filesys_8h.html

MP3播放器源代码, VS1003B

00499         next.<a class="code" href="unionAddress.html#o0">l</a> = <a class="code" href="buffer_8c.html#a0">diskSect</a>.<a class="code" href="unionDiskBlock.html#o4">Fat32Table</a>[entryNumber];
00500       }
00501     }<span class="comment">//This repeats until there is a discontinuity</span>
00502     
00503     <span class="comment">/* next.l now has the cluster entry for last cluster in fragment</span>
00504 <span class="comment">       it has a high value if eof (see FAT spec) */</span>
00505 
00506     
00507     ConsoleWrite(<span class="stringliteral">"Size: "</span>);
00508     ConsolePutUInt(fragment[c].length);
00509     ConsoleWrite(<span class="stringliteral">"sectors."</span>);
00510 
00511     <span class="comment">//EOF test</span>
00512     <span class="keywordflow">if</span> ((next.<a class="code" href="unionAddress.html#o1">b</a>.<a class="code" href="structAddress_1_1B.html#o3">b3</a>&amp;0x08) <span class="comment">//Quick test</span>
00513         &amp;&amp; ((next.<a class="code" href="unionAddress.html#o0">l</a>&gt;0x0ffffff0) | !<a class="code" href="filesys_8h.html#a0">IS_FAT_32</a>)){ <span class="comment">//Complete test</span>
00514       <span class="comment">//EOF</span>
00515       ConsoleWrite(<span class="stringliteral">" &lt;EOF&gt;\r"</span>);
00516       <a class="code" href="buffer_8c.html#a2">sectorAddress</a>.<a class="code" href="unionAddress.html#o1">b</a>.<a class="code" href="structAddress_1_1B.html#o3">b3</a> = 0xff;
00517     }<span class="keywordflow">else</span>{
00518       
00519       <span class="comment">//Determine next physical sector for next fragment</span>
00520       <a class="code" href="buffer_8c.html#a2">sectorAddress</a>.<a class="code" href="unionAddress.html#o0">l</a> = next.<a class="code" href="unionAddress.html#o0">l</a>;
00521       <a class="code" href="buffer_8c.html#a2">sectorAddress</a>.<a class="code" href="unionAddress.html#o0">l</a> *= <a class="code" href="filesys_8c.html#a5">fatSectorsPerCluster</a>;
00522       <a class="code" href="buffer_8c.html#a2">sectorAddress</a>.<a class="code" href="unionAddress.html#o0">l</a> += <a class="code" href="filesys_8c.html#a4">dataStart</a>;
00523     }
00524     
00525     c++; <span class="comment">//Advance to next fragment number</span>
00526     
00527     <span class="keywordflow">if</span> (c==<a class="code" href="filesys_8c.html#a0">MAX_NUMBER_FRAGMENTS</a>){
00528       <span class="comment">//End of RAM space allocated for fragment table</span>
00529       <span class="comment">//Force end-of-file</span>
00530       <a class="code" href="buffer_8c.html#a2">sectorAddress</a>.<a class="code" href="unionAddress.html#o1">b</a>.<a class="code" href="structAddress_1_1B.html#o3">b3</a>=0xff;
00531     }
00532     
00533   }<span class="comment">//break or continue to next cluster</span>
00534   
00535   <span class="keywordflow">return</span> c; <span class="comment">//Return number of fragments;</span>
00536 }
</div></pre>
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<a class="anchor" name="a9" doxytag="filesys.h::FGetChar" ></a><p>
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          <td class="md" nowrap valign="top"> unsigned char FGetChar           </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="mdname1" valign="top" nowrap>          </td>
          <td class="md" valign="top">&nbsp;)&nbsp;</td>
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<p>
Read a character from current file. 
<p>
This can be called after calling OpenFile. It is a slow method for reading character based file data. fileSize holds the number of characters still left in file to be read, check for fileSize=0 to detect end-of-file. If FGetChar is called after the end of file is reached, it does nothing and returns 0. 
<p>
Definition at line <a class="el" href="filesys_8c-source.html#l00561">561</a> of file <a class="el" href="filesys_8c-source.html">filesys.c</a>.
<p>
References <a class="el" href="buffer_8h-source.html#l00107">DiskBlock::Raw::buf</a>, <a class="el" href="buffer_8c-source.html#l00013">dataBufPtr</a>, <a class="el" href="buffer_8c-source.html#l00010">diskSect</a>, <a class="el" href="filesys_8c-source.html#l00047">fileSize</a>, <a class="el" href="buffer_8h-source.html#l00129">Address::l</a>, <a class="el" href="filesys_8c-source.html#l00541">LoadNextSector()</a>, <a class="el" href="board_8h-source.html#l00280">Public</a>, <a class="el" href="unionDiskBlock.html#o1">DiskBlock::raw</a>, <a class="el" href="storage_8c-source.html#l00110">ReadDiskSector()</a>, and <a class="el" href="buffer_8c-source.html#l00015">sectorAddress</a>.
<p>
Referenced by <a class="el" href="aviplay_8c-source.html#l00015">GetAVIBlock()</a>.
<p>
<pre class="fragment"><div>00561                                {
00562 
00563   <span class="keywordflow">if</span> (!<a class="code" href="filesys_8c.html#a7">fileSize</a>) <span class="keywordflow">return</span> 0; <span class="comment">//return 0 for end-of-file</span>
00564 
00565   <span class="keywordflow">if</span> (<a class="code" href="buffer_8c.html#a1">dataBufPtr</a>==0){
00566     <span class="comment">/* A file has been opened but not read from yet, so read the first</span>
00567 <span class="comment">       sector. */</span>
00568     <a class="code" href="storage_8h.html#a2">ReadDiskSector</a>(<a class="code" href="buffer_8c.html#a2">sectorAddress</a>.<a class="code" href="unionAddress.html#o0">l</a>);
00569     <a class="code" href="buffer_8c.html#a1">dataBufPtr</a> = <a class="code" href="buffer_8c.html#a0">diskSect</a>.<a class="code" href="unionDiskBlock.html#o1">raw</a>.<a class="code" href="structDiskBlock_1_1Raw.html#o0">buf</a>;
00570   }
00571 
00572   <span class="keywordflow">if</span> (<a class="code" href="buffer_8c.html#a1">dataBufPtr</a>&gt;<a class="code" href="buffer_8c.html#a0">diskSect</a>.<a class="code" href="unionDiskBlock.html#o1">raw</a>.<a class="code" href="structDiskBlock_1_1Raw.html#o0">buf</a>+511){
00573     <span class="comment">/* An end of sector has been reached, read the next sector */</span>    
00574     <span class="keywordflow">if</span> (<a class="code" href="filesys_8c.html#a20">LoadNextSector</a>()){
00575       <span class="comment">/* Error, end-of-file according to FAT records */</span>
00576       <span class="keywordflow">return</span> 0; <span class="comment">/* must return something */</span>
00577     }
00578     <a class="code" href="buffer_8c.html#a1">dataBufPtr</a>=<a class="code" href="buffer_8c.html#a0">diskSect</a>.<a class="code" href="unionDiskBlock.html#o1">raw</a>.<a class="code" href="structDiskBlock_1_1Raw.html#o0">buf</a>;
00579   }
00580 
00581   <span class="comment">/* Everything should now be ok for reading a byte. */</span>
00582 
00583   <a class="code" href="filesys_8c.html#a7">fileSize</a>--;
00584   <span class="keywordflow">return</span> (*<a class="code" href="buffer_8c.html#a1">dataBufPtr</a>++);
00585 }
</div></pre>
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<a class="anchor" name="a7" doxytag="filesys.h::InitFileSystem" ></a><p>
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          <td class="md" nowrap valign="top"> unsigned char InitFileSystem           </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="mdname1" valign="top" nowrap>          </td>
          <td class="md" valign="top">&nbsp;)&nbsp;</td>
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