117 lines
2.3 KiB
C
117 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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*
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* Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include "ntfs_fs.h"
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static inline u16 upcase_unicode_char(const u16 *upcase, u16 chr)
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{
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if (chr < 'a')
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return chr;
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if (chr <= 'z')
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return chr - ('a' - 'A');
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return upcase[chr];
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}
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/*
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* ntfs_cmp_names
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*
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* Thanks Kari Argillander <kari.argillander@gmail.com> for idea and implementation 'bothcase'
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*
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* Straight way to compare names:
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* - Case insensitive
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* - If name equals and 'bothcases' then
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* - Case sensitive
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* 'Straight way' code scans input names twice in worst case.
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* Optimized code scans input names only once.
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*/
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int ntfs_cmp_names(const __le16 *s1, size_t l1, const __le16 *s2, size_t l2,
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const u16 *upcase, bool bothcase)
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{
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int diff1 = 0;
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int diff2;
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size_t len = min(l1, l2);
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if (!bothcase && upcase)
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goto case_insentive;
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for (; len; s1++, s2++, len--) {
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diff1 = le16_to_cpu(*s1) - le16_to_cpu(*s2);
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if (diff1) {
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if (bothcase && upcase)
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goto case_insentive;
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return diff1;
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}
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}
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return l1 - l2;
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case_insentive:
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for (; len; s1++, s2++, len--) {
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diff2 = upcase_unicode_char(upcase, le16_to_cpu(*s1)) -
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upcase_unicode_char(upcase, le16_to_cpu(*s2));
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if (diff2)
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return diff2;
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}
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diff2 = l1 - l2;
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return diff2 ? diff2 : diff1;
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}
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int ntfs_cmp_names_cpu(const struct cpu_str *uni1, const struct le_str *uni2,
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const u16 *upcase, bool bothcase)
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{
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const u16 *s1 = uni1->name;
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const __le16 *s2 = uni2->name;
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size_t l1 = uni1->len;
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size_t l2 = uni2->len;
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size_t len = min(l1, l2);
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int diff1 = 0;
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int diff2;
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if (!bothcase && upcase)
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goto case_insentive;
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for (; len; s1++, s2++, len--) {
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diff1 = *s1 - le16_to_cpu(*s2);
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if (diff1) {
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if (bothcase && upcase)
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goto case_insentive;
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return diff1;
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}
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}
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return l1 - l2;
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case_insentive:
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for (; len; s1++, s2++, len--) {
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diff2 = upcase_unicode_char(upcase, *s1) -
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upcase_unicode_char(upcase, le16_to_cpu(*s2));
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if (diff2)
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return diff2;
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}
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diff2 = l1 - l2;
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return diff2 ? diff2 : diff1;
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}
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/* Helper function for ntfs_d_hash. */
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unsigned long ntfs_names_hash(const u16 *name, size_t len, const u16 *upcase,
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unsigned long hash)
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{
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while (len--) {
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unsigned int c = upcase_unicode_char(upcase, *name++);
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hash = partial_name_hash(c, hash);
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}
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return hash;
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}
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