 consecutive
bytes. We store the most significant byte to the lowest address.
@param[in]      b       pointer to 8 bytes where to store
@param[in]      n       64-bit integer to be stored */
static inline void mach_write_to_8(void *b, uint64_t n);
 
/** The following function is used to fetch data from 8 consecutive
bytes. The most significant byte is at the lowest address.
@param[in]      b       pointer to 8 bytes to read
@return 64-bit integer */
[[nodiscard]] static inline uint64_t mach_read_from_8(const byte *b);
 
/** Writes a 64-bit integer in a compressed form (5..9 bytes).
@param[in]      b       pointer to memory where to store
@param[in]      n       64-bit integer to be stored
@return size in bytes */
static inline ulint mach_u64_write_compressed(byte *b, uint64_t n);
 
/** Read a 64-bit integer in a compressed form.
@param[in,out]  b       pointer to memory where to read;
advanced by the number of bytes consumed
@return unsigned value */
static inline uint64_t mach_u64_read_next_compressed(const byte **b);
 
/** Writes a 64-bit integer in a compressed form (1..11 bytes).
@param[in]      b       pointer to memory where to store
@param[in]      n       64-bit integer to be stored
@return size in bytes */
static inline ulint mach_u64_write_much_compressed(byte *b, uint64_t n);
 
/** Reads a 64-bit integer in a compressed form.
@param[in]      b       pointer to memory from where to read
@return the value read */
[[nodiscard]] static inline uint64_t mach_u64_read_much_compressed(
    const byte *b);
 
/** Read a 64-bit integer in a much compressed form.
@param[in,out]  ptr     pointer to memory from where to read,
advanced by the number of bytes consumed, or set NULL if out of space
@param[in]      end_ptr end of the buffer
@return unsigned 64-bit integer */
uint64_t mach_parse_u64_much_compressed(const byte **ptr, const byte *end_ptr);
 
/** Read a 32-bit integer in a compressed form.
@param[in,out]  ptr     pointer to memory from where to read;
advanced by the number of bytes consumed, or set NULL if out of space
@param[in]      end_ptr end of the buffer
@return unsigned value */
uint32_t mach_parse_compressed(const byte **ptr, const byte *end_ptr);
 
/** Read a 64-bit integer in a compressed form.
@param[in,out]  ptr     pointer to memory from where to read;
advanced by the number of bytes consumed, or set NULL if out of space
@param[in]      end_ptr end of the buffer
@return unsigned value */
static inline uint64_t mach_u64_parse_compressed(const byte **ptr,
                                                 const byte *end_ptr);
 
/** Reads a double. It is stored in a little-endian format.
 @return double read */
[[nodiscard]] static inline double mach_double_read(
    const byte *b); /*!< in: pointer to memory from where to read */
 
/** Writes a double. It is stored in a little-endian format.
@param[in]      b       pointer to memory where to write
@param[in]      d       double */
static inline void mach_double_write(byte *b, double d);
 
/** Reads a float. It is stored in a little-endian format.
 @return float read */
[[nodiscard]] static inline float mach_float_read(
    const byte *b); /*!< in: pointer to memory from where to read */
 
/** Writes a float. It is stored in a little-endian format.
@param[in]      b       pointer to memory where to write
@param[in]      d       float */
static inline void mach_float_write(byte *b, float d);
 
#ifndef UNIV_HOTBACKUP
/** Reads a ulint stored in the little-endian format.
@param[in] buf      From where to read.
@param[in] buf_size From how many bytes to read.
@return unsigned long int */
[[nodiscard]] static inline ulint mach_read_from_n_little_endian(
    const byte *buf, ulint buf_size);
 
/** Writes a ulint in the little-endian format.
@param[in]      dest            where to write
@param[in]      dest_size       into how many bytes to write
@param[in]      n               unsigned long int to write */
static inline void mach_write_to_n_little_endian(byte *dest, ulint dest_size,
                                                 ulint n);
 
/** Reads a ulint stored in the little-endian format.
 @return unsigned long int */
[[nodiscard]] static inline ulint mach_read_from_2_little_endian(
    const byte *buf); /*!< in: from where to read */
 
/** Writes a ulint in the little-endian format.
@param[in]      dest            where to write
@param[in]      n               unsigned long int to write */
static inline void mach_write_to_2_little_endian(byte *dest, ulint n);
 
/** Convert integral type from storage byte order (big endian) to host byte
order.
@param[in]      src             where to read from
@param[in]      len             length of src
@param[in]      unsigned_type   signed or unsigned flag
@return integer value */
static inline uint64_t mach_read_int_type(const byte *src, ulint len,
                                          bool unsigned_type);
 
/** Convert integral type from host byte order to (big-endian) storage
byte order.
@param[in]      dest    where to write
@param[in]      src     where to read
@param[in]      len     length of src
@param[in]      usign   signed or unsigned flag */
static inline void mach_write_int_type(byte *dest, const byte *src, ulint len,
                                       bool usign);
 
/** Convert a ulonglong integer from host byte order to (big-endian) storage
byte order.
@param[in]      dest    where to write
@param[in]      src     where to read from
@param[in]      len     length of dest
@param[in]      usign   signed or unsigned flag */
static inline void mach_write_ulonglong(byte *dest, ulonglong src, ulint len,
                                        bool usign);
 
#endif
 
/** Read 1 to 4 bytes from a file page buffered in the buffer pool.
@param[in]      ptr     pointer where to read
@param[in]      type    MLOG_1BYTE, MLOG_2BYTES, or MLOG_4BYTES
@return value read */
[[nodiscard]] static inline uint32_t mach_read_ulint(const byte *ptr,
                                                     mlog_id_t type);
 
#include "mach0data.ic"
 
#endif