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authorDaniel Hartwig <mandyke@gmail.com>2013-02-17 16:38:31 +0800
committerDaniel Hartwig <mandyke@gmail.com>2013-02-18 10:21:43 +0800
commit3330f00f54649cdd0914b6ff03c7b7bbc38ffa8d (patch)
tree300aa688b6c2a940e0cfdf05f7829321709288dd /libguile/hashtab.c
parent3d2b2676e3fc0a5b243b8a4188d07bba1b4b40a4 (diff)
downloadguile-3330f00f54649cdd0914b6ff03c7b7bbc38ffa8d.tar.gz
add hash-count for native tables
* libguile/hashtab.c (scm_hash_count): New function. Count the number of elements in a hash table. * doc/ref/api-compound.texi (Hash Tables): Update examples and reference. * test-suite/tests/hash.test (hash-count): New test.
Diffstat (limited to 'libguile/hashtab.c')
-rw-r--r--libguile/hashtab.c28
1 files changed, 28 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