#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <stdint.h>

#include "gen.h"

int eulpf(float x)

{

	union { float f; uint32_t i; } u = { x };

	int e = u.i>>23 & 0xff;

	if (!e)

		e++;

	return e - 0x7f - 23;

}

int eulp(double x)

{

	union { double f; uint64_t i; } u = { x };

	int e = u.i>>52 & 0x7ff;

	if (!e)

		e++;

	return e - 0x3ff - 52;

}

int eulpl(long double x)

{

#if LDBL_MANT_DIG == 53

	return eulp(x);

#elif LDBL_MANT_DIG == 64

	union { long double f; struct {uint64_t m; uint16_t e; uint16_t pad;} i; } u = { x };

	int e = u.i.e & 0x7fff;

	if (!e)

		e++;

	return e - 0x3fff - 63;

#else

	// TODO

	return 0;

#endif

}

double ulperr(double y, double ycr, double dy)

{

	return dy + scalbn(ycr - y, -eulp(ycr));

}

char *skipstr(char *buf, char *sep)

{

	while (*buf && strchr(sep, *buf))

		buf++;

	return buf;

}

int splitstr(char **a, int n, char *buf, char *sep)

{

	int i, j;

	for (i = j = 0; j < n; j++) {

		for (; buf[i] && strchr(sep, buf[i]); i++)

				buf[i] = 0;

		a[j] = buf + i;

		if (buf[i] == 0)

			break;

		for (i++; buf[i] && !strchr(sep, buf[i]); i++);

	}

	return j;

}

char *dropcomm(char *buf)

{

	char *p = buf;

	for (; *p; p++)

		if (*p == '/' && p[1] == '/') {

			*p = 0;

			break;

		}

	return buf;

}

#define length(a) (sizeof(a)/sizeof(*a))

#define flag(x) {x, #x}

static struct {

	int flag;

	char *s;

} eflags[] = {

	flag(INEXACT),

	flag(INVALID),

	flag(DIVBYZERO),

	flag(UNDERFLOW),

	flag(OVERFLOW)

};

char *estr(int f)

{

	static char buf[256];

	char *p = buf;

	int i, all = 0;

	for (i = 0; i < length(eflags); i++)

		if (f & eflags[i].flag) {

			p += sprintf(p, "%s%s", all ? "|" : "", eflags[i].s);

			all |= eflags[i].flag;

		}

	if (all != f) {

		p += sprintf(p, "%s%d", all ? "|" : "", f & ~all);

		all = f;

	}

	p += sprintf(p, "%s", all ? "" : "0");

	return buf;

}

int econv(int *f, char *s)

{

	char *a[16];

	char *e;

	int i,j,k,n;

	*f = 0;

	n = splitstr(a, length(a), s, "|");

	for (i = 0; i < n; i++) {

		for (j = 0; j < length(eflags); j++)

			if (strcmp(a[i], eflags[j].s) == 0) {

				*f |= eflags[j].flag;

				break;

			}

		if (j == length(eflags)) {

			k = strtol(a[i], &e, 0);

			if (*e)

				return -1;

			*f |= k;

		}

	}

	return 0;

}

char *rstr(int r)

{

	switch (r) {

	case RN: return "RN";

	case RZ: return "RZ";

	case RU: return "RU";

	case RD: return "RD";

	}

	return "R?";

}

int rconv(int *r, char *s)

{

	if (strcmp(s, "RN") == 0)

		*r = RN;

	else if (strcmp(s, "RZ") == 0)

		*r = RZ;

	else if (strcmp(s, "RD") == 0)

		*r = RD;

	else if (strcmp(s, "RU") == 0)

		*r = RU;

	else

		return -1;

	return 0;

}

void setupfenv(int r)

{

	fesetround(r);

	feclearexcept(FE_ALL_EXCEPT);

}

int getexcept(void)

{

	return fetestexcept(INEXACT|INVALID|DIVBYZERO|UNDERFLOW|OVERFLOW);

}