Fix Enumerable#hash on non 32-bit integer conf.

1 files changed, 55 insertions, 1 deletions

diff --git a/src/enum.c b/src/enum.c
index adb815bf1..ed3ebdd9f 100644
--- a/src/enum.c
+++ b/src/enum.c
@@ -5,10 +5,64 @@
 */
 
 #include <mruby.h>
+#include <mruby/proc.h>
+
+typedef struct enumerable_hash_context {
+  mrb_int hash;
+  mrb_int index;
+} enumerable_hash_context;
+
+static mrb_value
+enumerable_hash_each(mrb_state *mrb, mrb_value self)
+{
+  mrb_value item;
+  mrb_value closure;
+
+  mrb_get_args(mrb, "o", &item);
+  closure = mrb_proc_cfunc_env_get(mrb, 0);
+
+  if (mrb_cptr_p(closure)) {
+    mrb_value item_hash;
+    enumerable_hash_context *context = (enumerable_hash_context *)mrb_cptr(closure);
+
+    item_hash = mrb_funcall(mrb, item, "hash", 0);
+    if (mrb_fixnum_p(item_hash)) {
+      context->hash ^= (mrb_fixnum(item_hash) << (context->index % 16));
+      ++context->index;
+      return mrb_nil_value();
+    }
+  }
+
+  mrb_raise(mrb, E_TYPE_ERROR, "can't calculate hash");
+}
+
+static mrb_value
+enumerable_hash(mrb_state *mrb, mrb_value self)
+{
+  /* redefine #hash 15.3.1.3.15 */
+  struct RProc *proc;
+  enumerable_hash_context context;
+  mrb_value closure;
+  mrb_value blk;
+  int ai = mrb_gc_arena_save(mrb);
+
+  context.hash = 12347;
+  context.index = 0;
+  closure = mrb_cptr_value(mrb, &context);
+
+  proc = mrb_proc_new_cfunc_with_env(mrb, enumerable_hash_each, 1, &closure);
+  blk = mrb_obj_value(proc);
+  mrb_funcall_with_block(mrb, self, mrb_intern_cstr(mrb, "each"), 0, NULL, blk);
+
+  mrb_gc_arena_restore(mrb, ai);
+  return mrb_fixnum_value(context.hash);
+}
 
 void
 mrb_init_enumerable(mrb_state *mrb)
 {
-  mrb_define_module(mrb, "Enumerable");  /* 15.3.2 */
+  struct RClass *enumerable;
+  enumerable = mrb_define_module(mrb, "Enumerable");  /* 15.3.2 */
+  mrb_define_module_function(mrb, enumerable, "hash", enumerable_hash, MRB_ARGS_NONE());
 }