C开源hash代码uthash的用法总结（2）

5．完整程序例子

5.1．key类型为int的完整的例子

#include    /* gets */
#include   /* atoi, malloc */
#include   /* strcpy */
#include "uthash.h"

struct my_struct {
    int ikey;                    /* key */
    char value[10];
    UT_hash_handle hh;         /* makes this structure hashable */
};

static struct my_struct *g_users = NULL;

void add_user(int mykey, char *value) {
    struct my_struct *s;

    HASH_FIND_INT(users, &mykey, s);  /* mykey already in the hash? */
    if (s==NULL) {
      s = (struct my_struct*)malloc(sizeof(struct my_struct));
      s->ikey = mykey;
      HASH_ADD_INT( users, ikey, s );  /* ikey: name of key field */
    }
    strcpy(s->value, value);
}

struct my_struct *find_user(int mykey) {
    struct my_struct *s;

    HASH_FIND_INT( users, &mykey, s );  /* s: output pointer */
    return s;
}

void delete_user(struct my_struct *user) {
    HASH_DEL( users, user);  /* user: pointer to deletee */
    free(user);
}

void delete_all() {
  struct my_struct *current_user, *tmp;

  HASH_ITER(hh, users, current_user, tmp) {
    HASH_DEL(users,current_user);  /* delete it (users advances to next) */
    free(current_user);            /* free it */
  }
}

void print_users() {
    struct my_struct *s;

    for(s=users; s != NULL; s=(struct my_struct*)(s->hh.next)) {
        printf("user ikey %d: value %s\n", s->ikey, s->value);
    }
}

int name_sort(struct my_struct *a, struct my_struct *b) {
    return strcmp(a->value,b->value);
}

int id_sort(struct my_struct *a, struct my_struct *b) {
    return (a->ikey - b->ikey);
}

void sort_by_name() {
    HASH_SORT(users, name_sort);
}

void sort_by_id() {
    HASH_SORT(users, id_sort);
}

int main(int argc, char *argv[]) {
    char in[10];
    int ikey=1, running=1;
    struct my_struct *s;
    unsigned num_users;

    while (running) {
        printf(" 1. add user\n");
        printf(" 2. add/rename user by id\n");
        printf(" 3. find user\n");
        printf(" 4. delete user\n");
        printf(" 5. delete all users\n");
        printf(" 6. sort items by name\n");
        printf(" 7. sort items by id\n");
        printf(" 8. print users\n");
        printf(" 9. count users\n");
        printf("10. quit\n");
        gets(in);
        switch(atoi(in)) {
            case 1:
                printf("name?\n");
                add_user(ikey++, gets(in));
                break;
            case 2:
                printf("id?\n");
                gets(in); ikey = atoi(in);
                printf("name?\n");
                add_user(ikey, gets(in));
                break;
            case 3:
                printf("id?\n");
                s = find_user(atoi(gets(in)));
                printf("user: %s\n", s ? s->value : "unknown");
                break;
            case 4:
                printf("id?\n");
                s = find_user(atoi(gets(in)));
                if (s) delete_user(s);
                else printf("id unknown\n");
                break;
            case 5:
                delete_all();
                break;
            case 6:
                sort_by_name();
                break;
            case 7:
                sort_by_id();
                break;
            case 8:
                print_users();
                break;
            case 9:
                num_users=HASH_COUNT(users);
                printf("there are %u users\n", num_users);
                break;
            case 10:
                running=0;
                break;
        }
    }

    delete_all();  /* free any structures */
    return 0;
}

5.2．key类型为字符数组的完整的例子

#include   /* strcpy */
#include   /* malloc */
#include    /* printf */
#include "uthash.h"

struct my_struct {
    char name[10];             /* key (string is WITHIN the structure) */
    int id;
    UT_hash_handle hh;         /* makes this structure hashable */
};


int main(int argc, char *argv[]) {
    const char **n, *names[] = { "joe", "bob", "betty", NULL };
    struct my_struct *s, *tmp, *users = NULL;
    int i=0;

    for (n = names; *n != NULL; n++) {
        s = (struct my_struct*)malloc(sizeof(struct my_struct));
        strncpy(s->name, *n,10);
        s->id = i++;
        HASH_ADD_STR( users, name, s );
    }

    HASH_FIND_STR( users, "betty", s);
    if (s) printf("betty's id is %d\n", s->id);

    /* free the hash table contents */
    HASH_ITER(hh, users, s, tmp) {
      HASH_DEL(users, s);
      free(s);
    }
    return 0;
}

5.3．key类型为字符指针的完整的例子

#include   /* strcpy */
#include   /* malloc */
#include    /* printf */
#include "uthash.h"

struct my_struct {
    const char *name;          /* key */
    int id;
    UT_hash_handle hh;         /* makes this structure hashable */
};


int main(int argc, char *argv[]) {
    const char **n, *names[] = { "joe", "bob", "betty", NULL };
    struct my_struct *s, *tmp, *users = NULL;
    int i=0;

    for (n = names; *n != NULL; n++) {
        s = (struct my_struct*)malloc(sizeof(struct my_struct));
        s->name = *n;
        s->id = i++;
        HASH_ADD_KEYPTR( hh, users, s->name, strlen(s->name), s );
    }

    HASH_FIND_STR( users, "betty", s);
    if (s) printf("betty's id is %d\n", s->id);

    /* free the hash table contents */
    HASH_ITER(hh, users, s, tmp) {
      HASH_DEL(users, s);
      free(s);
    }
    return 0;
}