简单解析xml属性值

//下面的代码可以每次获取一个标签元素,每个元素包含多个属性值对
//只支持不带结束标签的xml,如：<path file="C://1.txt"> 或者<path file=C://1.txt> 

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <string>
#include <iostream>

typedef struct Property
{
    char *name_;
    char *value_;
    Property *next_;
}Property;

typedef struct Element
{
    char *element_name_;
    Property *prop_;
}Element;



Property *GetParameters(const char* input)
{
    Property *head = NULL;
    Property *cur_prop = head;
    while(*input) {
        std::string name;

        while(*input && isspace(*input))
                ++input;

        while(*input && !isspace(*input) && *input != '=') {
                name += *input;
                ++input;
        }

        while(*input && isspace(*input))
                ++input;

        if(*input) {
            if(*input != '=')
            {
                //失败
                break;
            }
            else
               ++input;
        }

        Property *prop = (Property *)malloc(sizeof(Property));
        memset(prop, 0, sizeof(Property));

        if (cur_prop)
        {
            cur_prop->next_ = prop;
        }
        else
        {
            head = prop;
            cur_prop = prop;
        }

        int len = name.size() + 1;
        prop->name_ = (char *)malloc(len);
        memset(prop->name_, 0, len);
        strcpy(prop->name_, name.c_str());

        //获取value
        std::string value = "";
        while(*input && isspace(*input))
                ++input;

        if(*input && *input == '\"') {
            ++input;
            while(*input && *input != '\"') {
                   value += *input++;
            }

            if(*input && *input == '\"')
                ++input;
        } else {
            while(*input && !isspace(*input))
                    name += *input++;
        }

        len = value.size() + 1;
        prop->value_ = (char *)malloc(len);
        memset(prop->value_, 0, len);
        strcpy(prop->value_, value.c_str());
    }

    return head;
}


Element *HandleTag(const std::string& tag)
{
    if(tag.empty())
        return NULL;

    size_t i;
    for(i = 0; i < tag.length(); ++i)
    {
        if(isspace(tag[i]))
           continue;
        else
           break;
    }

    if(i == tag.length())
        return NULL;

    Element *elem = (Element *)malloc(sizeof(Element));
    memset(elem, 0, sizeof(Element));

    std::string tagName;
    for( ; i != tag.length(); ++i) {
        if(!isspace(tag[i]))
            tagName += tag[i];
        else
            break;
    }

    int len = tagName.size() + 1;
    elem->element_name_ = (char *)malloc(len);
    memset(elem->element_name_, 0, len);
    strcpy(elem->element_name_, tagName.c_str());

    Property *prop = GetParameters(tag.c_str() + i);
    elem->prop_ = prop;
    return elem;
}

Element *Parse(FILE *f)
{
    bool inquote = false;
    bool intag = false;
    std::string tag = "";
    Element *elem = NULL;
    int c;
    while(c = fgetc(f)) {

        if (feof(f)) {
            break;
        }
        switch(c) {
        
        case '\"':
            inquote = !inquote;
            break;

        case '<':
            if(!inquote) {
                intag = true;
                tag = "";
                continue;  //不能换成break;
            }

        case '>':
            if(!inquote)
            {
                elem = HandleTag(tag);
                intag = false;
                return elem;  //不能换成break;
            }
        }

        if(intag)
            tag += (char)c;
    }
    return elem;
}

void DelElement(Element *elem)
{
    if (!elem)
    {
        return;
    }

    Property *next_prop = elem->prop_;
    while (next_prop)
    {
        Property *cur_prop = next_prop;
        next_prop = next_prop->next_;
        if (cur_prop->name_)
        {
            free(cur_prop->name_);
            cur_prop->name_ = NULL;
        }
        if (cur_prop->value_)
        {
            free(cur_prop->value_);
            cur_prop->value_ = NULL;
        }
        free(cur_prop);
    }
}



int main(int argc, char *argv[])
{
    FILE *fd = fopen(argv[1], "rb");
    Element *elem = NULL;
    while (elem = Parse(fd))
    {
        std::cout<<">elem name: "<< elem->element_name_<< std::endl;
        Property *prop = elem->prop_;
        while (prop)
        {
            std::cout<<">>>prop name :"<<prop->name_<<std::endl;
            std::cout<<">>>prop value :"<<prop->value_<<std::endl;
            prop = prop->next_;
        }
        DelElement(elem);
    }
    fclose(fd);
    return 0;
}