group__fat.html

This project provides a general purpose library which implements read and write support for MMC, SD

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<dl class="return" compact><dt><b>Returns:</b></dt><dd>0 on failure, 1 on success. </dd></dl>
<dl class="see" compact><dt><b>See also:</b></dt><dd><a class="el" href="group__fat.html#g2d74af47cb9fd44f7c974834f810225f" title="Resets a directory handle.">fat_reset_dir</a> </dd></dl>

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<a class="anchor" name="g48e17b173bede64cb08cef05b88fd0ca"></a><!-- doxytag: member="fat.h::fat_read_file" ref="g48e17b173bede64cb08cef05b88fd0ca" args="(struct fat_file_struct *fd, uint8_t *buffer, uintptr_t buffer_len)" -->
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          <td class="memname">intptr_t fat_read_file           </td>
          <td>(</td>
          <td class="paramtype">struct fat_file_struct *&nbsp;</td>
          <td class="paramname"> <em>fd</em>, </td>
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          <td class="paramkey"></td>
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          <td class="paramtype">uint8_t *&nbsp;</td>
          <td class="paramname"> <em>buffer</em>, </td>
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          <td class="paramkey"></td>
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          <td class="paramtype">uintptr_t&nbsp;</td>
          <td class="paramname"> <em>buffer_len</em></td><td>&nbsp;</td>
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<p>
Reads data from a file. 
<p>
The data requested is read from the current file location.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
  <table border="0" cellspacing="2" cellpadding="0">
    <tr><td valign="top"><tt>[in]</tt>&nbsp;</td><td valign="top"><em>fd</em>&nbsp;</td><td>The file handle of the file from which to read. </td></tr>
    <tr><td valign="top"><tt>[out]</tt>&nbsp;</td><td valign="top"><em>buffer</em>&nbsp;</td><td>The buffer into which to write. </td></tr>
    <tr><td valign="top"><tt>[in]</tt>&nbsp;</td><td valign="top"><em>buffer_len</em>&nbsp;</td><td>The amount of data to read. </td></tr>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>The number of bytes read, 0 on end of file, or -1 on failure. </dd></dl>
<dl class="see" compact><dt><b>See also:</b></dt><dd><a class="el" href="group__fat.html#g6782ff80eb6fba9b6ed1a66f33dae60a" title="Writes data to a file.">fat_write_file</a> </dd></dl>

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<a class="anchor" name="g2d74af47cb9fd44f7c974834f810225f"></a><!-- doxytag: member="fat.h::fat_reset_dir" ref="g2d74af47cb9fd44f7c974834f810225f" args="(struct fat_dir_struct *dd)" -->
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          <td class="memname">uint8_t fat_reset_dir           </td>
          <td>(</td>
          <td class="paramtype">struct fat_dir_struct *&nbsp;</td>
          <td class="paramname"> <em>dd</em>          </td>
          <td>&nbsp;)&nbsp;</td>
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<p>
Resets a directory handle. 
<p>
Resets the directory handle such that reading restarts with the first directory entry.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
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    <tr><td valign="top"><tt>[in]</tt>&nbsp;</td><td valign="top"><em>dd</em>&nbsp;</td><td>The directory handle to reset. </td></tr>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>0 on failure, 1 on success. </dd></dl>
<dl class="see" compact><dt><b>See also:</b></dt><dd><a class="el" href="group__fat.html#gb4bc79452dbf5ac2a2f3e1fccafd9534" title="Reads the next directory entry contained within a parent directory.">fat_read_dir</a> </dd></dl>

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<a class="anchor" name="gce4858e7a145684f6c8cd14debe14255"></a><!-- doxytag: member="fat.h::fat_resize_file" ref="gce4858e7a145684f6c8cd14debe14255" args="(struct fat_file_struct *fd, uint32_t size)" -->
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          <td class="memname">uint8_t fat_resize_file           </td>
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          <td class="paramtype">struct fat_file_struct *&nbsp;</td>
          <td class="paramname"> <em>fd</em>, </td>
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          <td class="paramtype">uint32_t&nbsp;</td>
          <td class="paramname"> <em>size</em></td><td>&nbsp;</td>
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<p>
Resizes a file to have a specific size. 
<p>
Enlarges or shrinks the file pointed to by the file descriptor to have exactly the specified size.<p>
If the file is truncated, all bytes having an equal or larger offset than the given size are lost. If the file is expanded, the additional bytes are allocated.<p>
<dl class="note" compact><dt><b>Note:</b></dt><dd>Please be aware that this function just allocates or deallocates disk space, it does not explicitely clear it. To avoid data leakage, this must be done manually.</dd></dl>
<dl compact><dt><b>Parameters:</b></dt><dd>
  <table border="0" cellspacing="2" cellpadding="0">
    <tr><td valign="top"><tt>[in]</tt>&nbsp;</td><td valign="top"><em>fd</em>&nbsp;</td><td>The file decriptor of the file which to resize. </td></tr>
    <tr><td valign="top"><tt>[in]</tt>&nbsp;</td><td valign="top"><em>size</em>&nbsp;</td><td>The new size of the file. </td></tr>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>0 on failure, 1 on success. </dd></dl>

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<a class="anchor" name="gd4c305cf004bae9bea48730ed20c87ec"></a><!-- doxytag: member="fat.h::fat_seek_file" ref="gd4c305cf004bae9bea48730ed20c87ec" args="(struct fat_file_struct *fd, int32_t *offset, uint8_t whence)" -->
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          <td class="memname">uint8_t fat_seek_file           </td>
          <td>(</td>
          <td class="paramtype">struct fat_file_struct *&nbsp;</td>
          <td class="paramname"> <em>fd</em>, </td>
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          <td class="paramtype">int32_t *&nbsp;</td>
          <td class="paramname"> <em>offset</em>, </td>
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          <td class="paramtype">uint8_t&nbsp;</td>
          <td class="paramname"> <em>whence</em></td><td>&nbsp;</td>
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<p>
Repositions the read/write file offset. 
<p>
Changes the file offset where the next call to <a class="el" href="group__fat__file.html#g48e17b173bede64cb08cef05b88fd0ca" title="Reads data from a file.">fat_read_file()</a> or <a class="el" href="group__fat__file.html#g6782ff80eb6fba9b6ed1a66f33dae60a" title="Writes data to a file.">fat_write_file()</a> starts reading/writing.<p>
If the new offset is beyond the end of the file, <a class="el" href="group__fat__file.html#gce4858e7a145684f6c8cd14debe14255" title="Resizes a file to have a specific size.">fat_resize_file()</a> is implicitly called, i.e. the file is expanded.<p>
The new offset can be given in different ways determined by the <code>whence</code> parameter:<ul>
<li><b>FAT_SEEK_SET:</b> <code>*offset</code> is relative to the beginning of the file.</li><li><b>FAT_SEEK_CUR:</b> <code>*offset</code> is relative to the current file position.</li><li><b>FAT_SEEK_END:</b> <code>*offset</code> is relative to the end of the file.</li></ul>
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The resulting absolute offset is written to the location the <code>offset</code> parameter points to.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
  <table border="0" cellspacing="2" cellpadding="0">
    <tr><td valign="top"><tt>[in]</tt>&nbsp;</td><td valign="top"><em>fd</em>&nbsp;</td><td>The file decriptor of the file on which to seek. </td></tr>
    <tr><td valign="top"><tt>[in,out]</tt>&nbsp;</td><td valign="top"><em>offset</em>&nbsp;</td><td>A pointer to the new offset, as affected by the <code>whence</code> parameter. The function writes the new absolute offset to this location before it returns. </td></tr>
    <tr><td valign="top"><tt>[in]</tt>&nbsp;</td><td valign="top"><em>whence</em>&nbsp;</td><td>Affects the way <code>offset</code> is interpreted, see above. </td></tr>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>0 on failure, 1 on success. </dd></dl>

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<a class="anchor" name="g6782ff80eb6fba9b6ed1a66f33dae60a"></a><!-- doxytag: member="fat.h::fat_write_file" ref="g6782ff80eb6fba9b6ed1a66f33dae60a" args="(struct fat_file_struct *fd, const uint8_t *buffer, uintptr_t buffer_len)" -->
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          <td class="memname">intptr_t fat_write_file           </td>
          <td>(</td>
          <td class="paramtype">struct fat_file_struct *&nbsp;</td>
          <td class="paramname"> <em>fd</em>, </td>
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          <td class="paramtype">const uint8_t *&nbsp;</td>
          <td class="paramname"> <em>buffer</em>, </td>
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          <td class="paramtype">uintptr_t&nbsp;</td>
          <td class="paramname"> <em>buffer_len</em></td><td>&nbsp;</td>
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<p>
Writes data to a file. 
<p>
The data is written to the current file location.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
  <table border="0" cellspacing="2" cellpadding="0">
    <tr><td valign="top"><tt>[in]</tt>&nbsp;</td><td valign="top"><em>fd</em>&nbsp;</td><td>The file handle of the file to which to write. </td></tr>
    <tr><td valign="top"><tt>[in]</tt>&nbsp;</td><td valign="top"><em>buffer</em>&nbsp;</td><td>The buffer from which to read the data to be written. </td></tr>
    <tr><td valign="top"><tt>[in]</tt>&nbsp;</td><td valign="top"><em>buffer_len</em>&nbsp;</td><td>The amount of data to write. </td></tr>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>The number of bytes written, 0 on disk full, or -1 on failure. </dd></dl>
<dl class="see" compact><dt><b>See also:</b></dt><dd><a class="el" href="group__fat.html#g48e17b173bede64cb08cef05b88fd0ca" title="Reads data from a file.">fat_read_file</a> </dd></dl>

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