dosnames.c

DOS操作系统的C语言源代码 强烈推荐！！！ 可以用来学习基于字符界面的操作系统的设计

/****************************************************************/
/*								*/
/*			   dosnames.c				*/
/*			     DOS-C				*/
/*								*/
/*    Generic parsing functions for file name specifications	*/
/*								*/
/*			Copyright (c) 1994			*/
/*			Pasquale J. Villani			*/
/*			All Rights Reserved			*/
/*								*/
/* This file is part of DOS-C.					*/
/*								*/
/* DOS-C 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; either version	*/
/* 2, or (at your option) any later version.			*/
/*								*/
/* DOS-C 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 DOS-C; see the file COPYING.  If not,	*/
/* write to the Free Software Foundation, 675 Mass Ave,		*/
/* Cambridge, MA 02139, USA.					*/
/*								*/
/****************************************************************/

#include "../../hdr/portab.h"

/* $Logfile:   C:/dos-c/src/fs/dosnames.c_v  $ */
#ifdef VERSION_STRINGS
static BYTE *dosnamesRcsId = "$Header:   C:/dos-c/src/fs/dosnames.c_v   1.8   22 Jan 1998  4:09:00   patv  $";
#endif

/* $Log:   C:/dos-c/src/fs/dosnames.c_v  $
 * 
 *    Rev 1.8   22 Jan 1998  4:09:00   patv
 * Fixed pointer problems affecting SDA
 * 
 *    Rev 1.7   04 Jan 1998 23:14:38   patv
 * Changed Log for strip utility
 * 
 *    Rev 1.6   03 Jan 1998  8:36:04   patv
 * Converted data area to SDA format
 * 
 *    Rev 1.5   16 Jan 1997 12:46:36   patv
 * pre-Release 0.92 feature additions
 * 
 *    Rev 1.4   29 May 1996 21:15:12   patv
 * bug fixes for v0.91a
 * 
 *    Rev 1.3   19 Feb 1996  3:20:08   patv
 * Added NLS, int2f and config.sys processing
 * 
 *    Rev 1.2   01 Sep 1995 17:48:44   patv
 * First GPL release.
 * 
 *    Rev 1.1   30 Jul 1995 20:50:26   patv
 * Eliminated version strings in ipl
 * 
 *    Rev 1.0   02 Jul 1995  8:05:56   patv
 * Initial revision.
 *
 */ 
/* $EndLog$ */

#include "globals.h"

#define PathSep(c) ((c)=='/'||(c)=='\\')
#define DriveChar(c) (((c)>='A'&&(c)<='Z')||((c)>='a'&&(c)<='z'))

static BOOL bFileChar(UCOUNT uChar);
VOID XlateLcase (BYTE *szFname, COUNT nChars);
VOID DosTrimPath (BYTE FAR *lpszPathNamep);


static BOOL bFileChar(UCOUNT uChar)
{
	BYTE *pszValChar = ".\"/\\[]:|<>+=;,", *pszPtr;

	/* Null is not a valid character				*/
	if(NULL == uChar)
		return FALSE;

	/* Loop through invalid character set				*/
	for (pszPtr = pszValChar; *pszPtr != NULL; pszPtr++)
		if(uChar == *pszPtr)
			return FALSE;

	/* Not in excluded set, it's ok.				*/
	return TRUE;
}


/* Should be converted to a portable version after v1.0 is released.	*/
VOID
XlateLcase (BYTE *szFname, COUNT nChars)
{
	while(nChars--)
	{
		if(*szFname >= 'a' && *szFname <= 'z')
			*szFname -= ('a' - 'A');
		++szFname;
	}
}


VOID
SpacePad(BYTE *szString, COUNT nChars)
{
	REG COUNT i;

	for(i = strlen(szString); i < nChars; i++)
		szString[i] = ' ';
}


COUNT
ParseDosName(BYTE FAR *lpszFileName,
	     COUNT *pnDrive,
	     BYTE *pszDir,
	     BYTE *pszFile,
	     BYTE *pszExt)
{
	COUNT nDirCnt, nFileCnt, nExtCnt;
	BYTE FAR *lpszLclDir, FAR *lpszLclFile, FAR *lpszLclExt;


	/* Initialize the users data fields				*/
	if(pszDir)
		*pszDir = '\0';
	if(pszFile)
		*pszFile = '\0';
	if(pszExt)
		*pszExt = '\0';
	lpszLclFile = lpszLclExt = lpszLclDir = 0;
	nDirCnt = nFileCnt = nExtCnt = 0;

	/* Start by cheking for a drive specifier ...			*/
	if(DriveChar(*lpszFileName) && ':' == lpszFileName[1])
	{
		/* found a drive, fetch it and bump pointer past drive	*/
		/* NB: this code assumes ASCII				*/
		if(pnDrive)
		{
			*pnDrive = *lpszFileName - 'A';
			if(*pnDrive > 26)
				*pnDrive -= ('a' - 'A');
		}
		lpszFileName += 2;
	}
	else
	{
		if(pnDrive)
		{
			*pnDrive = -1;
		}
	}
	if(!pszDir && !pszFile && !pszExt)
		return SUCCESS;

	/* Now see how long a directory component we have.  We've	*/
	/* initialized the count before and moved the passed in pointer	*/
	/* past the optional drive component.  Now, we initialize the	*/
	/* directory count variable to a one if and only if we see a	*/
	/* leading root drive specifier because we can't be certain	*/
	/* that what follows is a directory until we see at least a	*/
	/* single path seperator.  So we count to the end and work	*/
	/* backwards to the last seperator subtracting one for each	*/
	/* character until we see one (seperator).			*/
	lpszLclDir = lpszFileName;
	while(bFileChar(*lpszFileName)
	   || PathSep(*lpszFileName)
	   || '.' == *lpszFileName)
	{
		++nDirCnt;
		++lpszFileName;
	}
	if(nDirCnt > 1)
	{
		while(lpszFileName >lpszLclDir)
		{
			BYTE cChar = *--lpszFileName;

			if(PathSep(cChar))
				break;
			--nDirCnt;
		}
		/* Once we've moved the pointer back, we want to bump	*/
		/* it past the seperator.				*/
		if(PathSep(*lpszFileName))
			++lpszFileName;
	}

	/* Parse out the file name portion.				*/
	lpszLclFile = lpszFileName;
	while(bFileChar(*lpszFileName) && '.' != *lpszFileName)
	{
		++nFileCnt;
		++lpszFileName;
	}

	/* Now we have pointers set to the directory portion and the	*/
	/* file portion.  Now determine the existance of an extension.	*/
	lpszLclExt = lpszFileName;
	if('.' == *lpszFileName)
	{
		lpszLclExt = ++lpszFileName;
		while(bFileChar(*lpszFileName))
		{
			++nExtCnt;
			++lpszFileName;
		}
	}

	/* Fix lengths to maximums allowed by MS-DOS.			*/
	if(nDirCnt > PARSE_MAX)
		nDirCnt = PARSE_MAX;
	if(nFileCnt > FNAME_SIZE)
		nFileCnt = FNAME_SIZE;
	if(nExtCnt > FEXT_SIZE)
		nExtCnt = FEXT_SIZE;

	/* Finally copy whatever the user wants extracted to the user's	*/
	/* buffers.							*/
	if(pszDir)
	{
		fbcopy(lpszLclDir, (BYTE FAR *)pszDir, nDirCnt);
		pszDir[nDirCnt] = '\0';
	}
	if(pszFile)
	{
		fbcopy(lpszLclFile, (BYTE FAR *)pszFile, nFileCnt);
		pszFile[nFileCnt] = '\0';
	}
	if(pszExt)
	{
		fbcopy(lpszLclExt, (BYTE FAR *)pszExt, nExtCnt);
		pszExt[nExtCnt] = '\0';
	}

	/* Clean up before leaving				*/
	if(pszDir)
		DosTrimPath(pszDir);

	return SUCCESS;
}


COUNT
ParseDosPath(BYTE FAR *lpszFileName,
	     COUNT *pnDrive,
	     BYTE *pszDir,
	     BYTE *pszCurPath)
{
	COUNT nDirCnt, nPathCnt;
	BYTE FAR *lpszLclDir, *pszBase = pszDir;


	/* Initialize the users data fields				*/
	*pszDir = '\0';
	lpszLclDir = 0;
	nDirCnt = nPathCnt = 0;

	/* Start by cheking for a drive specifier ...			*/
	if(DriveChar(*lpszFileName) && ':' == lpszFileName[1])
	{
		/* found a drive, fetch it and bump pointer past drive	*/
		/* NB: this code assumes ASCII				*/
		if(pnDrive)
		{
			*pnDrive = *lpszFileName - 'A';
			if(*pnDrive > 26)
				*pnDrive -= ('a' - 'A');
		}
		lpszFileName += 2;
	}
	else
	{
		if(pnDrive)
		{
			*pnDrive = -1;
		}
	}

	lpszLclDir = lpszFileName;
	if(!PathSep(*lpszLclDir))
	{
		strncpy(pszDir, pszCurPath, PARSE_MAX);
		nPathCnt = strlen(pszCurPath);
		if(!PathSep(pszDir[nPathCnt - 1]) && nPathCnt < PARSE_MAX)
			pszDir[nPathCnt++] = '\\';
		if(nPathCnt > PARSE_MAX)
			nPathCnt = PARSE_MAX;
		pszDir += nPathCnt;
	}

	/* Now see how long a directory component we have.  		*/
	while(bFileChar(*lpszFileName)
	   || PathSep(*lpszFileName)
	   || '.' == *lpszFileName)
	{
		++nDirCnt;
		++lpszFileName;
	}

	/* Fix lengths to maximums allowed by MS-DOS.			*/
	if((nDirCnt + nPathCnt)> PARSE_MAX)
		nDirCnt = PARSE_MAX - nPathCnt;

	/* Finally copy whatever the user wants extracted to the user's	*/
	/* buffers.							*/
	if(pszDir)
	{
		fbcopy(lpszLclDir, (BYTE FAR *)pszDir, nDirCnt);
		pszDir[nDirCnt] = '\0';
	}

	/* Clean up before leaving				*/
	DosTrimPath((BYTE FAR *)pszBase);

	/* Before returning to the user, eliminate any useless		*/
	/* trailing "\\." since the path prior to this is sufficient.	*/
	nPathCnt = strlen(pszBase);
	if(2 == nPathCnt)  		/* Special case, root		*/
	{
		if(!strcmp(pszBase, "\\."))
			pszBase[1] = '\0';
	}
	else if(2 < nPathCnt)
	{
		if(!strcmp(&pszBase[nPathCnt - 2], "\\."))
			pszBase[nPathCnt - 2] = '\0';
	}

	return SUCCESS;
}


BOOL
IsDevice (BYTE *pszFileName)
{
	REG struct dhdr FAR *dhp = (struct dhdr FAR *)&nul_dev;
	BYTE szName[FNAME_SIZE];

	/* break up the name first				*/
	ParseDosName((BYTE FAR *)pszFileName,
	 (COUNT *)0, TempBuffer, szName, (BYTE *)0);
	SpacePad(szName, FNAME_SIZE);

	/* Test 1 - does it start with a \dev or /dev		*/
	if((strcmp(szName, "/dev") == 0)
	 || (strcmp(szName, "\\dev") == 0))
		return TRUE;

	/* Test 2 - is it on the device chain?			*/
	for(; -1l != (LONG)dhp; dhp = dhp -> dh_next)
	{
		COUNT nIdx;

		/* Skip if not char device			*/
		if(!(dhp -> dh_attr & ATTR_CHAR))
			continue;

		/* now compare					*/
		for(nIdx = 0; nIdx < FNAME_SIZE; ++nIdx)
		{
			if(dhp -> dh_name[nIdx] != szName[nIdx])
				break;
		}
		if(nIdx >= FNAME_SIZE)
			return TRUE;
	}

	return FALSE;
}


VOID
DosTrimPath (BYTE FAR *lpszPathNamep)
{
	BYTE FAR *lpszLast, FAR *lpszNext, FAR *lpszRoot = (BYTE FAR *)0;
	COUNT nChars, flDotDot;

	/* First, convert all '/' to '\'.  Look for root as we scan	*/
	if(*lpszPathNamep == '\\')
		lpszRoot = lpszPathNamep;
	for(lpszNext = lpszPathNamep; *lpszNext; ++lpszNext)
	{
		if(*lpszNext == '/')
			*lpszNext = '\\';
		if(!lpszRoot &&
		 *lpszNext == ':' && *(lpszNext + 1) == '\\')
			lpszRoot = lpszNext + 1;
	}

	for(lpszLast = lpszNext = lpszPathNamep, nChars = 0;
	  *lpszNext != '\0' && nChars < NAMEMAX; )
	{
		/* Initialize flag for loop.				*/
		flDotDot = FALSE;

		/* If we are at a path seperator, check for extra path	*/
		/* seperator, '.' and '..' to reduce.			*/
		if(*lpszNext == '\\')
		{
			/* If it's '\', just move everything down one.	*/
			if(*(lpszNext + 1) == '\\')
				fstrncpy(lpszNext, lpszNext + 1, NAMEMAX);
			/* also check for '.' and '..' and move down	*/
			/* as appropriate.				*/
			else if(*(lpszNext + 1) == '.')
			{
				if(*(lpszNext + 2) == '.'
				 && !(*(lpszNext + 3)))
				{
					/* At the end, just truncate	*/
					/* and exit.			*/
					if(lpszLast == lpszRoot)
						*(lpszLast + 1) = '\0';
					else
						*lpszLast = '\0';
					return;
				}

				if(*(lpszNext + 2) == '.'
				 && *(lpszNext + 3) == '\\')
				{
					fstrncpy(lpszLast, lpszNext + 3, NAMEMAX);
					/* bump back to the last	*/
					/* seperator.			*/
					lpszNext = lpszLast;
					/* set lpszLast to the last one	*/
					if(lpszLast <= lpszPathNamep)
						continue;
					do
					{
						--lpszLast;
					}
					while(lpszLast != lpszPathNamep
					 && *lpszLast != '\\');
					flDotDot = TRUE;
				}
				/* Note: we skip strange stuff that	*/
				/* starts with '.'			*/
				else if(*(lpszNext + 2) == '\\')
				{
					fstrncpy(lpszNext, lpszNext + 2, NAMEMAX);
				}
				/* If we're at the end of a string,	*/
				/* just exit.				*/
				else if(*(lpszNext + 2) == NULL)
					return;
			}
			else
			{
				/* No '.' or '\' so mark it and bump	*/
				/* past					*/
				lpszLast = lpszNext++;
				continue;
			}

			/* Done.  Now set last to next to mark this	*/
			/* instance of path seperator.			*/
			if(!flDotDot)
				lpszLast = lpszNext;
		}
		else
			/* For all other cases, bump lpszNext for the	*/
			/* next check					*/
			++lpszNext;
	}
}