/*
 * Copyright (C)2005-2016 Haxe Foundation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */
#include <hl.h>
#include <time.h>
#include <string.h>
#if defined(HL_WIN_DESKTOP)
#	include <windows.h>
#	include <process.h>
#elif defined(HL_CONSOLE)
#	include <posix/posix.h>
#else
#	include <sys/time.h>
#	include <sys/types.h>
#	include <unistd.h>
#endif

#define NSEEDS	25
#define MAX		7

typedef struct _rnd rnd;

struct _rnd {
	unsigned long seeds[NSEEDS];
	unsigned long cur;
};

static unsigned long mag01[2]={
	0x0, 0x8ebfd028 // magic, don't change
};

static const unsigned long init_seeds[] = {
	0x95f24dab, 0x0b685215, 0xe76ccae7, 0xaf3ec239, 0x715fad23,
	0x24a590ad, 0x69e4b5ef, 0xbf456141, 0x96bc1b7b, 0xa7bdf825,
	0xc1de75b7, 0x8858a9c9, 0x2da87693, 0xb657f9dd, 0xffdc8a9f,
	0x8121da71, 0x8b823ecb, 0x885d05f5, 0x4e20cd47, 0x5a9ad5d9,
	0x512c0c03, 0xea857ccd, 0x4cc1d30f, 0x8891a8a1, 0xa6b7aadb
};

HL_PRIM rnd *hl_rnd_alloc() {
	return (rnd*)hl_gc_alloc_noptr(sizeof(rnd));
}

HL_PRIM void hl_rnd_set_seed( rnd *r, int s ) {
	int i;
	r->cur = 0;
	memcpy(r->seeds,init_seeds,sizeof(init_seeds));
	for(i=0;i<NSEEDS;i++)
		r->seeds[i] ^= s;
}

HL_PRIM rnd *hl_rnd_init_system() {
	rnd *r = hl_rnd_alloc();
	int pid = getpid();
	unsigned int time;
#ifdef HL_WIN
	time = GetTickCount();
#else
	struct timeval t;
	gettimeofday(&t,NULL);
	time = t.tv_sec * 1000000 + t.tv_usec;
#endif
#ifdef HL_DEBUG_REPRO
	// fixed random seed
	time = 4644546;
	pid = 0;
#endif
	hl_rnd_set_seed(r,time ^ (pid | (pid << 16)));
	return r;
}

HL_PRIM unsigned int hl_rnd_int( rnd *r ) {
	unsigned int y;
	int pos = r->cur++;
    if( pos >= NSEEDS ) {
		int kk;
		for(kk=0;kk<NSEEDS-MAX;kk++)
			r->seeds[kk] = r->seeds[kk+MAX] ^ (r->seeds[kk] >> 1) ^ mag01[r->seeds[kk] % 2];
		for(;kk<NSEEDS;kk++)
			r->seeds[kk] = r->seeds[kk+(MAX-NSEEDS)] ^ (r->seeds[kk] >> 1) ^ mag01[r->seeds[kk] % 2];
		r->cur = 1;
		pos = 0;
	}
    y = r->seeds[pos];
    y ^= (y << 7) & 0x2b5b2500;
    y ^= (y << 15) & 0xdb8b0000;
    y ^= (y >> 16);
	return y;
}

HL_PRIM double hl_rnd_float( rnd *r ) {
	double big = 4294967296.0;
	return ((hl_rnd_int(r) / big + hl_rnd_int(r)) / big + hl_rnd_int(r)) / big;
}

#define _RND	_ABSTRACT(hl_random)

DEFINE_PRIM(_RND,rnd_alloc,_NO_ARG);
DEFINE_PRIM(_RND,rnd_init_system, _NO_ARG);
DEFINE_PRIM(_VOID,rnd_set_seed, _RND _I32);
DEFINE_PRIM(_I32,rnd_int, _RND);
DEFINE_PRIM(_F64,rnd_float, _RND);