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+/* Copyright (C) 2001-2012 Artifex Software, Inc.
+   All Rights Reserved.
+
+   This software is provided AS-IS with no warranty, either express or
+   implied.
+
+   This software is distributed under license and may not be copied,
+   modified or distributed except as expressly authorized under the terms
+   of the license contained in the file LICENSE in this distribution.
+
+   Refer to licensing information at http://www.artifex.com or contact
+   Artifex Software, Inc.,  7 Mt. Lassen Drive - Suite A-134, San Rafael,
+   CA  94903, U.S.A., +1(415)492-9861, for further information.
+*/
+
+
+/* Internals of dictionary implementation */
+
+#ifndef idictdef_INCLUDED
+#  define idictdef_INCLUDED
+
+/*
+ * A dictionary of capacity M is a structure containing the following
+ * elements (refs):
+ *
+ *      keys - a t_shortarray or t_array of M+1 elements, containing
+ *      the keys.
+ *
+ *      values - a t_array of M+1 elements, containing the values.
+ *
+ *      count - a t_integer whose value tells how many entries are
+ *      occupied (N).
+ *
+ *      maxlength - a t_integer whose value gives the client's view of
+ *      the capacity (C).  C may be less than M (see below).
+ *
+ *      memory - a foreign t_struct referencing the allocator used to
+ *      create this dictionary, which will also be used to expand or
+ *      unpack it if necessary.
+ *
+ * C < M is possible because on large-memory systems, we usually round up M
+ * so that M is a power of 2 (see idict.h for details); this allows us to
+ * use masking rather than division for computing the initial hash probe.
+ * However, C is always the maxlength specified by the client, so clients
+ * get a consistent story.
+ *
+ * As noted above, the keys may be either in packed or unpacked form.
+ * The markers for unused and deleted entries are different in the two forms.
+ * In the packed form:
+ *      unused entries contain packed_key_empty;
+ *      deleted entries contain packed_key_deleted.
+ * In the unpacked form:
+ *      unused entries contain a literal null;
+ *      deleted entries contain an executable null.
+ *
+ * The first entry is always marked deleted, to reduce the cost of the
+ * wrap-around check.
+ *
+ * Note that if the keys slot in the dictionary is new,
+ * all the key slots are new (more recent than the last save).
+ * We use this fact to avoid saving stores into packed keys
+ * for newly created dictionaries.
+ *
+ * Note that name keys with indices above packed_name_max_index require using
+ * the unpacked form.  */
+#define dict_is_packed(dct) r_has_type(&(dct)->keys, t_shortarray)
+#define packed_key_empty (pt_tag(pt_integer) + 0)
+#define packed_key_deleted (pt_tag(pt_integer) + 1)
+#define packed_key_impossible pt_tag(pt_full_ref)	/* never matches */
+#define packed_name_key(nidx)\
+  ((nidx) <= packed_name_max_index ? pt_tag(pt_literal_name) + (nidx) :\
+   packed_key_impossible)
+/*
+ * Using a special mark for deleted entries causes lookup time to degrade
+ * as entries are inserted and deleted.  This is not a problem, because
+ * entries are almost never deleted.
+ */
+#define d_maxlength(dct) ((uint)((dct)->maxlength.value.intval))
+#define d_set_maxlength(dct,siz) ((dct)->maxlength.value.intval = (siz))
+#define nslots(dct) r_size(&(dct)->values)
+#define npairs(dct) (nslots(dct) - 1)
+#define d_length(dct) ((uint)((dct)->count.value.intval))
+
+/* packed_search_value_pointer simplifies the access to
+   packed dictionary search template data - see idicttpl.h . */
+#define packed_search_value_pointer (pdict->values.value.refs + (kp - kbot))
+
+#endif /* idictdef_INCLUDED */