URI Parser in C: hostとpathに分割するので，SocketでHTTP系の処理するときにラクだと思う． ポインタ操作のオンパレード．

uriparser.c

typedef struct uri {
    char host[REQ_HEAD_HOST_SZ];
    char *path;
    char *filename;
    int port;
} Uri;

int
parse_uri(char uri[], Uri *parsed)
{
    char *host = strstr(uri,"://");
    if (host == NULL) return 0;
    host += 3;
    char *path = strstr(host,"/");
    if (path == NULL) {
        if ((uri = realloc(uri,strlen(uri)+2)) == NULL) {
                perror("malloc");
                exit(1);
        }
        if ((path = realloc(path,2)) == NULL) {
                perror("malloc");
                exit(1);
        }
        strlcpy(path,"/",2);
        strlcat(uri,path,strlen(uri)+3);
        host = strstr(uri,"://") + 3;
        path = strstr(host,"/");
    }
    if ((parsed->path = malloc(strlen(path)) + 1) == NULL) {
            perror("malloc");
            exit(1);
    }
    strlcpy(parsed->path,path,strlen(path) + 1);
    char *ret;
    if ((ret = strrchr(path,'/'))) {
        if ((parsed->filename = malloc(strlen(++ret) + 1)) == NULL) {
                perror("malloc");
                exit(1);
        }
        if (strlen(ret) == 0)
                ;
        else
            strlcpy(parsed->filename,ret,strlen(ret) + 1);
    }
    char *port;
    if ((port = strstr(host,":")) != NULL) {
        int bytes = 0;
        *port++;
        while (isdigit(*port)) {
           *port++;
            ++bytes;
        }
        if (bytes > 0) {
            port[0] = '\0';
            parsed->port = atoi(port-bytes);
            *(host+strlen(host)-bytes-1) = '\0';
        }
    }
    else {
        parsed->port = 80;
    }
    *(host+strlen(host)-strlen(path)) = '\0';
    strlcpy(parsed->host,host,256);

    return 1;
}