/* -*-c-*-
*
- * $Id: sym.h,v 1.6 1999/05/26 21:08:31 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 1.6 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 SYM_H
-#define SYM_H
+#ifndef MLIB_SYM_H
+#define MLIB_SYM_H
#ifdef __cplusplus
extern "C" {
#include <stddef.h>
+#ifndef MLIB_BITS_H
+# include "bits.h"
+#endif
+
+#ifndef MLIB_HASH_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 {
- unsigned long mask; /* Bit mask for hashing purposes */
- size_t c; /* Down counter for growing table */
- struct sym_base **a; /* Array of hash bins */
+ hash_table t;
+ subarena *s;
+ size_t load;
} sym_table;
/* --- A symbol table entry --- *
* sufficient to allow me to manipulate such objects.
*/
-#define SYM_BUFSZ 16 /* Size of local string buffer */
-
typedef struct sym_base {
- struct sym_base *next; /* Next symbol in hash bin */
- unsigned long hash; /* Hash value for symbol's name */
- 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 --- */
-typedef struct sym_iter {
- sym_table *t; /* Symbol table being iterated */
- sym_base *n; /* Address of next item to return */
- size_t i; /* Index of next hash bin to use */
-} sym_iter;
+typedef struct { hash_iter i; } sym_iter;
/*----- External functions ------------------------------------------------*/
/* --- @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.
* may be given, in which case the name may contain arbitrary
* binary data, or it may be given as a negative number, in
* which case the length of the name is calculated as
- * @strlen(n)@.
+ * @strlen(n) + 1@.
*
* The return value is the address of a pointer to a @sym_base@
* block (which may have other things on the end, as above). If
/* --- @sym_remove@ --- *
*
- * Arguments: @sym_table *i@ = pointer to a symbol table object
+ * Arguments: @sym_table *t@ = pointer to a symbol table object
* @void *b@ = pointer to symbol table entry
*
* Returns: ---
* iterate through a symbol table.
*/
+#define SYM_MKITER(i_, t_) HASH_MKITER(&(i_)->i, &(t_)->t)
+
extern void sym_mkiter(sym_iter */*i*/, sym_table */*t*/);
/* --- @sym_next@ --- *
* returned in any particular order.
*/
+#define SYM_NEXT(i_, p) do { \
+ hash_base *_q; \
+ HASH_NEXT(&(i_)->i, _q); \
+ (p) = (void *)_q; \
+} while (0)
+
extern void *sym_next(sym_iter */*i*/);
/*----- That's all, folks -------------------------------------------------*/