/*****************************************************************************
Function:
BOOL MPFSSeek(MPFS_HANDLE hMPFS, DWORD dwOffset, MPFS_SEEK_MODE tMode)
Description:
Moves the current read pointer to a new location.
Precondition:
The file handle referenced by hMPFS is already open.
Parameters:
hMPFS - the file handle to seek with
dwOffset - offset from the specified position in the specified direction
tMode - one of the MPFS_SEEK_MODE constants
Returns:
TRUE - the seek was successful
FALSE - either the new location or the handle itself was invalid
***************************************************************************/
BOOL MPFSSeek(MPFS_HANDLE hMPFS, DWORD dwOffset, MPFS_SEEK_MODE tMode)
{
DWORD temp;
// Make sure a valid file is open
if(hMPFS > MAX_MPFS_HANDLES)
return FALSE;
if(MPFSStubs[hMPFS].addr == MPFS_INVALID)
return FALSE;
switch(tMode)
{
// Seek offset bytes from start
case MPFS_SEEK_START:
temp = MPFSGetSize(hMPFS);
if(dwOffset > temp)
return FALSE;
MPFSStubs[hMPFS].addr = MPFSGetStartAddr(hMPFS) + dwOffset;
MPFSStubs[hMPFS].bytesRem = temp - dwOffset;
return TRUE;
// Seek forwards offset bytes
case MPFS_SEEK_FORWARD:
if(dwOffset > MPFSStubs[hMPFS].bytesRem)
return FALSE;
MPFSStubs[hMPFS].addr += dwOffset;
MPFSStubs[hMPFS].bytesRem -= dwOffset;
return TRUE;
// Seek backwards offset bytes
case MPFS_SEEK_REWIND:
temp = MPFSGetStartAddr(hMPFS);
if(MPFSStubs[hMPFS].addr < temp + dwOffset)
return FALSE;
MPFSStubs[hMPFS].addr -= dwOffset;
MPFSStubs[hMPFS].bytesRem += dwOffset;
return TRUE;
// Seek so that offset bytes remain in file
case MPFS_SEEK_END:
temp = MPFSGetSize(hMPFS);
if(dwOffset > temp)
return FALSE;
MPFSStubs[hMPFS].addr = MPFSGetEndAddr(hMPFS) - dwOffset;
MPFSStubs[hMPFS].bytesRem = dwOffset;
return TRUE;
default:
return FALSE;
}
}
/*****************************************************************************
Function:
bool MPFS_EOF( uintptr_t handle )
Description:
Returns if the present file pointer already reached end of file?
Precondition:
None
Parameters:
handle - a valie handle to the file
Returns:
End of file - true
Not end of file - false
*/
bool MPFS_EOF( uintptr_t handle )
{
MPFS_HANDLE hMPFS = ((MPFS_HANDLE )handle);
volatile unsigned long len, position;
len = MPFSGetSize ( hMPFS );
position = MPFSGetPosition ( hMPFS );
if(position == len)
return 1;
else
return 0;
// return (position == len ? 1 : 0);
}
/*****************************************************************************
Function:
uint32_t MPFS_GetSize ( uintptr_t handle )
Description:
Obtains the size of the file
Precondition:
None
Parameters:
handle - a valie handle to the file
Returns:
The size of file.
*/
uint32_t MPFS_GetSize ( uintptr_t handle )
{
MPFS_HANDLE address = ((MPFS_HANDLE )handle);
return (MPFSGetSize ( address ));
}
