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engines/ags/shared/util/utf8.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+ //=============================================================================
+ //
+ // UTF-8 utilities.
+ // Based on utf8 code from https://c9x.me/irc/ (public domain)
+ //
+ //=============================================================================
+
+#ifndef AGS_SHARED_UTIL_UTF8_H
+#define AGS_SHARED_UTIL_UTF8_H
+
+#include "common/std/algorithm.h"
+#include "ags/shared/core/types.h"
+
+namespace AGS3 {
+namespace Utf8 {
+
+typedef int32_t Rune;
+const size_t UtfSz = 4;
+const Rune RuneInvalid = 0xFFFD;
+
+const unsigned char utfbyte[UtfSz + 1] = { 0x80,    0, 0xC0, 0xE0, 0xF0 };
+const unsigned char utfmask[UtfSz + 1] = { 0xC0, 0x80, 0xE0, 0xF0, 0xF8 };
+const Rune utfmin[UtfSz + 1] = { 0,    0,  0x80,  0x800,  0x10000 };
+const Rune utfmax[UtfSz + 1] = { 0x10FFFF, 0x7F, 0x7FF, 0xFFFF, 0x10FFFF };
+
+
+inline size_t Validate(Rune *u, size_t i) {
+	if (*u < utfmin[i] || *u > utfmax[i] || (0xD800 <= *u && *u <= 0xDFFF))
+		*u = RuneInvalid;
+	for (i = 1; *u > utfmax[i]; ++i)
+		;
+	return i;
+}
+
+inline Rune DecodeByte(unsigned char c, size_t *i) {
+	for (*i = 0; *i < UtfSz + 1; ++(*i))
+		if ((c & utfmask[*i]) == utfbyte[*i])
+			return c & ~utfmask[*i];
+	return 0;
+}
+
+inline char EncodeByte(Rune u, size_t i) {
+	return utfbyte[i] | (u & ~utfmask[i]);
+}
+
+// Read a single utf8 codepoint from the c-string;
+// returns codepoint's size in bytes (may be used to advance string pos)
+inline size_t GetChar(const char *c, size_t clen, Rune *u) {
+	size_t i, j, len, type;
+	Rune udecoded;
+	*u = RuneInvalid;
+	if (!clen || !*c)
+		return 0;
+	udecoded = DecodeByte(c[0], &len);
+	if (len < 1 || len > UtfSz)
+		return 1;
+	for (i = 1, j = 1; i < clen && j < len; ++i, ++j) {
+		udecoded = (udecoded << 6) | DecodeByte(c[i], &type);
+		if (type != 0)
+			return j;
+	}
+	if (j < len)
+		return 0;
+	*u = udecoded;
+	Validate(u, len);
+	return len;
+}
+
+// Convert utf8 codepoint to the string representation and write to the buffer
+inline size_t SetChar(Rune u, char *c, size_t clen) {
+	size_t len, i;
+	len = Validate(&u, 0);
+	if (len > UtfSz || len > clen)
+		return 0;
+	for (i = len - 1; i != 0; --i) {
+		c[i] = EncodeByte(u, 0);
+		u >>= 6;
+	}
+	c[0] = EncodeByte(u, len);
+	return len;
+}
+
+// Calculates utf8 string length in characters
+inline size_t GetLength(const char *c) {
+	size_t len = 0;
+	Rune r;
+	for (size_t chr_sz = 0; (chr_sz = GetChar(c, UtfSz, &r)) > 0; c += chr_sz, ++len);
+	return len;
+}
+
+} // namespace Utf8
+} // namespace AGS3
+
+#endif