#include "signal.h"
#include <errno.h>
#include <string.h>
#include <ctype.h>

#define SIG(s) [SIG##s-1] = #s

static const char map[][4] = {
	SIG(HUP),
	SIG(INT),
	SIG(QUIT),
	SIG(ILL),
	SIG(TRAP),
	SIG(ABRT),
	SIG(BUS),
	SIG(FPE),
	SIG(KILL),
	SIG(USR1),
	SIG(SEGV),
	SIG(USR2),
	SIG(PIPE),
	SIG(ALRM),
	SIG(TERM),
	SIG(CHLD),
	SIG(CONT),
	SIG(STOP),
	SIG(TSTP),
	SIG(TTIN),
	SIG(TTOU),
	SIG(URG),
	SIG(XCPU),
	SIG(XFSZ),
	SIG(PROF),
	SIG(IO),
	SIG(PWR),
	SIG(SYS),
#ifdef SIGEMT
	SIG(EMT),
#endif
};

static const char other[] = {
#ifdef SIGSTKFLT
	SIGSTKFLT,	'S','T','K','F','L','T', 0,
#endif
	SIGVTALRM,	'V','T','A','L','R','M', 0,
	SIGWINCH,	'W','I','N','C','H', 0,
	RTMIN,		'R','T','M','I','N', 0,
	RTMAX,		'R','T','M','A','X', 0,
	/* aliases */
	SIGPOLL,	'P','O','L','L', 0,
	SIGIOT,		'I','O','T', 0,
	SIGUNUSED,	'U','N','U','S','E','D', 0,
	0
};

int sig2str(int sig, char *str)
{
	const char *p;
	int i, num;

	if (sig > 0 && sig-1 < sizeof map/sizeof *map && *map[sig-1]) {
		for (i = 0; i < sizeof *map; i++)
			str[i] = map[sig-1][i];
		str[i] = 0;
		return 0;
	} else if (sig > RTMIN && sig < RTMAX) {
		for (i = 0; i < 6; i++)
			str[i] = "RTMIN+"[i];
		num = sig-RTMIN;
		if (num > 10)
			str[i++] = '0'+num/10;
		str[i++] = '0'+num%10;
		str[i] = 0;
		return 0;
	} else for (p = other, i = 0; i < 5; i++) {
		if (*p++ == sig) {
			for (i = 0; p[i]; i++)
				str[i] = p[i];
			return 0;
		}
		while (*p++)
			;
		p++;
	}
	errno = EINVAL;
	return -1;
}

int str2sig(const char *restrict str, int *restrict sig)
{
	const char *p;
	size_t len;
	int i, num;

	len = strnlen(str, 5);
	if (len == 3 || len == 4)
		for (i = 0; i < sizeof map/sizeof *map; i++)
			if (strncmp(str, map[i], 4) == 0)
				return (*sig = i+1, 0);
	if (len <= 6)
		for (p = other; *p; p += len+1)
			if (strncmp(str, p+1, (len = strnlen(p+1, 6)+1)) == 0)
				return (*sig = *p, 0);

	i = strncmp(str, "RTMIN+", 6)==0||strncmp(str, "RTMAX-", 6)==0?6:0;
	if (str[i] >= '1' && str[i] <= '9') {
		num = str[i++]-'0';
		if (isdigit(str[i]))
			num = num*10+str[i++]-'0';
		if (!str[i]) {
			if (isdigit(*str)) {
				if (num <= RTMAX)
					return (*sig = num, 0);
			} else if (num < RTMAX-RTMIN)
				return (*sig = str[5]=='+'?RTMIN+num:RTMAX-num, 0);
		}
	}
	/* errno = EINVAL ? */
	return -1;
}