mirror of
https://github.com/borgbackup/borg.git
synced 2024-12-23 16:26:29 +00:00
369 lines
11 KiB
C
369 lines
11 KiB
C
#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#if defined(BYTE_ORDER)&&(BYTE_ORDER == BIG_ENDIAN)
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#define _le32toh(x) __builtin_bswap32(x)
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#define _htole32(x) __builtin_bswap32(x)
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#elif defined(BYTE_ORDER)&&(BYTE_ORDER == LITTLE_ENDIAN)
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#define _le32toh(x) (x)
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#define _htole32(x) (x)
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#else
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#error Unknown byte order
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#endif
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typedef struct {
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char magic[8];
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int32_t num_entries;
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int32_t num_buckets;
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int8_t key_size;
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int8_t value_size;
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} __attribute__((__packed__)) HashHeader;
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typedef struct {
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void *data;
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void *buckets;
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int num_entries;
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int num_buckets;
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int key_size;
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int value_size;
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off_t bucket_size;
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int lower_limit;
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int upper_limit;
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off_t data_len;
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} HashIndex;
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#define MAGIC "BORG_IDX"
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#define EMPTY _htole32(0xffffffff)
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#define DELETED _htole32(0xfffffffe)
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#define MAX_BUCKET_SIZE 512
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#define BUCKET_LOWER_LIMIT .25
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#define BUCKET_UPPER_LIMIT .90
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#define MIN_BUCKETS 1024
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#define MAX(x, y) ((x) > (y) ? (x): (y))
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#define BUCKET_ADDR(index, idx) (index->buckets + (idx * index->bucket_size))
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#define BUCKET_IS_DELETED(index, idx) (*((uint32_t *)(BUCKET_ADDR(index, idx) + index->key_size)) == DELETED)
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#define BUCKET_IS_EMPTY(index, idx) (*((uint32_t *)(BUCKET_ADDR(index, idx) + index->key_size)) == EMPTY)
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#define BUCKET_MATCHES_KEY(index, idx, key) (memcmp(key, BUCKET_ADDR(index, idx), index->key_size) == 0)
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#define BUCKET_MARK_DELETED(index, idx) (*((uint32_t *)(BUCKET_ADDR(index, idx) + index->key_size)) = DELETED)
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#define BUCKET_MARK_EMPTY(index, idx) (*((uint32_t *)(BUCKET_ADDR(index, idx) + index->key_size)) = EMPTY)
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#define EPRINTF(msg, ...) fprintf(stderr, "hashindex: " msg "\n", ##__VA_ARGS__)
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#define EPRINTF_PATH(path, msg, ...) fprintf(stderr, "hashindex: %s: " msg "\n", path, ##__VA_ARGS__)
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static HashIndex *hashindex_read(const char *path);
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static int hashindex_write(HashIndex *index, const char *path);
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static HashIndex *hashindex_init(int capacity, int key_size, int value_size);
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static const void *hashindex_get(HashIndex *index, const void *key);
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static int hashindex_set(HashIndex *index, const void *key, const void *value);
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static int hashindex_delete(HashIndex *index, const void *key);
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static void *hashindex_next_key(HashIndex *index, const void *key);
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/* Private API */
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static int
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hashindex_index(HashIndex *index, const void *key)
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{
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return _le32toh(*((uint32_t *)key)) % index->num_buckets;
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}
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static int
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hashindex_lookup(HashIndex *index, const void *key)
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{
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int didx = -1;
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int start = hashindex_index(index, key);
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int idx = start;
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for(;;) {
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if(BUCKET_IS_EMPTY(index, idx))
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{
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return -1;
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}
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if(BUCKET_IS_DELETED(index, idx)) {
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if(didx == -1) {
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didx = idx;
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}
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}
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else if(BUCKET_MATCHES_KEY(index, idx, key)) {
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if (didx != -1) {
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memcpy(BUCKET_ADDR(index, didx), BUCKET_ADDR(index, idx), index->bucket_size);
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BUCKET_MARK_DELETED(index, idx);
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idx = didx;
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}
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return idx;
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}
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idx = (idx + 1) % index->num_buckets;
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if(idx == start) {
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return -1;
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}
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}
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}
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static int
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hashindex_resize(HashIndex *index, int capacity)
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{
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HashIndex *new;
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void *key = NULL;
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if(!(new = hashindex_init(capacity, index->key_size, index->value_size))) {
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return 0;
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}
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while((key = hashindex_next_key(index, key))) {
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hashindex_set(new, key, hashindex_get(index, key));
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}
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free(index->data);
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index->data = new->data;
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index->data_len = new->data_len;
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index->num_buckets = new->num_buckets;
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index->lower_limit = new->lower_limit;
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index->upper_limit = new->upper_limit;
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index->buckets = new->buckets;
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free(new);
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return 1;
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}
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/* Public API */
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static HashIndex *
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hashindex_read(const char *path)
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{
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FILE *fd;
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off_t length;
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off_t bytes_read;
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HashHeader header;
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HashIndex *index = NULL;
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if((fd = fopen(path, "r")) == NULL) {
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EPRINTF_PATH(path, "fopen failed");
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return NULL;
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}
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bytes_read = fread(&header, 1, sizeof(HashHeader), fd);
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if(bytes_read != sizeof(HashHeader)) {
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EPRINTF_PATH(path, "fread header failed (expected %ld, got %ld)", sizeof(HashHeader), bytes_read);
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goto fail;
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}
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if(fseek(fd, 0, SEEK_END) < 0) {
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EPRINTF_PATH(path, "fseek failed");
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goto fail;
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}
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if((length = ftell(fd)) < 0) {
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EPRINTF_PATH(path, "ftell failed");
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goto fail;
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}
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if(fseek(fd, 0, SEEK_SET) < 0) {
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EPRINTF_PATH(path, "fseek failed");
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goto fail;
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}
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if(memcmp(header.magic, MAGIC, 8)) {
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EPRINTF_PATH(path, "Unknown file header");
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goto fail;
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}
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if(length != sizeof(HashHeader) + (off_t)_le32toh(header.num_buckets) * (header.key_size + header.value_size)) {
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EPRINTF_PATH(path, "Incorrect file length");
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goto fail;
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}
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if(!(index = malloc(sizeof(HashIndex)))) {
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EPRINTF_PATH(path, "malloc failed");
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goto fail;
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}
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if(!(index->data = malloc(length))) {
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EPRINTF_PATH(path, "malloc failed");
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free(index);
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index = NULL;
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goto fail;
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}
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bytes_read = fread(index->data, 1, length, fd);
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if(bytes_read != length) {
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EPRINTF_PATH(path, "fread hashindex failed (expected %ld, got %ld)", length, bytes_read);
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free(index->data);
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free(index);
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index = NULL;
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goto fail;
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}
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index->data_len = length;
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index->num_entries = _le32toh(header.num_entries);
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index->num_buckets = _le32toh(header.num_buckets);
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index->key_size = header.key_size;
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index->value_size = header.value_size;
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index->bucket_size = index->key_size + index->value_size;
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index->buckets = index->data + sizeof(HashHeader);
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index->lower_limit = index->num_buckets > MIN_BUCKETS ? ((int)(index->num_buckets * BUCKET_LOWER_LIMIT)) : 0;
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index->upper_limit = (int)(index->num_buckets * BUCKET_UPPER_LIMIT);
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fail:
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if(fclose(fd) < 0) {
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EPRINTF_PATH(path, "fclose failed");
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}
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return index;
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}
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static HashIndex *
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hashindex_init(int capacity, int key_size, int value_size)
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{
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HashIndex *index;
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HashHeader header = {
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.magic = MAGIC, .num_entries = 0, .key_size = key_size, .value_size = value_size
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};
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int i;
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capacity = MAX(MIN_BUCKETS, capacity);
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if(!(index = malloc(sizeof(HashIndex)))) {
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EPRINTF("malloc failed");
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return NULL;
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}
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index->data_len = sizeof(HashHeader) + (off_t)capacity * (key_size + value_size);
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if(!(index->data = calloc(index->data_len, 1))) {
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EPRINTF("malloc failed");
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free(index);
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return NULL;
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}
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index->num_entries = 0;
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index->key_size = key_size;
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index->value_size = value_size;
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index->num_buckets = capacity;
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index->bucket_size = index->key_size + index->value_size;
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index->lower_limit = index->num_buckets > MIN_BUCKETS ? ((int)(index->num_buckets * BUCKET_LOWER_LIMIT)) : 0;
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index->upper_limit = (int)(index->num_buckets * BUCKET_UPPER_LIMIT);
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index->buckets = index->data + sizeof(HashHeader);
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memcpy(index->data, &header, sizeof(HashHeader));
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for(i = 0; i < capacity; i++) {
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BUCKET_MARK_EMPTY(index, i);
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}
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return index;
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}
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static void
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hashindex_free(HashIndex *index)
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{
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free(index->data);
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free(index);
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}
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static int
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hashindex_write(HashIndex *index, const char *path)
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{
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FILE *fd;
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int ret = 1;
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if((fd = fopen(path, "w")) == NULL) {
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EPRINTF_PATH(path, "open failed");
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fprintf(stderr, "Failed to open %s for writing\n", path);
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return 0;
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}
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*((uint32_t *)(index->data + 8)) = _htole32(index->num_entries);
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*((uint32_t *)(index->data + 12)) = _htole32(index->num_buckets);
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if(fwrite(index->data, 1, index->data_len, fd) != index->data_len) {
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EPRINTF_PATH(path, "fwrite failed");
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ret = 0;
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}
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if(fclose(fd) < 0) {
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EPRINTF_PATH(path, "fclose failed");
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}
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return ret;
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}
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static const void *
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hashindex_get(HashIndex *index, const void *key)
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{
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int idx = hashindex_lookup(index, key);
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if(idx < 0) {
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return NULL;
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}
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return BUCKET_ADDR(index, idx) + index->key_size;
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}
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static int
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hashindex_set(HashIndex *index, const void *key, const void *value)
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{
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int idx = hashindex_lookup(index, key);
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uint8_t *ptr;
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if(idx < 0)
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{
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if(index->num_entries > index->upper_limit) {
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if(!hashindex_resize(index, index->num_buckets * 2)) {
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return 0;
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}
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}
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idx = hashindex_index(index, key);
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while(!BUCKET_IS_EMPTY(index, idx) && !BUCKET_IS_DELETED(index, idx)) {
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idx = (idx + 1) % index->num_buckets;
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}
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ptr = BUCKET_ADDR(index, idx);
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memcpy(ptr, key, index->key_size);
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memcpy(ptr + index->key_size, value, index->value_size);
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index->num_entries += 1;
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}
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else
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{
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memcpy(BUCKET_ADDR(index, idx) + index->key_size, value, index->value_size);
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}
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return 1;
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}
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static int
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hashindex_delete(HashIndex *index, const void *key)
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{
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int idx = hashindex_lookup(index, key);
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if (idx < 0) {
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return 1;
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}
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BUCKET_MARK_DELETED(index, idx);
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index->num_entries -= 1;
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if(index->num_entries < index->lower_limit) {
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if(!hashindex_resize(index, index->num_buckets / 2)) {
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return 0;
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}
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}
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return 1;
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}
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static void *
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hashindex_next_key(HashIndex *index, const void *key)
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{
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int idx = 0;
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if(key) {
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idx = 1 + (key - index->buckets) / index->bucket_size;
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}
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if (idx == index->num_buckets) {
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return NULL;
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}
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while(BUCKET_IS_EMPTY(index, idx) || BUCKET_IS_DELETED(index, idx)) {
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idx ++;
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if (idx == index->num_buckets) {
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return NULL;
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}
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}
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return BUCKET_ADDR(index, idx);
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}
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static int
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hashindex_get_size(HashIndex *index)
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{
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return index->num_entries;
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}
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static void
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hashindex_summarize(HashIndex *index, long long *total_size, long long *total_csize, long long *total_unique_size, long long *total_unique_csize)
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{
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int64_t size = 0, csize = 0, unique_size = 0, unique_csize = 0;
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const int32_t *values;
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void *key = NULL;
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while((key = hashindex_next_key(index, key))) {
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values = key + 32;
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unique_size += values[1];
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unique_csize += values[2];
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size += values[0] * values[1];
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csize += values[0] * values[2];
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}
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*total_size = size;
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*total_csize = csize;
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*total_unique_size = unique_size;
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*total_unique_csize = unique_csize;
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}
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