X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/mLib/blobdiff_plain/a5d14edee10f6c07549259fd145bda7d00c0d26f..2ae5376b8a8158f38cbbe9c0238b5428ee3ce711:/sym.h diff --git a/sym.h b/sym.h index 82668a1..db49ff5 100644 --- a/sym.h +++ b/sym.h @@ -1,34 +1,69 @@ /* -*-c-*- * - * $Id: sym.h,v 1.2 1998/11/26 19:27:34 mdw Exp $ + * $Id: sym.h,v 1.12 2001/01/20 11:49:37 mdw Exp $ * * Symbol table management * * (c) 1998 Straylight/Edgeware */ -/*----- Licensing notice --------------------------------------------------* +/*----- 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 General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * + * 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 General Public License for more details. - * - * You should have received a copy of the GNU 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. + * 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. */ /*----- Revision history --------------------------------------------------* * * $Log: sym.h,v $ + * Revision 1.12 2001/01/20 11:49:37 mdw + * Export tuning parameters from header file, for the benefit of other + * hashtable implementations. Change the storage of symbol names: store + * the name after the allocated symbol block in all cases. This replaces + * the previous complicated and slightly wasteful arrangement. + * + * Revision 1.11 2000/06/17 10:37:39 mdw + * Add support for arena management. + * + * 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. * @@ -37,8 +72,8 @@ * */ -#ifndef SYM_H -#define SYM_H +#ifndef MLIB_SYM_H +#define MLIB_SYM_H #ifdef __cplusplus extern "C" { @@ -48,6 +83,39 @@ #include +#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 --- * @@ -58,9 +126,9 @@ */ 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 --- * @@ -72,48 +140,41 @@ typedef struct sym_table { * 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_createTable@ --- * +/* --- @sym_create@ --- * * - * Arguments: @sym_table *t@ = symbol table to initialise + * Arguments: @sym_table *t@ = symbol table to initialize * * Returns: --- * - * Use: Initialises the given symbol table. Raises @EXC_NOMEM@ if + * Use: Initializes the given symbol table. Raises @EXC_NOMEM@ if * there isn't enough memory. */ -extern void sym_createTable(sym_table */*t*/); +extern void sym_create(sym_table */*t*/); -/* --- @sym_destroyTable@ --- * +/* --- @sym_destroy@ --- * * * Arguments: @sym_table *t@ = pointer to symbol table in question * @@ -123,7 +184,7 @@ extern void sym_createTable(sym_table */*t*/); * occupy. */ -extern void sym_destroyTable(sym_table */*t*/); +extern void sym_destroy(sym_table */*t*/); /* --- @sym_find@ --- * * @@ -141,7 +202,7 @@ extern void sym_destroyTable(sym_table */*t*/); * 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 @@ -161,7 +222,7 @@ extern void *sym_find(sym_table */*t*/, const char */*n*/, long /*l*/, /* --- @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: --- @@ -173,7 +234,7 @@ extern void *sym_find(sym_table */*t*/, const char */*n*/, long /*l*/, extern void sym_remove(sym_table */*t*/, void */*b*/); -/* --- @sym_createIter@ --- * +/* --- @sym_mkiter@ --- * * * Arguments: @sym_iter *i@ = pointer to an iterator object * @sym_table *t@ = pointer to a symbol table object @@ -184,7 +245,9 @@ extern void sym_remove(sym_table */*t*/, void */*b*/); * iterate through a symbol table. */ -extern void sym_createIter(sym_iter */*i*/, sym_table */*t*/); +#define SYM_MKITER(i_, t_) HASH_MKITER(&(i_)->i, &(t_)->t) + +extern void sym_mkiter(sym_iter */*i*/, sym_table */*t*/); /* --- @sym_next@ --- * * @@ -196,6 +259,12 @@ extern void sym_createIter(sym_iter */*i*/, sym_table */*t*/); * 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 -------------------------------------------------*/