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1/* SPDX-License-Identifier: GPL-2.0-only */2/*3 * Copyright 2023 Red Hat4 */5 6#ifndef UDS_HASH_UTILS_H7#define UDS_HASH_UTILS_H8 9#include "numeric.h"10 11#include "geometry.h"12#include "indexer.h"13 14/* Utilities for extracting portions of a request name for various uses. */15 16/* How various portions of a record name are apportioned. */17enum {18 VOLUME_INDEX_BYTES_OFFSET = 0,19 VOLUME_INDEX_BYTES_COUNT = 8,20 CHAPTER_INDEX_BYTES_OFFSET = 8,21 CHAPTER_INDEX_BYTES_COUNT = 6,22 SAMPLE_BYTES_OFFSET = 14,23 SAMPLE_BYTES_COUNT = 2,24};25 26static inline u64 uds_extract_chapter_index_bytes(const struct uds_record_name *name)27{28 const u8 *chapter_bits = &name->name[CHAPTER_INDEX_BYTES_OFFSET];29 u64 bytes = (u64) get_unaligned_be16(chapter_bits) << 32;30 31 bytes |= get_unaligned_be32(chapter_bits + 2);32 return bytes;33}34 35static inline u64 uds_extract_volume_index_bytes(const struct uds_record_name *name)36{37 return get_unaligned_be64(&name->name[VOLUME_INDEX_BYTES_OFFSET]);38}39 40static inline u32 uds_extract_sampling_bytes(const struct uds_record_name *name)41{42 return get_unaligned_be16(&name->name[SAMPLE_BYTES_OFFSET]);43}44 45/* Compute the chapter delta list for a given name. */46static inline u32 uds_hash_to_chapter_delta_list(const struct uds_record_name *name,47 const struct index_geometry *geometry)48{49 return ((uds_extract_chapter_index_bytes(name) >> geometry->chapter_address_bits) &50 ((1 << geometry->chapter_delta_list_bits) - 1));51}52 53/* Compute the chapter delta address for a given name. */54static inline u32 uds_hash_to_chapter_delta_address(const struct uds_record_name *name,55 const struct index_geometry *geometry)56{57 return uds_extract_chapter_index_bytes(name) & ((1 << geometry->chapter_address_bits) - 1);58}59 60static inline unsigned int uds_name_to_hash_slot(const struct uds_record_name *name,61 unsigned int slot_count)62{63 return (unsigned int) (uds_extract_chapter_index_bytes(name) % slot_count);64}65 66#endif /* UDS_HASH_UTILS_H */67