+/* -*-c-*-
+ *
+ * $Id: sym.c,v 1.1 2000/05/21 11:28:30 mdw Exp $
+ *
+ * Symbol table management
+ *
+ * (c) 1998 Straylight
+ * (c) 2000 Mark Wooding
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * Copyright (c) 2000 Mark Wooding
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2, Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * 3. The name of the authors may not be used to endorse or promote
+ * products derived from this software without specific prior written
+ * permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
+ * NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Instead of accepting the above terms, you may redistribute and/or modify
+ * this software under the terms of either the GNU General Public License,
+ * or the GNU Library General Public License, published by the Free
+ * Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+/*----- Revision history --------------------------------------------------*
+ *
+ * $Log: sym.c,v $
+ * Revision 1.1 2000/05/21 11:28:30 mdw
+ * Initial check-in.
+ *
+ * --- Past lives (Become) --- *
+ *
+ * Revision 1.4 1998/01/12 16:46:28 mdw
+ * Fix copyright date.
+ *
+ * Revision 1.3 1997/08/20 16:22:59 mdw
+ * Patch memory leak.
+ *
+ * Revision 1.2 1997/08/04 10:24:25 mdw
+ * Sources placed under CVS control.
+ *
+ * Revision 1.1 1997/07/21 13:47:44 mdw
+ * Initial revision
+ *
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "bits.h"
+#include "sym.h"
+
+/*----- 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 256 /* 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 */
+
+/*----- CRC table ---------------------------------------------------------*/
+
+/*****************************************************************/
+/* */
+/* CRC LOOKUP TABLE */
+/* ================ */
+/* */
+/* The following CRC lookup table was generated automagically */
+/* by `crcgen', which is based on the Rocksoft^tm Model CRC */
+/* Algorithm Table Generation Program. The model parameters */
+/* supplied to `crcgen' were: */
+/* */
+/* Width : 32 bits */
+/* Poly : 0x04C11DB7 */
+/* Init : 0xFFFFFFFF */
+/* XorOut : 0xFFFFFFFF */
+/* Reverse : Yes */
+/* Check : 0xCBF43926 */
+/* */
+/* For more information on the Rocksoft^tm Model CRC Algorithm, */
+/* see the document titled `A Painless Guide to CRC Error */
+/* Detection Algorithms' by Ross Williams */
+/* (ross@@guest.adelaide.edu.au.). This document is likely to be */
+/* in the FTP archive `ftp.adelaide.edu.au/pub/rocksoft'. */
+/* */
+/*****************************************************************/
+
+static uint32 crctab[256] = {
+ 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
+ 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
+ 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+ 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
+ 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
+ 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+ 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
+ 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
+ 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+ 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
+ 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
+ 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+ 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
+ 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
+ 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+ 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
+ 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
+ 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+ 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
+ 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
+ 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+ 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
+ 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
+ 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+ 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
+ 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
+ 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+ 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
+ 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
+ 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+ 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
+ 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
+ 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+ 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
+ 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
+ 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+ 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
+ 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
+ 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+ 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
+ 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
+ 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+ 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
+ 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
+ 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+ 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
+ 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
+ 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+ 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
+ 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
+ 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+ 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
+ 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
+ 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+ 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
+ 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
+ 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+ 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
+ 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
+ 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+ 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
+ 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
+ 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+ 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
+};
+
+/*****************************************************************/
+/* End of CRC Lookup Table */
+/*****************************************************************/
+
+/* --- Work out the CRC of a bytestring --- */
+
+#define CRC(_s, _l, _hv) do { \
+ uint32 _h = 0xffffffff; \
+ const char *_p = _s; \
+ const char *_e = (_s) + (_l); \
+ \
+ while (_p < _e) \
+ _h = (_h >> 8) ^ (crctab[(*_p++ ^ _h) & 0xFF]); \
+ _hv = ~_h & 0xffffffff; \
+} while (0)
+
+/*----- Memory allocation -------------------------------------------------*/
+
+static void die(const char *p)
+{
+ fprintf(stderr, "%s\n", p);
+ exit(EXIT_FAILURE);
+}
+
+static void *xmalloc(size_t sz)
+{
+ void *p = malloc(sz);
+ if (!p)
+ die("not enough memory");
+ return (p);
+}
+
+static void *xrealloc(void *p, size_t sz)
+{
+ p = realloc(p, sz);
+ if (!p)
+ die("not enough memory");
+ return (p);
+}
+
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @sym_create@ --- *
+ *
+ * Arguments: @sym_table *t@ = symbol table to initialize
+ *
+ * Returns: ---
+ *
+ * Use: Initialises the given symbol table.
+ */
+
+void sym_create(sym_table *t)
+{
+ size_t i;
+
+ t->mask = SYM_INITSZ - 1;
+ t->c = SYM_LIMIT(SYM_INITSZ);
+ t->a = xmalloc((t->mask + 1) * sizeof(sym_base *));
+
+ for (i = 0; i < SYM_INITSZ + 1; i++)
+ t->a[i] = 0;
+}
+
+/* --- @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.
+ */
+
+void sym_destroy(sym_table *t)
+{
+ size_t i;
+ sym_base *p, *q;
+
+ for (i = 0; i <= t->mask; i++) {
+ p = t->a[i];
+ while (p) {
+ q = p->next;
+ free(p->name);
+ free(p);
+ p = q;
+ }
+ }
+ free(t->a);
+}
+
+/* --- @sym_find@ --- *
+ *
+ * Arguments: @sym_table *t@ = pointer to symbol table in question
+ * @const char *n@ = pointer to symbol table 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 value of @*f@ indicates whether a new symbol entry was
+ * created: a nonzero value indicates that an old value was
+ * found.
+ */
+
+void *sym_find(sym_table *t, const char *n, long l, size_t sz, unsigned *f)
+{
+ uint32 hash;
+ size_t len = l < 0 ? strlen(n) + 1 : l;
+ sym_base *bin;
+ sym_base *p, *q;
+
+ /* --- Find the correct bin --- */
+
+ CRC(n, len, hash);
+ bin = p = (sym_base *)(t->a + (hash & t->mask));
+
+ /* --- Search the bin list --- */
+
+ while (p->next) {
+ if (hash == p->next->hash && len == p->next->len &&
+ !memcmp(n, p->next->name, len)) {
+
+ /* --- Found a match --- *
+ *
+ * As a minor, and probably pointless, tweak, move the item to the
+ * front of its bin list.
+ */
+
+ q = p->next;
+ p->next = q->next;
+ q->next = bin->next;
+ bin->next = q;
+
+ /* --- Return the block --- */
+
+ if (f) *f = 1;
+ return (q);
+ }
+
+ p = p->next;
+ }
+
+ /* --- Couldn't find the item there --- */
+
+ if (f) *f = 0;
+ if (!sz) return (0);
+
+ /* --- Create a new symbol block and initialize it --- */
+
+ p = xmalloc(sz);
+ p->next = bin->next;
+ p->hash = hash;
+ p->name = xmalloc(len);
+ p->len = len;
+ memcpy(p->name, n, len);
+
+ bin->next = p;
+
+ /* --- Consider growing the array --- */
+
+ if (!--t->c) {
+ uint32 m = t->mask + 1;
+ sym_base *p, *q, *r;
+ size_t i, lim;
+
+ /* --- Update values in the anchor block --- */
+
+ t->c = SYM_LIMIT(t->mask + 1);
+ t->mask = (t->mask + 1) * 2 - 1;
+ t->a = xrealloc(t->a, (t->mask + 1) * sizeof(sym_base *));
+
+ /* --- Now wander through the table rehashing things --- *
+ *
+ * This loop is very careful to avoid problems with aliasing. The items
+ * are dealt with from the end backwards to avoid overwriting bins before
+ * they've been processed.
+ */
+
+ lim = (t->mask + 1) >> 1;
+ for (i = 0; i < lim; i++) {
+
+ /* --- Some initialization --- */
+
+ r = t->a[i];
+ p = (sym_base *)(t->a + i);
+ q = (sym_base *)(t->a + i + lim);
+
+ /* --- Now go through the @r@ list --- */
+
+ while (r) {
+ if (r->hash & m)
+ q = q->next = r;
+ else
+ p = p->next = r;
+ r = r->next;
+ }
+ p->next = q->next = 0;
+ }
+ }
+
+ /* --- Finished that, so return the new symbol block --- */
+
+ return (p);
+}
+
+/* --- @sym_remove@ --- *
+ *
+ * Arguments: @sym_table *i@ = 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.
+ */
+
+void sym_remove(sym_table *t, void *b)
+{
+ /* --- A quick comment --- *
+ *
+ * Since the @sym_base@ block contains the hash, finding the element in the
+ * bin list is really quick -- it's not worth bothering with things like
+ * doubly linked lists.
+ */
+
+ sym_base *p = b;
+ sym_base *bin = (sym_base *)(t->a + (p->hash & t->mask));
+
+ /* --- Find the item in the bin list --- */
+
+ while (bin->next) {
+ if (bin->next == p)
+ break;
+ bin = bin->next;
+ }
+ if (!bin->next)
+ return;
+
+ /* --- Now just remove the item from the list and free it --- *
+ *
+ * Oh, and bump the load counter.
+ */
+
+ bin->next = p->next;
+ free(p->name);
+ free(p);
+ t->c++;
+}
+
+/* --- @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.
+ */
+
+void sym_mkiter(sym_iter *i, sym_table *t)
+{
+ i->t = t;
+ i->i = 0;
+ i->n = 0;
+}
+
+/* --- @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.
+ */
+
+void *sym_next(sym_iter *i)
+{
+ sym_base *p;
+
+ /* --- Find the next item --- */
+
+ while (!i->n) {
+ if (i->i > i->t->mask)
+ return (0);
+ i->n = i->t->a[i->i++];
+ }
+
+ /* --- Update the iterator block --- */
+
+ p = i->n;
+ i->n = p->next;
+
+ /* --- Done --- */
+
+ return (p);
+}
+
+/*----- That's all, folks -------------------------------------------------*/
~mdw / storin / commitdiff