从C中的char *数组中删除空格 [英] remove spaces from char* array in C

问题描述

我正在为游戏模拟器使用 C 中的插件，在检查输入消息是否包含任何网站URL之前，我想从聊天消息中删除所有空格.

I am working on a plugin in C for a game emulator, where I would like to remove all spaces from chat message before checking if the input messages contain any website urls.

所以，我有这样的功能来消除空白(从输入消息中删除空格):

So, I have this function like this to deblank (remove spaces from input message):

char* deblank(char* input) {
    int i, j;
    char *output = input;
    for (i = 0, j = 0; i < strlen(input); i++, j++) {
        if (input[i] != ' ')
            output[j] = input[i];
        else
            j--;
    }
    output[j] = 0;
    return output;
}

我在插件钩子中这样使用它:

I use it in my plugin hook like this:

bool my_pc_process_chat_message(bool retVal___, struct map_session_data *sd, const char *message) {
    if (retVal___ == true) {
        char* check_message = deblank(message);
        bool url_detected = (stristr(check_message, "://") || stristr(check_message, "www.") || stristr(check_message, "vvvvvv.") || stristr(check_message, "wvvw."));
        if (!url_detected) {
            int len = sizeof(tld_list) / sizeof(tld_list[0]);
            int i;
            for (i = 0; i < len; ++i) {
                if (stristr(check_message, tld_list[i])) {
                    url_detected = true;
                    break;
                }
            }
        }
        if (url_detected) {
            clif->messagecolor_self(sd->fd, COLOR_RED, "Possible GM Impersonation Detected - you cannot type website URLs in chat.");
            return false;
        }
    }
    return retVal___;
}

以上方法有效，但有副作用.似乎正在发生的事情是，当输入消息不包含任何网站网址时，输入消息将被修改，并且所有消息中的空格都将被删除.

The above works, but there's a side-effect. What seems to be happening is that the input message is getting modified and all spaces from the message being removed, when it doesn't contain any website urls.

例如，如果我输入:

转到www.some-domain.com

Go to www.some-domain.com

上面的内容被阻止，所以这样做(当玩家尝试变得更聪明并使用空格时):

The above get's blocked, So does this (when players try to be clever and use spaces):

w w w w.S o e e-d o m a n n.c o m

w w w . s o m e - d o m a i n . c o m

但是，当您键入不包含任何网站网址的普通消息时，

However, when you type a normal message that doesn't contain any website urls like this:

你好，你好吗?

它变成了以下内容:

你好，你好吗?

这是因为以下行: char * check_message = deblank(message); 删除功能似乎正在修改原始消息.我以为该函数将返回原始消息的新副本，不带空格.

This is because of this line: char* check_message = deblank(message); The deblank function appears to be modifying the original message. I thought the function would return a new copy of the orignal message, without spaces.

在检查之前，有没有办法我可以临时复制原始 input消息，并从中删除空格?

Is there a way I can make a temporary copy of the original input message, remove spaces from that, before doing my check?

此外，如何清除分配给原始输入的临时副本的内存?我不希望这个问题持续存在.还是在代码完成作用域的执行后，C会自动清除该临时字符数组?

Also, how do you clear allocated memory to the temp copy of the orignal input? I don't want this to linger around. Or does C automatically clears that temp char array once the code finishes it's execution in the scope?

推荐答案

不，您实际上不能这样做.

No, you can't actually do that.

有两种解决方案:-第一次循环字符串以计算有多少个非空格字符，这样您就知道需要分配多少.

There are two solutions: - Loop the string a first time to count how many non-space characters there are, so you know how much you need to allocate.

int count_not_empty(const char *str)
{
  int n = 0;

  for (; *str; ++str) {
    if (*str != ' ') n++;
  }
  return n + 1; // the +1 is for the nulbyte at the end
}

• 分配一个与要修剪的字符串一样大的字符串，并在末尾填充nbytes.

即

char *copy_not_empty(const char *str)
{
  size_t i;
  size_t j;
  char *new = malloc(strlen(str) + 1);

  for (i = j = 0; i < strlen(str); ++i)
  {
    if (str[i] != ' ')
      new[j++] = str[i];
  }
  for (; j <= i; j++)
    new[j] = 0; // pad with nulbytes
  return new;
}

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