1 files changed, 127 insertions, 0 deletions
diff --git a/libgo/runtime/go-map-index.c b/libgo/runtime/go-map-index.c
new file mode 100644
index 0000000000..1561c97a6e
--- /dev/null
+++ b/libgo/runtime/go-map-index.c
@@ -0,0 +1,127 @@
+/* go-map-index.c -- find or insert an entry in a map.
+
+   Copyright 2009 The Go Authors. All rights reserved.
+   Use of this source code is governed by a BSD-style
+   license that can be found in the LICENSE file.  */
+
+#include <stddef.h>
+#include <stdlib.h>
+
+#include "go-alloc.h"
+#include "go-assert.h"
+#include "map.h"
+
+/* Rehash MAP to a larger size.  */
+
+static void
+__go_map_rehash (struct __go_map *map)
+{
+  const struct __go_map_descriptor *descriptor;
+  const struct __go_type_descriptor *key_descriptor;
+  size_t key_offset;
+  size_t key_size;
+  size_t (*hashfn) (const void *, size_t);
+  size_t old_bucket_count;
+  void **old_buckets;
+  size_t new_bucket_count;
+  void **new_buckets;
+  size_t i;
+
+  descriptor = map->__descriptor;
+
+  key_descriptor = descriptor->__map_descriptor->__key_type;
+  key_offset = descriptor->__key_offset;
+  key_size = key_descriptor->__size;
+  hashfn = key_descriptor->__hashfn;
+
+  old_bucket_count = map->__bucket_count;
+  old_buckets = map->__buckets;
+
+  new_bucket_count = __go_map_next_prime (old_bucket_count * 2);
+  new_buckets = (void **) __go_alloc (new_bucket_count * sizeof (void *));
+  __builtin_memset (new_buckets, 0, new_bucket_count * sizeof (void *));
+
+  for (i = 0; i < old_bucket_count; ++i)
+    {
+      char* entry;
+      char* next;
+
+      for (entry = old_buckets[i]; entry != NULL; entry = next)
+	{
+	  size_t key_hash;
+	  size_t new_bucket_index;
+
+	  /* We could speed up rehashing at the cost of memory space
+	     by caching the hash code.  */
+	  key_hash = hashfn (entry + key_offset, key_size);
+	  new_bucket_index = key_hash % new_bucket_count;
+
+	  next = *(char **) entry;
+	  *(char **) entry = new_buckets[new_bucket_index];
+	  new_buckets[new_bucket_index] = entry;
+	}
+    }
+
+  __go_free (old_buckets);
+
+  map->__bucket_count = new_bucket_count;
+  map->__buckets = new_buckets;
+}
+
+/* Find KEY in MAP, return a pointer to the value.  If KEY is not
+   present, then if INSERT is false, return NULL, and if INSERT is
+   true, insert a new value and zero-initialize it before returning a
+   pointer to it.  */
+
+void *
+__go_map_index (struct __go_map *map, const void *key, _Bool insert)
+{
+  const struct __go_map_descriptor *descriptor;
+  const struct __go_type_descriptor *key_descriptor;
+  size_t key_offset;
+  _Bool (*equalfn) (const void*, const void*, size_t);
+  size_t key_hash;
+  size_t key_size;
+  size_t bucket_index;
+  char *entry;
+
+  descriptor = map->__descriptor;
+
+  key_descriptor = descriptor->__map_descriptor->__key_type;
+  key_offset = descriptor->__key_offset;
+  key_size = key_descriptor->__size;
+  __go_assert (key_size != 0 && key_size != -1UL);
+  equalfn = key_descriptor->__equalfn;
+
+  key_hash = key_descriptor->__hashfn (key, key_size);
+  bucket_index = key_hash % map->__bucket_count;
+
+  entry = (char *) map->__buckets[bucket_index];
+  while (entry != NULL)
+    {
+      if (equalfn (key, entry + key_offset, key_size))
+	return entry + descriptor->__val_offset;
+      entry = *(char **) entry;
+    }
+
+  if (!insert)
+    return NULL;
+
+  if (map->__element_count >= map->__bucket_count)
+    {
+      __go_map_rehash (map);
+      bucket_index = key_hash % map->__bucket_count;
+    }
+
+  entry = (char *) __go_alloc (descriptor->__entry_size);
+  __builtin_memset (entry, 0, descriptor->__entry_size);
+
+  __builtin_memcpy (entry + key_offset, key, key_size);
+
+  *(char **) entry = map->__buckets[bucket_index];
+  map->__buckets[bucket_index] = entry;
+
+  map->__element_count += 1;
+
+  return entry + descriptor->__val_offset;
+}