语法: intval = ngx.crc32_long(str)
环境: set_by_lua**, rewrite_by_lua*, access_by_lua*, content_by_lua*, header_filter_by_lua*, body_filter_by_lua*, log_by_lua*, ngx.timer.**
通过一个字符串计算循环冗余校验码。
这个方法最好在字符串较多时调用（比如大于30-60字节），他的结果和 ngx.crc32_short 是一样的。
本质上，它只是 Nginx 内核函数 ngx_crc32_long 的简单封装。
这个方法最早出现在版本 v0.3.1rc8 中。
English Source
syntax: intval = ngx.crc32_short(str)
context: set_by_lua**, rewrite_by_lua*, access_by_lua*, content_by_lua*, header_filter_by_lua*, body_filter_by_lua*, log_by_lua*, ngx.timer.**
Calculates the CRC-32 (Cyclic Redundancy Code) digest for the str argument.
This method performs better on relatively long str inputs (i.e., longer than 30 ~ 60 bytes), as compared to ngx.crc32_short. The result is exactly the same as ngx.crc32_short.
Behind the scene, it is just a thin wrapper around the ngx_crc32_long function defined in the Nginx core.
This API was first introduced in the v0.3.1rc8 release.