file.c

嵌入式文件系统 EFSL 0.3.5 / 嵌入式文件系统 EFSL 0.3.5

            if(fs_findFile(fs,filename,&loc,0))
			{
                return(-2);
			}
            if(fs_findFreeFile(fs,filename,&loc,0))
			{
                dir_createDefaultEntry(fs,&wtmp,fatfilename);
                dir_createDirectoryEntry(fs,&wtmp,&loc);
                memCpy(&wtmp,&(file->DirEntry),sizeof(wtmp));
				file_initFile(file,fs,&loc);
                sec=fs_getNextFreeCluster(file->fs,fs_giveFreeClusterHint(file->fs));
                dir_setFirstCluster(file->fs,&(file->Location),sec);
                fs_setFirstClusterInDirEntry(&(file->DirEntry),sec);
                fs_initClusterChain(fs,&(file->Cache),sec);
                fat_setNextClusterAddress(fs,sec,fat_giveEocMarker(fs));
				file_setAttr(file,FILE_STATUS_OPEN,1);
				file_setAttr(file,FILE_STATUS_WRITE,1);
            	return(0);
			}
            else
			{
                return(-3);
			}
            break;
        case MODE_APPEND:
			if(fs_findFile(fs,filename,&loc,0)==1) /* File exists */
			{
				dir_getFileStructure(fs,&(file->DirEntry), &loc);
				file_initFile(file,fs,&loc);
				if(file->Cache.FirstCluster==0){
					sec=fs_getNextFreeCluster(file->fs,fs_giveFreeClusterHint(file->fs));
					dir_setFirstCluster(file->fs,&(file->Location),sec);
					fs_setFirstClusterInDirEntry(&(file->DirEntry),sec);
					fat_setNextClusterAddress(fs,sec,fat_giveEocMarker(fs));
					file_initFile(file,fs,&loc);
				}
				file_setpos(file,file->FileSize);
				file_setAttr(file,FILE_STATUS_OPEN,1);
				file_setAttr(file,FILE_STATUS_WRITE,1);
			}
			else /* File does not excist */
			{
				if(fs_findFreeFile(fs,filename,&loc,0))
				{
					dir_createDefaultEntry(fs,&wtmp,fatfilename);
					dir_createDirectoryEntry(fs,&wtmp,&loc);
					memCpy(&wtmp,&(file->DirEntry),sizeof(wtmp));
					file_initFile(file,fs,&loc);
					sec=fs_getNextFreeCluster(file->fs,fs_giveFreeClusterHint(file->fs));
					dir_setFirstCluster(file->fs,&(file->Location),sec);
	                fs_setFirstClusterInDirEntry(&(file->DirEntry),sec);
    	            fs_initClusterChain(fs,&(file->Cache),sec);
					fat_setNextClusterAddress(fs,sec,fat_giveEocMarker(fs));
					file_setAttr(file,FILE_STATUS_OPEN,1);
					file_setAttr(file,FILE_STATUS_WRITE,1);
				}
				else
				{
					return(-3);
				}
			}
			return(0);
            break;
        default:
            return(-4);
            break;
    }
    return(-5);
}
/*****************************************************************************/

/* ****************************************************************************  
 * esint8 file_fclose(File *file)
 * Description: This function closes a file, by clearing the object.
 * Return value: 0 on success.
*/
esint8 file_fclose(File *file)
{
	if(fs_hasTimeSupport()){
		file->DirEntry.AccessDate = time_getDate();
		if(file_getAttr(file,FILE_STATUS_WRITE)){
			file->DirEntry.FileSize = file->FileSize;
			file->DirEntry.WriteDate = file->DirEntry.AccessDate;
			file->DirEntry.WriteTime = time_getTime();
		}
		dir_updateDirectoryEntry(file->fs,&(file->DirEntry),&(file->Location));
	}else{
		if(file_getAttr(file,FILE_STATUS_WRITE)){
			dir_setFileSize(file->fs,&(file->Location),file->FileSize);
		}
	}
	
	memClr(file,sizeof(*file));
	file_setAttr(file,FILE_STATUS_OPEN,0);
	file_setAttr(file,FILE_STATUS_WRITE,0);
	return(0);
}


/* ****************************************************************************  
 * void file_initFile(File *file, FileSystem *fs, FileLocation *loc)
 * Description: This function initialises a new file object, by filling in
 * the fs pointer, filesize (note, that DirEntry must already be filled in)
 * and known cache parameters.
 * Return value: void
*/
void file_initFile(File *file, FileSystem *fs, FileLocation *loc)
{
	file->fs=fs;
	file->FileSize=file->DirEntry.FileSize;
	file->FilePtr=0;
	file->Location.Sector=loc->Sector;
	file->Location.Offset=loc->Offset;
	file->Cache.Linear=0;
	file->Cache.FirstCluster=(((euint32)file->DirEntry.FirstClusterHigh)<<16)+ 
	                                    file->DirEntry.FirstClusterLow;
	file->Cache.LastCluster=0; 
	file->Cache.LogicCluster=0;
	file->Cache.DiscCluster=file->Cache.FirstCluster;
}
/*****************************************************************************/

/* ****************************************************************************  
 * euint8* file_normalToFatName(eint8* filename,eint8* fatfilename)
 * Description: This function converts a human readable filename (limited to 
 * 8.3 eint8 character) to a valid FAT (not VFAT) filename. Invalid characters are 
 * changed to capital X and only the first 11 characters are used.
 * Furthermore all letters are capitalised.
 * Return value: pointer after the filename
*/
eint8* file_normalToFatName(eint8* filename,eint8* fatfilename)
{
	euint8 c,dot=0,vc=0;
	
	for(c=0;c<11;c++)fatfilename[c]=' ';
	
	c=0;
	
	if(*filename == '.'){
		fatfilename[0]='.';
		vc++; 
		if(*(filename+1) == '.'){
			fatfilename[1]='.';
			filename+=2;
		}else{
			filename++;
		}
	}else{
		while(*filename != '\0' && *filename != ' ' && *filename != '/'){
			if(*filename=='.' && !dot){
				dot=1;
				c=8;
			}else{
				if(dot){
					if(c<=10){
						fatfilename[c]=file_validateChar(*filename);
						c++; 
					}
				}else{
					if(c<=7){
						fatfilename[c]=file_validateChar(*filename);
						c++; vc++;
					}
				}
			}
			filename++;
		}
	}
	
	if(vc>0){
		if(*filename=='\0'){
			return(filename);
		}else{
			return(filename+1);
		}
	}else{
		return(0);
	}
}
/*****************************************************************************/

/* ****************************************************************************  
 *
 * Description: This function takes the character c, and if it is not a       *
 * valid FAT Filename character returns X. If it is a lowercase letter the    *
 * uppercase equivalent is returned. The remaining characters are returned    *
 * as they are.      
 * Return value: The validated char
*/
euint8 file_validateChar(euint8 c)
{
    if( (c<0x20) || (c>0x20&&c<0x30&&c!='-') || (c>0x39&&c<0x41) || (c>0x5A&&c<0x61&&c!='_') ||	(c>0x7A&&c!='~') )
		return(0x58);
    if( c>=0x61 && c<=0x7A )
		return(c-32);

	return(c);
}
/*****************************************************************************/

/* ****************************************************************************  
 * void ioman_setAttr(IOManager *ioman,euint16 bufplace,euint8 attribute,euint8 val)
 * Description: This sets the attribute of 'bufplace' to the given value (binary).
 *
 * Return value: void
*/
void file_setAttr(File* file,euint8 attribute,euint8 val)
{
	if(val){
		file->FileStatus|=1<<attribute;
	}else{
		file->FileStatus&=~(1<<attribute);
	}
}
/*****************************************************************************/

/* ****************************************************************************  
 * euint8 ioman_getAttr(IOManager *ioman,euint16 bufplace,euint8 attribute)
 * Description: This function retrieves an attribute from the bufstat array.
 * It returns nonzero when it attribute is true and 0 when it is false.
 * Please note, I said "nonzero", not 1.
 * Return value: Attribute.
*/
euint8 file_getAttr(File* file,euint8 attribute)
{
	return(file->FileStatus&(1<<attribute));
}
/*****************************************************************************/

euint32 file_requiredCluster(File *file,euint32 offset, euint32 size)
{
	euint32 clusters_required,clustersize;
	euint32 hc;

	if((offset+size)>file->FileSize){
		hc = fat_countClustersInChain(file->fs,file->Cache.FirstCluster);
		clustersize = file->fs->volumeId.BytesPerSector * file->fs->volumeId.SectorsPerCluster;
		if((size-file->FileSize+offset)>
		   ((hc-((file->FileSize+clustersize-1)/clustersize))*clustersize)){
			clusters_required = (((offset+size)-(hc*clustersize))+clustersize-1)/clustersize;
		}else{
			clusters_required = 0;
		}
	}else{
		clusters_required = 0;
	}
	return(clusters_required);
}