8.Function specification-1

8.1 Directory management

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Title function specification

Function Initialize/mount file system

Function name GFS_Init

No 1.1

Format

Sint32 GFS_Init(Sint32 open_max, void *work, GfsDirTbl *dirtbl)

input

open_max	: Maximum number of files to open at the same time (1 to 24)
work	: work area for library
dirtbl	:Directory information management structure

output

dirtbl: Directory information management structure (directory information storage area)

function value

Number of directory information read. Returns a negative error code when an error occurs.

 If NULL is specified for the argument pointer to the directory information management structure, the number of directory information held by the CD block file system is returned as the function value.

function

Initializes the file system and mounts the CD-ROM.
Specify the directory management function by specifying dirtbl.

dirtbl	Directory management functions used
directory management structure	Directory management for this library
NULL	CD block file system directory management

remarks

1. work must be aligned on a 4-byte boundary.

2. The INT_ChgMsk function enables the SCU's level 0-DMA end interrupt.

3. Initialize the CD block as follows.

(The ECC count and retry count are set to the maximum values, and the rest remain default.)

・CD block soft reset	:do not
・Subcode decoding	:do not
・Mode 2 subheader recognition	:do
・Form 2 read retry	:do not
・CD-ROM data read	: Maximum speed (currently 2x speed)
・Standby time	:180 seconds
・ECC number	:5 times
·number of retries	:15 times

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Title function specification

Function Load directory information

Function name GFS_LoadDir

No 1.2

Format

Sint32 GFS_LoadDir(Sint32 fid, GfsDirTbl *dirtbl)

input

fid	: directory file identifier
dirtbl	:Directory information management structure

output

dirtbl: Directory information management structure (directory information storage area)

function value

Number of directories read. Returns a negative error code when an error occurs.

 If NULL is specified for the argument pointer to the directory information management structure, the number of directory information held by the CD block file system is returned as the function value.

function

Reads directory information from the specified directory file.
The storage location of directory information changes depending on the dirtbl specification.

dirtbl	Directory information storage area
directory management structure	dirtbl directory information storage area
NULL	File management information area in CD block

If NULL is specified for dirtbl, an error will occur if the CD block file system is not declared in GFS_Init. However, it is always possible to pass dirtbl a non-NULL pointer to an appropriate directory information management structure.

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Title function specification

Function Setting the current directory

Function name GFS_SetDir

No 1.3

Format

Sint 32GFS_SetDir(GfsDirTbl *dirtbl);

input

dirtbl: Directory information management structure

output

none

function value

Error code.

function

Sets the specified directory information to the current directory.
The directory information used changes depending on the dirtbl specification.

dirtbl	Directory information to use
directory management structure	contents of dirtbl
NULL	File management information in CD block

If you specify NULL for dirtbl, an error will occur unless you declare in GFS_Init that the CD block file system will be used. However, it is always possible to pass dirtbl a non-NULL pointer to an appropriate directory information management structure.

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Title function specification

Function Convert name to file identifier

Function name GFS_NameToId

No 1.4

Format

Sint 32GFS_NameToId(Sint8 *fname)

input

fname: File name

output

none

function value

File identifier. A negative error code if an error occurs.

function

Returns the file identifier corresponding to the file name.

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Title function specification

Function Converting an identifier to a file name

Function name GFS_IdToName

No 1.5

Format

const Sint8 *GFS_IdToName(Sint32 fid)

input

fid: file identifier

output

none

function value

Pointer to file name. NULL if an error occurs.

function

Returns a pointer to the file name corresponding to the file identifier. This pointer points to the conversion table area used by this library.

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Title function specification

Function Get directory information

Function name GFS_GetDirInfo

No 1.6

Format

Sint32 GFS_GetDirInfo(Sint32 fid, GfsDirId *dirrec)

input

fid: file identifier

output

dirrec: Directory information

function value

Error code

function

Get directory information from a file identifier.

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Title function specification

Function Resetting the file system

Function name GFS_Reset

No 1.7

Format

void GFS_Reset(void)

input

none

output

none

function value

none

function

Closes all open files and resets the file system.
(Initializes everything other than directory information.)

remarks

If you are using a stream system, close the stream before executing this function.