/* -*-c-*-
*
- * $Id: sym.h,v 1.10 1999/12/10 23:42:04 mdw Exp $
+ * $Id: sym.h,v 1.14 2004/04/08 01:36:13 mdw Exp $
*
* Symbol table management
*
* MA 02111-1307, USA.
*/
-/*----- Revision history --------------------------------------------------*
- *
- * $Log: sym.h,v $
- * Revision 1.10 1999/12/10 23:42:04 mdw
- * Change header file guard names.
- *
- * Revision 1.9 1999/08/02 16:53:48 mdw
- * Improve type safety for sym_iter objects.
- *
- * Revision 1.8 1999/08/02 14:45:48 mdw
- * Break low-level hashtable code out from sym.
- *
- * Revision 1.7 1999/06/01 09:49:33 mdw
- * Allow things to be looked up by just their caller-supplied hashes. This
- * actually needs to be thought through better.
- *
- * Revision 1.6 1999/05/26 21:08:31 mdw
- * Rename symbols in line with newer conventions.
- *
- * Revision 1.5 1999/05/13 22:48:37 mdw
- * Change `-ise' to `-ize' throughout.
- *
- * Revision 1.4 1999/05/06 19:51:35 mdw
- * Reformatted the LGPL notice a little bit.
- *
- * Revision 1.3 1999/05/05 18:50:31 mdw
- * Change licensing conditions to LGPL.
- *
- * Revision 1.2 1998/11/26 19:27:34 mdw
- * Move SYM_NAME into the header file. Fix bugs.
- *
- * Revision 1.1.1.1 1998/06/17 23:44:42 mdw
- * Initial version of mLib
- *
- */
-
#ifndef MLIB_SYM_H
#define MLIB_SYM_H
# include "hash.h"
#endif
+#ifndef MLIB_SUB_H
+# include "sub.h"
+#endif
+
+/*----- Tuning parameters -------------------------------------------------*/
+
+/* --- Initial hash table size --- *
+ *
+ * This is the initial @mask@ value. It must be of the form %$2^n - 1$%,
+ * so that it can be used to mask of the bottom bits of a hash value.
+ */
+
+#define SYM_INITSZ 32 /* Size of a new hash table */
+
+/* --- Maximum load factor --- *
+ *
+ * This parameter controls how much the table has to be loaded before the
+ * table is extended. The number of elements %$n$%, the number of bins %$b$%
+ * and the limit %$l$% satisfy the relation %$n < bl$%; if a new item is
+ * added to the table and this relation is found to be false, the table is
+ * doubled in size.
+ */
+
+#define SYM_LIMIT(n) ((n) * 2) /* Load factor for growing table */
+
/*----- Type definitions --------------------------------------------------*/
/* --- Symbol table --- *
typedef struct sym_table {
hash_table t;
+ subarena *s;
size_t load;
} sym_table;
* sufficient to allow me to manipulate such objects.
*/
-#define SYM_BUFSZ 16 /* Size of local string buffer */
-
typedef struct sym_base {
- hash_base b;
- union {
- char *p; /* Pointer to name string */
- char b[SYM_BUFSZ]; /* Buffer containing a short name */
- } name; /* Name of this symbol */
+ hash_base b; /* Base structure */
+ char *name; /* Pointer to name string */
size_t len; /* Length of the symbol's name */
} sym_base;
-/* --- A macro to pick a symbol's name out from the mess --- */
+/* --- Macros for picking out useful information --- *
+ *
+ * Note that @SYM_LEN@ returns the size of the symbol key. For textual keys,
+ * this will include the terminating null.
+ */
-#define SYM_NAME(sy) \
- (((sym_base *)(sy))->len > SYM_BUFSZ ? \
- ((sym_base *)(sy))->name.p : \
- ((sym_base *)(sy))->name.b)
+#define SYM_NAME(sy) ((const char *)(((sym_base *)(sy))->name))
+#define SYM_LEN(sy) (((sym_base *)(sy))->len + 0)
+#define SYM_HASH(sy) (((sym_base *)(sy))->b.hash + 0)
/* --- An iterator block --- */
/* --- @sym_find@ --- *
*
* Arguments: @sym_table *t@ = pointer to symbol table in question
- * @const char *n@ = pointer to symbol table to look up
+ * @const char *n@ = pointer to symbol name to look up
* @long l@ = length of the name string or negative to measure
* @size_t sz@ = size of desired symbol object, or zero
* @unsigned *f@ = pointer to a flag, or null.
~mdw / mLib / blobdiff