_mfs_error MFS_Extend_chain
(
MFS_DRIVE_STRUCT_PTR drive_ptr, /*[IN] the drive on which to operate */
uint_32 cluster_number, /*[IN] number of a cluster within the chain */
uint_32 num_clusters, /*[IN] number of clusters to append to chain */
uint_32_ptr added_cluster /* [IN] pointer to the place where we should put the # of the first new cluster. */
)
{
uint_32 next_cluster;
_mfs_error error_code;
boolean extended;
#if MFSCFG_READ_ONLY_CHECK
if (MFS_is_read_only (NULL, drive_ptr))
{
return MFS_DISK_IS_WRITE_PROTECTED;
}
#endif
extended = FALSE;
error_code = MFS_NO_ERROR;
if ( cluster_number < CLUSTER_MIN_GOOD || cluster_number > drive_ptr->LAST_CLUSTER )
{
error_code = MFS_INVALID_CLUSTER_NUMBER;
}
else if ( num_clusters )
{
/*
** Find the end of the chain
*/
next_cluster = cluster_number;
do
{
cluster_number = next_cluster;
error_code = MFS_get_cluster_from_fat(drive_ptr,next_cluster, &next_cluster);
if ( error_code != MFS_NO_ERROR )
{
return error_code;
}
else if ( (next_cluster > drive_ptr->LAST_CLUSTER || next_cluster < CLUSTER_MIN_GOOD) && next_cluster != CLUSTER_EOF )
{
return(MFS_LOST_CHAIN);
}
} while ( next_cluster != CLUSTER_EOF );
/*
** Find a free cluster
*/
next_cluster = MFS_Find_unused_cluster_from(drive_ptr, cluster_number+1);
/*
** Check to see if the disk is not full.
*/
if ( next_cluster == CLUSTER_INVALID )
{
return MFS_DISK_FULL;
}
/*
** Link the free cluster to the chain, at the end.
*/
*added_cluster = next_cluster;
error_code = MFS_Put_fat(drive_ptr,cluster_number, next_cluster);
extended = TRUE;
while ( --num_clusters && !error_code )
{
/*
** Find a free cluster
*/
cluster_number = next_cluster;
next_cluster = MFS_Find_unused_cluster_from(drive_ptr, cluster_number+1);
/*
** Check to see if the disk is not full.
*/
if ( next_cluster == CLUSTER_INVALID )
{
error_code = MFS_Put_fat(drive_ptr,cluster_number, CLUSTER_EOF);
return MFS_DISK_FULL;
}
else
{
/*
** Link the free cluster to the chain, at the end.
*/
error_code = MFS_Put_fat(drive_ptr,cluster_number, next_cluster);
}
}
if ( extended && !error_code )
{
error_code = MFS_Put_fat(drive_ptr,next_cluster, CLUSTER_EOF);
}
}
return(error_code);
}
_mfs_error MFS_Add_cluster_to_chain
(
MFS_DRIVE_STRUCT_PTR drive_ptr, /*[IN] the drive on which to operate */
uint_32 cluster_number, /*[IN] number of a cluster within the chain */
uint_32_ptr added_cluster /*[IN] pointer to the place where we should put the # of the new cluster. */
)
{
uint_32 next_cluster,free_cluster;
_mfs_error error_code;
#if MFSCFG_READ_ONLY_CHECK
if (MFS_is_read_only (NULL, drive_ptr))
{
return MFS_DISK_IS_WRITE_PROTECTED;
}
#endif
if ( cluster_number < CLUSTER_MIN_GOOD ||
cluster_number > drive_ptr->LAST_CLUSTER )
{
error_code = MFS_INVALID_CLUSTER_NUMBER;
}
else
{
free_cluster = MFS_Find_unused_cluster_from(drive_ptr, drive_ptr->NEXT_FREE_CLUSTER);
/*
** Check to see if the disk is not full.
*/
if ( free_cluster == CLUSTER_INVALID )
{
error_code = MFS_DISK_FULL;
}
else
{
/*
** Find the end of the chain
*/
next_cluster = cluster_number;
do
{
cluster_number = next_cluster;
error_code = MFS_get_cluster_from_fat(drive_ptr,next_cluster, &next_cluster);
if ( error_code != MFS_NO_ERROR )
{
break;
}
else if ( next_cluster > drive_ptr->LAST_CLUSTER && next_cluster != CLUSTER_EOF )
{
error_code = MFS_BAD_DISK_UNIT;
break;
}
} while ( next_cluster != CLUSTER_EOF );
/*
** Link the free cluster to the chain, at the end.
*/
if ( error_code == MFS_NO_ERROR )
{
error_code = MFS_Put_fat(drive_ptr,cluster_number, free_cluster);
if ( error_code )
{
return(error_code);
}
error_code = MFS_Put_fat(drive_ptr,free_cluster, CLUSTER_EOF);
if ( error_code )
{
return(error_code);
}
*added_cluster = free_cluster;
}
}
}
return(error_code);
}
/*FUNCTION*-------------------------------------------------------------------
*
* Function Name : MFS_Write_device_sector
* Returned Value : error_code
* Comments :
* Reads or writes consecutive clusters.
*END*---------------------------------------------------------------------*/
_mfs_error MFS_Write_device_sector
(
MFS_DRIVE_STRUCT_PTR drive_ptr,
uint_32 sector_number, /*[IN] sector number to read/write from/to file system medium */
char_ptr buffer_ptr /*[IN/OUT] address of where data is to be stored/written */
)
{
uint_32 new_cluster_number, next_cluster, bad_cluster_number;
uint_32 i;
uint_32 retries, attempts;
uint_32 new_sector_number, no_of_sectors;
char_ptr temp_buffer_ptr;
int_32 num, expect_num, shifter, seek_loc, tmp;
_mfs_error error;
#if MFSCFG_READ_ONLY_CHECK
if (MFS_is_read_only (NULL, drive_ptr))
{
return MFS_DISK_IS_WRITE_PROTECTED;
}
#endif
error = MFS_NO_ERROR;
MFS_LOG(printf("MFS_Write_device_sector %d\n", sector_number));
if ( sector_number > drive_ptr->BPB.MEGA_SECTORS )
{
return(MFS_SECTOR_NOT_FOUND);
}
attempts = 0;
/* Lock device */
ioctl(drive_ptr->DEV_FILE_PTR, IO_IOCTL_DEV_LOCK, &drive_ptr->DRV_NUM);
if ( drive_ptr->BLOCK_MODE )
{
shifter = 0;
seek_loc = sector_number;
expect_num = 1;
}
else
{
shifter = drive_ptr->SECTOR_POWER;
seek_loc = sector_number << shifter;
expect_num = 1 << shifter;
}
MFS_device_write_internal(drive_ptr, seek_loc, buffer_ptr, &expect_num, &buffer_ptr, shifter);
if ( expect_num > 0 )
{
error = drive_ptr->DEV_FILE_PTR->ERROR;
#if MFSCFG_MAX_CLUSTER_REMAP_ATTEMPTS
/*
** Check to see if the write failed due to a bad sector. If so,
** rewrite cluster by cluster until we find bad cluster, then move
** it.
*/
temp_buffer_ptr = buffer_ptr;
if ( drive_ptr->BLOCK_MODE )
{
expect_num = drive_ptr->BPB.SECTORS_PER_CLUSTER;
}
else
{
expect_num = drive_ptr->CLUSTER_SIZE_BYTES;
}
tmp = expect_num;
for ( i = 0; i < no_of_clusters; i++ )
{
MFS_device_write_internal(drive_ptr, seek_loc, temp_buffer_ptr, &expect_num, &buffer_ptr, shifter);
if ( expect_num > 0 )
{
error_code = drive_ptr->DEV_FILE_PTR->ERROR;
ioctl(drive_ptr->DEV_FILE_PTR, IO_IOCTL_DEV_UNLOCK, &drive_ptr->DRV_NUM);
bad_cluster_number = cluster_number + i;
error_code = MFS_get_cluster_from_fat(drive_ptr, bad_cluster_number, &next_cluster);
if ( error_code != MFS_NO_ERROR )
{
/*
** This is done so that the unlock at end of function
** works properly
*/
ioctl(drive_ptr->DEV_FILE_PTR, IO_IOCTL_DEV_LOCK, &drive_ptr->DRV_NUM);
break;
}
retries = MFSCFG_MAX_CLUSTER_REMAP_ATTEMPTS;
while ( (error_code != MFS_NO_ERROR) && retries-- )
{
/*
** Mark old cluster BAD
*/
error_code = MFS_Put_fat(drive_ptr, bad_cluster_number, CLUSTER_BAD);
if ( error_code )
{
break;
}
/*
** Find available fat, update old FAT as invalid,
** update new fat, and write new cluster.
*/
new_cluster_number = MFS_Find_unused_cluster_from(drive_ptr, bad_cluster_number);
if ( new_cluster_number == CLUSTER_INVALID )
{
/*
** No more clusters
*/
return MFS_DISK_FULL;
}
new_sector_number = drive_ptr->DATA_START_SECTOR + ((uint_32)(new_cluster_number - CLUSTER_MIN_GOOD)) * drive_ptr->BPB.SECTORS_PER_CLUSTER;
ioctl(drive_ptr->DEV_FILE_PTR, IO_IOCTL_DEV_LOCK, &drive_ptr->DRV_NUM);
expect_num = tmp;
MFS_device_write_internal(drive_ptr, new_sector_number << shifter, temp_buffer_ptr, &expect_num, &buffer_ptr, shifter);
if ( expect_num > 0 )
{
error_code = drive_ptr->DEV_FILE_PTR->ERROR;
}
ioctl(drive_ptr->DEV_FILE_PTR, IO_IOCTL_DEV_UNLOCK, &(drive_ptr->DRV_NUM));
bad_cluster_number = new_cluster_number;
}
if ( error_code != MFS_NO_ERROR )
{
return MFS_WRITE_FAULT;
}
/*
** update chain,
*/
error_code = MFS_Put_fat(drive_ptr, new_cluster_number, next_cluster);
if ( error_code )
{
return(error_code);
}
if ( handle->PREVIOUS_CLUSTER )
{
error_code = MFS_Put_fat(drive_ptr,handle->PREVIOUS_CLUSTER, new_cluster_number );
if ( error_code )
{
return(error_code);
}
}
else
{
clustod(handle->DIR_ENTRY.HFIRST_CLUSTER, handle->DIR_ENTRY.LFIRST_CLUSTER, new_cluster_number);
}
handle->PREVIOUS_CLUSTER = new_cluster_number;
ioctl(drive_ptr->DEV_FILE_PTR, IO_IOCTL_DEV_LOCK, &drive_ptr->DRV_NUM);
}
else
{
handle->PREVIOUS_CLUSTER = cluster_number+i;
}
temp_buffer_ptr += drive_ptr->CLUSTER_SIZE_BYTES;
sector_number += drive_ptr->BPB.SECTORS_PER_CLUSTER;
}
#endif
}
/* Unlock device under MFS */
ioctl(drive_ptr->DEV_FILE_PTR, IO_IOCTL_DEV_UNLOCK, &drive_ptr->DRV_NUM);
switch ( error )
{
case IO_ERROR_WRITE_PROTECTED:
error = MFS_DISK_IS_WRITE_PROTECTED;
break;
case IO_ERROR_WRITE:
error = MFS_WRITE_FAULT;
break;
case IO_ERROR_WRITE_ACCESS:
error = MFS_SECTOR_NOT_FOUND;
break;
case IO_ERROR_READ:
error = MFS_READ_FAULT;
break;
case IO_ERROR_READ_ACCESS:
error = MFS_SECTOR_NOT_FOUND;
break;
default:
break;
}
return(error);
}
_mfs_error MFS_Create_subdir
(
MFS_DRIVE_STRUCT_PTR drive_ptr,
char *pathname /*[IN] pathname of the directory to be created */
)
{
MFS_DIR_ENTRY_PTR dir_entry_ptr;
uint32_t dir_cluster;
uint32_t parent_cluster;
uint32_t free_cluster;
uint32_t dir_index;
_mfs_error error_code;
char *temp_dirname;
char *temp_filename;
if ( (pathname == NULL) || (*pathname == '\0') )
{
return MFS_INVALID_PARAMETER;
}
#if MFSCFG_READ_ONLY_CHECK
if (MFS_is_read_only (drive_ptr))
{
return MFS_DISK_IS_WRITE_PROTECTED;
}
#endif
error_code = MFS_alloc_2paths(&temp_dirname,&temp_filename);
if ( error_code != MFS_NO_ERROR )
{
return( error_code );
}
error_code = MFS_lock_dos_disk( drive_ptr );
if ( error_code != MFS_NO_ERROR )
{
MFS_free_path(temp_dirname);
MFS_free_path(temp_filename);
return error_code;
}
MFS_Parse_pathname (temp_dirname, temp_filename, pathname);
dir_cluster = drive_ptr->CUR_DIR_CLUSTER;
parent_cluster = MFS_Find_directory (drive_ptr, temp_dirname, dir_cluster);
dir_cluster = parent_cluster;
if ( MFS_is_valid_lfn(temp_filename) )
{
if ( dir_cluster != CLUSTER_INVALID )
{
/*
** We'll obtain a cluster for the new directory first. If we
** cannot create the directory afterwards, it is easier to re-free
** the cluster than to remove the new entry.
*/
free_cluster = MFS_Find_unused_cluster_from(drive_ptr, drive_ptr->NEXT_FREE_CLUSTER);
if ( free_cluster != CLUSTER_INVALID )
{
error_code = MFS_Clear_cluster(drive_ptr, free_cluster);
if ( error_code )
{
MFS_unlock(drive_ptr,TRUE);
MFS_free_path(temp_dirname);
MFS_free_path(temp_filename);
return( error_code );
}
error_code = MFS_Put_fat(drive_ptr, free_cluster, CLUSTER_EOF);
dir_entry_ptr = MFS_Create_directory_entry(drive_ptr, temp_filename, MFS_ATTR_DIR_NAME, &dir_cluster, &dir_index, &error_code);
if ( error_code == MFS_NO_ERROR )
{
clustod(dir_entry_ptr->HFIRST_CLUSTER, dir_entry_ptr->LFIRST_CLUSTER, free_cluster);
drive_ptr->DIR_SECTOR_DIRTY = TRUE;
/*
** We shall now create the "." and ".." entries.
*/
dir_cluster = free_cluster;
dir_entry_ptr = MFS_Create_directory_entry(drive_ptr,".", MFS_ATTR_DIR_NAME, &dir_cluster, &dir_index, &error_code);
if ( error_code == MFS_NO_ERROR )
{
clustod(dir_entry_ptr->HFIRST_CLUSTER, dir_entry_ptr->LFIRST_CLUSTER, free_cluster);
drive_ptr->DIR_SECTOR_DIRTY = TRUE;
dir_entry_ptr = MFS_Create_directory_entry(drive_ptr,"..", MFS_ATTR_DIR_NAME, &dir_cluster, &dir_index, &error_code);
if ( error_code == MFS_NO_ERROR )
{
if ( drive_ptr->FAT_TYPE == MFS_FAT32 )
{
if ( drive_ptr->BPB32.ROOT_CLUSTER == parent_cluster )
{
/*
** Even though the FAT32 root sector can be
** anywhere, it is identified as 0 when referenced
** through a directory entry
*/
parent_cluster = 0;
}
}
clustod(dir_entry_ptr->HFIRST_CLUSTER, dir_entry_ptr->LFIRST_CLUSTER, parent_cluster);
drive_ptr->DIR_SECTOR_DIRTY = TRUE;
}
}
}
else
{
MFS_Put_fat(drive_ptr, free_cluster, CLUSTER_UNUSED);
}
}
else
{
error_code = MFS_DISK_FULL;
}
}
else
{
error_code = MFS_PATH_NOT_FOUND;
}
}
else if ( MFS_lfn_dirname_valid(temp_filename) )
{
if ( dir_cluster )
{
error_code = MFS_FILE_EXISTS;
}
else
{
error_code = MFS_CANNOT_CREATE_DIRECTORY;
}
}
else
{
error_code = MFS_INVALID_PARAMETER;
}
MFS_free_path(temp_dirname);
MFS_free_path(temp_filename);
MFS_unlock(drive_ptr,TRUE);
return(error_code);
}
uint32_t MFS_Write
(
MFS_HANDLE_PTR handle,
MFS_DRIVE_STRUCT_PTR drive_ptr,
uint32_t num_bytes, /*[IN] number of bytes to be written */
char *buffer_address, /*[IN/OUT] bytes are written from this buffer */
_mfs_error_ptr error_ptr /*[IN/OUT] error code is written to this address */
)
{
uint32_t bytes_written;
uint32_t copy_size;
uint32_t cluster_offset;
uint32_t sector_number, sector_index;
uint32_t sector_offset;
uint32_t whole_sectors;
uint32_t cont_sectors;
uint32_t proc_sectors;
_mfs_error error, temp_error;
uint32_t file_size;
uint32_t next_cluster;
bool need_hwread;
uint32_t location;
uint32_t num_zeros;
uint32_t zeros_written;
uint32_t zero_size;
#if MFSCFG_READ_ONLY_CHECK
if (MFS_is_read_only (drive_ptr))
{
MFS_set_error_and_return(error_ptr,MFS_DISK_IS_WRITE_PROTECTED,0);
}
#endif
if ( buffer_address == NULL )
{
MFS_set_error_and_return(error_ptr,MFS_INVALID_PARAMETER,0);
}
if ( num_bytes == 0 )
{
MFS_set_error_and_return(error_ptr,MFS_NO_ERROR,0);
}
error = MFS_lock_dos_disk( drive_ptr );
if ( error != MFS_NO_ERROR )
{
MFS_set_error_and_return(error_ptr,error,0);
}
if ( handle->ACCESS == MFS_ACCESS_READ_ONLY )
{
MFS_unlock(drive_ptr,FALSE);
MFS_set_error_and_return(error_ptr,MFS_ACCESS_DENIED,0);
}
/*
** Setup the current cluster. If this is the first time writing to the file, a cluster needs to be added.
*/
if ( handle->CURRENT_CLUSTER == 0 )
{
handle->PREVIOUS_CLUSTER = 0;
handle->CURRENT_CLUSTER = clustoh(handle->DIR_ENTRY.HFIRST_CLUSTER, handle->DIR_ENTRY.LFIRST_CLUSTER);
if ( handle->CURRENT_CLUSTER==0 )
{
next_cluster = MFS_Find_unused_cluster_from(drive_ptr,drive_ptr->NEXT_FREE_CLUSTER);
if ( next_cluster != CLUSTER_INVALID )
{
clustod(handle->DIR_ENTRY.HFIRST_CLUSTER, handle->DIR_ENTRY.LFIRST_CLUSTER, next_cluster);
handle->TOUCHED = 1;
error = MFS_Put_fat(drive_ptr, next_cluster, CLUSTER_EOF);
if ( error == MFS_NO_ERROR )
{
handle->CURRENT_CLUSTER = next_cluster;
}
else
{
MFS_unlock(drive_ptr,FALSE);
MFS_set_error_and_return(error_ptr,error,0);
}
}
else
{
MFS_unlock(drive_ptr,FALSE);
MFS_set_error_and_return(error_ptr,MFS_DISK_FULL,0);
}
}
}
else if ( handle->CURRENT_CLUSTER == CLUSTER_EOF )
{
error = MFS_Add_cluster_to_chain(drive_ptr, handle->PREVIOUS_CLUSTER, &handle->CURRENT_CLUSTER);
if ( MFS_NO_ERROR != error )
{
MFS_unlock(drive_ptr,FALSE);
MFS_set_error_and_return(error_ptr,error,0);
}
}
else if ( handle->CURRENT_CLUSTER > drive_ptr->LAST_CLUSTER )
{
MFS_unlock(drive_ptr,FALSE);
MFS_set_error_and_return(error_ptr,MFS_DISK_FULL,0);
}
/* Make sure location (local variable) never points behind the end of file */
file_size = mqx_dtohl(handle->DIR_ENTRY.FILE_SIZE);
location = (handle->LOCATION > file_size) ? file_size : handle->LOCATION;
/* Calculate sector number and offsets within cluster and sector */
cluster_offset = OFFSET_WITHIN_CLUSTER(location);
sector_index = CLUSTER_OFFSET_TO_SECTOR(cluster_offset);
sector_number = CLUSTER_TO_SECTOR(handle->CURRENT_CLUSTER) + sector_index;
sector_offset = OFFSET_WITHIN_SECTOR(location);
/* Calculate possible gap to fill in by zeros if writing behind the end of file */
num_zeros = handle->LOCATION - location;
zeros_written = 0;
bytes_written = 0;
/* Write zeros to fill in gap if LOCATION points behind the end of file */
while (zeros_written < num_zeros)
{
/* If offset is non-zero, then reading the data is required */
error = MFS_Read_data_sector(drive_ptr, handle, sector_number, sector_offset != 0);
if ( error != MFS_NO_ERROR )
break;
/* Zero the buffer */
zero_size = min(num_zeros-zeros_written, drive_ptr->BPB.SECTOR_SIZE-sector_offset);
_mem_zero(&drive_ptr->DATA_SECTOR_PTR[sector_offset], zero_size);
drive_ptr->DATA_SECTOR_DIRTY = TRUE;
if ( drive_ptr->WRITE_CACHE_POLICY == MFS_WRITE_THROUGH_CACHE )
{
error = MFS_Flush_data_sector_buffer(drive_ptr);
if ( error != MFS_NO_ERROR )
break;
}
zeros_written += zero_size;
sector_offset += zero_size;
/*
** Check to see if we need to advance to the next sector, which has
** the side effect of increasing the cluster number if required.
*/
if ( sector_offset >= drive_ptr->BPB.SECTOR_SIZE )
{
temp_error = MFS_next_data_sector(drive_ptr, handle, §or_index, §or_number);
if (temp_error == MFS_EOF)
{
/* Always allocate new cluster, there is something to be written for sure */
error = MFS_Add_cluster_to_chain(drive_ptr, handle->PREVIOUS_CLUSTER, &handle->CURRENT_CLUSTER);
if ( MFS_NO_ERROR == error )
{
sector_number = CLUSTER_TO_SECTOR(handle->CURRENT_CLUSTER);
sector_index = 0;
}
}
else
{
error = temp_error;
}
sector_offset = 0;
}
}
/* Write partial sector if sector_offset is non-zero */
if ((sector_offset != 0) && (error == MFS_NO_ERROR))
{
/* Offset is non-zero, reading the data is required */
error = MFS_Read_data_sector(drive_ptr, handle, sector_number, TRUE);
if (error == MFS_NO_ERROR)
{
/* The requested lenght of data may span the sector to it's end */
copy_size = min(num_bytes, drive_ptr->BPB.SECTOR_SIZE-sector_offset);
_mem_copy(buffer_address, &drive_ptr->DATA_SECTOR_PTR[sector_offset], copy_size);
drive_ptr->DATA_SECTOR_DIRTY = TRUE;
if (drive_ptr->WRITE_CACHE_POLICY == MFS_WRITE_THROUGH_CACHE)
{
error = MFS_Flush_data_sector_buffer(drive_ptr);
}
if (error == MFS_NO_ERROR)
{
bytes_written = copy_size;
/*
** Check to see if we need to advance to the next sector, which has
** the side effect of increasing the cluster number if required.
*/
if ((sector_offset + bytes_written) >= drive_ptr->BPB.SECTOR_SIZE)
{
temp_error = MFS_next_data_sector(drive_ptr, handle, §or_index, §or_number);
/* Only an error if we are not done writing and can't extend the chain */
if (bytes_written < num_bytes)
{
if (temp_error == MFS_EOF)
{
/* Allocate new cluster */
error = MFS_Add_cluster_to_chain(drive_ptr, handle->PREVIOUS_CLUSTER, &handle->CURRENT_CLUSTER);
/* Update sector_number and index unconditionally - if there was an error the value is never used anyways. */
sector_number = CLUSTER_TO_SECTOR(handle->CURRENT_CLUSTER);
sector_index = 0;
}
else
{
error = temp_error;
}
}
}
}
}
}
/* Check whether the application buffer is properly aligned */
if ((((uint32_t)buffer_address+bytes_written) & drive_ptr->ALIGNMENT_MASK) == 0)
{
/* Yes, use zero copy approach */
whole_sectors = (num_bytes - bytes_written) >> drive_ptr->SECTOR_POWER;
while ((whole_sectors > 0) && (error == MFS_NO_ERROR))
{
cont_sectors = drive_ptr->BPB.SECTORS_PER_CLUSTER - sector_index;
if (cont_sectors > whole_sectors)
cont_sectors = whole_sectors;
error = MFS_Write_device_sectors(drive_ptr, sector_number, cont_sectors, MFSCFG_MAX_WRITE_RETRIES, buffer_address+bytes_written, &proc_sectors);
if (proc_sectors > 0)
{
bytes_written += proc_sectors * drive_ptr->BPB.SECTOR_SIZE;
whole_sectors -= proc_sectors;
/* Advance to next unprocessed sector */
sector_index += proc_sectors - 1;
temp_error = MFS_next_data_sector(drive_ptr, handle, §or_index, §or_number);
/* Go on only if we are not done writing yet */
if ((error == MFS_NO_ERROR) && (bytes_written < num_bytes))
{
if (temp_error == MFS_EOF)
{
/* Allocate new cluster */
error = MFS_Add_cluster_to_chain(drive_ptr, handle->PREVIOUS_CLUSTER, &handle->CURRENT_CLUSTER);
/* Update sector_number and index unconditionally - if there was an error the value is never used anyways. */
sector_number = CLUSTER_TO_SECTOR(handle->CURRENT_CLUSTER);
sector_index = 0;
}
else
{
error = temp_error;
}
}
}
}
}
/*!
* \brief Find a free cluster, follow a chain and add it to the chain.
*
* \param[in] drive_ptr The drive on which to operate.
* \param[in] cluster_number Number of a cluster within the chain.
* \param[in] num_clusters Number of clusters to append to chain.
* \param[in] added_cluster Pointer to the place where we should put the # of the first new cluster.
*
* \return _mfs_error
*/
_mfs_error MFS_Extend_chain(
MFS_DRIVE_STRUCT_PTR drive_ptr,
uint32_t cluster_number,
uint32_t num_clusters,
uint32_t *added_cluster)
{
uint32_t next_cluster;
uint32_t extended;
_mfs_error error_code;
if (cluster_number < CLUSTER_MIN_GOOD || cluster_number > drive_ptr->LAST_CLUSTER)
{
return MFS_INVALID_CLUSTER_NUMBER;
}
if (num_clusters <= 0)
{
return MFS_NO_ERROR;
}
/* Find the end of the chain */
next_cluster = cluster_number;
do
{
cluster_number = next_cluster;
error_code = MFS_get_cluster_from_fat(drive_ptr, cluster_number, &next_cluster);
if (error_code != MFS_NO_ERROR)
{
return error_code;
}
else if ((next_cluster > drive_ptr->LAST_CLUSTER || next_cluster < CLUSTER_MIN_GOOD) && next_cluster != CLUSTER_EOF)
{
return MFS_LOST_CHAIN;
}
} while (next_cluster != CLUSTER_EOF);
extended = 0;
while (num_clusters)
{
/* Find a free cluster */
next_cluster = MFS_Find_unused_cluster_from(drive_ptr, cluster_number + 1);
/* Check to see if the disk is not full */
if (next_cluster == CLUSTER_INVALID)
{
break; /* Condition handled after the loop */
}
/* Link the free cluster to the chain, at the end */
error_code = MFS_Put_fat(drive_ptr, cluster_number, next_cluster);
if (error_code != MFS_NO_ERROR)
{
return error_code;
}
if (extended == 0 && added_cluster != NULL)
{
*added_cluster = next_cluster;
}
extended++;
cluster_number = next_cluster;
num_clusters--;
}
/* If the chain was extended, write EOF to it's last link */
if (extended)
{
error_code = MFS_Put_fat(drive_ptr, cluster_number, CLUSTER_EOF);
}
if (num_clusters && !error_code)
{
error_code = MFS_DISK_FULL;
}
return error_code;
}
