#include <stdint.h>

#include "standard.h"

int string_equal(const char* a, const char* b) {
	while (*a && *b) {
		if (*a != *b) { return 0; }
		a++; b++;
	}
	return 1;
}

#define sin_table_count 256

static const int sin_table[sin_table_count] = {
	0, 25, 50, 75,
	100, 125, 150, 175,
	200, 224, 249, 273,
	297, 321, 345, 369,
	392, 415, 438, 460,
	483, 505, 526, 548,
	569, 590, 610, 630,
	650, 669, 688, 706,
	724, 742, 759, 775,
	792, 807, 822, 837,
	851, 865, 878, 891,
	903, 915, 926, 936,
	946, 955, 964, 972,
	980, 987, 993, 999,
	1004, 1009, 1013, 1016,
	1019, 1021, 1023, 1024,
	1024, 1024, 1023, 1021,
	1019, 1016, 1013, 1009,
	1004, 999, 993, 987,
	980, 972, 964, 955,
	946, 936, 926, 915,
	903, 891, 878, 865,
	851, 837, 822, 807,
	792, 775, 759, 742,
	724, 706, 688, 669,
	650, 630, 610, 590,
	569, 548, 526, 505,
	483, 460, 438, 415,
	392, 369, 345, 321,
	297, 273, 249, 224,
	200, 175, 150, 125,
	100, 75, 50, 25,
	0, -25, -50, -75,
	-100, -125, -150, -175,
	-200, -224, -249, -273,
	-297, -321, -345, -369,
	-392, -415, -438, -460,
	-483, -505, -526, -548,
	-569, -590, -610, -630,
	-650, -669, -688, -706,
	-724, -742, -759, -775,
	-792, -807, -822, -837,
	-851, -865, -878, -891,
	-903, -915, -926, -936,
	-946, -955, -964, -972,
	-980, -987, -993, -999,
	-1004, -1009, -1013, -1016,
	-1019, -1021, -1023, -1024,
	-1024, -1024, -1023, -1021,
	-1019, -1016, -1013, -1009,
	-1004, -999, -993, -987,
	-980, -972, -964, -955,
	-946, -936, -926, -915,
	-903, -891, -878, -865,
	-851, -837, -822, -807,
	-792, -775, -759, -742,
	-724, -706, -688, -669,
	-650, -630, -610, -590,
	-569, -548, -526, -505,
	-483, -460, -438, -415,
	-392, -369, -345, -321,
	-297, -273, -249, -224,
	-200, -175, -150, -125,
	-100, -75, -50, -25
};

int fsqrt(int n) {
	int lo, hi, mid, i, mm;

	if (n <= 0) { return INT32_MAX; }

	lo = mini(1, n);
	hi = maxi(1, n);

	while ((100 << fbits * lo * lo) >> fbits * 2) {
		lo *= (10 << fbits) >> fbits;
	}

	while ((5 * hi * hi) >> fbits * 2 > n) {
		hi *= (1 << fbits) / 10;
	}

	for (i = 0; i < 100; i++) {
		mid = ((lo + hi) * (1 << fbits)) / (2 << fbits);
		mm = mid * mid >> fbits;
		if (mm == n) { return mid; }
		if (mm > n)  { hi = mid; }
		else         { lo = mid; }
	}

	return mid;
}

int absolute(int x) {
	return x >= 0 ? x : -x;
}

int fsin(int t) {
	int index;
	int sign;

	sign = t >= 0 ? 1 : -1;
	t = absolute(t);

	index = (t * (sin_table_count) / ((1 << fbits) * 2));
	index = index % sin_table_count;

	return sign * sin_table[index];
}

int fcos(int t) {
	return fsin((1 << fbits) / 2 - t);
}

int ftan(int t) {
	return (fsin(t) << fbits) / fcos(t);
}

int flerp(int a, int b, int t) {
	return a + ((t * (b - a)) >> fbits);
}

int int_to_buf(int n, char* buf) {
	int i, sign, t;
	unsigned n1;

	if(n == 0) {
		buf[0] = '0';
		buf[1] = '\0';
		return 1;
	}

	i = 0;
	sign = n < 0;

	n1 = sign ? -n : n;

	while (n1 != 0) {
		buf[i++] = n1 % 10 + '0';
		n1 =n1 / 10;
	}

	if(sign) {
		buf[i++] = '-';
 	}

	buf[i] = '\0';

	for (t = 0; t < i / 2; t++) {
		buf[t] ^= buf[i - t - 1];
		buf[i - t - 1] ^= buf[t];
		buf[t] ^= buf[i - t - 1];
	}

	return i;
}

int f_to_buf(int f, char* buf) {
	int frac, w, i;

	frac = (((f) % (1 << fbits)) * 100) >> fbits;
	w = f >> fbits;

	i = 0;

	if (f < 0) {
		buf[i] = '-';
		i++;
	}

	i += int_to_buf(absolute(w), buf + i);
	buf[i] = '.';
	i++;
	i += int_to_buf(absolute(frac), buf + i);

	return i;
}