/***
*tolower.c - convert character to lower case
*
*	Copyright (c) 1985-1991, Microsoft Corporation. All rights reserved.
*
*Purpose:
*	Defines function versions of _tolower() and tolower().
*
*Revision History:
*	11-09-84  DFW	created
*	12-11-87  JCR	Added "_LOAD_DS" to declaration
*	02-23-89  GJF	Added function version of _tolower and cleaned up.
*	03-26-89  GJF	Migrated to 386 tree
*	03-06-90  GJF	Fixed calling type, added #include <cruntime.h> and
*			fixed copyright.
*	09-27-90  GJF	New-style function declarators.
*	10-11-91  ETC	Locale support for tolower under _INTL switch.
*	12-10-91  ETC	Updated nlsapi; added multithread.
*	12-17-92  KRS	Updated and optimized for latest NLSAPI.  Bug-fixes.
*       01-19-93  CFW   Fixed typo.
*       03-25-93  CFW   _tolower now defined when _INTL.
*       06-02-93  SRW   ignore _INTL if _NTSUBSET_ defined.
*	09-15-93  CFW	Change buffer to unsigned char to fix nasty cast bug.
*
*******************************************************************************/

#include <cruntime.h>
#include <ctype.h>
#include <stddef.h>
#ifdef _INTL
#include <locale.h>
#include <setlocal.h>
#include <os2dll.h>
#endif

/* remove macro defintions of _tolower() and tolower()
 */
#undef	_tolower
#undef	tolower

/* define function-like macro equivalent to _tolower()
 */
#define mklower(c)	( (c)-'A'+'a' )

/***
*int _tolower(c) - convert character to lower case
*
*Purpose:
*	_tolower() is simply a function version of the macro of the same name.
*
*Entry:
*	c - int value of character to be converted
*
*Exit:
*	returns int value of lower case representation of c
*
*Exceptions:
*
*******************************************************************************/

int _CALLTYPE1 _tolower (
	int c
	)
{
	return(mklower(c));
}

/***
*int tolower(c) - convert character to lower case
*
*Purpose:
*	tolower() is simply a function version of the macro of the same name.
*
*Entry:
*	c - int value of character to be converted
*
*Exit:
*	if c is an upper case letter, returns int value of lower case
*	representation of c. otherwise, it returns c.
*
*Exceptions:
*
*******************************************************************************/


int _CALLTYPE1 tolower (
	int c
	)
{
#if defined(_INTL) && !defined(_NTSUBSET_)
	wchar_t widechar1[2], widechar2[2];
	int size;
	unsigned char buffer[3];

	_mlock (_LC_CTYPE_LOCK);

	if ((_lc_handle[LC_CTYPE] == _CLOCALEHANDLE) &&
		(_lc_codepage == _CLOCALECP)) {
		if (isupper(c))
			c = c + ('a' - 'A');
		_munlock (_LC_CTYPE_LOCK);
		return c;
	}

	/* if checking case of c does not require API call, do it */
	if (c < 256) {
		if (!isupper(c)) {
			_munlock (_LC_CTYPE_LOCK);
			return c;
		}
	}
			
	/* convert c to wide char */
	if (isleadbyte(c>>8 & 0xff))
		{
		buffer[0] = (c>>8 & 0xff); /* put lead-byte at start of str */
		buffer[1] = (unsigned char)c;
		buffer[2] = 0;
		}
	else
		{
		buffer[0] = (unsigned char)c;
		buffer[1] = 0;
		}
	if (!(size=MultiByteToWideChar(_lc_codepage,MB_PRECOMPOSED,
		 buffer, -1, widechar1, 2))) {
			_munlock (_LC_CTYPE_LOCK);
			return c;
	}

	/* convert wide char to uppercase */
	if (!(size=LCMapStringW(_lc_handle[LC_CTYPE], LCMAP_LOWERCASE, 
		widechar1, size, widechar2, 2))) {
			_munlock (_LC_CTYPE_LOCK);
			return c;
	}
	
	/* convert wide char back to multibyte */
	if (!(size=WideCharToMultiByte(_lc_codepage,(WC_COMPOSITECHECK|WC_DISCARDNS),
		widechar2, size, buffer, 2, NULL, NULL))) {
			_munlock (_LC_CTYPE_LOCK);
			return c;
	}
	
	_munlock (_LC_CTYPE_LOCK);

	/* construct integer return value */
	if (size == 1)
		return ((int)buffer[0]);
	else
		return ((int)buffer[0] | ((int)buffer[1] << 8));
#else
	return(isupper(c) ? mklower(c) : c);
#endif /* _INTL */
}