/uClinux-dist/user/squid/src/filemap.c
C | 172 lines | 114 code | 15 blank | 43 comment | 12 complexity | b0f8d8c5edc85a2b9b25797d3646b098 MD5 | raw file
Possible License(s): GPL-2.0, BSD-3-Clause, LGPL-2.1, MPL-2.0-no-copyleft-exception, ISC, AGPL-1.0, LGPL-2.0, GPL-3.0, LGPL-3.0, 0BSD
- /*
- * $Id: filemap.c,v 1.39 2001/10/24 07:45:34 hno Exp $
- *
- * DEBUG: section 8 Swap File Bitmap
- * AUTHOR: Harvest Derived
- *
- * SQUID Web Proxy Cache http://www.squid-cache.org/
- * ----------------------------------------------------------
- *
- * Squid is the result of efforts by numerous individuals from
- * the Internet community; see the CONTRIBUTORS file for full
- * details. Many organizations have provided support for Squid's
- * development; see the SPONSORS file for full details. Squid is
- * Copyrighted (C) 2001 by the Regents of the University of
- * California; see the COPYRIGHT file for full details. Squid
- * incorporates software developed and/or copyrighted by other
- * sources; see the CREDITS file for full details.
- *
- * This program 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.
- *
- * This program 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 this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
- *
- */
- #include "squid.h"
- /* Number of bits in a long */
- #if SIZEOF_LONG == 8
- #define LONG_BIT_SHIFT 6
- #define BITS_IN_A_LONG 0x40
- #define LONG_BIT_MASK 0x3F
- #define ALL_ONES (unsigned long) 0xFFFFFFFFFFFFFFFF
- #elif SIZEOF_LONG == 4
- #define LONG_BIT_SHIFT 5
- #define BITS_IN_A_LONG 0x20
- #define LONG_BIT_MASK 0x1F
- #define ALL_ONES (unsigned long) 0xFFFFFFFF
- #else
- #define LONG_BIT_SHIFT 5
- #define BITS_IN_A_LONG 0x20
- #define LONG_BIT_MASK 0x1F
- #define ALL_ONES (unsigned long) 0xFFFFFFFF
- #endif
- #define FM_INITIAL_NUMBER (1<<14)
- fileMap *
- file_map_create(void)
- {
- fileMap *fm = xcalloc(1, sizeof(fileMap));
- fm->max_n_files = FM_INITIAL_NUMBER;
- fm->nwords = fm->max_n_files >> LONG_BIT_SHIFT;
- debug(8, 3) ("file_map_create: creating space for %d files\n", fm->max_n_files);
- debug(8, 5) ("--> %d words of %d bytes each\n",
- fm->nwords, (int) sizeof(*fm->file_map));
- fm->file_map = xcalloc(fm->nwords, sizeof(*fm->file_map));
- /* XXX account fm->file_map */
- return fm;
- }
- static void
- file_map_grow(fileMap * fm)
- {
- int old_sz = fm->nwords * sizeof(*fm->file_map);
- void *old_map = fm->file_map;
- fm->max_n_files <<= 1;
- assert(fm->max_n_files <= (1 << 24)); /* swap_filen is 25 bits, signed */
- fm->nwords = fm->max_n_files >> LONG_BIT_SHIFT;
- debug(8, 3) ("file_map_grow: creating space for %d files\n", fm->max_n_files);
- fm->file_map = xcalloc(fm->nwords, sizeof(*fm->file_map));
- debug(8, 3) ("copying %d old bytes\n", old_sz);
- xmemcpy(fm->file_map, old_map, old_sz);
- xfree(old_map);
- /* XXX account fm->file_map */
- }
- int
- file_map_bit_set(fileMap * fm, int file_number)
- {
- unsigned long bitmask = (1L << (file_number & LONG_BIT_MASK));
- while (file_number >= fm->max_n_files)
- file_map_grow(fm);
- fm->file_map[file_number >> LONG_BIT_SHIFT] |= bitmask;
- fm->n_files_in_map++;
- return file_number;
- }
- /*
- * WARNING: file_map_bit_reset does not perform array bounds
- * checking! It assumes that 'file_number' is valid, and that the
- * bit is already set. The caller must verify both of those
- * conditions by calling file_map_bit_test() first.
- */
- void
- file_map_bit_reset(fileMap * fm, int file_number)
- {
- unsigned long bitmask = (1L << (file_number & LONG_BIT_MASK));
- fm->file_map[file_number >> LONG_BIT_SHIFT] &= ~bitmask;
- fm->n_files_in_map--;
- }
- int
- file_map_bit_test(fileMap * fm, int file_number)
- {
- unsigned long bitmask = (1L << (file_number & LONG_BIT_MASK));
- if (file_number >= fm->max_n_files)
- return 0;
- /* be sure the return value is an int, not a u_long */
- return (fm->file_map[file_number >> LONG_BIT_SHIFT] & bitmask ? 1 : 0);
- }
- int
- file_map_allocate(fileMap * fm, int suggestion)
- {
- int word;
- int bit;
- int count;
- if (suggestion >= fm->max_n_files)
- suggestion = 0;
- if (!file_map_bit_test(fm, suggestion))
- return suggestion;
- word = suggestion >> LONG_BIT_SHIFT;
- for (count = 0; count < fm->nwords; count++) {
- if (fm->file_map[word] != ALL_ONES)
- break;
- word = (word + 1) % fm->nwords;
- }
- for (bit = 0; bit < BITS_IN_A_LONG; bit++) {
- suggestion = ((unsigned long) word << LONG_BIT_SHIFT) | bit;
- if (!file_map_bit_test(fm, suggestion)) {
- return suggestion;
- }
- }
- debug(8, 3) ("growing from file_map_allocate\n");
- file_map_grow(fm);
- return file_map_allocate(fm, fm->max_n_files >> 1);
- }
- void
- filemapFreeMemory(fileMap * fm)
- {
- safe_free(fm->file_map);
- safe_free(fm);
- }
- #ifdef TEST
- #define TEST_SIZE 1<<16
- main(argc, argv)
- {
- int i;
- fm = file_map_create(TEST_SIZE);
- for (i = 0; i < TEST_SIZE; ++i) {
- file_map_bit_set(i);
- assert(file_map_bit_test(i));
- file_map_bit_reset(i);
- }
- }
- #endif