efs.c

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/*
 *  Copyright 2006 by Texas Instruments Incorporated.
 *  All rights reserved. Property of Texas Instruments Incorporated.
 *  Restricted rights to use, duplicate or disclose this code are
 *  granted through contract.
 *
 *  @(#) TCP/IP_Network_Developers_Kit 1.91.00.08 08-22-2006 (ndk-a08)
 */
//--------------------------------------------------------------------------
// OS Demonstration Software
//--------------------------------------------------------------------------
// EFS.C
//
// Embedded File System
//
// This file contains a file IO API similar to standard C, which allows
// it to be easily ported to a system which has its own file system.
//
// Author: Michael A. Denio
// Copyright 1999, 2001 by Texas Instruments Inc.
//--------------------------------------------------------------------------
#include <netmain.h>
#include <_oskern.h>

//
// Internal File Header
//
typedef struct _fileheader
     {
        uint               Type;
        struct _fileheader *pNext;
        char               Filename[EFS_FILENAME_MAX];
        INT32              Length;
        INT32              RefCount;
        uint               Flags;
#define EFSFLG_DESTROY_PENDING  0x0001
        EFSFUN             pMemMgrCallback;
        UINT32             MemMgrArg;
        UINT8              *pData;
     } FILEHEADER;

//
// Internal File Pointer
//
typedef struct _fileptr
     {
        uint               Type;
        struct _fileheader *pfh;
        INT32              Pos;
     } FILEPTR;

static FILEHEADER *pRoot = 0;

//--------------------------------------------------------------------
//  Local Functions
//--------------------------------------------------------------------

static FILEHEADER *efs_findfile( char *name );
static void        efs_internal_remove( FILEHEADER *pfh );


//--------------------------------------------------------------------
// efs_findfile
//
// Finds file by name, and potentially removes file
//
// CALLED IN KERNEL MODE
//--------------------------------------------------------------------
FILEHEADER *efs_findfile( char *name )
{
    FILEHEADER *pfh;

    // Find
    pfh     = pRoot;

    while( pfh )
    {
        if( !(pfh->Flags & EFSFLG_DESTROY_PENDING) &&
                      !stricmp( name, pfh->Filename ) )
            break;
        pfh = pfh->pNext;
    }

    return( pfh );
}

//--------------------------------------------------------------------
// efs_internal_remove
//
// Removes file
//
// CALLED IN KERNEL MODE
//--------------------------------------------------------------------
static void efs_internal_remove( FILEHEADER *pfh )
{
    FILEHEADER *pfhTmp;
    FILEHEADER *pfhPrev;

    pfhTmp  = pRoot;
    pfhPrev = 0;

    while( pfhTmp )
    {
        if( pfhTmp == pfh )
            break;
        else
        {
            pfhPrev = pfhTmp;
            pfhTmp = pfhTmp->pNext;
        }
    }

    if( !pfhTmp )
        return;

    // Remove
    // pfh is entry to remove
    if( !pfhPrev )
        pRoot = pfh->pNext;
    else
        pfhPrev->pNext = pfh->pNext;

    // Zap type for debug
    pfh->Type = 0;
    if( pfh->pMemMgrCallback )
        (pfh->pMemMgrCallback)( pfh->MemMgrArg );

    mmFree( pfh );
}


//--------------------------------------------------------------------
// efs_createfile
//
// Creates a new file from a given name, length and data pointer
//--------------------------------------------------------------------
void efs_createfile( char *name, INT32 length, UINT8 *pData )
{
    efs_createfilecb( name, length, pData, 0, 0 );
}


//--------------------------------------------------------------------
// efs_createfilecb
//
// Creates a new file from a given name, length and data pointer
//--------------------------------------------------------------------
void efs_createfilecb( char *name, INT32 length, UINT8 *pData,
                       EFSFUN pllDestroyFun, UINT32 MemMgrArg )
{
    FILEHEADER *pfh;

    // Allocate the file header structure
    pfh = mmAlloc( sizeof(FILEHEADER) );
    if( !pfh )
        return;

    pfh->Type = HTYPE_EFSFILEHEADER;

    // Record the filename, size, and data pointer
    strncpy( pfh->Filename, name, EFS_FILENAME_MAX-1 );
    pfh->Filename[EFS_FILENAME_MAX-1] = 0;
    pfh->Length     = length;
    pfh->RefCount   = 0;
    pfh->pData      = pData;
    pfh->Flags      = 0;
    pfh->pMemMgrCallback = pllDestroyFun;
    pfh->MemMgrArg = MemMgrArg;

    llEnter();

    // Put it in our list
    pfh->pNext = pRoot;
    pRoot      = pfh;

    llExit();

}


//--------------------------------------------------------------------
// efs_destroyfile
//
// Removes a file from the list and frees header
//--------------------------------------------------------------------
void efs_destroyfile( char *name )
{
    FILEHEADER *pfh;

    llEnter();

    pfh = efs_findfile( name );
    if( !pfh )
        goto dest_exit;

    if( !pfh->RefCount )
        efs_internal_remove( pfh );
    else
        pfh->Flags |= EFSFLG_DESTROY_PENDING;

dest_exit:
    llExit();

}

//--------------------------------------------------------------------
// efs_loadfunction
//
// Loads a function into memory by filename and returns a function
// pointer (or NULL on error)
//--------------------------------------------------------------------
EFSFUN efs_loadfunction( char *name )
{
    FILEHEADER *pfh;
    EFSFUN     pFun = 0;

    llEnter();

    pfh = efs_findfile( name );
    if( pfh )
        pFun = (EFSFUN)pfh->pData;

    llExit();

    return( pFun );
}

//--------------------------------------------------------------------
// efs_fopen
//
// Opens a file and returns file pointer (or NULL on error)
//--------------------------------------------------------------------
EFS_FILE *efs_fopen( char *name, char *mode )
{
    FILEHEADER *pfh;
    FILEPTR    *pf;

    // Verify the read mode
    if( stricmp( mode, "rb" ) )
        return(0);

    llEnter();

    pfh = efs_findfile( name );

    if( !pfh )
    {
        llExit();
        return(0);
    }

    // Allocate the file header structure
    pf = mmAlloc( sizeof(FILEPTR) );
    if( !pf )
    {
        llExit();
        return(0);
    }

    pf->Type = HTYPE_EFSFILEPOINTER;
    pf->pfh = pfh;
    pf->Pos = 0;

    pfh->RefCount++;

    llExit();

    return( pf );
}

//--------------------------------------------------------------------
// efs_fclose
//
// Closes a file
//--------------------------------------------------------------------
int efs_fclose( EFS_FILE *stream )
{
    FILEPTR *pf     = (FILEPTR *)stream;
    FILEHEADER *pfh = pf->pfh;

    llEnter();

    // Zap type for debug
    pf->Type = 0;
    mmFree( pf );

    pfh->RefCount--;

    if( !pfh->RefCount && (pfh->Flags & EFSFLG_DESTROY_PENDING) )
        efs_internal_remove( pfh );

    llExit();

    return(0);
}

//--------------------------------------------------------------------
// efs_feof
//
// Returns non-zero if at end of file
//--------------------------------------------------------------------
int efs_feof( EFS_FILE *stream )
{
    FILEPTR    *pf  = (FILEPTR *)stream;
    FILEHEADER *pfh = pf->pfh;

    if( pf->Pos >= pfh->Length )
        return(1);
    return(0);
}

//--------------------------------------------------------------------
// efs_fread
//
// Returns number of objects read (set size to 1 to read bytes)
//--------------------------------------------------------------------
size_t efs_fread( void *ptr, size_t size, size_t nobj, EFS_FILE *stream )
{