[PHP] substr占用内存谨慎使用

在下面的场景中使用substr的时候, 有时候会报超出内存fatal error ,当curl读取的内容过大的时候

            $header_size = curl_getinfo($curl_handle, curlinfo_header_size);            $this->respon_headers = substr($this->respon, 0, $header_size);        圣诞树的寓意    春回地暖打一生肖$this->respon_body = substr($this-枸杞怎么吃有营养>respon, $header_size);            $this->respon_code = curl_getinfo($curl_handle, curlinfo_http_code);            $this->respon_info = curl_getinfo($curl_handle);

用substr切分curl返回的内容 , 分出header头和body体

1. 测试一下:

<?php$start=memory_get_usage();$str="123";var_dump(memory_get_usage()-$start);//$a=substr($str,0,1);$a=$str;var_dump(memory_get_usage()-$start-24);$b=$str;//$b=mb_substr($str,1);var_dump(memory_get_usage()-$start-24);$c=$str;//$b=mb_substr($str,1);var_dump(memory_ge胜球灯饰t_usage()-$start-24);

这个变量赋值,占48字节

2.使用substr切分后

<?php$start=memory_get_usage();$str="123";var_du五年级数学教学论文mp(memory_get_usage()-$start);//$a=substr($str,0,1);$a=$str;var_dump(memory_get_usage()-$start-24);//$b=$str;$b=substr($str,0,1);var_dump(memory_get_usage()-$start-24);//$c=$str;$c=substr($str,1);var_dump(memory_get_usage()-$start-24);

切分后赋值,占到了92字节 和 96字节 , 比原变量涨了一倍多