/* Common utilities that are include everywhere */
#ifndef COMMON_H
#define COMMON_H

#include "../config.h"
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

/* Allow for inclusion in C++ code. For easy of use, two macros BEGIN_C_DECLS
   and END_C_DECLS are defined. */
#ifdef __cplusplus
# define BEGIN_C_DECLS extern "C" {
# define END_C_DECLS }
#else
# define BEGIN_C_DECLS	/* empty */
# define END_C_DECLS	/* empty */
#endif

#if __GNUC__ >= 4
# define DPT_EXTERN(type) extern __attribute__((visibility("default"))) type
#elif defined(_MSC_VER)
# define DPT_EXTERN(type) __declspec(dllexport) type
#else
# define DPT_EXTERN(type) extern type
#endif

#define B32	(double)(1ULL << 32)
#define B64	((double)B32*B32)
#define B128	((double)B64*B64)
#define B192	((double)B128*B64)
#define B256	((double)B128*B128)

#define LOWMASK ((1ULL << 32) - 1)
#define lo(x) ((x) & LOWMASK)
#define hi(x) ((x) >> 32)

#define u64(x) ((uint64_t)(x))
#define u64c(x) (__UINT64_C(x))

BEGIN_C_DECLS

typedef unsigned char byte;
typedef unsigned int uint;

/**
 * Representation of 128-bit number.
 */
typedef struct __blk128_t {
	uint64_t hi;
	uint64_t lo;
} blk128_t;

/**
 * Representation of 256-bit number. 'mx' contains two bits of information:
 * Potentially a 257'th bit and a sign bit (is this number negative).
 *
 * The 64-bit array stores the digits of the number, where x[0] is the least
 * significant digit and x[3] is the most.
 */
typedef struct __blk256_t {
	char     mx;		/* More generally flags */
	uint64_t x[4];
} blk256_t;

#define BLK128SIZ (sizeof(blk128_t))
#define BLK256SIZ (sizeof(uint64_t) << 2)

#define blk256_sign_bit(x) (((x)->mx & 0x2) >> 1)
#define blk256_is_positive(x) (!blk256_sign_bit(x)) /* Zero is considered positive */

#define blk256_set_sign_bit(x) ((x)->mx |= 0x2)
#define blk256_clear_sign_bit(x) ((x)->mx &= ~0x2)

#define blk256_high_bit(x) ((x)->mx & 0x1)
#define blk256_set_high_bit(x) ((x)->mx |= 1)
#define blk256_clear_high_bit(x) ((x)->mx &= ~1)

/**
 * sgn() function for 256-bit numbers. Contrary to standard definition, this
 * returns 1 when all digits are zero (it is considered "not a negative"-number)
 */
#define blk256_sign(b) (blk256_sign_bit(b) ? -1 : 1)

END_C_DECLS
#endif