file.html

fat16文件系统源码。需要的请下

- Sector size is 512 bytes
- 2 fats management
- 512 entries in the root directory
<HR>
<A NAME="fat_fputc"></A>
<H3> fat_fputc </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>void <A HREF="#fat_fputc">fat_fputc</A>  ( Byte d )  </PRE></TD>

</TABLE>
<P>
Write one byte to file
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  d: data byte to write
return:</PRE></TD>

</TABLE>
<H4> Note </H4>
<P>
As this function is called very often it must be short and optimized
in execution time
<HR>
<A NAME="fat_fputc"></A>
<H3> fat_fputc </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>void <A HREF="#fat_fputc">fat_fputc</A>  ( Byte d )  </PRE></TD>

</TABLE>
<P>
Write one byte to file
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  d: data byte to write
return:</PRE></TD>

</TABLE>
<H4> Note </H4>
<P>
As this function is called very often it must be short and optimized
in execution time
<HR>
<A NAME="fat_free_space"></A>
<H3> fat_free_space </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE><A HREF="#fat_st_free_space">fat_st_free_space</A> <A HREF="#fat_free_space">fat_free_space</A> ( void )  </PRE></TD>

</TABLE>
<P>
Get free space
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  
return:
  number of free cluster</PRE></TD>

</TABLE>
<H4> Note </H4>
<P>
<P>
<HR>
<A NAME="fat_fseek"></A>
<H3> fat_fseek </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>bit <A HREF="#fat_fseek">fat_fseek</A>  ( Int32 offset )  </PRE></TD>

</TABLE>
<P>
Change file pointer of an openned file
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  offset: relative signed seek offset in file
*
return:
  seek status:  - OK: seek done
                - KO: out of file seek</PRE></TD>

</TABLE>
<H4> Note </H4>
<P>
In read mode, seek is done with byte boundary
In write mode, seek is done with sector boundary
<HR>
<A NAME="fat_fseek"></A>
<H3> fat_fseek </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>bit <A HREF="#fat_fseek">fat_fseek</A>  ( Int32 offset )  </PRE></TD>

</TABLE>
<P>
Change file pointer of an openned file
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  offset: relative signed seek offset in file
*
return:
  seek status:  - OK: seek done
                - KO: out of file seek</PRE></TD>

</TABLE>
<H4> Note </H4>
<P>
In read mode, seek is done with byte boundary
In write mode, seek is done with sector boundary
<HR>
<A NAME="fat_fseek_abs"></A>
<H3> fat_fseek_abs </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>void <A HREF="#fat_fseek_abs">fat_fseek_abs</A>  ( Uint32 offset )  </PRE></TD>

</TABLE>
<P>
Move ahead file read pointer of an openned file
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  offset: absolute seek offset in file
*
return:</PRE></TD>

</TABLE>
<HR>
<A NAME="fat_fseek_abs"></A>
<H3> fat_fseek_abs </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>void <A HREF="#fat_fseek_abs">fat_fseek_abs</A>  ( Uint32 offset )  </PRE></TD>

</TABLE>
<P>
Move ahead file read pointer of an openned file
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  offset: absolute seek offset in file
*
return:</PRE></TD>

</TABLE>
<HR>
<A NAME="fat_get_clusters"></A>
<H3> fat_get_clusters </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>bit <A HREF="#fat_get_clusters">fat_get_clusters</A>  ( <A HREF="#fat_st_clust_chain">fat_st_clust_chain</A> xdata  * chain ,  Byte nb_frag )  </PRE></TD>

</TABLE>
<P>
Prepare a list of the file clusters:
chain[n].cluster contains the starting cluster number of a fragment
chain[n].number contains the number of contiguous clusters in fragment
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  chain:   allocation list address
  nb_frag: maximum number of fragment 
*
return:
  - OK: allocation done
  - KO: allocation done but truncated: file too much fragmented</PRE></TD>

</TABLE>
<H4> Note </H4>
<P>
File cluster list is limited by the nb_frag parameter.
If memory is too much fragmented, file may not be fully played.
Last list item always has single cluster
<HR>
<A NAME="fat_get_clusters"></A>
<H3> fat_get_clusters </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>bit <A HREF="#fat_get_clusters">fat_get_clusters</A>  ( <A HREF="#fat_st_clust_chain">fat_st_clust_chain</A> xdata  * chain ,  Byte nb_frag )  </PRE></TD>

</TABLE>
<P>
Prepare a list of the file clusters:
chain[n].cluster contains the starting cluster number of a fragment
chain[n].number contains the number of contiguous clusters in fragment
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  chain:   allocation list address
  nb_frag: maximum number of fragment 
*
return:
  - OK: allocation done
  - KO: allocation done but truncated: file too much fragmented</PRE></TD>

</TABLE>
<H4> Note </H4>
<P>
File cluster list is limited by the nb_frag parameter.
If memory is too much fragmented, file may not be fully played.
Last list item always has single cluster
<HR>
<A NAME="fat_get_dir_entry"></A>
<H3> fat_get_dir_entry </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>void <A HREF="#fat_get_dir_entry">fat_get_dir_entry</A>  ( <A HREF="#fat_st_dir_entry">fat_st_dir_entry</A> xdata  * entry )  </PRE></TD>

</TABLE>
<P>
Get from directory all information about a directory or file entry
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  entry: directory entry structure
*
return:</PRE></TD>

</TABLE>
<H4> Note </H4>
<P>
This function reads directly datas from sectors
It automaticaly computes difference between LFN and normal entries
<HR>
<A NAME="fat_get_dir_file_list"></A>
<H3> fat_get_dir_file_list </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>void <A HREF="#fat_get_dir_file_list">fat_get_dir_file_list</A>  ( Byte id )  </PRE></TD>

</TABLE>
<P>
Give information about the directory :
- total number of entries
- number of deleted entries
- number of filtered entries (filter is done by checking id value)
- total number of clusters used by the directory
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  id: file extension to select
*
return:</PRE></TD>

</TABLE>
<H4> Example </H4>
<PRE></PRE>

<H4> Note </H4>
<P>
<P>
<HR>
<A NAME="fat_get_dir_file_list"></A>
<H3> fat_get_dir_file_list </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>void <A HREF="#fat_get_dir_file_list">fat_get_dir_file_list</A>  ( Byte id )  </PRE></TD>

</TABLE>
<P>
Give information about the directory :
- total number of entries
- number of deleted entries
- number of filtered entries (filter is done by checking id value)
- total number of clusters used by the directory
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  id: file extension to select
*
return:</PRE></TD>

</TABLE>
<H4> Example </H4>
<PRE></PRE>

<H4> Note </H4>
<P>
<P>
<HR>
<A NAME="fat_get_free_clusters"></A>
<H3> fat_get_free_clusters </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>bit <A HREF="#fat_get_free_clusters">fat_get_free_clusters</A>  ( bit init )  </PRE></TD>

</TABLE>
<P>
Prepare a list of the free clusters:
chain[n].cluster contains the starting cluster number of a fragment
chain[n].number contains the number of contiguous clusters in fragment
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>*
return:
  - OK: allocation done
  - KO: allocation cannot be done : no free cluster</PRE></TD>

</TABLE>
<H4> Note </H4>
<P>
Free cluster list is limited by the nb_frag parameter.
If memory is too much fragmented, created file may be limited in size.
Last list item always has single cluster
<HR>
<A NAME="fat_get_name"></A>
<H3> fat_get_name </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>char pdata  *  <A HREF="#fat_get_name">fat_get_name</A>  ( void )  </PRE></TD>

</TABLE>
<P>
Return the address of the file name string
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>*
return:</PRE></TD>

</TABLE>
<HR>
<A NAME="fat_get_name"></A>
<H3> fat_get_name </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>char pdata  *  <A HREF="#fat_get_name">fat_get_name</A>  ( void )  </PRE></TD>

</TABLE>
<P>
Return the address of the file name string
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>*
return:</PRE></TD>

</TABLE>
<HR>
<A NAME="fat_get_root_directory"></A>
<H3> fat_get_root_directory </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>bit <A HREF="#fat_get_root_directory">fat_get_root_directory</A>  ( Byte id )  </PRE></TD>

</TABLE>
<P>
Select first available file/dir in root diretory
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  id: file extension to select
*
return:
  - OK: file available
  - KO: no requested file found
  - KO: low_level memory error</PRE></TD>

</TABLE>
<H4> Note </H4>
<P>
Fill all the cache information for the first time
<HR>
<A NAME="fat_get_root_directory"></A>
<H3> fat_get_root_directory </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>bit <A HREF="#fat_get_root_directory">fat_get_root_directory</A>  ( Byte id )  </PRE></TD>

</TABLE>
<P>
Select first available file/dir in root diretory
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  id: file extension to select
*
return:
  - OK: file available
  - KO: no requested file found
  - KO: low_level memory error</PRE></TD>

</TABLE>
<H4> Note </H4>
<P>
Fill all the cache information for the first time
<HR>
<A NAME="fat_goto_next"></A>
<H3> fat_goto_next </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>bit <A HREF="#fat_goto_next">fat_goto_next</A>  ( void )  </PRE></TD>

</TABLE>
<P>
Fetch the next dir/file info in cache
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>*
return:
  - OK: next file available
  - KO: last file reached
  - KO: low_level memory error</PRE></TD>

</TABLE>
<HR>
<A NAME="fat_goto_next"></A>
<H3> fat_goto_next </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>bit <A HREF="#fat_goto_next">fat_goto_next</A>  ( void )  </PRE></TD>

</TABLE>
<P>
Fetch the next dir/file info in cache
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>*
return:
  - OK: next file available
  - KO: last file reached
  - KO: low_level memory error</PRE></TD>

</TABLE>
<HR>
<A NAME="fat_goto_parentdir"></A>
<H3> fat_goto_parentdir </H3>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#D6E8FF"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>bit <A HREF="#fat_goto_parentdir">fat_goto_parentdir</A>  ( Byte id )  </PRE></TD>

</TABLE>
<P>
Go to the parent directory
<P>
<TABLE BORDER="0"  WIDTH="100 %"  BGCOLOR="#FFD0D0"  CELLPADDING="6">
<TR>
 <TD VALIGN=MIDDLE><PRE>  id: file extension to select
*
return:</PRE></TD>

</TABLE>