在PHP中读取文件的一部分 [英] Read part of a file in PHP

问题描述

我想读取MP3文件的最后1兆字节，并仅为该文件的该部分计算SHA1校验和.我想要这样做的原因是，当我寻找重复的MP3时，即使是相同的音频文件，标题信息(歌曲标题，专辑等)也可能会有所不同，所以我认为最好进行校验和检查.文件末尾的一部分而不是整个文件的一部分.有有效的方法吗?

I would like to read the last 1 megabyte of a MP3 file and calculate SHA1 checksum for just that part of the file. The reason that I would want this is that when I'm looking for duplicate MP3's, the header info (song title, album etc.) can differ even though it's the exakt same audio file, so I figured I would be better of to checksum a part of the file at the end instead of the whole one. Is there an efficient way of doing this?

推荐答案

您必须使用c包装程序来进行文件操作: fseek 和阅读:

You'd have to use the c wrappers for file manipulation: fopen, fseek and fread:

$size = 1024 * 1000;
$handle = fopen($file, 'r');
fseek($handle, -$size);
$limitedContent = fread($handle, $size);
$hash = md5($limitedContent);

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