//*****************************************************************************
//
// sd_card.c - Example program for reading files from an SD card.
//
// Copyright (c) 2013-2014 Texas Instruments Incorporated.  All rights reserved.
// Software License Agreement
// 
// Texas Instruments (TI) is supplying this software for use solely and
// exclusively on TI's microcontroller products. The software is owned by
// TI and/or its suppliers, and is protected under applicable copyright
// laws. You may not combine this software with "viral" open-source
// software in order to form a larger program.
// 
// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
// NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT
// NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY
// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
// DAMAGES, FOR ANY REASON WHATSOEVER.
// 
// This is part of revision 2.1.0.12573 of the DK-TM4C129X Firmware Package.
//
//*****************************************************************************

#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include "driverlib/rom.h"
#include "driverlib/rom_map.h"
#include "driverlib/sysctl.h"
#include "driverlib/systick.h"
#include "grlib/grlib.h"
#include "grlib/widget.h"
#include "grlib/canvas.h"
#include "grlib/listbox.h"
#include "grlib/pushbutton.h"
#include "utils/cmdline.h"
#include "utils/uartstdio.h"
#include "utils/ustdlib.h"
#include "fatfs/src/ff.h"
#include "fatfs/src/diskio.h"
#include "drivers/frame.h"
#include "drivers/kentec320x240x16_ssd2119.h"
#include "drivers/pinout.h"
#include "drivers/touch.h"

//*****************************************************************************
//
//! \addtogroup example_list
//! <h1>SD card using FAT file system (sd_card)</h1>
//!
//! This example application demonstrates reading a file system from
//! an SD card.  It makes use of FatFs, a FAT file system driver.  It
//! provides a simple widget-based console on the display and also a
//! UART-based command line for viewing and navigating the file system
//! on the SD card.
//!
//! For additional details about FatFs, see the following site:
//! http://elm-chan.org/fsw/ff/00index_e.html
//!
//! The application may also be operated via a serial terminal attached to
//! UART0. The RS232 communication parameters should be set to 115,200 bits
//! per second, and 8-n-1 mode.  When the program is started a message will
//! be printed to the terminal.  Type ``help'' for command help.
//
//*****************************************************************************

//*****************************************************************************
//
// Defines the size of the buffers that hold the path, or temporary data from
// the SD card.  There are two buffers allocated of this size.  The buffer size
// must be large enough to hold the longest expected full path name, including
// the file name, and a trailing null character.
//
//*****************************************************************************
#define PATH_BUF_SIZE   80

//*****************************************************************************
//
// Defines the size of the buffer that holds the command line.
//
//*****************************************************************************
#define CMD_BUF_SIZE    64

//*****************************************************************************
//
// This buffer holds the full path to the current working directory.  Initially
// it is root ("/").
//
//*****************************************************************************
static char g_pcCwdBuf[PATH_BUF_SIZE] = "/";

//*****************************************************************************
//
// A temporary data buffer used when manipulating file paths, or reading data
// from the SD card.
//
//*****************************************************************************
static char g_pcTmpBuf[PATH_BUF_SIZE];

//*****************************************************************************
//
// The buffer that holds the command line.
//
//*****************************************************************************
static char g_pcCmdBuf[CMD_BUF_SIZE];

//*****************************************************************************
//
// The following are data structures used by FatFs.
//
//*****************************************************************************
static FATFS g_sFatFs;
static DIR g_sDirObject;
static FILINFO g_sFileInfo;
static FIL g_sFileObject;

//*****************************************************************************
//
// A structure that holds a mapping between an FRESULT numerical code, and a
// string representation.  FRESULT codes are returned from the FatFs FAT file
// system driver.
//
//*****************************************************************************
typedef struct
{
    FRESULT iFResult;
    char *pcResultStr;
}
tFResultString;

//*****************************************************************************
//
// A macro to make it easy to add result codes to the table.
//
//*****************************************************************************
#define FRESULT_ENTRY(f)        { (f), (#f) }

//*****************************************************************************
//
// A table that holds a mapping between the numerical FRESULT code and it's
// name as a string.  This is used for looking up error codes for printing to
// the console.
//
//*****************************************************************************
tFResultString g_psFResultStrings[] =
{
    FRESULT_ENTRY(FR_OK),
    FRESULT_ENTRY(FR_DISK_ERR),
    FRESULT_ENTRY(FR_INT_ERR),
    FRESULT_ENTRY(FR_NOT_READY),
    FRESULT_ENTRY(FR_NO_FILE),
    FRESULT_ENTRY(FR_NO_PATH),
    FRESULT_ENTRY(FR_INVALID_NAME),
    FRESULT_ENTRY(FR_DENIED),
    FRESULT_ENTRY(FR_EXIST),
    FRESULT_ENTRY(FR_INVALID_OBJECT),
    FRESULT_ENTRY(FR_WRITE_PROTECTED),
    FRESULT_ENTRY(FR_INVALID_DRIVE),
    FRESULT_ENTRY(FR_NOT_ENABLED),
    FRESULT_ENTRY(FR_NO_FILESYSTEM),
    FRESULT_ENTRY(FR_MKFS_ABORTED),
    FRESULT_ENTRY(FR_TIMEOUT),
    FRESULT_ENTRY(FR_LOCKED),
    FRESULT_ENTRY(FR_NOT_ENOUGH_CORE),
    FRESULT_ENTRY(FR_TOO_MANY_OPEN_FILES),
    FRESULT_ENTRY(FR_INVALID_PARAMETER),
};

//*****************************************************************************
//
// Error reasons returned by ChangeDirectory().
//
//*****************************************************************************
#define NAME_TOO_LONG_ERROR 1
#define OPENDIR_ERROR       2

//*****************************************************************************
//
// A macro that holds the number of result codes.
//
//*****************************************************************************
#define NUM_FRESULT_CODES       (sizeof(g_psFResultStrings) /                 \
                                 sizeof(tFResultString))

//*****************************************************************************
//
// Storage for the filename listbox widget string table.
//
//*****************************************************************************
#define NUM_LIST_STRINGS 48
const char *g_ppcDirListStrings[NUM_LIST_STRINGS];

//*****************************************************************************
//
// Storage for the names of the files in the current directory.  Filenames
// are stored in format "(D) filename.ext" for directories or "(F) filename.ext"
// for files.
//
//*****************************************************************************
#define MAX_FILENAME_STRING_LEN (4 + 8 + 1 + 3 + 1)
char g_pcFilenames[NUM_LIST_STRINGS][MAX_FILENAME_STRING_LEN];

//*****************************************************************************
//
// Storage for the strings which appear in the status box at the bottom of the
// display.
//
//****************************************************************************
#define NUM_STATUS_STRINGS 6
#define MAX_STATUS_STRING_LEN (36 + 1)
char g_pcStatus[NUM_STATUS_STRINGS][MAX_STATUS_STRING_LEN];

//*****************************************************************************
//
// Storage for the status listbox widget string table.
//
//*****************************************************************************
const char *g_ppcStatusStrings[NUM_STATUS_STRINGS] =
{
    g_pcStatus[0],
    g_pcStatus[1],
    g_pcStatus[2],
    g_pcStatus[3],
    g_pcStatus[4],
    g_pcStatus[5]
};
uint32_t g_ui32StatusStringIndex = 0;

//*****************************************************************************
//
// Graphics context used to show text on the display.
//
//*****************************************************************************
tContext g_sContext;

//*****************************************************************************
//
// The system clock frequency in Hz.
//
//*****************************************************************************
uint32_t g_ui32SysClock;

//*****************************************************************************
//
// Forward declarations for functions called by the widgets used in the user
// interface.
//
//*****************************************************************************
void OnListBoxChange(tWidget *psWidget, int16_t i16Selected);
void OnBtnCD(tWidget *psWidget);
void OnBtnUp(tWidget *psWidget);
static int PopulateFileListBox(bool bRedraw);
static FRESULT ChangeToDirectory(char *pcDirectory, uint32_t *pui32Reason);
static int PrintfStatus(char *pcFormat, ...);
static const char *StringFromFResult(FRESULT iFResult);

//*****************************************************************************
//
// Widget definitions
//
//*****************************************************************************

//*****************************************************************************
//
// The listbox used to display directory contents.
//
//*****************************************************************************
extern tCanvasWidget g_sBackground;
extern tCanvasWidget g_sUpBackground;
extern tCanvasWidget g_sCDBackground;

ListBox(g_sStatusList, &g_sBackground, 0, 0, &g_sKentec320x240x16_SSD2119,
        40, 170, 220, 52, (LISTBOX_STYLE_OUTLINE | LISTBOX_STYLE_LOCKED |
        LISTBOX_STYLE_WRAP), ClrBlack, ClrBlack, ClrSilver, ClrSilver, ClrWhite,
        g_psFontFixed6x8, g_ppcStatusStrings,  NUM_STATUS_STRINGS,
        NUM_STATUS_STRINGS, 0);

ListBox(g_sDirList, &g_sBackground, &g_sStatusList, 0,
        &g_sKentec320x240x16_SSD2119,
        40, 60, 120, 100, LISTBOX_STYLE_OUTLINE, ClrBlack, ClrDarkBlue,
        ClrSilver, ClrWhite, ClrWhite, g_psFontCmss12, g_ppcDirListStrings,
        NUM_LIST_STRINGS, 0, OnListBoxChange);

//*****************************************************************************
//
// The canvas widget used to show the current directory prompt.
//
//*****************************************************************************
Canvas(g_sPWDTitle, &g_sBackground, &g_sDirList, 0,
       &g_sKentec320x240x16_SSD2119, 10, 35, 40, 20, CANVAS_STYLE_TEXT,
       ClrBlack, 0, ClrWhite, g_psFontCmss12, "PWD:", 0, 0);

//*****************************************************************************
//
// The canvas widget used to show the current directory.
//
//*****************************************************************************
Canvas(g_sPWD, &g_sBackground, &g_sPWDTitle, 0, &g_sKentec320x240x16_SSD2119,
       50, 35, 260, 20, (CANVAS_STYLE_TEXT | CANVAS_STYLE_FILL |
       CANVAS_STYLE_TEXT_LEFT), ClrBlack, 0, ClrWhite, g_psFontCmss12,
       g_pcCwdBuf, 0, 0);

//*****************************************************************************
//
// The button used to change to the selected directory directory.
//
//*****************************************************************************
RectangularButton(g_sCDBtn, &g_sCDBackground, 0, 0,
                  &g_sKentec320x240x16_SSD2119, 170, 75, 90, 30,
                  (PB_STYLE_OUTLINE | PB_STYLE_TEXT_OPAQUE | PB_STYLE_TEXT |
                   PB_STYLE_FILL | PB_STYLE_RELEASE_NOTIFY),
                   ClrBlack, ClrBlue, ClrWhite, ClrWhite,
                   g_psFontCm20, "CD", 0, 0, 0, 0, OnBtnCD);

//*****************************************************************************
//
// The canvas widget acting as the background to the CD button.
//
//*****************************************************************************
Canvas(g_sCDBackground, WIDGET_ROOT, 0, 0,
       &g_sKentec320x240x16_SSD2119, 170, 75, 90, 30,
       CANVAS_STYLE_FILL, ClrBlack, 0, 0, 0, 0, 0, 0);

//*****************************************************************************
//
// The button used to change to the next higher directory.
//
//*****************************************************************************
RectangularButton(g_sUpBtn, &g_sUpBackground, 0, 0,
                  &g_sKentec320x240x16_SSD2119, 170, 115, 90, 30,
                  (PB_STYLE_OUTLINE | PB_STYLE_TEXT_OPAQUE | PB_STYLE_TEXT |
                   PB_STYLE_FILL | PB_STYLE_RELEASE_NOTIFY),
                   ClrBlack, ClrBlue, ClrWhite, ClrWhite,
                   g_psFontCm20, "Up", 0, 0, 0, 0, OnBtnUp);

//*****************************************************************************
//
// The canvas widget acting as the background to the UP button.
//
//*****************************************************************************
Canvas(g_sUpBackground, WIDGET_ROOT, &g_sCDBackground, 0,
       &g_sKentec320x240x16_SSD2119, 170, 115, 90, 30,
       CANVAS_STYLE_FILL, ClrBlack, 0, 0, 0, 0, 0, 0);

//*****************************************************************************
//
// The canvas widget acting as the background to the left portion of the
// display.
//
//*****************************************************************************
Canvas(g_sBackground, WIDGET_ROOT, &g_sUpBackground, &g_sPWD,
       &g_sKentec320x240x16_SSD2119, 10, 60, 120, 160,
       CANVAS_STYLE_FILL, ClrBlack, 0, 0, 0, 0, 0, 0);

//*****************************************************************************
//
// The listbox widget callback function.
//
// This function is called whenever someone changes the selected entry in the
// listbox containing the files and directories found in the current directory.
//
//*****************************************************************************
void OnListBoxChange(tWidget *psWidget, int16_t i16Selected)
{
    int16_t i16Sel;

    //
    // Get the current selection from the list box.
    //
    i16Sel = ListBoxSelectionGet(&g_sDirList);

    //
    // Is there any selection?
    //
    if(i16Sel == -1)
    {
        return;
    }
    else
    {
        //
        // Is the selection a directory name?
        //
        if(g_pcFilenames[i16Sel][1] == 'D')
        {
            //
            // Enable the "CD" button.
            //
            WidgetAdd((tWidget *)&g_sCDBackground, (tWidget *)&g_sCDBtn);
        }
        else
        {
            //
            // Hide the "CD" button.
            //
            WidgetRemove((tWidget *)&g_sCDBtn);
        }

        //
        // Make sure the CD button (or its background) is drawn correctly).
        //
        WidgetPaint((tWidget *)&g_sCDBackground);
    }

    //
    // Update the status display to say what we've done.
    //
    PrintfStatus("Selected %s %s\n",
                 (g_pcFilenames[i16Sel][1] == 'D') ? "dir" : "file",
                 &g_pcFilenames[i16Sel][4]);
}

//*****************************************************************************
//
// The "CD" button widget callback function.
//
// This function is called whenever someone presses the "CD" button.
//
//*****************************************************************************
void OnBtnCD(tWidget *psWidget)
{
    int16_t i16Selected;
    uint32_t ui32Reason;
    FRESULT iFResult;
    //
    // Get the current selection from the list box.
    //
    i16Selected = ListBoxSelectionGet(&g_sDirList);

    //
    // Is there any selection?
    //
    if(i16Selected == -1)
    {
        return;
    }
    else
    {
        //
        // Is the selection a directory name?
        //
        if(g_pcFilenames[i16Selected][1] == 'D')
        {
            //
            // Yes - change to the new directory.
            //
            iFResult = ChangeToDirectory(&g_pcFilenames[i16Selected][4],
                                        &ui32Reason);

            if(iFResult != FR_OK)
            {
                //
                // Update the status display to show the error.
                //
                PrintfStatus("Error changing directory.");
                PrintfStatus((char *)StringFromFResult(iFResult));
            }
            else
            {
                //
                // Tell the user what happened.
                //
                PrintfStatus("Changed to %s", g_pcCwdBuf);

                //
                // Update the directory name and the list box contents.
                //
                PopulateFileListBox(true);
                WidgetPaint((tWidget *)&g_sPWD);

                //
                // Enable the "Up" button and disable the "CD" button.
                //
                WidgetAdd((tWidget *)&g_sUpBackground, (tWidget *)&g_sUpBtn);
                WidgetRemove((tWidget *)&g_sCDBtn);

                //
                // Make sure the buttons are repainted correctly.
                //
                WidgetPaint((tWidget *)&g_sUpBtn);
                WidgetPaint((tWidget *)&g_sCDBackground);
            }
        }
    }
}

//*****************************************************************************
//
// The "Up" button widget callback function.
//
// This function is called whenever someone presses the "Up" button.
//
//*****************************************************************************
void OnBtnUp(tWidget *psWidget)
{
    uint32_t ui32Reason;
    FRESULT iFResult;

    //
    // Change up one directory.
    //
    iFResult = ChangeToDirectory("..", &ui32Reason);

    if(iFResult != FR_OK)
    {
        //
        // Update the status display to show the error.
        //
        PrintfStatus("Error changing directory.");
        PrintfStatus((char *)StringFromFResult(iFResult));
    }
    else
    {
        //
        // Update the directory name and the list box contents.
        //
        WidgetPaint((tWidget *)&g_sPWD);
        PopulateFileListBox(true);

        //
        // If we are now in the root directory, hide the "Up" button.
        //
        if((strlen(g_pcCwdBuf) == 1) && (g_pcCwdBuf[0] == '/'))
        {
            WidgetRemove((tWidget *)&g_sUpBtn);
        }
        else
        {
            WidgetAdd((tWidget *)&g_sUpBackground, (tWidget *)&g_sUpBtn);
        }

        //
        // Disable the CD button since repopulating the list removes the
        // selection.
        //
        WidgetRemove((tWidget *)&g_sCDBtn);

        //
        // Tell the user what happened.
        //
        PrintfStatus("Changed to %s", g_pcCwdBuf);

        //
        // Repaint the buttons.
        //
        WidgetPaint((tWidget *)&g_sUpBackground);
        WidgetPaint((tWidget *)&g_sCDBackground);
    }
}

//*****************************************************************************
//
// This function is used to add a new string to the status list box at the
// bottom of the display.  This shows errors and echos user commands entered
// via the UART.
//
//*****************************************************************************
static int
PrintfStatus(char *pcFormat, ...)
{
    int32_t i32Ret;
    va_list vaArgP;

    //
    // Start the varargs processing.
    //
    va_start(vaArgP, pcFormat);

    //
    // Call vsnprintf to perform the conversion.
    //
    i32Ret = uvsnprintf(g_pcStatus[g_ui32StatusStringIndex],
                        MAX_STATUS_STRING_LEN, pcFormat, vaArgP);

    //
    // End the varargs processing.
    //
    va_end(vaArgP);

    //
    // Add the new string to the status listbox.
    //
    ListBoxTextAdd(&g_sStatusList, g_pcStatus[g_ui32StatusStringIndex]);

    //
    // Update our string index.
    //
    g_ui32StatusStringIndex++;
    if(g_ui32StatusStringIndex == NUM_STATUS_STRINGS)
    {
        g_ui32StatusStringIndex = 0;
    }

    //
    // Repaint the status listbox.
    //
    WidgetPaint((tWidget *)&g_sStatusList);

    //
    // Return the conversion count.
    //
    return(i32Ret);

}

//*****************************************************************************
//
// This function returns a string representation of an error code
// that was returned from a function call to FatFs.  It can be used
// for printing human readable error messages.
//
//*****************************************************************************
static const char *
StringFromFResult(FRESULT iFResult)
{
    uint32_t ui32Idx;

    //
    // Enter a loop to search the error code table for a matching error code.
    //
    for(ui32Idx = 0; ui32Idx < NUM_FRESULT_CODES; ui32Idx++)
    {
        //
        // If a match is found, then return the string name of the error code.
        //
        if(g_psFResultStrings[ui32Idx].iFResult == iFResult)
        {
            return(g_psFResultStrings[ui32Idx].pcResultStr);
        }
    }

    //
    // At this point no matching code was found, so return a string indicating
    // an unknown error.
    //
    return("UNKNOWN ERROR CODE");
}

//*****************************************************************************
//
// This is the handler for this SysTick interrupt.  FatFs requires a timer tick
// every 10 ms for internal timing purposes.
//
//*****************************************************************************
void
SysTickHandler(void)
{
    //
    // Call the FatFs tick timer.
    //
    disk_timerproc();
}

//*****************************************************************************
//
// This function implements the "ls" command.  It opens the current directory
// and enumerates through the contents, and prints a line for each item it
// finds.  It shows details such as file attributes, time and date, and the
// file size, along with the name.  It shows a summary of file sizes at the end
// along with free space.
//
//*****************************************************************************
int
Cmd_ls(int argc, char *argv[])
{
    uint32_t ui32TotalSize, ui32ItemCount, ui32FileCount, ui32DirCount;
    FRESULT iFResult;
    FATFS *psFatFs;
    char *pcFileName;
#if _USE_LFN
    char pucLfn[_MAX_LFN + 1];
    g_sFileInfo.lfname = pucLfn;
    g_sFileInfo.lfsize = sizeof(pucLfn);
#endif

    //
    // Empty the list box on the display.
    //
    ListBoxClear(&g_sDirList);

    //
    // Make sure the list box will be redrawn next time the message queue
    // is processed.
    //
    WidgetPaint((tWidget *)&g_sDirList);

    //
    // Open the current directory for access.
    //
    iFResult = f_opendir(&g_sDirObject, g_pcCwdBuf);

    //
    // Check for error and return if there is a problem.
    //
    if(iFResult != FR_OK)
    {
        //
        // Ensure that the error is reported.
        //
        ListBoxTextAdd(&g_sDirList, "Error from SD Card:");
        ListBoxTextAdd(&g_sDirList, (char *)StringFromFResult(iFResult));
        return(iFResult);
    }

    ui32TotalSize = 0;
    ui32FileCount = 0;
    ui32DirCount = 0;
    ui32ItemCount = 0;

    //
    // Give an extra blank line before the listing.
    //
    UARTprintf("\n");

    //
    // Enter loop to enumerate through all directory entries.
    //
    for(;;)
    {
        //
        // Read an entry from the directory.
        //
        iFResult = f_readdir(&g_sDirObject, &g_sFileInfo);

        //
        // Check for error and return if there is a problem.
        //
        if(iFResult != FR_OK)
        {
            return((int)iFResult);
        }

        //
        // If the file name is blank, then this is the end of the listing.
        //
        if(!g_sFileInfo.fname[0])
        {
            break;
        }

#if _USE_LFN
        pcFileName = ((*g_sFileInfo.lfname)?g_sFileInfo.lfname:g_sFileInfo.fname);
#else
        pcFileName = g_sFileInfo.fname;
#endif

        //
        // Print the entry information on a single line with formatting to show
        // the attributes, date, time, size, and name.
        //
        UARTprintf("%c%c%c%c%c %u/%02u/%02u %02u:%02u %9u  %s\n",
                 (g_sFileInfo.fattrib & AM_DIR) ? 'D' : '-',
                 (g_sFileInfo.fattrib & AM_RDO) ? 'R' : '-',
                 (g_sFileInfo.fattrib & AM_HID) ? 'H' : '-',
                 (g_sFileInfo.fattrib & AM_SYS) ? 'S' : '-',
                 (g_sFileInfo.fattrib & AM_ARC) ? 'A' : '-',
                 (g_sFileInfo.fdate >> 9) + 1980,
                 (g_sFileInfo.fdate >> 5) & 15,
                 g_sFileInfo.fdate & 31,
                 (g_sFileInfo.ftime >> 11),
                 (g_sFileInfo.ftime >> 5) & 63,
                 g_sFileInfo.fsize,
                 pcFileName);

        //
        // Add the information as a line in the listbox widget.
        //
        if(ui32ItemCount < NUM_LIST_STRINGS)
        {
            usprintf(g_pcFilenames[ui32ItemCount], "(%c) %12s",
                     (g_sFileInfo.fattrib & AM_DIR) ? 'D' : 'F',
                      g_sFileInfo.fname);
            ListBoxTextAdd(&g_sDirList, g_pcFilenames[ui32ItemCount]);
        }

        //
        // If the attribute is directory, then increment the directory count.
        //
        if(g_sFileInfo.fattrib & AM_DIR)
        {
            ui32DirCount++;
        }

        //
        // Otherwise, it is a file.  Increment the file count, and
        // add in the file size to the total.
        //
        else
        {
            ui32FileCount++;
            ui32TotalSize += g_sFileInfo.fsize;
        }

        //
        // Move to the next entry in the item array we use to populate the
        // list box.
        //
        ui32ItemCount++;

        //
        // Wait for the UART transmit buffer to empty.
        //
        UARTFlushTx(false);

    }   // endfor

    //
    // Print summary lines showing the file, dir, and size totals.
    //
    UARTprintf("\n%4u File(s),%10u bytes total\n%4u Dir(s)",
                ui32FileCount, ui32TotalSize, ui32DirCount);

    //
    // Get the free space.
    //
    iFResult = f_getfree("/", (DWORD *)&ui32TotalSize, &psFatFs);

    //
    // Check for error and return if there is a problem.
    //
    if(iFResult != FR_OK)
    {
        return((int)iFResult);
    }

    //
    // Display the amount of free space that was calculated.
    //
    UARTprintf(", %10uK bytes free\n", (ui32TotalSize *
                                        psFatFs->free_clust / 2));
    //
    // Wait for the UART transmit buffer to empty.
    //
    UARTFlushTx(false);

    //
    // Made it to here, return with no errors.
    //
    return(0);
}

//*****************************************************************************
//
// This function is called to read the contents of the current directory on
// the SD card and fill the listbox containing the names of all files and
// directories.
//
//*****************************************************************************
static int
PopulateFileListBox(bool bRepaint)
{
    uint32_t ui32ItemCount;
    FRESULT iFResult;

    //
    // Empty the list box on the display.
    //
    ListBoxClear(&g_sDirList);

    //
    // Make sure the list box will be redrawn next time the message queue
    // is processed.
    //
    if(bRepaint)
    {
        WidgetPaint((tWidget *)&g_sDirList);
    }

    //
    // Open the current directory for access.
    //
    iFResult = f_opendir(&g_sDirObject, g_pcCwdBuf);

    //
    // Check for error and return if there is a problem.
    //
    if(iFResult != FR_OK)
    {
        //
        // Ensure that the error is reported.
        //
        PrintfStatus("Error from SD Card:");
        PrintfStatus((char *)StringFromFResult(iFResult));
        return(iFResult);
    }

    ui32ItemCount = 0;

    //
    // Enter loop to enumerate through all directory entries.
    //
    for(;;)
    {
        //
        // Read an entry from the directory.
        //
        iFResult = f_readdir(&g_sDirObject, &g_sFileInfo);

        //
        // Check for error and return if there is a problem.
        //
        if(iFResult != FR_OK)
        {
            PrintfStatus("Error from SD Card:");
            PrintfStatus((char *)StringFromFResult(iFResult));
            return(iFResult);
        }

        //
        // If the file name is blank, then this is the end of the
        // listing.
        //
        if(!g_sFileInfo.fname[0])
        {
            break;
        }

        //
        // Add the information as a line in the listbox widget.
        //
        if(ui32ItemCount < NUM_LIST_STRINGS)
        {
            usnprintf(g_pcFilenames[ui32ItemCount], MAX_FILENAME_STRING_LEN,
                      "(%c) %s", (g_sFileInfo.fattrib & AM_DIR) ? 'D' : 'F',
                      g_sFileInfo.fname);
            ListBoxTextAdd(&g_sDirList, g_pcFilenames[ui32ItemCount]);
        }

        //
        // Move to the next entry in the item array we use to populate the
        // list box.
        //
        ui32ItemCount++;
    }   // endfor

    //
    // Made it to here, return with no errors.
    //
    return(0);
}

//*****************************************************************************
//
// This function implements the "cd" command.  It takes an argument
// that specifes the directory to make the current working directory.
// Path separators must use a forward slash "/".  The argument to cd
// can be one of the following:
// * root ("/")
// * a fully specified path ("/my/path/to/mydir")
// * a single directory name that is in the current directory ("mydir")
// * parent directory ("..")
//
// It does not understand relative paths, so dont try something like this:
// ("../my/new/path")
//
// Once the new directory is specified, it attempts to open the directory to
// make sure it exists.  If the new path is opened successfully, then the
// current working directory (cwd) is changed to the new path.
//
// In cases of error, the pui32Reason parameter will be written with one of
// the following values:
//
//*****************************************************************************
static FRESULT
ChangeToDirectory(char *pcDirectory, uint32_t *pui32Reason)
{
    uint32_t ui32Idx;
    FRESULT iFResult;

    //
    // Copy the current working path into a temporary buffer so it can be
    // manipulated.
    //
    strcpy(g_pcTmpBuf, g_pcCwdBuf);

    //
    // If the first character is /, then this is a fully specified path, and it
    // should just be used as-is.
    //
    if(pcDirectory[0] == '/')
    {
        //
        // Make sure the new path is not bigger than the cwd buffer.
        //
        if(strlen(pcDirectory) + 1 > sizeof(g_pcCwdBuf))
        {
            *pui32Reason = NAME_TOO_LONG_ERROR;
            return(FR_OK);
        }

        //
        // If the new path name (in argv[1])  is not too long, then
        // copy it into the temporary buffer so it can be checked.
        //
        else
        {
            strncpy(g_pcTmpBuf, pcDirectory, sizeof(g_pcTmpBuf));
        }
    }

    //
    // If the argument is .. then attempt to remove the lowest level
    // on the CWD.
    //
    else if(!strcmp(pcDirectory, ".."))
    {
        //
        // Get the index to the last character in the current path.
        //
        ui32Idx = strlen(g_pcTmpBuf) - 1;

        //
        // Back up from the end of the path name until a separator (/) is
        // found, or until we bump up to the start of the path.
        //
        while((g_pcTmpBuf[ui32Idx] != '/') && (ui32Idx > 1))
        {
            //
            // Back up one character.
            //
            ui32Idx--;
        }

        //
        // Now we are either at the lowest level separator in the current path,
        // or at the beginning of the string (root).  So set the new end of
        // string here, effectively removing that last part of the path.
        //
        g_pcTmpBuf[ui32Idx] = 0;
    }

    //
    // Otherwise this is just a normal path name from the current directory,
    // and it needs to be appended to the current path.
    //
    else
    {
        //
        // Test to make sure that when the new additional path is added on to
        // the current path, there is room in the buffer for the full new path.
        // It needs to include a new separator, and a trailing null character.
        //
        if(strlen(g_pcTmpBuf) + strlen(pcDirectory) + 1 + 1 > sizeof(g_pcCwdBuf))
        {
            *pui32Reason = NAME_TOO_LONG_ERROR;
            return(FR_INVALID_OBJECT);
        }

        //
        // The new path is okay, so add the separator and then append the new
        // directory to the path.
        //
        else
        {
            //
            // If not already at the root level, then append a /
            //
            if(strcmp(g_pcTmpBuf, "/"))
            {
                strcat(g_pcTmpBuf, "/");
            }

            //
            // Append the new directory to the path.
            //
            strcat(g_pcTmpBuf, pcDirectory);
        }
    }

    //
    // At this point, a candidate new directory path is in chTmpBuf.  Try to
    // open it to make sure it is valid.
    //
    iFResult = f_opendir(&g_sDirObject, g_pcTmpBuf);

    //
    // If it can't be opened, then it is a bad path.  Inform the user and
    // return.
    //
    if(iFResult != FR_OK)
    {
        *pui32Reason = OPENDIR_ERROR;
        return(iFResult);
    }

    //
    // Otherwise, it is a valid new path, so copy it into the CWD and update
    // the screen.
    //
    else
    {
        strncpy(g_pcCwdBuf, g_pcTmpBuf, sizeof(g_pcCwdBuf));
    }

    //
    // Return success.
    //
    return(FR_OK);
}

//*****************************************************************************
//
// This function implements the "cd" command.  It takes an argument
// that specifes the directory to make the current working directory.
// Path separators must use a forward slash "/".  The argument to cd
// can be one of the following:
// * root ("/")
// * a fully specified path ("/my/path/to/mydir")
// * a single directory name that is in the current directory ("mydir")
// * parent directory ("..")
//
// It does not understand relative paths, so dont try something like this:
// ("../my/new/path")
//
// Once the new directory is specified, it attempts to open the directory
// to make sure it exists.  If the new path is opened successfully, then
// the current working directory (cwd) is changed to the new path.
//
//*****************************************************************************
int
Cmd_cd(int argc, char *argv[])
{
    uint32_t ui32Reason;
    FRESULT iFResult;

    //
    // Try to change to the directory provided on the command line.
    //
    iFResult = ChangeToDirectory(argv[1], &ui32Reason);

    //
    // If an error was reported, try to offer some helpful information.
    //
    if(iFResult != FR_OK)
    {
        switch(ui32Reason)
        {
            case OPENDIR_ERROR:
                UARTprintf("Error opening new directory.\n");
                PrintfStatus("Error opening new directory.\n");
                break;

            case NAME_TOO_LONG_ERROR:
                UARTprintf("Resulting path name is too long.\n");
                PrintfStatus("Resulting path name is too long.\n");
                break;

            default:
                UARTprintf("An unrecognized error was reported.\n");
                PrintfStatus("An unrecognized error was reported.\n");
                break;
        }
    }
    else
    {
        //
        // Tell the user what happened.
        //
        PrintfStatus("Changed to %s", g_pcCwdBuf);

        //
        // Update the contents of the file list.
        //
        PopulateFileListBox(true);

        //
        // Update the current directory on the display.
        //
        WidgetPaint((tWidget *)&g_sPWD);

        //
        // Enable the "Up" button if we are no longer in the root directory.
        //
        if((g_pcCwdBuf[0] == '/') && (g_pcCwdBuf[1] == '\0'))
        {
            //
            // We are in the root directory so disable the "Up" button.
            //
            WidgetRemove((tWidget *)&g_sUpBtn);
        }
        else
        {
            //
            // Enable the "Up" button.
            //
            WidgetAdd((tWidget *)&g_sUpBackground, (tWidget *)&g_sUpBtn);
        }

        //
        // Make sure the "Up" button is repainted correctly.
        //
        WidgetPaint((tWidget *)&g_sUpBackground);
    }

    //
    // Return the appropriate error code.
    //
    return(iFResult);
}

//*****************************************************************************
//
// This function implements the "pwd" command.  It simply prints the current
// working directory.
//
//*****************************************************************************
int
Cmd_pwd(int argc, char *argv[])
{
    //
    // Print the CWD to the console.
    //
    UARTprintf("%s\n", g_pcCwdBuf);

    //
    // Wait for the UART transmit buffer to empty.
    //
    UARTFlushTx(false);

    //
    // Return success.
    //
    return(0);
}

//*****************************************************************************
//
// This function implements the "cat" command.  It reads the contents of a file
// and prints it to the console.  This should only be used on text files.  If
// it is used on a binary file, then a bunch of garbage is likely to printed on
// the console.
//
//*****************************************************************************
int
Cmd_cat(int argc, char *argv[])
{
    FRESULT iFResult;
    uint32_t ui32BytesRead;

    //
    // First, check to make sure that the current path (CWD), plus the file
    // name, plus a separator and trailing null, will all fit in the temporary
    // buffer that will be used to hold the file name.  The file name must be
    // fully specified, with path, to FatFs.
    //
    if(strlen(g_pcCwdBuf) + strlen(argv[1]) + 1 + 1 > sizeof(g_pcTmpBuf))
    {
        UARTprintf("Resulting path name is too long\n");
        return(0);
    }

    //
    // Copy the current path to the temporary buffer so it can be manipulated.
    //
    strcpy(g_pcTmpBuf, g_pcCwdBuf);

    //
    // If not already at the root level, then append a separator.
    //
    if(strcmp("/", g_pcCwdBuf))
    {
        strcat(g_pcTmpBuf, "/");
    }

    //
    // Now finally, append the file name to result in a fully specified file.
    //
    strcat(g_pcTmpBuf, argv[1]);

    //
    // Open the file for reading.
    //
    iFResult = f_open(&g_sFileObject, g_pcTmpBuf, FA_READ);

    //
    // If there was some problem opening the file, then return an error.
    //
    if(iFResult != FR_OK)
    {
        return((int)iFResult);
    }

    //
    // Enter a loop to repeatedly read data from the file and display it, until
    // the end of the file is reached.
    //
    do
    {
        //
        // Read a block of data from the file.  Read as much as can fit in the
        // temporary buffer, including a space for the trailing null.
        //
        iFResult = f_read(&g_sFileObject, g_pcTmpBuf, sizeof(g_pcTmpBuf) - 1,
                          (UINT *)&ui32BytesRead);

        //
        // If there was an error reading, then print a newline and return the
        // error to the user.
        //
        if(iFResult != FR_OK)
        {
            UARTprintf("\n");
            return((int)iFResult);
        }

        //
        // Null terminate the last block that was read to make it a null
        // terminated string that can be used with printf.
        //
        g_pcTmpBuf[ui32BytesRead] = 0;

        //
        // Print the last chunk of the file that was received.
        //
        UARTprintf("%s", g_pcTmpBuf);

        //
        // Wait for the UART transmit buffer to empty.
        //
        UARTFlushTx(false);

    //
    // Continue reading until less than the full number of bytes are
    // read.  That means the end of the buffer was reached.
    //
    }
    while(ui32BytesRead == sizeof(g_pcTmpBuf) - 1);

    //
    // Return success.
    //
    return(0);
}

//*****************************************************************************
//
// This function implements the "help" command.  It prints a simple list of the
// available commands with a brief description.
//
//*****************************************************************************
int
Cmd_help(int argc, char *argv[])
{
    tCmdLineEntry *psEntry;

    //
    // Print some header text.
    //
    UARTprintf("\nAvailable commands\n");
    UARTprintf("------------------\n");

    //
    // Point at the beginning of the command table.
    //
    psEntry = &g_psCmdTable[0];

    //
    // Enter a loop to read each entry from the command table.  The end of the
    // table has been reached when the command name is NULL.
    //
    while(psEntry->pcCmd)
    {
        //
        // Print the command name and the brief description.
        //
        UARTprintf("%6s: %s\n", psEntry->pcCmd, psEntry->pcHelp);

        //
        // Advance to the next entry in the table.
        //
        psEntry++;

        //
        // Wait for the UART to catch up.
        //
        UARTFlushTx(false);
    }

    //
    // Return success.
    //
    return(0);
}

//*****************************************************************************
//
// This is the table that holds the command names, implementing functions, and
// brief description.
//
//*****************************************************************************
tCmdLineEntry g_psCmdTable[] =
{
    { "help",   Cmd_help,   "Display list of commands" },
    { "h",      Cmd_help,   "alias for help" },
    { "?",      Cmd_help,   "alias for help" },
    { "ls",     Cmd_ls,     "Display list of files" },
    { "chdir",  Cmd_cd,     "Change directory" },
    { "cd",     Cmd_cd,     "alias for chdir" },
    { "pwd",    Cmd_pwd,    "Show current working directory" },
    { "cat",    Cmd_cat,    "Show contents of a text file" },
    { 0, 0, 0 }
};

//*****************************************************************************
//
// The error routine that is called if the driver library encounters an error.
//
//*****************************************************************************
#ifdef DEBUG
void
__error__(char *pcFilename, uint32_t ui32Line)
{
}
#endif

//*****************************************************************************
//
// The program main function.  It performs initialization, then runs a command
// processing loop to read commands from the console.
//
//*****************************************************************************
int
main(void)
{
    int nStatus;
    FRESULT iFResult;

    //
    // Run from the PLL at 120 MHz.
    //
    g_ui32SysClock = MAP_SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ |
                                             SYSCTL_OSC_MAIN |
                                             SYSCTL_USE_PLL |
                                             SYSCTL_CFG_VCO_480), 120000000);

    //
    // Configure the device pins.
    //
    PinoutSet();

    //
    // Initialize the display driver.
    //
    Kentec320x240x16_SSD2119Init(g_ui32SysClock);

    //
    // Initialize the graphics context.
    //
    GrContextInit(&g_sContext, &g_sKentec320x240x16_SSD2119);

    //
    // Draw the application frame.
    //
    FrameDraw(&g_sContext, "sd-card");

    //
    // Configure SysTick for a 100Hz interrupt.
    //
    ROM_SysTickPeriodSet(g_ui32SysClock / 100);
    ROM_SysTickEnable();
    ROM_SysTickIntEnable();

    //
    // Initialize the UART for console I/O.
    //
    UARTStdioConfig(0, 115200, g_ui32SysClock);

    //
    // Initialize the touch screen driver.
    //
    TouchScreenInit(g_ui32SysClock);

    //
    // Set the touch screen event handler.
    //
    TouchScreenCallbackSet(WidgetPointerMessage);

    //
    // Add the compile-time defined widgets to the widget tree.
    //
    WidgetAdd(WIDGET_ROOT, (tWidget *)&g_sBackground);

    //
    // Set some initial strings.
    //
    ListBoxTextAdd(&g_sDirList, "Initializing...");

    //
    // Issue the initial paint request to the widgets then immediately call
    // the widget manager to process the paint message.  This ensures that the
    // display is drawn as quickly as possible and saves the delay we would
    // otherwise experience if we processed the paint message after mounting
    // and reading the SD card.
    //
    WidgetPaint(WIDGET_ROOT);
    WidgetMessageQueueProcess();

    //
    // Print hello message to user.
    //
    UARTprintf("\n\nSD Card Example Program\n");
    UARTprintf("Type \'help\' for help.\n");

    //
    // Mount the file system, using logical disk 0.
    //
    iFResult = f_mount(0, &g_sFatFs);
    if(iFResult != FR_OK)
    {
        UARTprintf("f_mount error: %s\n", StringFromFResult(iFResult));
        return(1);
    }

    //
    // Populate the list box with the contents of the root directory.
    //
    PopulateFileListBox(true);

    //
    // Enter an (almost) infinite loop for reading and processing commands from
    // the user.
    //
    while(1)
    {
        //
        // Print a prompt to the console.  Show the CWD.
        //
        UARTprintf("\n%s> ", g_pcCwdBuf);

        //
        // Is there a command waiting to be processed?
        //
        while(UARTPeek('\r') < 0)
        {
            //
            // Process any messages in the widget message queue.
            //
            WidgetMessageQueueProcess();
        }

        //
        // Get a line of text from the user.
        //
        UARTgets(g_pcCmdBuf, sizeof(g_pcCmdBuf));

        //
        // Pass the line from the user to the command processor.  It will be
        // parsed and valid commands executed.
        //
        nStatus = CmdLineProcess(g_pcCmdBuf);

        //
        // Handle the case of bad command.
        //
        if(nStatus == CMDLINE_BAD_CMD)
        {
            UARTprintf("Bad command!\n");
        }

        //
        // Handle the case of too many arguments.
        //
        else if(nStatus == CMDLINE_TOO_MANY_ARGS)
        {
            UARTprintf("Too many arguments for command processor!\n");
        }

        //
        // Otherwise the command was executed.  Print the error code if one was
        // returned.
        //
        else if(nStatus != 0)
        {
            UARTprintf("Command returned error code %s\n",
                        StringFromFResult((FRESULT)nStatus));
        }
    }
}