--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/mujs/utf.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,285 @@
+/*
+ * The authors of this software are Rob Pike and Ken Thompson.
+ *              Copyright (c) 2002 by Lucent Technologies.
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose without fee is hereby granted, provided that this entire notice
+ * is included in all copies of any software which is or includes a copy
+ * or modification of this software and in all copies of the supporting
+ * documentation for such software.
+ * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE
+ * ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
+ * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
+ */
+#include <stdlib.h>
+#include <string.h>
+
+#include "utf.h"
+#include "utfdata.h"
+
+#define nelem(a) (int)(sizeof (a) / sizeof (a)[0])
+
+typedef unsigned char uchar;
+
+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 0000 0000 0111 1111 */
+	Rune2	= (1<<(Bit2+1*Bitx))-1,		/* 0000 0000 0000 0111 1111 1111 */
+	Rune3	= (1<<(Bit3+2*Bitx))-1,		/* 0000 0000 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
+chartorune(Rune *rune, const char *str)
+{
+	int c, c1, c2, c3;
+	int l;
+
+	/* overlong null character */
+	if((uchar)str[0] == 0xc0 && (uchar)str[1] == 0x80) {
+		*rune = 0;
+		return 2;
+	}
+
+	/*
+	 * one character sequence
+	 *	00000-0007F => T1
+	 */
+	c = *(uchar*)str;
+	if(c < Tx) {
+		*rune = c;
+		return 1;
+	}
+
+	/*
+	 * two character sequence
+	 *	0080-07FF => T2 Tx
+	 */
+	c1 = *(uchar*)(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 = *(uchar*)(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
+	 *	10000-10FFFF => T4 Tx Tx Tx
+	 */
+	if(UTFmax >= 4) {
+		c3 = *(uchar*)(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;
+			if(l > Runemax)
+				goto bad;
+			*rune = l;
+			return 4;
+		}
+	}
+
+	/*
+	 * bad decoding
+	 */
+bad:
+	*rune = Bad;
+	return 1;
+}
+
+int
+runetochar(char *str, const Rune *rune)
+{
+	int c = *rune;
+
+	/* overlong null character */
+	if (c == 0) {
+		str[0] = (char)0xc0;
+		str[1] = (char)0x80;
+		return 2;
+	}
+
+	/*
+	 * one character sequence
+	 *	00000-0007F => 00-7F
+	 */
+	if(c <= Rune1) {
+		str[0] = c;
+		return 1;
+	}
+
+	/*
+	 * two character sequence
+	 *	00080-007FF => T2 Tx
+	 */
+	if(c <= Rune2) {
+		str[0] = T2 | (c >> 1*Bitx);
+		str[1] = Tx | (c & Maskx);
+		return 2;
+	}
+
+	/*
+	 * three character sequence
+	 *	00800-0FFFF => T3 Tx Tx
+	 */
+	if(c > Runemax)
+		c = Runeerror;
+	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
+	 *	010000-1FFFFF => 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
+runelen(int c)
+{
+	Rune rune;
+	char str[10];
+
+	rune = c;
+	return runetochar(str, &rune);
+}
+
+static const Rune *
+ucd_bsearch(Rune c, const Rune *t, int n, int ne)
+{
+	const Rune *p;
+	int m;
+
+	while(n > 1) {
+		m = n/2;
+		p = t + m*ne;
+		if(c >= p[0]) {
+			t = p;
+			n = n-m;
+		} else
+			n = m;
+	}
+	if(n && c >= t[0])
+		return t;
+	return 0;
+}
+
+Rune
+tolowerrune(Rune c)
+{
+	const Rune *p;
+
+	p = ucd_bsearch(c, ucd_tolower2, nelem(ucd_tolower2)/3, 3);
+	if(p && c >= p[0] && c <= p[1])
+		return c + p[2];
+	p = ucd_bsearch(c, ucd_tolower1, nelem(ucd_tolower1)/2, 2);
+	if(p && c == p[0])
+		return c + p[1];
+	return c;
+}
+
+Rune
+toupperrune(Rune c)
+{
+	const Rune *p;
+
+	p = ucd_bsearch(c, ucd_toupper2, nelem(ucd_toupper2)/3, 3);
+	if(p && c >= p[0] && c <= p[1])
+		return c + p[2];
+	p = ucd_bsearch(c, ucd_toupper1, nelem(ucd_toupper1)/2, 2);
+	if(p && c == p[0])
+		return c + p[1];
+	return c;
+}
+
+int
+islowerrune(Rune c)
+{
+	const Rune *p;
+
+	p = ucd_bsearch(c, ucd_toupper2, nelem(ucd_toupper2)/3, 3);
+	if(p && c >= p[0] && c <= p[1])
+		return 1;
+	p = ucd_bsearch(c, ucd_toupper1, nelem(ucd_toupper1)/2, 2);
+	if(p && c == p[0])
+		return 1;
+	return 0;
+}
+
+int
+isupperrune(Rune c)
+{
+	const Rune *p;
+
+	p = ucd_bsearch(c, ucd_tolower2, nelem(ucd_tolower2)/3, 3);
+	if(p && c >= p[0] && c <= p[1])
+		return 1;
+	p = ucd_bsearch(c, ucd_tolower1, nelem(ucd_tolower1)/2, 2);
+	if(p && c == p[0])
+		return 1;
+	return 0;
+}
+
+int
+isalpharune(Rune c)
+{
+	const Rune *p;
+
+	p = ucd_bsearch(c, ucd_alpha2, nelem(ucd_alpha2)/2, 2);
+	if(p && c >= p[0] && c <= p[1])
+		return 1;
+	p = ucd_bsearch(c, ucd_alpha1, nelem(ucd_alpha1), 1);
+	if(p && c == p[0])
+		return 1;
+	return 0;
+}