Mini-XML的编译与使用

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* Author          :     lile
* Modified        :     2019年12月28日星期六  10:16:13
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libmxml (mini-xml) 一个轻量级的xml库，可完成读写。适合系统资源受限的嵌入式设备。

1. 下载

官网网址：https://www.msweet.org/mxml/
测试版本：mxml-3.0.tar.gz
测试环境：Ubuntu 14.04.5 LTS， x64

2. 编译

root@ubuntu:/opt/xml_lib/mxml-3.0#./configure

root@ubuntu:/opt/xml_lib/mxml-3.0# make 
Compiling mxml-attr.c
Compiling mxml-entity.c
Compiling mxml-file.c
Compiling mxml-get.c
Compiling mxml-index.c
Compiling mxml-node.c
Compiling mxml-search.c
Compiling mxml-set.c
Compiling mxml-private.c
Compiling mxml-string.c
Creating libmxml.so.1.6...
Creating libmxml.a...
a - mxml-attr.o
a - mxml-entity.o
a - mxml-file.o
a - mxml-get.o
a - mxml-index.o
a - mxml-node.o
a - mxml-search.o
a - mxml-set.o
a - mxml-private.o
a - mxml-string.o
Compiling testmxml.c
Linking testmxml...
Testing library...
Stdio file test passed!
String test passed!
File descriptor test passed!
root@ubuntu:/opt/xml_lib/mxml-3.0# make install
Installing libmxml.so to /usr/local/lib...
Installing libmxml.a to /usr/local/lib...
Installing documentation in /usr/local/share/doc/mxml...
/usr/bin/install: cannot stat ‘doc/mxmldoc.xsd’: No such file or directory
/usr/bin/install: cannot stat ‘COPYING’: No such file or directory
Installing header files in /usr/local/include...
Installing pkgconfig files in /usr/local/lib/pkgconfig...
Installing man pages in /usr/local/share/man...

默认安装路径为 /usr/local/lib，可以在 ./configure 命令行中指定，比如：

./configure --prefix=/opt/xml_lib/x64

如果指定了自定义安装路径，则需要手动指定 LD_LIBRARY_PATH，例如：

export LD_LIBRARY_PATH="/opt/xml_lib/x64/lib"

否则运行出错，如下：

root@ubuntu:/opt/xml_lib/x64/lib# gcc  -o testmxml testmxml.c -lmxml
root@ubuntu:/opt/xml_lib/x64/lib# 
root@ubuntu:/opt/xml_lib/x64/lib# ./testmxml 
./testmxml: error while loading shared libraries: libmxml.so.1: 
cannot open shared object file: No such file or directory


root@ubuntu:/opt/xml_lib/x64/lib# export LD_LIBRARY_PATH="/opt/xml_lib/x64/lib:$LD_LIBRARY_PATH"
root@ubuntu:/opt/xml_lib/x64/lib# ./testmxml 
Usage: testmxml filename.xml [string-output.xml]

configure详细用法可以使用 ./configure --help 来查看

3. 使用

官方指导用法如下图：

但是实测会报错，如下：

root@ubuntu:/opt/508/xml_lib/demo# gcc -o testMXML testMXML.c  -lmxml               
testMXML.c: In function ‘main’:
testMXML.c:27:23: error: dereferencing pointer to incomplete type
     printf("[%s}\n",id->child->value.text.string);
                       ^
testMXML.c:31:30: error: dereferencing pointer to incomplete type
      printf("[%s]\n",password->child->value.text.string);
                              ^

错误提示表明相关的结构体未定义，跟踪代码后可知，仅包含单个 #include 是不完全的，需要把三个相关的头文件均关联起来，demo代码如下：

//testMXML.c
//功能：实现XML文件的查询和修改
#include
#include
#include

//#include"mxml.h"
#include"mxml-private.h"

const char *whitespace_cb(mxml_node_t *node ,int w)
{
	//printf(" curNode:%s;    w: %d \n", mxmlGetElement(node), w);

	if ( w == MXML_WS_AFTER_OPEN 
	/*|| w == MXML_WS_BEFORE_CLOSE */
	  || w == MXML_WS_AFTER_CLOSE )
		return ("\n");
	else
		return NULL;
}


int main()
{
    FILE *fp;
    mxml_node_t *tree, *node;
	int ret = -1;
 
    fp = fopen("debug_settings.xml", "rb+");	
	if(fp == NULL){
		printf("can not open file!please check it\n");
		return -1;
	}
	
    tree = mxmlLoadFile(NULL, fp, MXML_TEXT_CALLBACK);
 
    node = mxmlFindElement(tree, tree, "note",NULL, NULL,MXML_DESCEND); 
    printf(" year:%s \n",mxmlElementGetAttr(node,"year"));
    printf(" date:%s \n",mxmlElementGetAttr(node,"date"));
    printf("month:%s \n",mxmlElementGetAttr(node,"month")); 
 
    mxml_node_t *id, *password;
    id = mxmlFindElement(node, tree, "id",NULL, NULL,MXML_DESCEND);
    printf("id[type=%d][value=%s}\n",id->type,  id->child->value.text.string);
	if(strcmp(id->child->value.text.string, "6666") == 0)
		ret = mxmlSetText(id, 0, "5555");
	else
		ret = mxmlSetText(id, 0, "6666");
	
    printf("mxmlSetText() ret: %d;\n", ret);
    printf("id[type=%d][value=%s}\n",id->type,  id->child->value.text.string);
 
    password = mxmlFindElement(node, tree, "password",NULL, NULL,MXML_DESCEND);
    printf("password[type=%d][value=%s}\n",password->type,  password->child->value.text.string);
 
    id = mxmlFindElement(node, tree, "id",NULL, NULL,MXML_DESCEND);
    printf("id[type=%d][value=%s}\n",id->type,  id->child->value.text.string);
	
	fseek(fp, 0, SEEK_SET);
	ret = mxmlSaveFile ( tree, fp, whitespace_cb );
    printf("mxmlSaveFile() ret: %d;\n", ret);
	
	if(ret)
		perror("mxmlSaveFile err:");
	
    fclose(fp);
	fp = NULL;
	
	mxmlDelete(tree);
 
    return 0 ;
}

文件结构

root@ubuntu:/opt/xml_lib/demo# ls -l
total 52
-rw-r--r-- 1 root   root     1840 May  5 19:00 config.h
-rwxr--r-- 1 nobody nogroup   138 May  5 23:33 debug_settings.xml
-rw-r--r-- 1 root   root    10334 May  5 18:47 mxml.h
-rw-r--r-- 1 root   root     2666 May  5 18:59 mxml-private.h
-rwxr--r-- 1 nobody nogroup  1834 May  5 23:33 testMXML.c

编译命令

 
root@ubuntu:/opt/xml_lib/demo# gcc  -Wall -g -O3  -o testMXML testMXML.c -lmxml
root@ubuntu:/opt/xml_lib/demo# file testMXML
testMXML: ELF 64-bit LSB  executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs),
 for GNU/Linux 2.6.24, BuildID[sha1]=7bbe65f23ec4bf400ae634208f3723ad6e9bc726, not stripped

测试文件

<note year="55" date="33" month="22">
    <id>6666id>
    <password>FE-D0-18-00password>
note>

4. 优点

• 轻量级 —— 代码量小
• 使用简单 —— 简单使用几个函数即可

5. 缺点

• 默认XML无格式，无可读性 —— 需要自己实现格式化函数 whitespace_cb() ，默认输出XML没有换行分割，如下图：
  

若有比较好的格式化函数 whitespace_cb()， 麻烦在评论中发一下。

6. 参考

1. 使用mini-XML库实现xml文件的创建以及解析 https://blog.csdn.net/alangdangjia/article/details/8874572
2. Mini-XML从入门到精通系列–源码获取及安装 https://blog.csdn.net/bbzhaohui/article/details/71512599
3. mini-XML 中文文档 https://blog.csdn.net/bluesonic/article/details/3887143
4. XML压缩、格式化工具 http://www.bejson.com/otherformat/xml/

以上