* benchmark/bm_hash_shift.rb: add benchmark for Hash#shift

* hash.c (rb_hash_shift): use st_shift if hash is not being iterated to
  delete element without iterating the whole hash.

* hash.c (shift_i): remove function

* include/ruby/st.h (st_shift): add st_shift function

* st.c (st_shift): ditto

[Bug #8312] [ruby-core:54524] Patch by funny-falcon

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40457 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 29 insertions, 0 deletions

diff --git a/st.c b/st.c
index 9151267263..5b59538966 100644
--- a/st.c
+++ b/st.c
@@ -793,6 +793,35 @@ st_delete_safe(register st_table *table, register st_data_t *key, st_data_t *val
     return 0;
 }
 
+int
+st_shift(register st_table *table, register st_data_t *key, st_data_t *value)
+{
+    st_index_t hash_val;
+    st_table_entry **prev;
+    register st_table_entry *ptr;
+
+    if (table->num_entries == 0) {
+        if (value != 0) *value = 0;
+        return 0;
+    }
+
+    if (table->entries_packed) {
+        if (value != 0) *value = PVAL(table, 0);
+        *key = PKEY(table, 0);
+        remove_packed_entry(table, 0);
+        return 1;
+    }
+
+    prev = &table->bins[table->head->hash % table->num_bins];
+    while ((ptr = *prev) != table->head) prev = &ptr->next;
+    *prev = ptr->next;
+    if (value != 0) *value = ptr->record;
+    *key = ptr->key;
+    remove_entry(table, ptr);
+    st_free_entry(ptr);
+    return 1;
+}
+
 void
 st_cleanup_safe(st_table *table, st_data_t never)
 {