159 lines
3.2 KiB
C
159 lines
3.2 KiB
C
/*
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* bitops.c --- Bitmap frobbing code. See bitops.h for the inlined
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* routines.
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*
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* Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
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*
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* %Begin-Header%
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* This file may be redistributed under the terms of the GNU Library
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* General Public License, version 2.
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* %End-Header%
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*/
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#include "config.h"
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#include <stdio.h>
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#if HAVE_SYS_TYPES_H
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#include <sys/types.h>
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#endif
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#include "ext2_fs.h"
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#include "ext2fs.h"
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#ifndef _EXT2_HAVE_ASM_BITOPS_
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/*
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* For the benefit of those who are trying to port Linux to another
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* architecture, here are some C-language equivalents. You should
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* recode these in the native assembly language, if at all possible.
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*
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* C language equivalents written by Theodore Ts'o, 9/26/92.
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* Modified by Pete A. Zaitcev 7/14/95 to be portable to big endian
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* systems, as well as non-32 bit systems.
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*/
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int ext2fs_set_bit(unsigned int nr,void * addr)
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{
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int mask, retval;
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unsigned char *ADDR = (unsigned char *) addr;
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ADDR += nr >> 3;
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mask = 1 << (nr & 0x07);
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retval = mask & *ADDR;
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*ADDR |= mask;
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return retval;
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}
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int ext2fs_clear_bit(unsigned int nr, void * addr)
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{
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int mask, retval;
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unsigned char *ADDR = (unsigned char *) addr;
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ADDR += nr >> 3;
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mask = 1 << (nr & 0x07);
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retval = mask & *ADDR;
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*ADDR &= ~mask;
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return retval;
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}
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int ext2fs_test_bit(unsigned int nr, const void * addr)
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{
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int mask;
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const unsigned char *ADDR = (const unsigned char *) addr;
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ADDR += nr >> 3;
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mask = 1 << (nr & 0x07);
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return (mask & *ADDR);
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}
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#endif /* !_EXT2_HAVE_ASM_BITOPS_ */
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void ext2fs_warn_bitmap(errcode_t errcode, unsigned long arg,
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const char *description)
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{
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#ifndef OMIT_COM_ERR
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if (description)
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com_err(0, errcode, "#%lu for %s", arg, description);
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else
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com_err(0, errcode, "#%lu", arg);
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#endif
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}
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/*
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* C-only 64 bit ops.
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*/
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int ext2fs_set_bit64(__u64 nr, void * addr)
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{
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int mask, retval;
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unsigned char *ADDR = (unsigned char *) addr;
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ADDR += nr >> 3;
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mask = 1 << (nr & 0x07);
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retval = mask & *ADDR;
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*ADDR |= mask;
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return retval;
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}
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int ext2fs_clear_bit64(__u64 nr, void * addr)
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{
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int mask, retval;
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unsigned char *ADDR = (unsigned char *) addr;
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ADDR += nr >> 3;
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mask = 1 << (nr & 0x07);
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retval = mask & *ADDR;
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*ADDR &= ~mask;
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return retval;
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}
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int ext2fs_test_bit64(__u64 nr, const void * addr)
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{
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int mask;
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const unsigned char *ADDR = (const unsigned char *) addr;
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ADDR += nr >> 3;
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mask = 1 << (nr & 0x07);
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return (mask & *ADDR);
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}
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static unsigned int popcount8(unsigned int w)
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{
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unsigned int res = w - ((w >> 1) & 0x55);
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res = (res & 0x33) + ((res >> 2) & 0x33);
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return (res + (res >> 4)) & 0x0F;
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}
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static unsigned int popcount32(unsigned int w)
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{
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unsigned int res = w - ((w >> 1) & 0x55555555);
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res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
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res = (res + (res >> 4)) & 0x0F0F0F0F;
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res = res + (res >> 8);
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return (res + (res >> 16)) & 0x000000FF;
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}
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unsigned int ext2fs_bitcount(const void *addr, unsigned int nbytes)
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{
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const unsigned char *cp = addr;
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const __u32 *p;
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unsigned int res = 0;
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while (((((uintptr_t) cp) & 3) != 0) && (nbytes > 0)) {
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res += popcount8(*cp++);
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nbytes--;
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}
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p = (const __u32 *) cp;
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while (nbytes > 4) {
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res += popcount32(*p++);
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nbytes -= 4;
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}
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cp = (const unsigned char *) p;
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while (nbytes > 0) {
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res += popcount8(*cp++);
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nbytes--;
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}
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return res;
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}
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