#ifndef BLOOM_H
#define BLOOM_H

#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>

#define BLOOM_MAX_NAME_LENGTH 255
#define BLOOM_MAX_HASHCOUNT 1024

typedef enum {
	BF_SUCCESS = 0,
	BF_OUTOFMEMORY,
	BF_FOPEN,
	BF_FREAD,
	BF_FWRITE,
	BF_FSTAT,
	BF_INVALIDFILE,
	// ERRORCOUNT is used as a counter. do not add anything below this line.
	BF_ERRORCOUNT
} bloom_error_t;


typedef struct {
	size_t   size;              /**< Size of the Bloom filter in bits */
	size_t   hashcount;         /**< Number of hashes performed per element */
	size_t   bitmap_size;       /**< Size of the bitmap in bytes */
	size_t   expected;          /**< Expected capacity of the filter */
	float    accuracy;          /**< Desired margin of error */
	char     name[BLOOM_MAX_NAME_LENGTH + 1];
	uint8_t *bitmap;            /**< Pointer to the bitmap of the filter */
} bloomfilter;

#define BLOOM_FILE_VERSION 1

typedef struct {
    uint8_t  magic[8];
    uint32_t version;

    uint8_t  name[BLOOM_MAX_NAME_LENGTH + 1];

    uint64_t size;
    uint64_t hashcount;
    uint64_t bitmap_size;
    uint64_t expected;

    float    accuracy;
} bloomfilter_file;


typedef struct {
    const bloomfilter_file *header;
    const uint8_t          *bitmap;

    void   *mapping;
    size_t  mapping_size;
} bloomfilter_mapped;

/* function declarations
 */
bloom_error_t  bloom_init(bloomfilter *, const size_t, const double);
void           bloom_destroy(bloomfilter *);
bool           bloom_set_name(bloomfilter *, const char *);
const char    *bloom_strerror(const bloom_error_t);
bloom_error_t  bloom_save(const bloomfilter *, const char *);
size_t         bloom_saturation_count(const bloomfilter *);
float          bloom_saturation(const bloomfilter *);

void           bloom_add(bloomfilter *, const void *, const size_t);
bloom_error_t  bloom_map_fd(bloomfilter_mapped *, int);
void           bloom_unmap(bloomfilter_mapped *);
bool           bloom_valid_name(const char *, size_t);

bool           bloom_mapped_lookup(const bloomfilter_mapped *, const void *, const size_t);
#endif /* BLOOM_H */