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e398d5f632
Closes #54
411 lines
11 KiB
C
411 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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#include <sys/mman.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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char *path;
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void *map_addr;
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off_t map_length;
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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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int bucket_size;
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int lower_limit;
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int upper_limit;
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int readonly;
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} HashIndex;
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#define MAGIC "ATTICIDX"
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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 EPRINTF(msg, ...) EPRINTF_PATH(index->path, msg, ##__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_open(const char *path, int readonly);
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static int hashindex_close(HashIndex *index);
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static int hashindex_clear(HashIndex *index);
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static int hashindex_flush(HashIndex *index);
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static HashIndex *hashindex_create(const char *path, 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 && !index->readonly) {
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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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char *new_path = malloc(strlen(index->path) + 5);
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int ret = 0;
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strcpy(new_path, index->path);
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strcat(new_path, ".tmp");
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HashIndex *new;
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if(!(new = hashindex_create(new_path, capacity, index->key_size, index->value_size))) {
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free(new_path);
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return 0;
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}
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void *key = NULL;
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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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munmap(index->map_addr, index->map_length);
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index->map_addr = new->map_addr;
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index->map_length = new->map_length;
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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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if(unlink(index->path) < 0) {
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EPRINTF("unlink failed");
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goto out;
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}
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if(rename(new_path, index->path) < 0) {
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EPRINTF_PATH(new_path, "rename failed");
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goto out;
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}
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ret = 1;
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out:
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free(new_path);
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free(new->path);
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free(new);
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return ret;
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}
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/* Public API */
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static HashIndex *
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hashindex_open(const char *path, int readonly)
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{
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void *addr;
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int fd, oflags, prot;
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off_t length;
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HashHeader *header;
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HashIndex *index;
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if(readonly) {
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oflags = O_RDONLY;
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prot = PROT_READ;
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}
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else {
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oflags = O_RDWR;
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prot = PROT_READ | PROT_WRITE;
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}
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if((fd = open(path, oflags)) < 0) {
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EPRINTF_PATH(path, "open failed");
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fprintf(stderr, "Failed to open %s\n", path);
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return NULL;
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}
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if((length = lseek(fd, 0, SEEK_END)) < 0) {
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EPRINTF_PATH(path, "lseek failed");
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if(close(fd) < 0) {
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EPRINTF_PATH(path, "close failed");
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}
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return NULL;
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}
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addr = mmap(0, length, prot, MAP_SHARED, fd, 0);
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if(close(fd) < 0) {
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EPRINTF_PATH(path, "close failed");
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return NULL;
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}
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if(addr == MAP_FAILED) {
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EPRINTF_PATH(path, "mmap failed");
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return NULL;
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}
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header = (HashHeader *)addr;
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if(memcmp(header->magic, MAGIC, 8)) {
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EPRINTF_PATH(path, "Unknown file header");
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return NULL;
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}
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if(length != sizeof(HashHeader) + _le32toh(header->num_buckets) * (header->key_size + header->value_size)) {
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EPRINTF_PATH(path, "Incorrect file length");
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return NULL;
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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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return NULL;
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}
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index->readonly = readonly;
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index->map_addr = addr;
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index->map_length = 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 = (addr + 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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if(!(index->path = strdup(path))) {
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EPRINTF_PATH(path, "strdup failed");
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free(index);
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return NULL;
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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_create(const char *path, int capacity, int key_size, int value_size)
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{
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FILE *fd;
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char bucket[MAX_BUCKET_SIZE] = {};
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int i, bucket_size;
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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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capacity = MAX(MIN_BUCKETS, capacity);
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header.num_buckets = _htole32(capacity);
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if(!(fd = fopen(path, "w"))) {
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EPRINTF_PATH(path, "fopen failed");
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return NULL;
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}
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bucket_size = key_size + value_size;
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if(fwrite(&header, 1, sizeof(header), fd) != sizeof(header)) {
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goto error;
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}
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*((uint32_t *)(bucket + key_size)) = EMPTY;
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for(i = 0; i < capacity; i++) {
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if(fwrite(bucket, 1, bucket_size, fd) != bucket_size) {
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goto error;
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}
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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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if(unlink(path) < 0) {
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EPRINTF_PATH(path, "unlink failed");
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}
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return NULL;
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}
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return hashindex_open(path, 0);
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error:
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if(unlink(path) < 0) {
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EPRINTF_PATH(path, "unlink failed");
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}
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EPRINTF_PATH(path, "fwrite failed");
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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 NULL;
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}
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static int
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hashindex_clear(HashIndex *index)
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{
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int i;
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for(i = 0; i < index->num_buckets; i++) {
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BUCKET_MARK_DELETED(index, i);
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}
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index->num_entries = 0;
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return hashindex_resize(index, MIN_BUCKETS);
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}
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static int
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hashindex_flush(HashIndex *index)
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{
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if(index->readonly) {
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return 1;
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}
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*((uint32_t *)(index->map_addr + 8)) = _htole32(index->num_entries);
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*((uint32_t *)(index->map_addr + 12)) = _htole32(index->num_buckets);
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if(msync(index->map_addr, index->map_length, MS_SYNC) < 0) {
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EPRINTF("msync failed");
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return 0;
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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_close(HashIndex *index)
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{
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int rv = 1;
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if(hashindex_flush(index) < 0) {
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rv = 0;
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}
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if(munmap(index->map_addr, index->map_length) < 0) {
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EPRINTF("munmap failed");
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rv = 0;
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}
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free(index->path);
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free(index);
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return rv;
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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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