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| <h2 id="fsutil_read_file"><font color="#F2853F" style="font-size:24pt">fsutil_read_file</font></h2> |
| <div class="codehilite" style="background: #ffffff"><pre style="line-height: 125%;"><span></span><code><span style="color: #A90D91">int</span> <span style="color: #000000">fsutil_read_file</span>(<span style="color: #A90D91">const</span> <span style="color: #A90D91">char</span> <span style="color: #000000">*path</span>, <span style="color: #A90D91">uint32_t</span> <span style="color: #000000">offset</span>, <span style="color: #A90D91">uint32_t</span> <span style="color: #000000">len</span>, |
| <span style="color: #A90D91">void</span> <span style="color: #000000">*dst</span>, <span style="color: #A90D91">uint32_t</span> <span style="color: #000000">*out_len</span>) |
| </code></pre></div> |
| |
| <p>Calls fs_open(), fs_read(), and fs_close() to open a file at the specified path, retrieve data from the file starting from the specified offset, and close the file and invalidate the file handle.</p> |
| <h4 id="arguments">Arguments</h4> |
| <table> |
| <thead> |
| <tr> |
| <th><em>Argument</em></th> |
| <th><em>Description</em></th> |
| </tr> |
| </thead> |
| <tbody> |
| <tr> |
| <td>path</td> |
| <td>Pointer to the directory entry to query</td> |
| </tr> |
| <tr> |
| <td>offset</td> |
| <td>Position of the file's read pointer</td> |
| </tr> |
| <tr> |
| <td>len</td> |
| <td>Number of bytes to attempt to read</td> |
| </tr> |
| <tr> |
| <td>dst</td> |
| <td>Destination buffer to read into</td> |
| </tr> |
| <tr> |
| <td>out_len</td> |
| <td>On success, the number of bytes actually read gets written here. Pass null if you don't care.</td> |
| </tr> |
| </tbody> |
| </table> |
| <h4 id="returned-values">Returned values</h4> |
| <ul> |
| <li>0 on success</li> |
| <li><a href="../fs_return_codes/">FS error code</a> on failure</li> |
| </ul> |
| <h4 id="notes">Notes</h4> |
| <p>This is a convenience function. It is useful when the amount of data to be read from the file is small (i.e., all the data read can easily fit in a single buffer).</p> |
| <h4 id="header-file">Header file</h4> |
| <div class="codehilite" style="background: #ffffff"><pre style="line-height: 125%;"><span></span><code><span style="color: #633820">#include</span> <span style="color: #177500">"fs/fs.h"</span> |
| </code></pre></div> |
| |
| <h4 id="example">Example</h4> |
| <p>This example demonstrates reading a small text file in its entirety and printing its contents to the console.</p> |
| <div class="codehilite" style="background: #ffffff"><pre style="line-height: 125%;"><span></span><code><span style="color: #A90D91">int</span> |
| <span style="color: #000000">print_status</span>(<span style="color: #A90D91">void</span>) |
| { |
| <span style="color: #A90D91">uint32_t</span> <span style="color: #000000">bytes_read</span>; |
| <span style="color: #A90D91">uint8_t</span> <span style="color: #000000">buf</span>[<span style="color: #1C01CE">16</span>]; |
| <span style="color: #A90D91">int</span> <span style="color: #000000">rc</span>; |
| |
| <span style="color: #177500">/* Read up to 15 bytes from the start of the file. */</span> |
| <span style="color: #000000">rc</span> <span style="color: #000000">=</span> <span style="color: #000000">fsutil_read_file</span>(<span style="color: #C41A16">"/cfg/status.txt"</span>, <span style="color: #1C01CE">0</span>, <span style="color: #A90D91">sizeof</span> <span style="color: #000000">buf</span> <span style="color: #000000">-</span> <span style="color: #1C01CE">1</span>, <span style="color: #000000">buf</span>, |
| <span style="color: #000000">&bytes_read</span>); |
| <span style="color: #A90D91">if</span> (<span style="color: #000000">rc</span> <span style="color: #000000">!=</span> <span style="color: #1C01CE">0</span>) <span style="color: #A90D91">return</span> <span style="color: #1C01CE">-1</span>; |
| |
| <span style="color: #177500">/* Null-terminate the string just read. */</span> |
| <span style="color: #000000">buf</span>[<span style="color: #000000">bytes_read</span>] <span style="color: #000000">=</span> <span style="color: #2300CE">'\0'</span>; |
| |
| <span style="color: #177500">/* Print the file contents to the console. */</span> |
| <span style="color: #000000">console_printf</span>(<span style="color: #C41A16">"%s\n"</span>, <span style="color: #000000">buf</span>); |
| |
| <span style="color: #A90D91">return</span> <span style="color: #1C01CE">0</span>; |
| } |
| </code></pre></div> |
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