100 lines
2.8 KiB
C
100 lines
2.8 KiB
C
/*
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* Copyright (c) 2012-2013 Spotify AB
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may not
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* use this file except in compliance with the License. You may obtain a copy of
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* the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations under
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* the License.
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*/
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#ifndef SPARKEY_HASHHEADER_H_INCLUDED
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#define SPARKEY_HASHHEADER_H_INCLUDED
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#include <stdint.h>
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#include "endiantools.h"
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#include "sparkey.h"
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#include "hashalgorithms.h"
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#define HASH_MAGIC_NUMBER (0x9a11318f)
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#define HASH_MAJOR_VERSION (1)
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#define HASH_MINOR_VERSION (1)
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#define HASH_HEADER_SIZE (112)
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typedef struct {
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uint32_t major_version;
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uint32_t minor_version;
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uint32_t file_identifier;
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uint32_t hash_seed;
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uint32_t header_size;
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uint64_t data_end;
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uint64_t max_key_len;
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uint64_t max_value_len;
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uint64_t garbage_size;
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uint64_t num_entries;
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uint32_t address_size;
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uint32_t hash_size;
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uint64_t hash_capacity;
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uint64_t max_displacement;
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uint64_t num_puts;
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uint32_t entry_block_bits;
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uint32_t entry_block_bitmask;
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uint64_t hash_collisions;
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uint64_t total_displacement;
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sparkey_hash_algorithm hash_algorithm;
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} sparkey_hashheader;
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/**
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* fills up a hashheader struct based on the contents at the beginning of the file.
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* @param header header struct to fill
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* @param filename a hash file
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* @returns an error code if it could not load the file.
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*/
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sparkey_returncode sparkey_load_hashheader(sparkey_hashheader *header, const char *filename);
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/**
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* Dumps a human readable representation of the header to stdout
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* @param header an initialized header struct
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*/
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void print_hashheader(sparkey_hashheader *header);
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/**
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* Writes a header to the current position in the file
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* @param fd a file descripter pointing to a file open for writing
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* @param header the header to write
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* @returns an error code if it could not write to file.
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*/
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sparkey_returncode write_hashheader(int fd, sparkey_hashheader *header);
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static inline uint64_t get_displacement(uint64_t capacity, uint64_t slot, uint64_t hash) {
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uint64_t wanted_slot = hash % capacity;
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return (capacity + (slot - wanted_slot)) % capacity;
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}
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static inline uint64_t read_addr(uint8_t *hashtable, uint64_t pos, int address_size) {
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switch (address_size) {
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case 4: return read_little_endian32(hashtable, pos);
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case 8: return read_little_endian64(hashtable, pos);
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}
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return -1;
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}
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static inline void write_addr(uint8_t *buf, uint64_t value, int address_size) {
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switch (address_size) {
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case 4: write_little_endian32(buf, value); return;
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case 8: write_little_endian64(buf, value); return;
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}
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}
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#endif
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