--- /dev/null
+/*
+ * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
+ * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
+ * Copyright 1996 Silicon Graphics. All rights reserved.
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose, provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ */
+/*
+ * Some simple primitives for allocation with explicit type information.
+ * Facilities for dynamic type inference may be added later.
+ * Should be used only for extremely performance critical applications,
+ * or if conservative collector leakage is otherwise a problem (unlikely).
+ * Note that this is implemented completely separately from the rest
+ * of the collector, and is not linked in unless referenced.
+ * This does not currently support GC_DEBUG in any interesting way.
+ */
+
+#ifndef GC_TYPED_H
+#define GC_TYPED_H
+
+#ifndef GC_H
+# include "gc.h"
+#endif
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+typedef GC_word * GC_bitmap;
+ /* The least significant bit of the first word is one if */
+ /* the first word in the object may be a pointer. */
+
+#define GC_WORDSZ (8 * sizeof(GC_word))
+#define GC_get_bit(bm, index) \
+ (((bm)[(index) / GC_WORDSZ] >> ((index) % GC_WORDSZ)) & 1)
+#define GC_set_bit(bm, index) \
+ ((bm)[(index) / GC_WORDSZ] |= (GC_word)1 << ((index) % GC_WORDSZ))
+#define GC_WORD_OFFSET(t, f) (offsetof(t,f) / sizeof(GC_word))
+#define GC_WORD_LEN(t) (sizeof(t) / sizeof(GC_word))
+#define GC_BITMAP_SIZE(t) ((GC_WORD_LEN(t) + GC_WORDSZ - 1) / GC_WORDSZ)
+
+typedef GC_word GC_descr;
+
+GC_API GC_descr GC_CALL GC_make_descriptor(GC_bitmap /* bm */,
+ size_t /* len */);
+ /* Return a type descriptor for the object whose layout */
+ /* is described by the argument. */
+ /* The least significant bit of the first word is one */
+ /* if the first word in the object may be a pointer. */
+ /* The second argument specifies the number of */
+ /* meaningful bits in the bitmap. The actual object */
+ /* may be larger (but not smaller). Any additional */
+ /* words in the object are assumed not to contain */
+ /* pointers. */
+ /* Returns a conservative approximation in the */
+ /* (unlikely) case of insufficient memory to build */
+ /* the descriptor. Calls to GC_make_descriptor */
+ /* may consume some amount of a finite resource. This */
+ /* is intended to be called once per type, not once */
+ /* per allocation. */
+
+/* It is possible to generate a descriptor for a C type T with */
+/* word aligned pointer fields f1, f2, ... as follows: */
+/* */
+/* GC_descr T_descr; */
+/* GC_word T_bitmap[GC_BITMAP_SIZE(T)] = {0}; */
+/* GC_set_bit(T_bitmap, GC_WORD_OFFSET(T,f1)); */
+/* GC_set_bit(T_bitmap, GC_WORD_OFFSET(T,f2)); */
+/* ... */
+/* T_descr = GC_make_descriptor(T_bitmap, GC_WORD_LEN(T)); */
+
+GC_API void * GC_CALL GC_malloc_explicitly_typed(size_t /* size_in_bytes */,
+ GC_descr /* d */);
+ /* Allocate an object whose layout is described by d. */
+ /* The resulting object MAY NOT BE PASSED TO REALLOC. */
+ /* The returned object is cleared. */
+
+GC_API void * GC_CALL GC_malloc_explicitly_typed_ignore_off_page(
+ size_t /* size_in_bytes */,
+ GC_descr /* d */);
+
+GC_API void * GC_CALL GC_calloc_explicitly_typed(size_t /* nelements */,
+ size_t /* element_size_in_bytes */,
+ GC_descr /* d */);
+ /* Allocate an array of nelements elements, each of the */
+ /* given size, and with the given descriptor. */
+ /* The element size must be a multiple of the byte */
+ /* alignment required for pointers. E.g. on a 32-bit */
+ /* machine with 16-bit aligned pointers, size_in_bytes */
+ /* must be a multiple of 2. */
+ /* Returned object is cleared. */
+
+#ifdef GC_DEBUG
+# define GC_MALLOC_EXPLICITLY_TYPED(bytes, d) GC_MALLOC(bytes)
+# define GC_CALLOC_EXPLICITLY_TYPED(n, bytes, d) GC_MALLOC((n) * (bytes))
+#else
+# define GC_MALLOC_EXPLICITLY_TYPED(bytes, d) \
+ GC_malloc_explicitly_typed(bytes, d)
+# define GC_CALLOC_EXPLICITLY_TYPED(n, bytes, d) \
+ GC_calloc_explicitly_typed(n, bytes, d)
+#endif
+
+#ifdef __cplusplus
+ } /* matches extern "C" */
+#endif
+
+#endif /* GC_TYPED_H */