mariadb/innobase/include/row0mysql.ic

/******************************************************
MySQL interface for Innobase

(C) 2001 Innobase Oy

Created 1/23/2001 Heikki Tuuri
*******************************************************/

/***********************************************************************
Stores a variable-length field (like VARCHAR) length to dest, in the
MySQL format. No real var implemented in MySQL yet! */
UNIV_INLINE
byte*
row_mysql_store_var_len(
/*====================*/
			/* out: dest + 2 */
	byte*	dest,	/* in: where to store */
	ulint	len __attribute__((unused)))  /* in: length, must fit in two
                                                 bytes */
{
	ut_ad(len < 256 * 256);
/*	
	mach_write_to_2_little_endian(dest, len);

	return(dest + 2);
*/
	return(dest);	/* No real var implemented in MySQL yet! */
}

/***********************************************************************
Reads a MySQL format variable-length field (like VARCHAR) length and
returns pointer to the field data. No real var implemented in MySQL yet! */
UNIV_INLINE
byte*
row_mysql_read_var_ref(
/*===================*/
			/* out: field + 2 */
	ulint*	len,	/* out: variable-length field length; does not work
			yet! */
	byte*	field)	/* in: field */
{
/*	
	*len = mach_read_from_2_little_endian(field);

	return(field + 2);
*/
	UT_NOT_USED(len);

	return(field);	/* No real var implemented in MySQL yet! */
}

/******************************************************************
Stores a non-SQL-NULL field given in the MySQL format in the Innobase
format. */
UNIV_INLINE
void
row_mysql_store_col_in_innobase_format(
/*===================================*/
	dfield_t*	dfield,		/* in/out: dfield */
	byte*		buf,		/* in/out: buffer for the converted
					value; this must be at least col_len
					long! */
	byte*		mysql_data,	/* in: MySQL column value, not
					SQL NULL; NOTE that dfield may also
					get a pointer to mysql_data,
					therefore do not discard this as long
					as dfield is used! */
	ulint		col_len,	/* in: MySQL column length */
	ulint		type,		/* in: data type */
	bool		comp,		/* in: TRUE=compact format */
	ulint		is_unsigned)	/* in: != 0 if unsigned integer type */
{
	byte*	ptr 	= mysql_data;

	if (type == DATA_INT) {
		/* Store integer data in Innobase in a big-endian format,
		sign bit negated */

		ptr = buf + col_len;

		for (;;) {
			ptr--;
			*ptr = *mysql_data;
			if (ptr == buf) {
				break;
			}
			mysql_data++;
		}

		if (!is_unsigned) {
			*ptr = (byte) (*ptr ^ 128);
		}
	} else if (type == DATA_VARCHAR || type == DATA_VARMYSQL
						|| type == DATA_BINARY) {
		/* Remove trailing spaces. */

		/* Handle UCS2 strings differently. */
		ulint	mbminlen	= dtype_get_mbminlen(
						dfield_get_type(dfield));
		ptr = row_mysql_read_var_ref(&col_len, mysql_data);
		if (mbminlen == 2) {
			/* space=0x0020 */
			/* Trim "half-chars", just in case. */
			col_len &= ~1;

			while (col_len >= 2 && ptr[col_len - 2] == 0x00
					&& ptr[col_len - 1] == 0x20) {
				col_len -= 2;
			}
		} else {
			ut_a(mbminlen == 1);
			/* space=0x20 */
			while (col_len > 0 && ptr[col_len - 1] == 0x20) {
				col_len--;
			}
		}
	} else if (comp && type == DATA_MYSQL
			&& dtype_get_mbminlen(dfield_get_type(dfield)) == 1
			&& dtype_get_mbmaxlen(dfield_get_type(dfield)) > 1) {
		/* We assume that this CHAR field is encoded in a
		variable-length character set where spaces have
		1:1 correspondence to 0x20 bytes, such as UTF-8.

		Consider a CHAR(n) field, a field of n characters.
		It will contain between n*mbminlen and n*mbmaxlen bytes.
		We will try to truncate it to n bytes by stripping
		space padding.  If the field contains single-byte
		characters only, it will be truncated to n characters.
		Consider a CHAR(5) field containing the string ".a   "
		where "." denotes a 3-byte character represented by
		the bytes "$%&".  After our stripping, the string will
		be stored as "$%&a " (5 bytes).  The string ".abc "
		will be stored as "$%&abc" (6 bytes).

		The space padding will be restored in row0sel.c, function
		row_sel_field_store_in_mysql_format(). */

		ulint		n_chars;
		dtype_t*	dtype = dfield_get_type(dfield);

		ut_a(!(dtype_get_len(dtype) % dtype_get_mbmaxlen(dtype)));
		n_chars = dtype_get_len(dtype) / dtype_get_mbmaxlen(dtype);

		/* Strip space padding. */
		while (col_len > n_chars && ptr[col_len - 1] == 0x20) {
			col_len--;
		}
	} else if (type == DATA_BLOB) {
		ptr = row_mysql_read_blob_ref(&col_len, mysql_data, col_len);
	}

	dfield_set_data(dfield, ptr, col_len);
}