Added more comments on the code and made some code polishing.

}

extern "C" {

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

This function finds charset information and returns the character

length for multibyte character set. */

ulint innobase_get_charset_mbmaxlen(

	ulint charset_id)	/* in: charset id */

{

  CHARSET_INFO*   charset;        /* charset used in the field */

  charset = get_charset(charset_id,MYF(MY_WME));

  ut_ad(charset);

  ut_ad(charset->mbmaxlen);

  return charset->mbmaxlen;

}

}

extern "C" {

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

This function finds charset information and returns position the nth 

character for multibyte character set.*/

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

This function is used to find storage length of prefix_len characters 

in bytes for prefix indexes using multibyte character set. 

Function finds charset information and returns length of

prefix_len characters in the index field in bytes. */

ulint innobase_get_at_most_n_mbchars(

/*=================================*/

	ulint charset_id,	/* in: character set id */

        ulint nth,		/* in: nth character    */

	ulint prefix_len,	/* in: prefix length of the index    */

	ulint data_len,         /* in: length of the sting in bytes */

	const char *pos)	/* in: character string */

{

	ut_ad(charset);

	ut_ad(charset->mbmaxlen);

	/* Calculate the storage length of the one character in bytes and

	how many characters the prefix index contains */

	char_length = byte_length / charset->mbmaxlen;

  nth = nth / charset->mbmaxlen;

	prefix_len = prefix_len / charset->mbmaxlen;

  if (byte_length > char_length)

  {

	char_length= my_charpos(charset, pos, pos + byte_length, nth);

	/* If length of the string is greater than storage length of the

	one character, we have to find the storage position of the 

	prefix_len character in the string */

	if (byte_length > char_length) {

		char_length = my_charpos(charset, pos, 

					 pos + byte_length, prefix_len);

		set_if_smaller(char_length, byte_length);

	} 

  else

    char_length = nth;

	else {

		char_length = prefix_len;

	}

	return char_length;

}