nginx 源码学习笔记（六）——nginx基本数据结构

简单的数据类型

在core/ngx_confing.h中定义了基本的数据类型的映射，大部分都映射到c语言自身的数据类型：

typedef intptr_t        ngx_int_t;

typedef uintptr_t       ngx_uint_t;

typedef intptr_t        ngx_flag_t;

其中ngx_int_t，ngx_flag_t都映射为intptr_t；ngx_uint_t映射为uintptr_t。

这两个类型在/usr/include/stdint.h的定义为：

[cpp] view plaincopyprint?

1. /* Types for `void *' pointers.  */  
2. #if __WORDSIZE == 64  
3. # ifndef __intptr_t_defined  
4. typedef long int                intptr_t;  
5. #  define __intptr_t_defined  
6. # endif  
7. typedef unsigned long int       uintptr_t;  
8. #else  
9. # ifndef __intptr_t_defined  
10. typedef int                     intptr_t;  
11. #  define __intptr_t_defined  
12. # endif  
13. typedef unsigned int            uintptr_t;  
14. #endif  

看到这里大家应该理解，基本操作应该都是一样的。

 

字符串的数据类型

nginx对c语言字符串类型进行了简单的封装，core/ngx_string.h/c里面包含了这些封装的内容。其中定义了

ngx_str_t,

ngx_keyval_t,

ngx_variable_value_t

这几个基础类型:

[cpp] view plaincopyprint?

1. typedef struct {  
2.     size_t      len;  
3.     u_char     *data;  
4. } ngx_str_t;  
5.   
6.   
7. typedef struct {  
8.     ngx_str_t   key;  
9.     ngx_str_t   value;  
10. } ngx_keyval_t;  
11.   
12.   
13. typedef struct {  
14.     unsigned    len:28;  
15.   
16.     unsigned    valid:1;  
17.     unsigned    no_cacheable:1;  
18.     unsigned    not_found:1;  
19.     unsigned    escape:1;  
20.   
21.     u_char     *data;  
22. } ngx_variable_value_t;  

ngx_str_t 包含两个属性：len即长度， data为数据；初始化使用ngx_string宏进行：

#define ngx_string(str)     {sizeof(str) -1,(u_chart*)str }

 

该模块在ngx_string.h和ngx_string.c中。字符串的操作一般包括：初始化，复制，格式化输出，大小写转换，查找子字符，查找子字符串，字符串转换成数字，字符串编码类型相关函数，字符串比较，trim，split等函数。在这个类中间没有调用其他模块的函数，作为一个http服务器，还需要实现URL转换，简单的html转换等函数。字符串的结构体非常简单实用，是非常值得刚入门的linux开发工程师学习的。

 

函数                                                                                       说明
ngx_string                                                                                       初始化函数
ngx_null_string                                                                               初始化空字符串函数
ngx_tolower                                                                                     字符转小写函数
ngx_toupper                                                                                    字符转大写函数
ngx_strncmp                                                                                   比较指定长度的字符串是否相同
ngx_strcmp                                                                                      比较字符串是否相同
ngx_strstr                                                                                        从字符串中找到需要的字符串
ngx_strlen                                                                                        字符串的长度
ngx_strchr                                                                                       在字符串中找到匹配的字符，返回 0为匹配
ngx_strlchr                                                                                     在字符串中找到匹配的字符，返回匹配的指针
ngx_memzero                                                                                 把一片内存区设置为0
ngx_memset                                                                                     把一片内存区设置为指定的数
ngx_memcpy                                                                                  复制内存，没有返回
ngx_cpymem                                                                                  复制内存，返回复制完了dst的最后一个字符的下一个字符的指针
ngx_copy                                                                                         同ngx_cpymem
ngx_memcmp                                                                                 比较内存中的数据是否相同
ngx_strlow                                                                                      把字符串都转换成小写
ngx_cpystrn                                                                                    复制字符串，并且返回字符串的最后一个字符的下一个字符的指针
ngx_pstrdup                                                                                    复制字符串到pool，返回字符串的指针
ngx_sprintf                                                                                       把各种类型的数据格式化输出到buf，最大的长度为65536
ngx_snprintf                                                                                     把各种类型的数据格式化输出到指定长度的buf
ngx_strcasecmp                                                                                不分大小写比较两个字符串是否相同
ngx_strncasecmp                                                                             指定长短不分大小写比较两个字符串是否相同
ngx_strnstr                                                                                      在指定大小一个字符串中是否有子字符串
ngx_strstrn                                                                                       在一个字符串中是否有子指定大小的字符串
ngx_strcasestrn                                                                               在一个字符串中是否有子指定大小的字符串，不区分大小写
ngx_rstrncmp                                                                                  从后往前比较两个字符串是否相同，返回相同的位置
ngx_rstrncasecmp                                                                           从后往前比较两个字符串是否相同，返回相同的位置，不区分大小写
ngx_memn2cmp                                                                              比较两个指定长度的内存是否相同，也比较长的内存是否包含短的内存
ngx_atoi                                                                                          指定长度的字符串转换成数字
ngx_atosz                                                                                         指定长度的字符串转换成ssize_t类型数字
ngx_atoof                                                                                        指定长度的字符串转换成off_t类型数字
ngx_atotm                                                                                       指定长度的字符串转换成time_t类型数字

ngx_hextoi                                                                                        指定长度的字符串转换成十六进制数字
ngx_hex_dump                                                                                 把数字转换成16进制的字符串
ngx_encode_base64                                                                          base64编码
ngx_decode_base64                                                                          base64解码
ngx_utf8_decode                                                                             把 utf8字符解码成双字节的 unicode或是单字节字符，但是该函数会移动*p的值，

 

请注意

ngx_utf8_length                          得到utf8编码的字符占几个字节
ngx_utf8_cpystrn                         赋值utf8字符串，保证完整的复制
ngx_escape_uri                           对uri进行编码
ngx_unescape_uri                        对uri的进行解码
ngx_escape_html                        对html进行编码
ngx_sort                                      排序，主要是用于数组排序
ngx_qsort                                    快速排序
ngx_value                                     把宏数字转换成字符串

为了测试，我们可以用以下两种方式打印出来
1 ngx_str_t str ;
2 printf (” %* s” , str . len , str . data );
3 prinrf (”%V”, & str );