diff options
Diffstat (limited to 'libguile')
-rw-r--r-- | libguile/hashtab.c | 28 | ||||
-rw-r--r-- | libguile/hashtab.h | 1 |
2 files changed, 29 insertions, 0 deletions
diff --git a/libguile/hashtab.c b/libguile/hashtab.c index 0abc7dc04..88cb199c5 100644 --- a/libguile/hashtab.c +++ b/libguile/hashtab.c @@ -584,6 +584,7 @@ SCM_DEFINE (scm_doubly_weak_hash_table_p, "doubly-weak-hash-table?", 1, 0, 0, } #undef FUNC_NAME + /* Accessing hash table entries. */ @@ -1371,6 +1372,33 @@ SCM_DEFINE (scm_hash_map_to_list, "hash-map->list", 2, 0, 0, } #undef FUNC_NAME +static SCM +count_proc (void *pred, SCM key, SCM data, SCM value) +{ + if (scm_is_false (scm_call_2 (SCM_PACK (pred), key, data))) + return value; + else + return scm_oneplus(value); +} + +SCM_DEFINE (scm_hash_count, "hash-count", 2, 0, 0, + (SCM pred, SCM table), + "Return the number of elements in the given hash TABLE that\n" + "cause `(PRED KEY VALUE)' to return true. To quickly determine\n" + "the total number of elements, use `(const #t)' for PRED.") +#define FUNC_NAME s_scm_hash_count +{ + SCM init; + + SCM_VALIDATE_PROC (1, pred); + SCM_VALIDATE_HASHTABLE (2, table); + + init = scm_from_int (0); + return scm_internal_hash_fold ((scm_t_hash_fold_fn) count_proc, + (void *) SCM_UNPACK (pred), init, table); +} +#undef FUNC_NAME + SCM diff --git a/libguile/hashtab.h b/libguile/hashtab.h index 314994630..dcebcb81e 100644 --- a/libguile/hashtab.h +++ b/libguile/hashtab.h @@ -164,6 +164,7 @@ SCM_API SCM scm_hash_fold (SCM proc, SCM init, SCM hash); SCM_API SCM scm_hash_for_each (SCM proc, SCM hash); SCM_API SCM scm_hash_for_each_handle (SCM proc, SCM hash); SCM_API SCM scm_hash_map_to_list (SCM proc, SCM hash); +SCM_API SCM scm_hash_count (SCM hash, SCM pred); SCM_INTERNAL void scm_i_hashtable_print (SCM exp, SCM port, scm_print_state *pstate); SCM_INTERNAL void scm_init_hashtab (void); |