mariadb/storage/innobase/include/ut0ut.h

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/******************************************************************//**
@file include/ut0ut.h
Various utilities

Created 1/20/1994 Heikki Tuuri
***********************************************************************/

#ifndef ut0ut_h
#define ut0ut_h

/* Do not include univ.i because univ.i includes this. */

#include <ostream>
#include <sstream>
#include <string.h>

#ifndef UNIV_INNOCHECKSUM

#include "db0err.h"

#include <time.h>

#ifndef MYSQL_SERVER
#include <ctype.h>
#endif /* MYSQL_SERVER */

#include <stdarg.h>

#include <string>

/** Index name prefix in fast index creation, as a string constant */
#define TEMP_INDEX_PREFIX_STR	"\377"

#define ut_max	std::max
#define ut_min	std::min

/*************************************************************//**
Calculates fast the remainder of n/m when m is a power of two.
@param n in: numerator
@param m in: denominator, must be a power of two
@return the remainder of n/m */
template <typename T> inline T ut_2pow_remainder(T n, T m){return n & (m - 1);}
/*************************************************************//**
Calculates the biggest multiple of m that is not bigger than n
when m is a power of two.  In other words, rounds n down to m * k.
@param n in: number to round down
@param m in: alignment, must be a power of two
@return n rounded down to the biggest possible integer multiple of m */
template <typename T> inline T ut_2pow_round(T n, T m) { return n & ~(m - 1); }
/********************************************************//**
Calculates the smallest multiple of m that is not smaller than n
when m is a power of two.  In other words, rounds n up to m * k.
@param n in: number to round up
@param m in: alignment, must be a power of two
@return n rounded up to the smallest possible integer multiple of m */
#define UT_CALC_ALIGN(n, m) ((n + m - 1) & ~(m - 1))
template <typename T> inline T ut_calc_align(T n, T m)
{ return static_cast<T>(UT_CALC_ALIGN(n, m)); }

/**********************************************************//**
Returns the number of milliseconds since some epoch.  The
value may wrap around.  It should only be used for heuristic
purposes.
@return ms since epoch */
ulint
ut_time_ms(void);
/*============*/
#endif /* !UNIV_INNOCHECKSUM */

/** Determine how many bytes (groups of 8 bits) are needed to
store the given number of bits.
@param b in: bits
@return number of bytes (octets) needed to represent b */
#define UT_BITS_IN_BYTES(b) (((b) + 7) >> 3)

/** Determines if a number is zero or a power of two.
@param[in]	n	number
@return nonzero if n is zero or a power of two; zero otherwise */
#define ut_is_2pow(n) (!((n) & ((n) - 1)))

/** Functor that compares two C strings. Can be used as a comparator for
e.g. std::map that uses char* as keys. */
struct ut_strcmp_functor
{
	bool operator()(
		const char*	a,
		const char*	b) const
	{
		return(strcmp(a, b) < 0);
	}
};

/**********************************************************//**
Prints a timestamp to a file. */
void
ut_print_timestamp(
/*===============*/
	FILE*	file)	/*!< in: file where to print */
	ATTRIBUTE_COLD __attribute__((nonnull));

#ifndef UNIV_INNOCHECKSUM

/**********************************************************//**
Sprintfs a timestamp to a buffer, 13..14 chars plus terminating NUL. */
void
ut_sprintf_timestamp(
/*=================*/
	char*	buf); /*!< in: buffer where to sprintf */

/*************************************************************//**
Prints the contents of a memory buffer in hex and ascii. */
void
ut_print_buf(
/*=========*/
	FILE*		file,	/*!< in: file where to print */
	const void*	buf,	/*!< in: memory buffer */
	ulint		len);	/*!< in: length of the buffer */

/*************************************************************//**
Prints the contents of a memory buffer in hex. */
void
ut_print_buf_hex(
/*=============*/
	std::ostream&	o,	/*!< in/out: output stream */
	const void*	buf,	/*!< in: memory buffer */
	ulint		len)	/*!< in: length of the buffer */
	MY_ATTRIBUTE((nonnull));
/*************************************************************//**
Prints the contents of a memory buffer in hex and ascii. */
void
ut_print_buf(
/*=========*/
	std::ostream&	o,	/*!< in/out: output stream */
	const void*	buf,	/*!< in: memory buffer */
	ulint		len)	/*!< in: length of the buffer */
	MY_ATTRIBUTE((nonnull));

/* Forward declaration of transaction handle */
struct trx_t;

/** Get a fixed-length string, quoted as an SQL identifier.
If the string contains a slash '/', the string will be
output as two identifiers separated by a period (.),
as in SQL database_name.identifier.
 @param		[in]	trx		transaction (NULL=no quotes).
 @param		[in]	name		table name.
 @retval	String quoted as an SQL identifier.
*/
std::string
ut_get_name(
	const trx_t*	trx,
	const char*	name);

/**********************************************************************//**
Outputs a fixed-length string, quoted as an SQL identifier.
If the string contains a slash '/', the string will be
output as two identifiers separated by a period (.),
as in SQL database_name.identifier. */
void
ut_print_name(
/*==========*/
	FILE*		ef,	/*!< in: stream */
	const trx_t*	trx,	/*!< in: transaction */
	const char*	name);	/*!< in: table name to print */

/**********************************************************************//**
Catenate files. */
void
ut_copy_file(
/*=========*/
	FILE*	dest,	/*!< in: output file */
	FILE*	src);	/*!< in: input file to be appended to output */

/*************************************************************//**
Convert an error number to a human readable text message. The
returned string is static and should not be freed or modified.
@return string, describing the error */
const char*
ut_strerr(
/*======*/
	dberr_t	num);	/*!< in: error number */

#endif /* !UNIV_INNOCHECKSUM */

namespace ib {

/** This is a wrapper class, used to print any unsigned integer type
in hexadecimal format.  The main purpose of this data type is to
overload the global operator<<, so that we can print the given
wrapper value in hex. */
struct hex {
	explicit hex(uintmax_t t): m_val(t) {}
	const uintmax_t	m_val;
};

/** This is an overload of the global operator<< for the user defined type
ib::hex.  The unsigned value held in the ib::hex wrapper class will be printed
into the given output stream in hexadecimal format.
@param[in,out]	lhs	the output stream into which rhs is written.
@param[in]	rhs	the object to be written into lhs.
@retval	reference to the output stream. */
inline
std::ostream&
operator<<(
	std::ostream&	lhs,
	const hex&	rhs)
{
	std::ios_base::fmtflags	ff = lhs.flags();
	lhs << std::showbase << std::hex << rhs.m_val;
	lhs.setf(ff);
	return(lhs);
}

/** This is a wrapper class, used to print any number in IEC style */
struct bytes_iec {
  explicit bytes_iec(unsigned long long t): m_val(t) {}
  double get_double() const { return static_cast<double>(m_val); }
  const unsigned long long m_val;
};

/** Like hex operator above, except for bytes_iec */
std::ostream &operator<<(std::ostream &lhs, const bytes_iec &rhs);

/** The class logger is the base class of all the error log related classes.
It contains a std::ostringstream object.  The main purpose of this class is
to forward operator<< to the underlying std::ostringstream object.  Do not
use this class directly, instead use one of the derived classes. */
class logger
{
protected:
  /* This class must not be used directly */
  ATTRIBUTE_COLD ATTRIBUTE_NOINLINE logger() = default;
public:
  template<typename T> ATTRIBUTE_COLD ATTRIBUTE_NOINLINE
  logger& operator<<(const T& rhs)
  {
    m_oss << rhs;
    return *this;
  }

  /** Handle a fixed character string in the same way as a pointer to
  an unknown-length character string, to reduce object code bloat. */
  template<size_t N> logger& operator<<(const char (&rhs)[N])
  { return *this << static_cast<const char*>(rhs); }

  /** Output an error code name */
  ATTRIBUTE_COLD logger& operator<<(dberr_t err);

  /** Append a string.
  @param buf   string buffer
  @param size  buffer size
  @return the output stream */
  ATTRIBUTE_COLD __attribute__((noinline))
  std::ostream &write(const char *buf, std::streamsize size)
  {
    return m_oss.write(buf, size);
  }

  std::ostream &write(const byte *buf, std::streamsize size)
  { return write(reinterpret_cast<const char*>(buf), size); }

  std::ostringstream m_oss;
};

/** The class info is used to emit informational log messages.  It is to be
used similar to std::cout.  But the log messages will be emitted only when
the dtor is called.  The preferred usage of this class is to make use of
unnamed temporaries as follows:

info() << "The server started successfully.";

In the above usage, the temporary object will be destroyed at the end of the
statement and hence the log message will be emitted at the end of the
statement.  If a named object is created, then the log message will be emitted
only when it goes out of scope or destroyed. */
class info : public logger {
public:
	ATTRIBUTE_COLD
	~info();
};

/** The class warn is used to emit warnings.  Refer to the documentation of
class info for further details. */
class warn : public logger {
public:
	ATTRIBUTE_COLD
	~warn();
};

/** The class error is used to emit error messages.  Refer to the
documentation of class info for further details. */
class error : public logger {
public:
	ATTRIBUTE_COLD
	~error();
	/** Indicates that error::~error() was invoked. Can be used to
	determine if error messages were logged during innodb code execution.
	@return true if there were error messages, false otherwise. */
	static bool was_logged() { return logged; }

private:
	/** true if error::~error() was invoked, false otherwise */
	static bool logged;
};

/** The class fatal is used to emit an error message and stop the server
by crashing it.  Use this class when MySQL server needs to be stopped
immediately.  Refer to the documentation of class info for usage details. */
class fatal : public logger {
public:
	ATTRIBUTE_NORETURN
	~fatal();
};

/** Emit an error message if the given predicate is true, otherwise emit a
warning message */
class error_or_warn : public logger {
public:
	ATTRIBUTE_COLD
	error_or_warn(bool	pred)
	: m_error(pred)
	{}

	ATTRIBUTE_COLD
	~error_or_warn();
private:
	const bool	m_error;
};

/** Emit a fatal message if the given predicate is true, otherwise emit a
error message. */
class fatal_or_error : public logger {
public:
	ATTRIBUTE_COLD
	fatal_or_error(bool	pred)
	: m_fatal(pred)
	{}

	ATTRIBUTE_COLD
	~fatal_or_error();
private:
	const bool	m_fatal;
};

} // namespace ib

#endif