diff options
Diffstat (limited to 'common/dhash/examples/dhash_example.c')
-rw-r--r-- | common/dhash/examples/dhash_example.c | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/common/dhash/examples/dhash_example.c b/common/dhash/examples/dhash_example.c new file mode 100644 index 00000000..7ed01d71 --- /dev/null +++ b/common/dhash/examples/dhash_example.c @@ -0,0 +1,118 @@ +#include <stdio.h> +#include <string.h> +#include <stdlib.h> +#include <assert.h> +#include "dhash.h" + +struct my_data_t { + int foo; + char bar[128]; +}; + +void delete_callback(hash_entry_t *entry, hash_destroy_enum type, void *pvt) +{ + if (entry->value.type == HASH_VALUE_PTR) free(entry->value.ptr); +} + +bool visit_callback(hash_entry_t *entry, void *user_data) +{ + unsigned long *count = (unsigned long *)user_data; + struct my_data_t *my_data = (struct my_data_t *) entry->value.ptr; + + (*count)++; + + printf("%s = [foo=%d bar=%s]\n", entry->key.str, my_data->foo, my_data->bar); + return true; +} + +struct my_data_t *new_data(int foo, const char *bar) +{ + struct my_data_t *my_data = malloc(sizeof(struct my_data_t)); + my_data->foo = foo; + strncpy(my_data->bar, bar, sizeof(my_data->bar)); + return my_data; +} +int main(int argc, char **argv) +{ + static hash_table_t *table = NULL; + hash_key_t key, *keys; + hash_value_t value; + struct hash_iter_context_t *iter; + hash_entry_t *entry; + unsigned long i, n_entries; + int error; + struct my_data_t *my_data = new_data(1024, "Hello World!"); + unsigned long count; + + /* Create a hash table */ + error = hash_create(10, &table, delete_callback, NULL); + if (error != HASH_SUCCESS) { + fprintf(stderr, "cannot create hash table (%s)\n", hash_error_string(error)); + return error; + } + + /* Enter a key named "My Data" and specify it's value as a pointer to my_data */ + key.type = HASH_KEY_STRING; + key.str = strdup("My Data"); + value.type = HASH_VALUE_PTR; + value.ptr = my_data; + + if ((error = hash_enter(table, &key, &value)) != HASH_SUCCESS) { + fprintf(stderr, "cannot add to table \"%s\" (%s)\n", key.str, hash_error_string(error)); + return error; + } + + /* Get a list of keys and print them out, free the list when we're done */ + if ((error = hash_keys(table, &count, &keys)) != HASH_SUCCESS) { + fprintf(stderr, "cannot get key list (%s)\n", hash_error_string(error)); + return error; + } + + for (i = 0; i < count; i++) + printf("key: %s\n", keys[i].str); + free(keys); + + /* Lookup the key named "My Data" */ + key.type = HASH_KEY_STRING; + key.str = strdup("My Data"); + if ((error = hash_lookup(table, &key, &value)) != HASH_SUCCESS) { + fprintf(stderr, "cannot find key \"%s\" (%s)\n", key.str, hash_error_string(error)); + } + + /* Visit each entry in the table, callback will increment count on each visit */ + printf("Iterate using callback\n"); + count = 0; + hash_iterate(table, visit_callback, &count); + + /* Assure number of visits equal the table size */ + assert(count == hash_count(table)); + + /* Visit each entry using iterator object */ + printf("Iterate using iterator\n"); + n_entries = 0; + iter = new_hash_iter_context(table); + while ((entry = iter->next(iter)) != NULL) { + struct my_data_t *data = (struct my_data_t *) entry->value.ptr; + + printf("%s = [foo=%d bar=%s]\n", entry->key.str, data->foo, data->bar); + n_entries++; + } + free(iter); + /* Assure number of visits equal the table size */ + assert(n_entries == hash_count(table)); + + /* Remove the entry, deletion callback will be invoked */ + key.type = HASH_KEY_STRING; + key.str = strdup("My Data"); + if ((error = hash_delete(table, &key)) != HASH_SUCCESS) { + fprintf(stderr, "cannot delete from table (%s)\n", hash_error_string(error)); + } + + /* Assure key is no longer in table */ + assert (!hash_has_key(table, &key)); + + /* Free the table */ + hash_destroy(table); + + return 0; +} |