介绍, man手册

txt版 http://www.pcre.org/original/pcre.txt

html版 http://www.pcre.org/original/doc/html/pcre.html

In addition to the Perl-compatible matching function, PCRE contains an alternative function that matches the same compiled patterns in a different way. 
In certain circumstances, the alternative function has some advantages. For a discussion of the two matching algorithms, see the pcrematching page.

pcrematching:

http://www.pcre.org/original/doc/html/pcrematching.html

摘要:

  0.  是批量处理的意思? 一个pattern处理多个subject么?

The set of strings that are matched by a regular expression can be represented as a tree structure.

  1.  Jeffrey Friedl's book "Mastering Regular Expressions"

  中文版:精通正则表达式:https://book.douban.com/subject/2154713/

  英文版PDF:https://doc.lagout.org/Others/O%27Reilly%20-%20Mastering%20Regular%20Expressions.pdf

  2, PCRE匹配分标准接口(pcre_exec(), pcre16_exec() and pcre32_exec() functions. )和非标准接口( pcre_dfa_exec(), pcre16_dfa_exec() and pcre32_dfa_exec() functions )两种。

    前者在同一个串中只能返回一个匹配结果,或者可以同时返回一个串中的多个匹配结果。

    标准接口返回的结果有可能是最长串,最短串或任意长度的串,这取决于贪婪与非贪婪的设置。

    标准接口就是NFA algorithm是深度优先查找树,同时可以有贪婪(greedy)与非贪婪(ungreedy)两种控制种类。

    非标准接口为广度优先查找树,为DFA算法( In Friedl's terminology, this is a kind of "DFA algorithm", though it is not implemented as a traditional finite state machine (it keeps multiple states active simultaneously).)subject串的扫描会一直进行到串的尾部或者没有其他需要遍历的路径。所有的已终结路径即代表了全部的匹配结果,返回的结果按照字符串长度递减。有一个开关设置第一个命中即返回,也就是最短命中串。

  3.  非标准方法的优点:

    a, 匹配多个结果,尤其是找到最长匹配。

    b, 可以对超长的subject数据进行多次分批次的匹配。

     非标准方法的缺点:

    a, 比标准方法慢。

    b, 不支持子串提取。

    c, Although atomic groups are supported, their use does not provide the performance advantage that it does for the standard algorithm.

pcrejit:

http://www.pcre.org/original/doc/html/pcrejit.html

摘要:

  JIT提供特别深度的优化. 牺牲额外的处理步骤,从而提高匹配性能。适合一次pattern编译多次match操作的应用场景。

  1. 只支持标准PCRE接口,不支持DFA匹配模式。

  2. PCRE默认不打开JIT,需要在编译的时候增加--enable-jit选项。

  3.  有硬件平台限制

  ARM v5, v7, and Thumb2
Intel x86 -bit and -bit
MIPS -bit
Power PC -bit and -bit
SPARC -bit (experimental)

  4.  the pcre_jit_exec() function was not available at all before 8.32

  5.  The JIT compiler generates different optimized code for each of the three modes (normal, soft partial, hard partial). When pcre_exec() is called, the appropriate code is run if it is available. Otherwise, the pattern is matched using interpretive code.

  6.  There are some pcre_exec() options that are not supported for JIT execution. There are also some pattern items that JIT cannot handle. Details are given below. In both cases, execution automatically falls back to the interpretive code.

  7.  Once a pattern has been studied, with or without JIT, it can be used as many times as you like for matching different subject strings.

  8.   The code that is generated by the JIT compiler is architecture-specific, and is also position dependent. For those reasons it cannot be saved (in a file or database) and restored later like the bytecode and other data of a compiled pattern.

  more info: http://www.pcre.org/original/doc/html/pcreprecompile.html

  9.  有时候JIT机器码没有成功编译,但是pcre_exec()仍然正常运行,只不过fallback回了解释码。我们在高性能场景下不希望使用解释码的时候,使用API pcre_jit_exec().

Because the API described above falls back to interpreted execution when JIT is not available, it is convenient for programs that are written 
for general use in many environments. However, calling JIT via pcre_exec() does have a performance impact. Programs that are written for use
where JIT is known to be available, and which need the best possible performance, can instead use a "fast path" API to call JIT execution directly
instead of calling pcre_exec() (obviously only for patterns that have been successfully studied by JIT).

  10.  pcre_exec()会做参数合法性的检测。pcre_jit_exec()为了提高性能,不做合法性检测,如果参数不合法,结果无法预期。

API:

http://www.pcre.org/original/doc/html/pcreapi.html

摘要:

  1,

The functions pcre_compile(), pcre_compile2(), pcre_study(), and pcre_exec() are used for compiling and matching regular expressions in a Perl-compatible manner.

  2, compile a pattern

    http://www.pcre.org/original/doc/html/pcreapi.html#SEC11

  3,    studying a pattern

Studying a pattern does two things: first, a lower bound for the length of subject string that is needed to match the pattern is computed. This does not mean 
that there are any strings of that length that match, but it does guarantee that no shorter strings match. The value is used to avoid wasting time by trying
to match strings that are shorter than the lower bound.
Studying a pattern is also useful for non-anchored patterns that do not have a single fixed starting character. A bitmap of possible starting bytes is created.
This speeds up finding a position in the subject at which to start matching.

  4,   matching a pattern

However, it is possible to save compiled patterns and study data, and then use them later in different processes, possibly even on different hosts. 
For a discussion about this, see the pcreprecompile documentation.

对比一下PCRE2:

[development][PCRE] PCRE

trie:

https://zh.wikipedia.org/zh-hans/Trie

-------------------

黑哥的blog:http://www.cnblogs.com/zzqcn/p/3525636.html

这个讲的很好,对比PCRE、PCRE-JIT,hyperscan:https://mp.weixin.qq.com/s?__biz=MzI3NDA4ODY4MA==&mid=2653334341&idx=1&sn=bf10ca6d8ca1452723b84a62f7fc436d&chksm=f0cb5cc2c7bcd5d4f423af8d78aeb58dd6d9494c1562b1e775579321df3b9f59a951656100d0&scene=21#wechat_redirect

[development][PCRE] old PCRE的更多相关文章

  1. 在C语言中利用PCRE实现正则表达式

    1. PCRE简介 2. 正则表达式定义 3. PCRE正则表达式的定义 4. PCRE的函数简介 5. 使用PCRE在C语言中实现正则表达式的解析 6. PCRE函数在C语言中的使用小例子 1. P ...

  2. Linux下编译安装PCRE库

    备注:如果没有root权限,使用 --prefix 指定安装路径 ./configure --prefix=/home/work/tools/pcre-8.xx =================== ...

  3. pcre 使用

    1.主页地址:http://www.pcre.org/     下载pcre-7.8.tar.bz22.解压缩:     tar xjpf pcre-7.8.tar.bz23.配置:     cd p ...

  4. PCRE正则库的使用

    使用pcre编写C或C++程序,然后编译. 对于C程序,编译命令为:gcc -I/usr/local/include/pcre -L/usr/local/lib/pcre -lpcre file.c ...

  5. PCRE的安装及使用

    摘自http://www.cnblogs.com/renhao/archive/2011/08/17/2143264.html PCRE的安装及使用 1.主页地址:http://www.pcre.or ...

  6. pcre函数具体解释

    PCRE是一个NFA正则引擎,不然不能提供全然与Perl一致的正则语法功能.但它同一时候也实现了DFA,仅仅是满足数学意义上的正则. PCRE提供了19个接口函数,为了简介,使用PCRE内带的測试程序 ...

  7. PCRE函数简介和使用示例【转】

    PCRE函数简介和使用示例 标签: 正则表达式listbuffercompilationnullperl 原文地址:http://blog.csdn.net/sulliy/article/detail ...

  8. Sword pcre库函数学习一

    0.pcre_exec 原型: #include <pcre.h> int pcre_exec(const pcre *code, const pcre_extra *extra, con ...

  9. PCRE library

    wget http://nginx.org/download/nginx-1.15.6.tar.gz tar -xvf nginx-1.15.6.tar.gz ln -s nginx-1.15.6 n ...

随机推荐

  1. 【Linux高级驱动】平台设备驱动机制的编程流程与编译进内核

    [平台设备驱动机制的编程流程] [如何将驱动静态的编译进内核镜像] 1.添加资源(dev-led.c) 1.1:一般来说,系统习惯上将资源放在arch/arm/plat-samsung/目录中 cp ...

  2. Excel中substitute替换函数的使用方法

    问题现象:在Excel中,对几千条数据按照时间顺序排序,但总是有部分数据不参与排序,单纯用单元格调整不起任何作用. 解决办法: 数据排列问题最重要的是数据格式的一致性.解决这个问题,建议按如下步骤: ...

  3. 【转】 Windows下配置Git

    [转自]http://blog.csdn.net/exlsunshine/article/details/18939329 1.从git官网下载windows版本的git:http://git-scm ...

  4. Java如何找到一个单词的每一次匹配?

    在Java编程中,如何查找字符串中特定单词的最后一个索引? 以下示例演示如何使用Matlass类的matchet.find()方法和Pattern类的Patter.compile()方法查找字符串中指 ...

  5. PISQLDAS 查询语句

    SELECT tag,CAST(value AS Float64) FROM piarchive..piavg WHERE tag = ? AND time >= DATE(?) AND tim ...

  6. IntelliJ IDEA下spring boot项目打包

    Spring Boot自带Tomcat插件,可以直接编写启动类,开启Tomcat服务 springboot适合前后端分离,打成jar进行部署更合适 application.properties配置端口 ...

  7. Apache Nginx URL 地址 重写

    URL重写这东西在工作中用了很多次了,但每次都忘记了要记得把知道的积累下来. 哎,要么认为没必要,要么就是没时间?! 一.Apache 篇 官方地址:http://man.chinaunix.net/ ...

  8. 我的Mac Pro coding环境配置

    新装了OS X 10.11.1. 记录一下开发用得到的一些玩意,方便下次再次配置. homebrew国内源:http://mirrors.tuna.tsinghua.edu.cn/help/#home ...

  9. puppet cron资源管理

    1.可用参数: ensure      ensure => {present|absent},   决定该计划任务的目标状态,present 如该cron不存在,则添加;absent 如该cro ...

  10. CentOS 6 添加root权限账户

    sudo adduser william sudo passwd william //两次输入密码 赋予root权限 visudo 找到 ## Allow root to run any comman ...