glib 解析xml

xml的用处越来越广泛了，解析xml得库也非常多，总的来说分为两种，一种是把xml当作一个“树”来进行解析，一种是基于事件类型的

 

glib就是使用事件类型解析xml。
有5种不同的事件类型
1）一个element的开始
2）一个element的结束
3）element得文本
4）一些stuff
5) 错误
There are five kinds of event which can happen:

• The start of an element
• The end of an element
• Some text (inside an element)
• Some other stuff (processing instructions, mainly, including comments and doctypes)
• An error

下面是一个简单的xml

simple.xml :

<zoo><animal noise="roar">lion</animal><animal noise="sniffle">bunny</animal><animal noise="lol">cat</animal><keeper/></zoo>

被解析成以下的动作

• Start of “zoo”.
• Start of “animal”, with a “noise” attribute of “roar”.
• The text “lion”.
• End of “animal”.
• Start of “animal”, with a “noise” attribute of “sniffle”.
• The text “bunny”.
• End of “animal”.
• Start of “animal”, with a “noise” attribute of “lol”.
• The text “cat”.
• End of “animal”.
• Start of “keeper”.
• End of “keeper”.
• End of “zoo”.

程序运行结果
I am a lion and I go roar. Can you do it?
I am a bunny and I go sniffle. Can you do it?
I am a cat and I go lol. Can you do it? 

 

# include < stdio. h> 

gchar * current_animal_noise = NULL ; 

static void start( GMarkupParseContext * context, 
        const gchar * element_name, 
        const gchar * * attribute_names, 
        const gchar * * attribute_values, 
        gpointer user_data, 
        GError * * error ) 
{ 
        const gchar * * name_cursor = attribute_names; 
        const gchar * * value_cursor = attribute_values; 

        while ( * name_cursor) { 
                if ( strcmp ( * name_cursor, "noise" ) = = 0) 
                current_animal_noise = g_strdup ( * value_cursor) ; 
                name_cursor+ + ; 
                value_cursor+ + ; 
        } 

} 

static void end( GMarkupParseContext * context, 
        const gchar * element_name, 
        gpointer user_data, 
        GError * * error ) 
{ 
        if ( current_animal_noise) 
        { 
                g_free ( current_animal_noise) ; 
                current_animal_noise = NULL ; 
        } 
} 


static void text( GMarkupParseContext * context, 
        const gchar * text, 
        gsize text_len, 
        gpointer user_data, 
        GError * * error ) 
{ 
        if ( current_animal_noise) 
                printf ( "I am a %*s and I go %s. Can you do it?/n" , 
                    text_len, text, current_animal_noise) ; 
        printf ( "test text/n" ) ; 
} 



GMarkupParser parser = { 
        . start_element = start, 
        . end_element = end, 
        . text = text, 
        . passthrough = NULL , 
        . error = NULL 
} ; 


int main( ) 
{ 
        char * buf; 
        gsize length; 
        GMarkupParseContext * context; 
        g_file_get_contents( "test.xml" , & buf, & length, NULL ) ; 
        g_printf( "%s/n" , buf) ; 
        context = g_markup_parse_context_new( & parser, 0, NULL , NULL ) ; 
        if ( g_markup_parse_context_parse( context, buf, length, NULL ) = = FALSE ) 
        { 
                printf ( "Couldn't load xml/n" ) ;

                g_markup_parse_context_free(context);
        return 0;
}