/*****************************************************************************

Copyright (c) 1995, 2009, Innobase Oy. All Rights Reserved.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 
51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

*****************************************************************************/

/******************************************************************//**
@file include/mach0data.ic
Utilities for converting data from the database file
to the machine format.

Created 11/28/1995 Heikki Tuuri
***********************************************************************/

#include "ut0mem.h"

/*******************************************************//**
The following function is used to store data in one byte. */
UNIV_INLINE
void
mach_write_to_1(
/*============*/
	byte*	b,	/*!< in: pointer to byte where to store */
	ulint	n)	/*!< in: ulint integer to be stored, >= 0, < 256 */
{
	ut_ad(b);
	ut_ad((n | 0xFFUL) <= 0xFFUL);

	b[0] = (byte)n;
}

/********************************************************//**
The following function is used to fetch data from one byte.
@return	ulint integer, >= 0, < 256 */
UNIV_INLINE
ulint
mach_read_from_1(
/*=============*/
	const byte*	b)	/*!< in: pointer to byte */
{
	return((ulint)(b[0]));
}

/*******************************************************//**
The following function is used to store data in two consecutive
bytes. We store the most significant byte to the lowest address. */
UNIV_INLINE
void
mach_write_to_2(
/*============*/
	byte*	b,	/*!< in: pointer to two bytes where to store */
	ulint	n)	/*!< in: ulint integer to be stored */
{
	ut_ad(b);
	ut_ad((n | 0xFFFFUL) <= 0xFFFFUL);

	b[0] = (byte)(n >> 8);
	b[1] = (byte)(n);
}

/********************************************************//**
The following function is used to fetch data from 2 consecutive
bytes. The most significant byte is at the lowest address.
@return	ulint integer */
UNIV_INLINE
ulint
mach_read_from_2(
/*=============*/
	const byte*	b)	/*!< in: pointer to 2 bytes */
{
	return(((ulint)(b[0]) << 8) | (ulint)(b[1]));
}

/********************************************************//**
The following function is used to convert a 16-bit data item
to the canonical format, for fast bytewise equality test
against memory.
@return	16-bit integer in canonical format */
UNIV_INLINE
uint16
mach_encode_2(
/*==========*/
	ulint	n)	/*!< in: integer in machine-dependent format */
{
	uint16	ret;
	ut_ad(2 == sizeof ret);
	mach_write_to_2((byte*) &ret, n);
	return(ret);
}
/********************************************************//**
The following function is used to convert a 16-bit data item
from the canonical format, for fast bytewise equality test
against memory.
@return	integer in machine-dependent format */
UNIV_INLINE
ulint
mach_decode_2(
/*==========*/
	uint16	n)	/*!< in: 16-bit integer in canonical format */
{
	ut_ad(2 == sizeof n);
	return(mach_read_from_2((const byte*) &n));
}

/*******************************************************//**
The following function is used to store data in 3 consecutive
bytes. We store the most significant byte to the lowest address. */
UNIV_INLINE
void
mach_write_to_3(
/*============*/
	byte*	b,	/*!< in: pointer to 3 bytes where to store */
	ulint	n)	/*!< in: ulint integer to be stored */
{
	ut_ad(b);
	ut_ad((n | 0xFFFFFFUL) <= 0xFFFFFFUL);

	b[0] = (byte)(n >> 16);
	b[1] = (byte)(n >> 8);
	b[2] = (byte)(n);
}

/********************************************************//**
The following function is used to fetch data from 3 consecutive
bytes. The most significant byte is at the lowest address.
@return	ulint integer */
UNIV_INLINE
ulint
mach_read_from_3(
/*=============*/
	const byte*	b)	/*!< in: pointer to 3 bytes */
{
	return( ((ulint)(b[0]) << 16)
		| ((ulint)(b[1]) << 8)
		| (ulint)(b[2])
		);
}

/*******************************************************//**
The following function is used to store data in four consecutive
bytes. We store the most significant byte to the lowest address. */
UNIV_INLINE
void
mach_write_to_4(
/*============*/
	byte*	b,	/*!< in: pointer to four bytes where to store */
	ulint	n)	/*!< in: ulint integer to be stored */
{
	ut_ad(b);

	b[0] = (byte)(n >> 24);
	b[1] = (byte)(n >> 16);
	b[2] = (byte)(n >> 8);
	b[3] = (byte)n;
}

/********************************************************//**
The following function is used to fetch data from 4 consecutive
bytes. The most significant byte is at the lowest address.
@return	ulint integer */
UNIV_INLINE
ulint
mach_read_from_4(
/*=============*/
	const byte*	b)	/*!< in: pointer to four bytes */
{
	return( ((ulint)(b[0]) << 24)
		| ((ulint)(b[1]) << 16)
		| ((ulint)(b[2]) << 8)
		| (ulint)(b[3])
		);
}

/*********************************************************//**
Writes a ulint in a compressed form where the first byte codes the
length of the stored ulint. We look at the most significant bits of
the byte. If the most significant bit is zero, it means 1-byte storage,
else if the 2nd bit is 0, it means 2-byte storage, else if 3rd is 0,
it means 3-byte storage, else if 4th is 0, it means 4-byte storage,
else the storage is 5-byte.
@return	compressed size in bytes */
UNIV_INLINE
ulint
mach_write_compressed(
/*==================*/
	byte*	b,	/*!< in: pointer to memory where to store */
	ulint	n)	/*!< in: ulint integer (< 2^32) to be stored */
{
	ut_ad(b);

	if (n < 0x80UL) {
		mach_write_to_1(b, n);
		return(1);
	} else if (n < 0x4000UL) {
		mach_write_to_2(b, n | 0x8000UL);
		return(2);
	} else if (n < 0x200000UL) {
		mach_write_to_3(b, n | 0xC00000UL);
		return(3);
	} else if (n < 0x10000000UL) {
		mach_write_to_4(b, n | 0xE0000000UL);
		return(4);
	} else {
		mach_write_to_1(b, 0xF0UL);
		mach_write_to_4(b + 1, n);
		return(5);
	}
}

/*********************************************************//**
Returns the size of a ulint when written in the compressed form.
@return	compressed size in bytes */
UNIV_INLINE
ulint
mach_get_compressed_size(
/*=====================*/
	ulint	n)	/*!< in: ulint integer (< 2^32) to be stored */
{
	if (n < 0x80UL) {
		return(1);
	} else if (n < 0x4000UL) {
		return(2);
	} else if (n < 0x200000UL) {
		return(3);
	} else if (n < 0x10000000UL) {
		return(4);
	} else {
		return(5);
	}
}

/*********************************************************//**
Reads a ulint in a compressed form.
@return	read integer (< 2^32) */
UNIV_INLINE
ulint
mach_read_compressed(
/*=================*/
	const byte*	b)	/*!< in: pointer to memory from where to read */
{
	ulint	flag;

	flag = mach_read_from_1(b);

	if (flag < 0x80UL) {
		return(flag);
	} else if (flag < 0xC0UL) {
		return(mach_read_from_2(b) & 0x7FFFUL);
	} else if (flag < 0xE0UL) {
		return(mach_read_from_3(b) & 0x3FFFFFUL);
	} else if (flag < 0xF0UL) {
		return(mach_read_from_4(b) & 0x1FFFFFFFUL);
	} else {
		ut_ad(flag == 0xF0UL);
		return(mach_read_from_4(b + 1));
	}
}

/*******************************************************//**
The following function is used to store data in 8 consecutive
bytes. We store the most significant byte to the lowest address. */
UNIV_INLINE
void
mach_write_to_8(
/*============*/
	byte*		b,	/*!< in: pointer to 8 bytes where to store */
	ib_uint64_t	n)	/*!< in: 64-bit integer to be stored */
{
	ut_ad(b);

	mach_write_to_4(b, (ulint) (n >> 32));
	mach_write_to_4(b + 4, (ulint) n);
}

/********************************************************//**
The following function is used to fetch data from 8 consecutive
bytes. The most significant byte is at the lowest address.
@return	64-bit integer */
UNIV_INLINE
ib_uint64_t
mach_read_from_8(
/*=============*/
	const byte*	b)	/*!< in: pointer to 8 bytes */
{
	ib_uint64_t	ull;

	ull = ((ib_uint64_t) mach_read_from_4(b)) << 32;
	ull |= (ib_uint64_t) mach_read_from_4(b + 4);

	return(ull);
}

/*******************************************************//**
The following function is used to store data in 7 consecutive
bytes. We store the most significant byte to the lowest address. */
UNIV_INLINE
void
mach_write_to_7(
/*============*/
	byte*		b,	/*!< in: pointer to 7 bytes where to store */
	ib_uint64_t	n)	/*!< in: 56-bit integer */
{
	ut_ad(b);

	mach_write_to_3(b, (ulint) (n >> 32));
	mach_write_to_4(b + 3, (ulint) n);
}

/********************************************************//**
The following function is used to fetch data from 7 consecutive
bytes. The most significant byte is at the lowest address.
@return	56-bit integer */
UNIV_INLINE
ib_uint64_t
mach_read_from_7(
/*=============*/
	const byte*	b)	/*!< in: pointer to 7 bytes */
{
	return(ut_ull_create(mach_read_from_3(b), mach_read_from_4(b + 3)));
}

/*******************************************************//**
The following function is used to store data in 6 consecutive
bytes. We store the most significant byte to the lowest address. */
UNIV_INLINE
void
mach_write_to_6(
/*============*/
	byte*		b,	/*!< in: pointer to 6 bytes where to store */
	ib_uint64_t	n)	/*!< in: 48-bit integer */
{
	ut_ad(b);

	mach_write_to_2(b, (ulint) (n >> 32));
	mach_write_to_4(b + 2, (ulint) n);
}

/********************************************************//**
The following function is used to fetch data from 6 consecutive
bytes. The most significant byte is at the lowest address.
@return	48-bit integer */
UNIV_INLINE
ib_uint64_t
mach_read_from_6(
/*=============*/
	const byte*	b)	/*!< in: pointer to 6 bytes */
{
	return(ut_ull_create(mach_read_from_2(b), mach_read_from_4(b + 2)));
}

/*********************************************************//**
Writes a 64-bit integer in a compressed form (5..9 bytes).
@return	size in bytes */
UNIV_INLINE
ulint
mach_ull_write_compressed(
/*======================*/
	byte*		b,	/*!< in: pointer to memory where to store */
	ib_uint64_t	n)	/*!< in: 64-bit integer to be stored */
{
	ulint	size;

	ut_ad(b);

	size = mach_write_compressed(b, (ulint) (n >> 32));
	mach_write_to_4(b + size, (ulint) n);

	return(size + 4);
}

/*********************************************************//**
Returns the size of a 64-bit integer when written in the compressed form.
@return	compressed size in bytes */
UNIV_INLINE
ulint
mach_ull_get_compressed_size(
/*=========================*/
	ib_uint64_t	n)	/*!< in: 64-bit integer to be stored */
{
	return(4 + mach_get_compressed_size((ulint) (n >> 32)));
}

/*********************************************************//**
Reads a 64-bit integer in a compressed form.
@return	the value read */
UNIV_INLINE
ib_uint64_t
mach_ull_read_compressed(
/*=====================*/
	const byte*	b)	/*!< in: pointer to memory from where to read */
{
	ib_uint64_t	n;
	ulint		size;

	n = (ib_uint64_t) mach_read_compressed(b);

	size = mach_get_compressed_size((ulint) n);

	n <<= 32;
	n |= (ib_uint64_t) mach_read_from_4(b + size);

	return(n);
}

/*********************************************************//**
Writes a 64-bit integer in a compressed form (1..11 bytes).
@return	size in bytes */
UNIV_INLINE
ulint
mach_ull_write_much_compressed(
/*===========================*/
	byte*		b,	/*!< in: pointer to memory where to store */
	ib_uint64_t	n)	/*!< in: 64-bit integer to be stored */
{
	ulint	size;

	ut_ad(b);

	if (!(n >> 32)) {
		return(mach_write_compressed(b, (ulint) n));
	}

	*b = (byte)0xFF;
	size = 1 + mach_write_compressed(b + 1, (ulint) (n >> 32));

	size += mach_write_compressed(b + size, (ulint) n & 0xFFFFFFFF);

	return(size);
}

/*********************************************************//**
Returns the size of a 64-bit integer when written in the compressed form.
@return	compressed size in bytes */
UNIV_INLINE
ulint
mach_ull_get_much_compressed_size(
/*==============================*/
	ib_uint64_t	n)	/*!< in: 64-bit integer to be stored */
{
	if (!(n >> 32)) {
		return(mach_get_compressed_size((ulint) n));
	}

	return(1 + mach_get_compressed_size((ulint) (n >> 32))
	       + mach_get_compressed_size((ulint) n & ULINT32_MASK));
}

/*********************************************************//**
Reads a 64-bit integer in a compressed form.
@return	the value read */
UNIV_INLINE
ib_uint64_t
mach_ull_read_much_compressed(
/*==========================*/
	const byte*	b)	/*!< in: pointer to memory from where to read */
{
	ib_uint64_t	n;
	ulint		size;

	if (*b != (byte)0xFF) {
		n = 0;
		size = 0;
	} else {
		n = (ib_uint64_t) mach_read_compressed(b + 1);

		size = 1 + mach_get_compressed_size((ulint) n);
		n <<= 32;
	}

	n |= mach_read_compressed(b + size);

	return(n);
}

/*********************************************************//**
Reads a 64-bit integer in a compressed form
if the log record fully contains it.
@return pointer to end of the stored field, NULL if not complete */
UNIV_INLINE
byte*
mach_ull_parse_compressed(
/*======================*/
	byte*		ptr,	/* in: pointer to buffer from where to read */
	byte*		end_ptr,/* in: pointer to end of the buffer */
	ib_uint64_t*	val)	/* out: read value */
{
	ulint		size;

	ut_ad(ptr);
	ut_ad(end_ptr);
	ut_ad(val);

	if (end_ptr < ptr + 5) {

		return(NULL);
	}

	*val = mach_read_compressed(ptr);

	size = mach_get_compressed_size((ulint) *val);

	ptr += size;

	if (end_ptr < ptr + 4) {

		return(NULL);
	}

	*val <<= 32;
	*val |= mach_read_from_4(ptr);

	return(ptr + 4);
}
#ifndef UNIV_HOTBACKUP
/*********************************************************//**
Reads a double. It is stored in a little-endian format.
@return	double read */
UNIV_INLINE
double
mach_double_read(
/*=============*/
	const byte*	b)	/*!< in: pointer to memory from where to read */
{
	double	d;
	ulint	i;
	byte*	ptr;

	ptr = (byte*)&d;

	for (i = 0; i < sizeof(double); i++) {
#ifdef WORDS_BIGENDIAN
		ptr[sizeof(double) - i - 1] = b[i];
#else
		ptr[i] = b[i];
#endif
	}

	return(d);
}

/*********************************************************//**
Writes a double. It is stored in a little-endian format. */
UNIV_INLINE
void
mach_double_write(
/*==============*/
	byte*	b,	/*!< in: pointer to memory where to write */
	double	d)	/*!< in: double */
{
	ulint	i;
	byte*	ptr;

	ptr = (byte*)&d;

	for (i = 0; i < sizeof(double); i++) {
#ifdef WORDS_BIGENDIAN
		b[i] = ptr[sizeof(double) - i - 1];
#else
		b[i] = ptr[i];
#endif
	}
}

/*********************************************************//**
Reads a float. It is stored in a little-endian format.
@return	float read */
UNIV_INLINE
float
mach_float_read(
/*============*/
	const byte*	b)	/*!< in: pointer to memory from where to read */
{
	float	d;
	ulint	i;
	byte*	ptr;

	ptr = (byte*)&d;

	for (i = 0; i < sizeof(float); i++) {
#ifdef WORDS_BIGENDIAN
		ptr[sizeof(float) - i - 1] = b[i];
#else
		ptr[i] = b[i];
#endif
	}

	return(d);
}

/*********************************************************//**
Writes a float. It is stored in a little-endian format. */
UNIV_INLINE
void
mach_float_write(
/*=============*/
	byte*	b,	/*!< in: pointer to memory where to write */
	float	d)	/*!< in: float */
{
	ulint	i;
	byte*	ptr;

	ptr = (byte*)&d;

	for (i = 0; i < sizeof(float); i++) {
#ifdef WORDS_BIGENDIAN
		b[i] = ptr[sizeof(float) - i - 1];
#else
		b[i] = ptr[i];
#endif
	}
}

/*********************************************************//**
Reads a ulint stored in the little-endian format.
@return	unsigned long int */
UNIV_INLINE
ulint
mach_read_from_n_little_endian(
/*===========================*/
	const byte*	buf,		/*!< in: from where to read */
	ulint		buf_size)	/*!< in: from how many bytes to read */
{
	ulint	n	= 0;
	const byte*	ptr;

	ut_ad(buf_size <= sizeof(ulint));
	ut_ad(buf_size > 0);

	ptr = buf + buf_size;

	for (;;) {
		ptr--;

		n = n << 8;

		n += (ulint)(*ptr);

		if (ptr == buf) {
			break;
		}
	}

	return(n);
}

/*********************************************************//**
Writes a ulint in the little-endian format. */
UNIV_INLINE
void
mach_write_to_n_little_endian(
/*==========================*/
	byte*	dest,		/*!< in: where to write */
	ulint	dest_size,	/*!< in: into how many bytes to write */
	ulint	n)		/*!< in: unsigned long int to write */
{
	byte*	end;

	ut_ad(dest_size <= sizeof(ulint));
	ut_ad(dest_size > 0);

	end = dest + dest_size;

	for (;;) {
		*dest = (byte)(n & 0xFF);

		n = n >> 8;

		dest++;

		if (dest == end) {
			break;
		}
	}

	ut_ad(n == 0);
}

/*********************************************************//**
Reads a ulint stored in the little-endian format.
@return	unsigned long int */
UNIV_INLINE
ulint
mach_read_from_2_little_endian(
/*===========================*/
	const byte*	buf)		/*!< in: from where to read */
{
	return((ulint)(buf[0]) | ((ulint)(buf[1]) << 8));
}

/*********************************************************//**
Writes a ulint in the little-endian format. */
UNIV_INLINE
void
mach_write_to_2_little_endian(
/*==========================*/
	byte*	dest,		/*!< in: where to write */
	ulint	n)		/*!< in: unsigned long int to write */
{
	ut_ad(n < 256 * 256);

	*dest = (byte)(n & 0xFFUL);

	n = n >> 8;
	dest++;

	*dest = (byte)(n & 0xFFUL);
}

/*********************************************************//**
Convert integral type from storage byte order (big endian) to
host byte order.
@return	integer value */
UNIV_INLINE
ullint
mach_read_int_type(
/*===============*/
	const byte*	src,		/*!< in: where to read from */
	ulint		len,		/*!< in: length of src */
	ibool		unsigned_type)	/*!< in: signed or unsigned flag */
{
	/* XXX this can be optimized on big-endian machines */

	ullint	ret;
	uint	i;

	if (unsigned_type || (src[0] & 0x80)) {

		ret = 0x0000000000000000ULL;
	} else {

		ret = 0xFFFFFFFFFFFFFF00ULL;
	}

	if (unsigned_type) {

		ret |= src[0];
	} else {

		ret |= src[0] ^ 0x80;
	}

	for (i = 1; i < len; i++) {
		ret <<= 8;
		ret |= src[i];
	}

	return(ret);
}
#endif /* !UNIV_HOTBACKUP */