1 // SPDX-License-Identifier: GPL-2.0
4 * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
8 #include <linux/types.h>
12 #define BITS_IN_SIZE_T (sizeof(size_t) * 8)
15 * fill_mask[i] - first i bits are '1' , i = 0,1,2,3,4,5,6,7,8
16 * fill_mask[i] = 0xFF >> (8-i)
18 static const u8 fill_mask[] = { 0x00, 0x01, 0x03, 0x07, 0x0F,
19 0x1F, 0x3F, 0x7F, 0xFF };
22 * zero_mask[i] - first i bits are '0' , i = 0,1,2,3,4,5,6,7,8
23 * zero_mask[i] = 0xFF << i
25 static const u8 zero_mask[] = { 0xFF, 0xFE, 0xFC, 0xF8, 0xF0,
26 0xE0, 0xC0, 0x80, 0x00 };
31 * Return: True if all bits [bit, bit+nbits) are zeros "0".
33 bool are_bits_clear(const ulong *lmap, size_t bit, size_t nbits)
36 const u8 *map = (u8 *)lmap + (bit >> 3);
40 return !nbits || !(*map & fill_mask[pos + nbits] &
43 if (*map++ & zero_mask[pos])
48 pos = ((size_t)map) & (sizeof(size_t) - 1);
50 pos = sizeof(size_t) - pos;
51 if (nbits >= pos * 8) {
52 for (nbits -= pos * 8; pos; pos--, map++) {
59 for (pos = nbits / BITS_IN_SIZE_T; pos; pos--, map += sizeof(size_t)) {
64 for (pos = (nbits % BITS_IN_SIZE_T) >> 3; pos; pos--, map++) {
70 if (pos && (*map & fill_mask[pos]))
79 * Return: True if all bits [bit, bit+nbits) are ones "1".
81 bool are_bits_set(const ulong *lmap, size_t bit, size_t nbits)
85 const u8 *map = (u8 *)lmap + (bit >> 3);
88 if (8 - pos >= nbits) {
89 mask = fill_mask[pos + nbits] & zero_mask[pos];
90 return !nbits || (*map & mask) == mask;
93 mask = zero_mask[pos];
94 if ((*map++ & mask) != mask)
99 pos = ((size_t)map) & (sizeof(size_t) - 1);
101 pos = sizeof(size_t) - pos;
102 if (nbits >= pos * 8) {
103 for (nbits -= pos * 8; pos; pos--, map++) {
110 for (pos = nbits / BITS_IN_SIZE_T; pos; pos--, map += sizeof(size_t)) {
111 if (*((size_t *)map) != MINUS_ONE_T)
115 for (pos = (nbits % BITS_IN_SIZE_T) >> 3; pos; pos--, map++) {
122 u8 mask = fill_mask[pos];
124 if ((*map & mask) != mask)