From 1034c9be4ee918000b6cce922b7ba5782bbcf010 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Wed, 24 Nov 2010 15:44:18 -0700
Subject: [PATCH] fix hashing on C pointers and missing tests

---
 collects/tests/racket/foreign-test.rktl | 15 +++++++++++++++
 src/racket/src/hash.c                   |  2 +-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/collects/tests/racket/foreign-test.rktl b/collects/tests/racket/foreign-test.rktl
index a8ef509b5c..182edfdea5 100644
--- a/collects/tests/racket/foreign-test.rktl
+++ b/collects/tests/racket/foreign-test.rktl
@@ -239,6 +239,21 @@
   (ptr-set! v _pointer (ptr-add #f 107))
   (test 107 ptr-ref v _intptr))
 
+;; Test equality and hashing of c pointers:
+(let ([seventeen1 (cast 17 _long _pointer)]
+      [seventeen2 (cast 17 _long _pointer)]
+      [seventeen3 (ptr-add (cast 13 _long _pointer) 4)]
+      [sixteen (cast 16 _long _pointer)])
+  (test #t equal? seventeen1 seventeen2)
+  (test #t equal? seventeen1 seventeen3)
+  (test #f equal? sixteen seventeen1)
+  (test #t = (equal-hash-code seventeen1) (equal-hash-code seventeen2))
+  (test #t = (equal-hash-code seventeen1) (equal-hash-code seventeen3))
+  (let ([ht (make-hash)])
+    (hash-set! ht seventeen1 'hello)
+    (test 'hello hash-ref ht seventeen2 #f)
+    (test 'hello hash-ref ht seventeen3 #f)))
+
 (delete-test-files)
 
 (report-errs)
diff --git a/src/racket/src/hash.c b/src/racket/src/hash.c
index b62edbfdfc..b9ac3e4766 100644
--- a/src/racket/src/hash.c
+++ b/src/racket/src/hash.c
@@ -1080,7 +1080,7 @@ static long equal_hash_key(Scheme_Object *o, long k, Hash_Info *hi)
     {
       k = (k << 3) + k;
       k += (long)((char *)SCHEME_CPTR_VAL(o) + SCHEME_CPTR_OFFSET(o));
-      break;
+      return k;
     }
   case scheme_vector_type:
   case scheme_fxvector_type: