c - 迭代 C 中的输入 char 参数？

Question

我正在尝试迭代 C 中的输入参数，我将其存储在指向 char 的指针中，如下所示:const char *page = argv[1];

现在参数将是一个 http 地址，因此它可能看起来像这样:

http://host:port/folder1/folder2/file.jpg

我想要的是:解析这个字符串并将其分成子字符串

char host = "host"; 
char port = "port"; 
char path = "/folder1/folder2/file.jpg";
char file = "file.jpg"; 

所以我认为一个简单的 for 循环(例如计算斜杠数量)可能会达到目的。

int slash_cnt = 0;
int i = 0;

for (i = 0, page[i] != '\0', i++)
{ 
    if (strcmp(&page[i], "/")) 
    { 
        slash_cnt++; 
    }
}

但这不起作用。

如果有人可以在这里帮助我，或者甚至建议一种更好的方法来解析输入中指定的http地址并将其相应地分开，我将非常感激!

Answer 1

strstr 可用于搜索分隔各部分的字符串 //、/ 和 :出于兴趣。 strrchr 可用于查找文件名前面的尾随 /。

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

int main()
{
    char *page = "http://host:port/folder1/folder2/file.jpg";
    char *slashes = "//";
    char *slash = "/";
    char *colon = ":";
    char *start = NULL;
    char *stop = NULL;
    char *host = NULL;
    char *port = NULL;
    char *path = NULL;
    char *file = NULL;
    size_t span = 0;

    if ( ( start = strstr ( page, slashes)) == NULL) {
        fputs ( "could not find \"//\"\n", stderr);
        return 1;
    }
    start += strlen ( slashes);//move pointer so the slashes are excluded
    if ( ( stop = strstr ( start, colon)) == NULL) {
        fputs ( "could not find \":\"\n", stderr);
        return 1;
    }
    span = stop - start;
    if ( ( host = malloc ( span)) == NULL) {
        fputs ( "malloc failed\n", stderr);
        return 1;
    }
    memmove ( host, start, span);
    host[span] = '\0';

    start = stop + strlen ( colon);
    if ( ( stop = strstr ( start, slash)) == NULL) {
        fputs ( "could not find leading \"/\"\n", stderr);
        return 1;
    }
    span = stop - start;
    if ( ( port = malloc ( span)) == NULL) {
        fputs ( "malloc failed\n", stderr);
        return 1;
    }
    memmove ( port, start, span);
    port[span] = '\0';

    span = strlen ( stop) + 1;
    if ( ( path = malloc ( span)) == NULL) {
        fputs ( "malloc failed\n", stderr);
        return 1;
    }
    memmove ( path, stop, span);
    path[span] = '\0';

    if ( ( start = strrchr ( page, slash[0])) == NULL) {
        fputs ( "could not find trailing \"/\"\n", stderr);
        return 1;
    }
    start += strlen ( slash);
    span = strlen ( start) + 1;
    if ( ( file = malloc ( span)) == NULL) {
        fputs ( "malloc failed\n", stderr);
        return 1;
    }
    memmove ( file, start, span);
    file[span] = '\0';

    puts ( host);
    puts ( port);
    puts ( path);
    puts ( file);

    free ( host);
    free ( port);
    free ( path);
    free ( file);

    return 0;
}