--- /dev/null
+/* -*-c-*-
+ *
+ * Symbol table management
+ *
+ * (c) 1998 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of the mLib utilities library.
+ *
+ * mLib is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * mLib is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with mLib; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+#ifndef MLIB_SYM_H
+#define MLIB_SYM_H
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+/*----- Required headers --------------------------------------------------*/
+
+#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 --- *
+ *
+ * A @sym_table@ contains the information needed to manage a symbol table.
+ * Users shouldn't fiddle with this information directly, but it needs to be
+ * here so that objects of the correct type can be created.
+ */
+
+typedef struct sym_table {
+ hash_table t;
+ subarena *s;
+ size_t load;
+} sym_table;
+
+/* --- A symbol table entry --- *
+ *
+ * I don't care what actually gets stored in symbol entries because I don't
+ * create them: that's the responsibility of my client. All I care about
+ * here is that whatever gets passed to me is a structure whose first member
+ * is a @sym_base@. The ANSI guarantees about structure layout are
+ * sufficient to allow me to manipulate such objects.
+ */
+
+typedef struct sym_base {
+ hash_base b; /* Base structure */
+ char *name; /* Pointer to name string */
+ size_t len; /* Length of the symbol's name */
+} sym_base;
+
+/* --- 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) ((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 { hash_iter i; } sym_iter;
+
+/*----- External functions ------------------------------------------------*/
+
+/* --- @sym_create@ --- *
+ *
+ * Arguments: @sym_table *t@ = symbol table to initialize
+ *
+ * Returns: ---
+ *
+ * Use: Initializes the given symbol table. Raises @EXC_NOMEM@ if
+ * there isn't enough memory.
+ */
+
+extern void sym_create(sym_table */*t*/);
+
+/* --- @sym_destroy@ --- *
+ *
+ * Arguments: @sym_table *t@ = pointer to symbol table in question
+ *
+ * Returns: ---
+ *
+ * Use: Destroys a symbol table, freeing all the memory it used to
+ * occupy.
+ */
+
+extern void sym_destroy(sym_table */*t*/);
+
+/* --- @sym_find@ --- *
+ *
+ * Arguments: @sym_table *t@ = pointer to symbol table in question
+ * @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.
+ *
+ * Returns: The address of a @sym_base@ structure, or null if not found
+ * and @sz@ is zero.
+ *
+ * Use: Looks up a symbol in a given symbol table. The name is
+ * passed by the address of its first character. The length
+ * 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) + 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
+ * the symbol could be found, the return value points to the
+ * symbol block. If the symbol wasn't there, then if @sz@ is
+ * nonzero, a new symbol is created and its address is returned;
+ * otherwise a null pointer is returned. The exception
+ * @EXC_NOMEM@ is raised if the block can't be allocated.
+ *
+ * The value of @*f@ indicates whether a new symbol entry was
+ * created: a nonzero value indicates that an old value was
+ * found.
+ */
+
+extern void *sym_find(sym_table */*t*/, const char */*n*/, long /*l*/,
+ size_t /*sz*/, unsigned */*f*/);
+
+/* --- @sym_remove@ --- *
+ *
+ * Arguments: @sym_table *t@ = pointer to a symbol table object
+ * @void *b@ = pointer to symbol table entry
+ *
+ * Returns: ---
+ *
+ * Use: Removes the object from the symbol table. The space occupied
+ * by the object and its name is freed; anything else attached
+ * to the entry should already be gone by this point.
+ */
+
+extern void sym_remove(sym_table */*t*/, void */*b*/);
+
+/* --- @sym_mkiter@ --- *
+ *
+ * Arguments: @sym_iter *i@ = pointer to an iterator object
+ * @sym_table *t@ = pointer to a symbol table object
+ *
+ * Returns: ---
+ *
+ * Use: Creates a new symbol table iterator which may be used to
+ * 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@ --- *
+ *
+ * Arguments: @sym_iter *i@ = pointer to iterator object
+ *
+ * Returns: Pointer to the next symbol found, or null when finished.
+ *
+ * Use: Returns the next symbol from the table. Symbols are not
+ * 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 -------------------------------------------------*/
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif
~mdw / mLib / blobdiff