#include "mupdf/fitz.h"

char *
fz_strsep(char **stringp, const char *delim)
{
	char *ret = *stringp;
	if (!ret) return NULL;
	if ((*stringp = strpbrk(*stringp, delim)) != NULL)
		*((*stringp)++) = '\0';
	return ret;
}

int
fz_strlcpy(char *dst, const char *src, int siz)
{
	register char *d = dst;
	register const char *s = src;
	register int n = siz;

	/* Copy as many bytes as will fit */
	if (n != 0 && --n != 0) {
		do {
			if ((*d++ = *s++) == 0)
				break;
		} while (--n != 0);
	}

	/* Not enough room in dst, add NUL and traverse rest of src */
	if (n == 0) {
		if (siz != 0)
			*d = '\0';		/* NUL-terminate dst */
		while (*s++)
			;
	}

	return(s - src - 1);	/* count does not include NUL */
}

int
fz_strlcat(char *dst, const char *src, int siz)
{
	register char *d = dst;
	register const char *s = src;
	register int n = siz;
	int dlen;

	/* Find the end of dst and adjust bytes left but don't go past end */
	while (*d != '\0' && n-- != 0)
		d++;
	dlen = d - dst;
	n = siz - dlen;

	if (n == 0)
		return dlen + strlen(s);
	while (*s != '\0') {
		if (n != 1) {
			*d++ = *s;
			n--;
		}
		s++;
	}
	*d = '\0';

	return dlen + (s - src);	/* count does not include NUL */
}

void
fz_dirname(char *dir, const char *path, int n)
{
	int i;

	if (!path || !path[0])
	{
		fz_strlcpy(dir, ".", n);
		return;
	}

	fz_strlcpy(dir, path, n);

	i = strlen(dir);
	for(; dir[i] == '/'; --i) if (!i) { fz_strlcpy(dir, "/", n); return; }
	for(; dir[i] != '/'; --i) if (!i) { fz_strlcpy(dir, ".", n); return; }
	for(; dir[i] == '/'; --i) if (!i) { fz_strlcpy(dir, "/", n); return; }
	dir[i+1] = 0;
}

static int ishex(int a)
{
	return (a >= 'A' && a <= 'F') ||
		(a >= 'a' && a <= 'f') ||
		(a >= '0' && a <= '9');
}

static int tohex(int c)
{
	if (c >= '0' && c <= '9') return c - '0';
	if (c >= 'a' && c <= 'f') return c - 'a' + 0xA;
	if (c >= 'A' && c <= 'F') return c - 'A' + 0xA;
	return 0;
}

char *
fz_urldecode(char *url)
{
	char *s = url;
	char *p = url;
	while (*s)
	{
		int c = (unsigned char) *s++;
		if (c == '%' && ishex(s[0]) && ishex(s[1]))
		{
			int a = tohex(*s++);
			int b = tohex(*s++);
			*p++ = a << 4 | b;
		}
		else
		{
			*p++ = c;
		}
	}
	*p = 0;
	return url;
}

#define SEP(x) ((x)=='/' || (x) == 0)

char *
fz_cleanname(char *name)
{
	char *p, *q, *dotdot;
	int rooted;

	rooted = name[0] == '/';

	/*
	 * invariants:
	 *		p points at beginning of path element we're considering.
	 *		q points just past the last path element we wrote (no slash).
	 *		dotdot points just past the point where .. cannot backtrack
	 *				any further (no slash).
	 */
	p = q = dotdot = name + rooted;
	while (*p)
	{
		if(p[0] == '/') /* null element */
			p++;
		else if (p[0] == '.' && SEP(p[1]))
			p += 1; /* don't count the separator in case it is nul */
		else if (p[0] == '.' && p[1] == '.' && SEP(p[2]))
		{
			p += 2;
			if (q > dotdot) /* can backtrack */
			{
				while(--q > dotdot && *q != '/')
					;
			}
			else if (!rooted) /* /.. is / but ./../ is .. */
			{
				if (q != name)
					*q++ = '/';
				*q++ = '.';
				*q++ = '.';
				dotdot = q;
			}
		}
		else /* real path element */
		{
			if (q != name+rooted)
				*q++ = '/';
			while ((*q = *p) != '/' && *q != 0)
				p++, q++;
		}
	}

	if (q == name) /* empty string is really "." */
		*q++ = '.';
	*q = '\0';
	return name;
}

enum
{
	UTFmax = 4, /* maximum bytes per rune */
	Runesync = 0x80, /* cannot represent part of a UTF sequence (<) */
	Runeself = 0x80, /* rune and UTF sequences are the same (<) */
	Runeerror = 0xFFFD, /* decoding error in UTF */
	Runemax = 0x10FFFF, /* maximum rune value */
};

enum
{
	Bit1 = 7,
	Bitx = 6,
	Bit2 = 5,
	Bit3 = 4,
	Bit4 = 3,
	Bit5 = 2,

	T1 = ((1<<(Bit1+1))-1) ^ 0xFF, /* 0000 0000 */
	Tx = ((1<<(Bitx+1))-1) ^ 0xFF, /* 1000 0000 */
	T2 = ((1<<(Bit2+1))-1) ^ 0xFF, /* 1100 0000 */
	T3 = ((1<<(Bit3+1))-1) ^ 0xFF, /* 1110 0000 */
	T4 = ((1<<(Bit4+1))-1) ^ 0xFF, /* 1111 0000 */
	T5 = ((1<<(Bit5+1))-1) ^ 0xFF, /* 1111 1000 */

	Rune1 = (1<<(Bit1+0*Bitx))-1, /* 0000 0000 0111 1111 */
	Rune2 = (1<<(Bit2+1*Bitx))-1, /* 0000 0111 1111 1111 */
	Rune3 = (1<<(Bit3+2*Bitx))-1, /* 1111 1111 1111 1111 */
	Rune4 = (1<<(Bit4+3*Bitx))-1, /* 0001 1111 1111 1111 1111 1111 */

	Maskx = (1<<Bitx)-1,	/* 0011 1111 */
	Testx = Maskx ^ 0xFF,	/* 1100 0000 */

	Bad = Runeerror,
};

int
fz_chartorune(int *rune, const char *str)
{
	int c, c1, c2, c3;
	long l;

	/*
	 * one character sequence
	 *	00000-0007F => T1
	 */
	c = *(const unsigned char*)str;
	if(c < Tx) {
		*rune = c;
		return 1;
	}

	/*
	 * two character sequence
	 *	0080-07FF => T2 Tx
	 */
	c1 = *(const unsigned char*)(str+1) ^ Tx;
	if(c1 & Testx)
		goto bad;
	if(c < T3) {
		if(c < T2)
			goto bad;
		l = ((c << Bitx) | c1) & Rune2;
		if(l <= Rune1)
			goto bad;
		*rune = l;
		return 2;
	}

	/*
	 * three character sequence
	 *	0800-FFFF => T3 Tx Tx
	 */
	c2 = *(const unsigned char*)(str+2) ^ Tx;
	if(c2 & Testx)
		goto bad;
	if(c < T4) {
		l = ((((c << Bitx) | c1) << Bitx) | c2) & Rune3;
		if(l <= Rune2)
			goto bad;
		*rune = l;
		return 3;
	}

	/*
	 * four character sequence (21-bit value)
	 *	10000-1FFFFF => T4 Tx Tx Tx
	 */
	c3 = *(const unsigned char*)(str+3) ^ Tx;
	if (c3 & Testx)
		goto bad;
	if (c < T5) {
		l = ((((((c << Bitx) | c1) << Bitx) | c2) << Bitx) | c3) & Rune4;
		if (l <= Rune3)
			goto bad;
		*rune = l;
		return 4;
	}
	/*
	 * Support for 5-byte or longer UTF-8 would go here, but
	 * since we don't have that, we'll just fall through to bad.
	 */

	/*
	 * bad decoding
	 */
bad:
	*rune = Bad;
	return 1;
}

int
fz_runetochar(char *str, int rune)
{
	/* Runes are signed, so convert to unsigned for range check. */
	unsigned long c = (unsigned long)rune;

	/*
	 * one character sequence
	 *	00000-0007F => 00-7F
	 */
	if(c <= Rune1) {
		str[0] = c;
		return 1;
	}

	/*
	 * two character sequence
	 *	0080-07FF => T2 Tx
	 */
	if(c <= Rune2) {
		str[0] = T2 | (c >> 1*Bitx);
		str[1] = Tx | (c & Maskx);
		return 2;
	}

	/*
	 * If the Rune is out of range, convert it to the error rune.
	 * Do this test here because the error rune encodes to three bytes.
	 * Doing it earlier would duplicate work, since an out of range
	 * Rune wouldn't have fit in one or two bytes.
	 */
	if (c > Runemax)
		c = Runeerror;

	/*
	 * three character sequence
	 *	0800-FFFF => T3 Tx Tx
	 */
	if (c <= Rune3) {
		str[0] = T3 | (c >> 2*Bitx);
		str[1] = Tx | ((c >> 1*Bitx) & Maskx);
		str[2] = Tx | (c & Maskx);
		return 3;
	}

	/*
	 * four character sequence (21-bit value)
	 *	10000-1FFFFF => T4 Tx Tx Tx
	 */
	str[0] = T4 | (c >> 3*Bitx);
	str[1] = Tx | ((c >> 2*Bitx) & Maskx);
	str[2] = Tx | ((c >> 1*Bitx) & Maskx);
	str[3] = Tx | (c & Maskx);
	return 4;
}

int
fz_runelen(int c)
{
	char str[10];
	return fz_runetochar(str, c);
}

int
fz_utflen(const char *s)
{
	int c, n, rune;
	n = 0;
	for(;;) {
		c = *(const unsigned char*)s;
		if(c < Runeself) {
			if(c == 0)
				return n;
			s++;
		} else
			s += fz_chartorune(&rune, s);
		n++;
	}
	return 0;
}

float fz_atof(const char *s)
{
	float result;

	errno = 0;
	result = fz_strtof(s, NULL);
	if ((errno == ERANGE && result == 0) || isnan(result))
		/* Return 1.0 on  underflow, as it's a small known value that won't cause a divide by 0.  */
		return 1;
	result = fz_clamp(result, -FLT_MAX, FLT_MAX);
	return result;
}

int fz_atoi(const char *s)
{
	if (s == NULL)
		return 0;
	return atoi(s);
}

fz_off_t fz_atoo(const char *s)
{
	if (s == NULL)
		return 0;
	return fz_atoo_imp(s);
}
