xtrim.cpp

把文字串頭去除空白或把文字串尾去除空白.

// XTrim.cpp  Version 1.0
//
// Author:  Hans Dietrich
//          [e-mail]
//
// Description:
//     XTrim.cpp implements _tcsltrim() and _tcsrtrim().
//
// History
//     Version 1.0 - 2003 May 21
//     - Initial public release 
//
// This software is released into the public domain.  You are free to use it 
// in any way you like.
//
// This software is provided "as is" with no expressed or implied warranty.  
// I accept no liability for any damage or loss of business that this software 
// may cause.
//
///////////////////////////////////////////////////////////////////////////////

#include <windows.h>
#include <tchar.h>
#include "XTrim.h"


///////////////////////////////////////////////////////////////////////////////
//
// _tcsltrim()
//
// Purpose:     Removes (trims) leading whitespace characters from a string
//
// Parameters:  pszSource - Pointer to the null-terminated string to be trimmed. 
//                          On return, pszSource will hold the trimmed string
//
// Returns:     TCHAR *   - pointer to trimmed string
//
TCHAR * _tcsltrim(TCHAR * pszSource)
{
	TCHAR * cp = pszSource;

	if (cp && *cp)
	{
		// find first non-whitespace character
		while (_istspace(*cp))
			cp++;

		if (cp != pszSource)
			memcpy(pszSource, cp, (_tcslen(cp)+1)*sizeof(TCHAR));
	}

	return pszSource;
}


///////////////////////////////////////////////////////////////////////////////
//
// _tcsrtrim()
//
// Purpose:     Removes (trims) trailing whitespace characters from a string
//
// Parameters:  pszSource - Pointer to the null-terminated string to be trimmed. 
//                          On return, pszSource will hold the trimmed string
//
// Returns:     TCHAR *   - pointer to trimmed string
//
TCHAR * _tcsrtrim(TCHAR * pszSource)
{
	TCHAR * cp = pszSource;

	if (cp && *cp)
	{
		BOOL bNonSpaceSeen = FALSE;

		// check if string is blank
		while (*cp)
		{
			if (!_istspace(*cp))
				bNonSpaceSeen = TRUE;
			cp++;
		}

		if (bNonSpaceSeen)
		{
			cp--;

			// find last non-whitespace character
			while ((cp >= pszSource) && (_istspace(*cp)))
				*cp-- = _T('\0');
		}
		else
		{
			// string contains only whitespace characters
			*pszSource = _T('\0');
		}
	}

	return pszSource;
}