ff_dev_support.c

/*
 * FreeRTOS+FAT V2.3.3
 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * https://www.FreeRTOS.org
 * https://github.com/FreeRTOS
 *
 */

#include <stdio.h>
#include <string.h>

/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "portable.h"

#include "ff_headers.h"
#include "ff_devices.h"

#ifndef ARRAY_SIZE
    #define  ARRAY_SIZE( x )    ( int ) ( sizeof( x ) / sizeof( x )[ 0 ] )
#endif

#if ( ffconfigDEV_SUPPORT == 0 )
    #error No use to include this module if ffconfigDEV_SUPPORT is disabled
#endif /* ffconfigDEV_SUPPORT == 0 */

struct SFileCache
{
    char pcFileName[ 16 ];
    uint32_t ulFileLength;
    uint32_t ulFilePointer;
};

struct SFileCache xFiles[ 16 ];

enum eCACHE_ACTION
{
    eCACHE_LOOKUP,
    eCACHE_ADD,
    eCACHE_REMOVE,
};

const char pcDevicePath[] = ffconfigDEV_PATH;

struct SFileCache * pxFindFile( const char * pcFname,
                                enum eCACHE_ACTION eAction )
{
    BaseType_t xIndex, xFreeIndex = -1;
    struct SFileCache * pxResult = NULL;

    for( xIndex = 0; xIndex < ARRAY_SIZE( xFiles ); xIndex++ )
    {
        if( xFiles[ xIndex ].pcFileName[ 0 ] == '\0' )
        {
            if( xFreeIndex < 0 )
            {
                xFreeIndex = xIndex;
            }
        }
        else if( strcmp( xFiles[ xIndex ].pcFileName, pcFname ) == 0 )
        {
            if( eAction == eCACHE_REMOVE )
            {
                xFiles[ xIndex ].pcFileName[ 0 ] = '\0';
            }

            pxResult = xFiles + xIndex;
            break;
        }
    }

    if( ( pxResult == NULL ) && ( eAction == eCACHE_ADD ) && ( xFreeIndex >= 0 ) )
    {
        pxResult = xFiles + xFreeIndex;
        snprintf( pxResult->pcFileName, sizeof( pxResult->pcFileName ), "%s", pcFname );
        pxResult->ulFileLength = 0;
        pxResult->ulFilePointer = 0;
    }

    return pxResult;
}

BaseType_t xCheckDevicePath( const char * pcPath )
{
    BaseType_t xDevLength;
    BaseType_t xPathLength;
    BaseType_t xIsDevice;

    xDevLength = sizeof( pcDevicePath ) - 1;
    xPathLength = strlen( pcPath );

    /* System "/dev" should not match with "/device/etc". */
    if( ( xPathLength >= xDevLength ) &&
        ( memcmp( pcDevicePath, pcPath, xDevLength ) == 0 ) &&
        ( ( pcPath[ xDevLength ] == '\0' ) || ( pcPath[ xDevLength ] == '/' ) ) )
    {
        xIsDevice = FF_DEV_CHAR_DEV;
    }
    else
    {
        xIsDevice = FF_DEV_NO_DEV;
    }

    return xIsDevice;
}

BaseType_t FF_Device_Open( const char * pcPath,
                           FF_FILE * pxStream )
{
    uint8_t ucIsDevice;

    ucIsDevice = xCheckDevicePath( pcPath );

    if( ucIsDevice != pdFALSE )
    {
        const char * pcBaseName = pcPath;

        if( memcmp( pcBaseName, pcDevicePath, sizeof( pcDevicePath ) - 1 ) == 0 )
        {
            pcBaseName = pcBaseName + sizeof( pcDevicePath );
        }

        pxStream->pxDevNode = pxFindFile( pcBaseName, eCACHE_ADD );

        if( pxStream->pxDevNode != NULL )
        {
            pxStream->pxDevNode->ulFilePointer = 0;

            if( ( pxStream->ucMode & ( FF_MODE_WRITE | FF_MODE_APPEND | FF_MODE_CREATE ) ) == 0 )
            {
                pxStream->ulFileSize = pxStream->pxDevNode->ulFileLength;
            }
        }
    }

    return ucIsDevice;
}

void FF_Device_Close( FF_FILE * pxStream )
{
    if( pxStream->pxDevNode != NULL )
    {
        pxStream->ulFileSize = 0ul;
        pxStream->ulFilePointer = 0ul;
    }
}

size_t FF_Device_Read( void * pvBuf,
                       size_t lSize,
                       size_t lCount,
                       FF_FILE * pxStream )
{
    lCount *= lSize;
    return lCount;
}

size_t FF_Device_Write( const void * pvBuf,
                        size_t lSize,
                        size_t lCount,
                        FF_FILE * pxStream )
{
    lCount *= lSize;

    if( pxStream->pxDevNode != NULL )
    {
        pxStream->pxDevNode->ulFilePointer += lCount;

        if( pxStream->pxDevNode->ulFileLength < pxStream->pxDevNode->ulFilePointer )
        {
            pxStream->pxDevNode->ulFileLength = pxStream->pxDevNode->ulFilePointer;
        }
    }

    return lCount;
}

int FF_Device_Seek( FF_FILE * pxStream,
                    long lOffset,
                    int iWhence )
{
    if( pxStream->pxDevNode != NULL )
    {
        if( iWhence == FF_SEEK_SET )
        {
            pxStream->pxDevNode->ulFilePointer = lOffset;
        }
        else if( iWhence == FF_SEEK_END )
        {
            pxStream->pxDevNode->ulFilePointer = pxStream->pxDevNode->ulFileLength - lOffset;
        }
    }

    return 0;
}

int FF_Device_GetDirEnt( const char * pcPath,
                         FF_DirEnt_t * pxDirEnt )
{
    BaseType_t xIsDotDir = 0;

    if( pxDirEnt->pcFileName[ 0 ] == '.' )
    {
        if( ( pxDirEnt->pcFileName[ 1 ] == '.' ) &&
            ( pxDirEnt->pcFileName[ 2 ] == '\0' ) )
        {
            xIsDotDir = 2;
        }
        else if( pxDirEnt->pcFileName[ 1 ] == '\0' )
        {
            xIsDotDir = 1;
        }
    }

    if( xIsDotDir == 0 )
    {
        struct SFileCache * pxDevNode;

        pxDevNode = pxFindFile( pxDirEnt->pcFileName, eCACHE_LOOKUP );

        pxDirEnt->ucIsDeviceDir = FF_DEV_CHAR_DEV;

        if( pxDevNode != NULL )
        {
            pxDirEnt->ulFileSize = pxDevNode->ulFileLength;
        }
        else if( pxDirEnt->ulFileSize < 2048 )
        {
            pxDirEnt->ulFileSize = 2048;
        }
    }

    return 1024;
}