Cut: Initial porting of Cut Gizmo

src/libslic3r/utils.cpp

@@ -1,3 +1,9 @@
+///|/ Copyright (c) Prusa Research 2016 - 2023 Pavel Mikuš @Godrak, Oleksandra Iushchenko @YuSanka, Vojtěch Bubník @bubnikv, Lukáš Matěna @lukasmatena, Filip Sykala @Jony01, David Kocík @kocikdav, Roman Beránek @zavorka, Enrico Turri @enricoturri1966, Tomáš Mészáros @tamasmeszaros, Vojtěch Král @vojtechkral
+///|/ Copyright (c) 2021 Justin Schuh @jschuh
+///|/ Copyright (c) Slic3r 2013 - 2015 Alessandro Ranellucci @alranel
+///|/
+///|/ PrusaSlicer is released under the terms of the AGPLv3 or higher
+///|/
 #include "Utils.hpp"
 #include "I18N.hpp"
 
@@ -1030,6 +1036,76 @@ bool is_shapes_dir(const std::string& dir)
 
 namespace Slic3r {
 
+size_t get_utf8_sequence_length(const std::string& text, size_t pos)
+{
+	assert(pos < text.size());
+	return get_utf8_sequence_length(text.c_str() + pos, text.size() - pos);
+}
+
+size_t get_utf8_sequence_length(const char *seq, size_t size)
+{
+	size_t length = 0;
+	unsigned char c = seq[0];
+	if (c < 0x80) { // 0x00-0x7F
+		// is ASCII letter
+		length++;
+	}
+	// Bytes 0x80 to 0xBD are trailer bytes in a multibyte sequence.
+	// pos is in the middle of a utf-8 sequence. Add the utf-8 trailer bytes.
+	else if (c < 0xC0) { // 0x80-0xBF
+		length++;
+		while (length < size) {
+			c = seq[length];
+			if (c < 0x80 || c >= 0xC0) {
+				break; // prevent overrun
+			}
+			length++; // add a utf-8 trailer byte
+		}
+	}
+	// Bytes 0xC0 to 0xFD are header bytes in a multibyte sequence.
+	// The number of one bits above the topmost zero bit indicates the number of bytes (including this one) in the whole sequence.
+	else if (c < 0xE0) { // 0xC0-0xDF
+	 // add a utf-8 sequence (2 bytes)
+		if (2 > size) {
+			return size; // prevent overrun
+		}
+		length += 2;
+	}
+	else if (c < 0xF0) { // 0xE0-0xEF
+	 // add a utf-8 sequence (3 bytes)
+		if (3 > size) {
+			return size; // prevent overrun
+		}
+		length += 3;
+	}
+	else if (c < 0xF8) { // 0xF0-0xF7
+	 // add a utf-8 sequence (4 bytes)
+		if (4 > size) {
+			return size; // prevent overrun
+		}
+		length += 4;
+	}
+	else if (c < 0xFC) { // 0xF8-0xFB
+	 // add a utf-8 sequence (5 bytes)
+		if (5 > size) {
+			return size; // prevent overrun
+		}
+		length += 5;
+	}
+	else if (c < 0xFE) { // 0xFC-0xFD
+	 // add a utf-8 sequence (6 bytes)
+		if (6 > size) {
+			return size; // prevent overrun
+		}
+		length += 6;
+	}
+	else { // 0xFE-0xFF
+	 // not a utf-8 sequence
+		length++;
+	}
+	return length;
+}
+
 // Encode an UTF-8 string to the local code page.
 std::string encode_path(const char *src)
 {