斯普利特的char *为char *数组 [英] Split char* to char * Array

问题描述

我想一个char *拆分为char *的C.数组
我习惯用Java / PHP的面向对象编程。我知道有几家简单的方法，在这些语言但在C ......我完全失去了。我经常有段错误数小时X）

I'm trying to split a char* to an array of char* in C. I'm used to program in Java / PHP OO. I know several easy way to do that in these languages but in C... I'm totally lost. I often have segfault for hours x)

我使用TinyXML的和得到的XML文件信息。

I'm using TinyXML and getting info from XML File.

下面就是我们找到阵列的结构。

Here's the struct where we find the array.

const int MAX_GATES = 64;

typedef struct {
    char *name;
    char *firstname;
    char *date;
    char *id;
    char *gates[MAX_GATES];
} UserInfos;

和这里的地方我填补了这一结构：

And here's where I fill this struct :

    UserInfos * infos = (UserInfos*)malloc(1024);

    infos->firstname = (char*)malloc(256);
    infos->name = (char*)malloc(128);
    infos->id = (char*)malloc(128);
    infos->date = (char*)malloc(128);

    sprintf(infos->firstname, "%s", card->FirstChild("firstname")->FirstChild()->Value());
    sprintf(infos->name, "%s", card->FirstChild("name")->FirstChild()->Value());
    sprintf(infos->date, "%s", card->FirstChild("date")->FirstChild()->Value());
    sprintf(infos->id, "%s", card->FirstChild("filename")->FirstChild()->Value());

    ////////////////////////
    // Gates
    char * gates = (char*) card->FirstChild("gates")->FirstChild()->Value();

    //////////////////////////

唯一的问题是'门'。
输入表单XML看起来像GATE1 / GATE2 / gate3或只是空白的时候。

The only problem is on 'gates'. The input form XML looks like "gate1/gate2/gate3" or just blank sometimes.

我要GATE1是在infos->门[0];等等
我希望能够在事后列出门阵列..

I want gate1 to be in infos->gates[0] ; etc. I want to be able to list the gates array afterwards..

我一直有一个段错误，当我尝试。
顺便说一句，我真的不现在如何初始化数组的指针。我总是初始化所有门[I]为NULL，但似乎我有段错误，当我做
    的for（int i = 0;我

感谢所有。

I always have a segfault when I try. Btw, I don't really now how to initialize this array of pointers. I always initialize all gates[i] to NULL but It seems that I've a segfault when I do for(int i=0;i

Thanks for all.

这是确定的，当我只有三分球，但是当字符串（字符*）/数组/指针混合..我不能管理= P

It's OK when I've only pointers but when String(char*) / Arrays / Pointers are mixed.. I can't manage =P

我还看到，我们可以使用类似
    为int * myArray的=释放calloc（NbOfRows，NbOfRows *的sizeof（INT））;
我们为什么要申报这样的一个数组..？ X）

I saw too that we can use something like int *myArray = calloc(NbOfRows, NbOfRows*sizeof(int)); Why should we declare an array like that.. ? x)

谢谢！

推荐答案

这是人们经常对XML的问题是，他们承担所有的元素都可以。这并不总是安全的。因此，这个语句：

The problem that people frequently have with XML is that they assume all the elements are available. That's not always safe. Thus this statement:

sprintf(infos->firstname, "%s", card->FirstChild("firstname")->FirstChild()->Value());

是不是安全的做法，因为你是不知道如果所有这些
实际上函数返回的有效对象。你真正需要的东西
像下面的（即不可以优化速度，因为我不
知道被人在每一个点，从而返回TinyXml的结构名
我不是存储结果一次和我通话，而每个功能
多次：

Isn't safe to do because you don't actually know if all of those functions actually return valid objects. You really need something like the following (which is not optimized for speed, as I don't know the tinyXML structure name being returned at each point and thus am not storing the results once and am rather calling each function multiple times:

if (card->FirstChild("firstname") &&
   card->FirstChild("firstname")->FirstChild()) {
   sprintf(infos->firstname, "%s", card->FirstChild("firstname")->FirstChild()->Value());
}

然后，防止缓冲区从你如果数据溢出
真的是这样做的：

And then, to protect against buffer overflows from the data you should really be doing:

if (card->FirstChild("firstname") &&
   card->FirstChild("firstname")->FirstChild()) {
   infos->firstname[sizeof(infos->firstname)-1] = '\0';
   snprintf(infos->firstname, sizeof(infos->firstname)-1, "%s", card->FirstChild("firstname")->FirstChild()->Value());
}

难道你不喜欢的错误处理？

Don't you just love error handling?

至于您的其他问题：

我还看到，我们可以使用类似为int * myArray的=
释放calloc（NbOfRows，NbOfRows *的sizeof（INT））;我们为什么要声明一个数组
像那样.. ？ X）

释放calloc 首先初始化所产生的内存为0，不像malloc的。
如果你看到上面的，我设置缓冲区'\\ 0'的结束（这是
其实0），那是因为的malloc返回缓冲区可能
在它的随机（非零）的数据。释放calloc将首先设置整个缓冲区
都为0的第一，它可以是一般更安全。

calloc first initializes the resulting memory to 0, unlike malloc. If you see above where I set the end of the buffer to '\0' (which is actually 0), that's because malloc returns a buffer with potentially random (non-zero) data in it. calloc will first set the entire buffer to all 0s first, which can be generally safer.

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