file.c

一个操作系统源代码 用于嵌入式设备 在Vc++环境下仿真 成功移植到多款处理器上

				num = 0;
			else if( (fp->fcb->file_length - curp - (BLOCKSIZE - n)) % BLOCKSIZE )
				num = (fp->fcb->file_length - curp - (BLOCKSIZE - n)) / BLOCKSIZE + 1;
			else
				num = (fp->fcb->file_length - curp - (BLOCKSIZE - n)) / BLOCKSIZE;
			/*m is the num of block and n is the offset in the m+1 block
			which is occupied by remained data */
			size = size - ( BLOCKSIZE - n );
			m = size / BLOCKSIZE;
			n = size % BLOCKSIZE;
			/*remained data will be written in the i+1 subfcb block*/
			if( m + 1 + j + 1 < NUM2 ){
				for( s = 1; s < m + 1; s++ ){
					if( num != 0 ){
						blkid = *((unsigned int*)((SUBFCB_S*)p+1) + j + s);
						num--;
					}
					else{
						if( (blkid = get_block( fp->fcb->partition )) < 0 ) goto UNLOCK;
						*((unsigned int*)((SUBFCB_S*)p+1) + j + s) = blkid;
					}
					write_block( &fp->link, blkid, 0, BLOCKSIZE , buffer, NORMAL_WRITE );
					buffer += BLOCKSIZE;
					count += BLOCKSIZE;
				}
				if( num != 0 ){
					blkid = *((unsigned int*)((SUBFCB_S*)p+1) + j + s);
					num--;
				}
				else{
					if( (blkid = get_block( fp->fcb->partition )) < 0 ) goto UNLOCK;
					*((unsigned int*)((SUBFCB_S*)p+1) + j + s) = blkid;
				}
				write_block( &fp->link, blkid, 0, n , buffer, NORMAL_WRITE );
				count += n;
				if( fp->fcb->file_length < curp + count )
					fp->fcb->file_length = curp + count;
//				return count;
				goto UNLOCK;
			}
			/*remained data will be written in the i+1 subfcb block and the i+2...subfcb block*/
			else{
				/*write in the i+1 subfcb block*/
				for( s = 1; s <= NUM2 - ( j + 1 ); s++ ){
					if( num != 0 ){
						blkid = *((unsigned int*)((SUBFCB_S*)p+1) + j + s);
						num--;
					}
					else{
						if( (blkid = get_block( fp->fcb->partition )) < 0 ) goto UNLOCK;
						*((unsigned int*)((SUBFCB_S*)p+1) + j + s) = blkid;
					}
					write_block( &fp->link, blkid, 0, BLOCKSIZE , buffer, NORMAL_WRITE );
					buffer += BLOCKSIZE;
					count += BLOCKSIZE;
				}
				/* create the fcb list and write the data 
				   s + 1 is num of subfcb
				   t + 1 is block num in last subfcb*/
				s = (m - (NUM2 - (j + 1))) / NUM2;
				t = (m - (NUM2 - (j + 1))) % NUM2;
				/* write s subfcbs */
				for( i = 0; i < s; i++ ){
					if( num != 0 ){
						if( ((FCB_S*)q)->nextfcb == NULL ){
							p = (unsigned int *)read_FCB(((FCB_S*)q)->nextblk, NULL);
							((FCB_S*)q)->nextfcb = (SUBFCB_S*)p;
						}
						else
							p = ((FCB_S*)q)->nextfcb;
					}
					else{
						if ( (p = (unsigned int*)new_SUBFCB( fp->fcb )) == NULL ) goto UNLOCK;
						((FCB_S*)q)->nextfcb = (SUBFCB_S*)p;
						((FCB_S*)q)->nextblk = ((SUBFCB_S*)p)->blkid;
					}
					q = p;
					((FCB_S*)q)->flag = BE_USED;
					for( u = 0; u < NUM2; u++ ){
						if( num != 0 ){
							blkid = *((unsigned int*)((SUBFCB_S*)q+1) + u);
							num--;
						}
						else{
							if( (blkid = get_block( fp->fcb->partition )) < 0 ) goto UNLOCK;
							*((unsigned int*)((SUBFCB_S*)q+1) + u) = blkid;
						}
						write_block( &fp->link, blkid, 0, BLOCKSIZE , buffer, NORMAL_WRITE );
						buffer += BLOCKSIZE;
						count += BLOCKSIZE;
					}
				}
				/*write t blocks in the s+1 sub*/
				if( num != 0 ){
					if( ((FCB_S*)q)->nextfcb == NULL ){
						p = (unsigned int *)read_FCB(((FCB_S*)q)->nextblk, NULL);
						((FCB_S*)q)->nextfcb = (SUBFCB_S*)p;
					}
					else
						p = ((FCB_S*)q)->nextfcb;
				}
				else{
					if( (p = (unsigned int*)new_SUBFCB( fp->fcb )) == NULL )goto UNLOCK;
					((FCB_S*)q)->nextfcb = (SUBFCB_S*)p;
					((FCB_S*)q)->nextblk = ((SUBFCB_S*)p)->blkid;
				}
				q = p;
				((FCB_S*)q)->flag = BE_USED;
				for( i = 0; i < t; i++ ){
					if( num != 0 ){
						blkid = *((unsigned int*)((SUBFCB_S*)q+1) + i);
						num--;
					}
					else{
						if( (blkid = get_block( fp->fcb->partition )) < 0 ) goto UNLOCK;
						*((unsigned int*)((SUBFCB_S*)q+1) + i) = blkid;
					}
					write_block( &fp->link, blkid, 0, BLOCKSIZE , buffer, NORMAL_WRITE );
					buffer += BLOCKSIZE;
					count += BLOCKSIZE;
				}
				/*write the t+1 block in the s+1 sub*/
				if( num != 0 ){
					blkid = *((unsigned int*)((SUBFCB_S*)q+1) + i);
					num--;
				}else{
					if( (blkid = get_block( fp->fcb->partition )) < 0 ) goto UNLOCK;
					*((unsigned int*)((SUBFCB_S*)q+1) + i) = blkid;
				}
				write_block( &fp->link, blkid, 0, n , buffer, NORMAL_WRITE );
				count += n;
				if( fp->fcb->file_length < curp + count )
					fp->fcb->file_length = curp + count;
//				return count;
				goto UNLOCK;
			}
		}
	}
	UNLOCK:
//		write_block( &fp->link, fp->fcb->blkid, 0, BLOCKSIZE, fp->fcb, NORMAL_WRITE );
//		fp->curp += count;
		curp += count;
		set_curp( fp, curp );
		/* UNLOCK should be added here!*/
		FS_UNLOCK( FILE_S_LOCK_ID );
	return count;
}


/* this function is only used in this C file and only used by read_FILE(  ) */
int read_cycle( FILE_S* fp, char* buffer, unsigned int size, unsigned short m, unsigned short n )
{
	unsigned int blkid,count;
	unsigned short i,j,s,t,u;
	unsigned int *p,*q;
	
	count = 0;
	
	if( m < NUM1 ){/* m < NUM1 follow */
		blkid = *(unsigned int *)((unsigned int *)(fp->fcb + 1) + m);
		/* the data to be readed in the m+1 block */
		if( n + size < BLOCKSIZE ){
			read_block( &fp->link, blkid, n, size, buffer );
			count += size;
			return count;
		}
		/* the data to be readed will exceed the m+1 block */
		else{
			read_block( &fp->link, blkid, n, BLOCKSIZE - n , buffer );
			buffer += ( BLOCKSIZE - n );
			count += ( BLOCKSIZE - n );
			size = size - ( BLOCKSIZE - n );
			/*i is the num of block and j is the offset in the i+1 block
			which is occupied by remained data */
			i = size / BLOCKSIZE;
			j = size % BLOCKSIZE;
			/*remained data will be readed in the fcb block*/
			if( m + 1 + i + 1 < NUM1 ){
				for( n = 1; n < i + 1; n++ ){
					blkid = *(unsigned int*)((unsigned int *)(fp->fcb + 1) + m + n);
					read_block( &fp->link, blkid, 0, BLOCKSIZE , buffer );
					buffer += BLOCKSIZE;
					count += BLOCKSIZE;
				}
				blkid = *(unsigned int *)((unsigned int *)(fp->fcb + 1) + m + n);
				read_block( &fp->link, blkid, 0, j , buffer );
				count += j;
				return count;
			}
			/*remained data will be readed in the fcb block and subfcb block */
			else{
			/* readed in the fcb block */
				for( n = 1; n <= NUM1 - ( m + 1 ); n++ ){
					blkid = *(unsigned int *)((unsigned int *)(fp->fcb + 1) + m + n);
					read_block( &fp->link, blkid, 0, BLOCKSIZE , buffer );
					buffer += BLOCKSIZE;
					count += BLOCKSIZE;
				}
				/* create the fcb list and read the data 
				   s + 1 is num of subfcb
				   t + 1 is block num in last subfcb*/
				s = (i - (NUM1 - (m + 1))) / NUM2;
				t = (i - (NUM1 - (m + 1))) % NUM2;
				/*read s subfcbs*/
				q = (unsigned int *)fp->fcb;
				for( n = 0; n < s; n++ ){
					if( ((FCB_S*)q)->nextfcb == NULL ){
						p = (unsigned int*)read_FCB( ((FCB_S*)q)->nextblk, NULL );
						((FCB_S*)q)->nextfcb = (struct _subfcb_s *)p;
					}
					else
						p = ((FCB_S*)q)->nextfcb;
					q = p;
					for( u = 0; u < NUM2; u++ ){
						blkid = *(unsigned int *)((unsigned int*)((SUBFCB_S*)p + 1) + u);
						read_block( &fp->link, blkid, 0, BLOCKSIZE , buffer );
						buffer += BLOCKSIZE;
						count += BLOCKSIZE;
					}
				}
				/*read t blocks in the s+1 subfcb*/
				if( ((FCB_S*)q)->nextfcb == NULL ){
					p = (unsigned int*)read_FCB( ((FCB_S*)q)->nextblk, NULL );
					((FCB_S*)q)->nextfcb = (struct _subfcb_s *)p;
				}
				else
					p = ((FCB_S*)q)->nextfcb;
				for( n = 0; n < t; n++ ){
					blkid = *(unsigned int *)((unsigned int*)((SUBFCB_S*)p + 1) + n);
					read_block( &fp->link, blkid, 0, BLOCKSIZE , buffer );
					buffer += BLOCKSIZE;
					count += BLOCKSIZE;
				}
				/*read the t+1 block in the s+1 subfcb*/
				blkid = *(unsigned int *)((unsigned int*)((SUBFCB_S*)p + 1) + n);
				read_block( &fp->link, blkid, 0, j , buffer );
				count += j;
				return count;
			}
		}
	}
	/* m > NUM1 follow */
	else{
		/*i is num of whole subfcb will be excced
		  j is num of block will be exceed in the last subfcb */
		i = (m - NUM1) / NUM2;
		j = (m - NUM1) % NUM2;
		/* create the fcb list */
		q = (unsigned int *)fp->fcb;
		for( s = 0; s <= i; s++ ){
			if( ((FCB_S*)q)->nextfcb == NULL){
				p = (unsigned int*)read_FCB( ((FCB_S*)q)->nextblk, NULL );
				((FCB_S*)q)->nextfcb = (struct _subfcb_s *)p;
			}
			else
				p = ((FCB_S*)q)->nextfcb;
			q = p;
		}
		blkid = *(unsigned int *)((unsigned int*)((SUBFCB_S*)p + 1) + j);
		/* the data to be readed in the j+1 block */
		if( n + size < BLOCKSIZE ){
			read_block( &fp->link, blkid, n, size, buffer );
			count += size;
			return count;
		}
		/* the data to be readed will exceed the j+1 block */
		else{
			read_block( &fp->link, blkid, n, BLOCKSIZE - n , buffer );
			buffer += ( BLOCKSIZE - n );
			count += ( BLOCKSIZE - n );
			/*m is the num of block and n is the offset in the m+1 block
			which is occupied by remained data */
			size = size - ( BLOCKSIZE - n );
			m = size / BLOCKSIZE;
			n = size % BLOCKSIZE;
			/*remained data will be readed in the i+1 subfcb block*/
			if( m + 1 + j + 1 < NUM2 ){
				for( s = 1; s < m + 1; s++ ){
					blkid = *(unsigned int *)((unsigned int*)((SUBFCB_S*)p + 1) + j + s);
					read_block( &fp->link, blkid, 0, BLOCKSIZE , buffer );
					buffer += BLOCKSIZE;
					count += BLOCKSIZE;
				}
				blkid = *(unsigned int *)((unsigned int*)((SUBFCB_S*)p + 1) + j + s);
				read_block( &fp->link, blkid, 0, n , buffer );
				count += n;
				return count;
			}
			/*remained data will be written in the i+1 subfcb block and the i+2...subfcb block*/
			else{
				/*read in the i+1 subfcb block*/
				for( s = 1; s <= NUM2 - ( j + 1 ); s++ ){
					blkid = *(unsigned int *)((unsigned int*)((SUBFCB_S*)p + 1) + j + s);
					read_block( &fp->link, blkid, 0, BLOCKSIZE , buffer );
					buffer += BLOCKSIZE;
					count += BLOCKSIZE;
				}
				/* create the fcb list and read the data 
				   s + 1 is num of subfcb
				   t + 1 is block num in last subfcb*/
				s = (m - (NUM2 - (j + 1))) / NUM2;
				t = (m - (NUM2 - (j + 1))) % NUM2;
				for( i = 0; i < s; i++ ){
					if( ((FCB_S*)q)->nextfcb == NULL ){
						p = (unsigned int*)read_FCB( ((FCB_S*)q)->nextblk, NULL );
						((FCB_S*)q)->nextfcb = (struct _subfcb_s *)p;
					}
					else
						p = ((FCB_S*)q)->nextfcb;
					q = p;
					for( u = 0; u < NUM2; u++ ){
						blkid = *(unsigned int *)((unsigned int*)((SUBFCB_S*)p + 1) + u);
						read_block( &fp->link, blkid, 0, BLOCKSIZE , buffer );
						buffer += BLOCKSIZE;
						count += BLOCKSIZE;
					}
				}
				/*write t blocks in the s+1 sub*/
				if( ((FCB_S*)q)->nextfcb == NULL ){
					p = (unsigned int*)read_FCB( ((FCB_S*)q)->nextblk, NULL );
					((FCB_S*)q)->nextfcb = (struct _subfcb_s *)p;
				}
				else
					p = ((FCB_S*)q)->nextfcb;
				for( i = 0; i < t; i++ ){
					blkid = *(unsigned int *)((unsigned int*)((SUBFCB_S*)p + 1) + i);
					read_block( &fp->link, blkid, 0, BLOCKSIZE , buffer );
					buffer += BLOCKSIZE;
					count += BLOCKSIZE;
				}
				/*write the t+1 block in the s+1 sub*/
				blkid = *(unsigned int *)((unsigned int*)((SUBFCB_S*)p + 1) + i);
				read_block( &fp->link, blkid, 0, n , buffer );
				count += n;
				return count;
			}
		}
	}
}