From 22ab0244d8138e5a0c732d5c4339cdbeb88c9452 Mon Sep 17 00:00:00 2001
From: frosch <frosch@openttd.org>
Date: Tue, 1 Apr 2025 18:17:37 +0200
Subject: [PATCH] Codechange: Use Utf8View in Textbuf.

---
 src/textbuf.cpp | 56 +++++++++++++++++++++++--------------------------
 1 file changed, 26 insertions(+), 30 deletions(-)

diff --git a/src/textbuf.cpp b/src/textbuf.cpp
index f41023b966..9b4573d0da 100644
--- a/src/textbuf.cpp
+++ b/src/textbuf.cpp
@@ -12,6 +12,7 @@
 #include "textbuf_type.h"
 #include "string_func.h"
 #include "strings_func.h"
+#include "core/utf8.hpp"
 #include "gfx_type.h"
 #include "gfx_func.h"
 #include "gfx_layout.h"
@@ -58,45 +59,44 @@ bool Textbuf::DeleteChar(uint16_t keycode)
 
 	if (!CanDelChar(backspace)) return false;
 
-	auto s = this->buf.begin() + this->caretpos;
-	uint16_t len = 0;
-
+	size_t start;
+	size_t len;
 	if (word) {
 		/* Delete a complete word. */
 		if (backspace) {
 			/* Delete whitespace and word in front of the caret. */
-			len = this->caretpos - (uint16_t)this->char_iter->Prev(StringIterator::ITER_WORD);
-			s -= len;
+			start = this->char_iter->Prev(StringIterator::ITER_WORD);
+			len = this->caretpos - start;
 		} else {
 			/* Delete word and following whitespace following the caret. */
-			len = (uint16_t)this->char_iter->Next(StringIterator::ITER_WORD) - this->caretpos;
+			start = this->caretpos;
+			len = this->char_iter->Next(StringIterator::ITER_WORD) - start;
 		}
 		/* Update character count. */
-		for (auto ss = s; ss < s + len; Utf8Consume(ss)) {
-			this->chars--;
-		}
+		this->chars -= static_cast<uint16_t>(Utf8StringLength(std::string_view(this->buf).substr(start, len)));
 	} else {
 		/* Delete a single character. */
 		if (backspace) {
 			/* Delete the last code point in front of the caret. */
-			s = Utf8PrevChar(s);
-			char32_t c;
-			len = (uint16_t)Utf8Decode(&c, s);
+			Utf8View view(this->buf);
+			auto it = view.GetIterAtByte(this->caretpos);
+			--it;
+			start = it.GetByteOffset();
+			len = this->caretpos - start;
 			this->chars--;
 		} else {
 			/* Delete the complete character following the caret. */
-			len = (uint16_t)this->char_iter->Next(StringIterator::ITER_CHARACTER) - this->caretpos;
+			start = this->caretpos;
+			len = this->char_iter->Next(StringIterator::ITER_CHARACTER) - start;
 			/* Update character count. */
-			for (auto ss = s; ss < s + len; Utf8Consume(ss)) {
-				this->chars--;
-			}
+			this->chars -= static_cast<uint16_t>(Utf8StringLength(std::string_view(this->buf).substr(start, len)));
 		}
 	}
 
 	/* Move the remaining characters over the marker */
-	this->buf.erase(s - this->buf.begin(), len);
+	this->buf.erase(start, len);
 
-	if (backspace) this->caretpos -= len;
+	if (backspace) this->caretpos -= static_cast<uint16_t>(len);
 
 	this->UpdateStringIter();
 	this->UpdateWidth();
@@ -232,17 +232,11 @@ bool Textbuf::InsertClipboard()
  */
 void Textbuf::DeleteText(uint16_t from, uint16_t to, bool update)
 {
-	uint c = 0;
-	auto s = this->buf.begin() + from;
-	auto end = this->buf.begin() + to;
-	while (s < end) {
-		Utf8Consume(s);
-		c++;
-	}
+	assert(from <= to);
 
 	/* Strip marked characters from buffer. */
+	this->chars -= static_cast<uint16_t>(Utf8StringLength(std::string_view(this->buf).substr(from, to - from)));
 	this->buf.erase(from, to - from);
-	this->chars -= c;
 
 	auto fixup = [&](uint16_t &pos) {
 		if (pos <= from) return;
@@ -426,11 +420,13 @@ void Textbuf::Assign(const std::string_view text)
 
 	/* Make sure the name isn't too long for the text buffer in the number of
 	 * characters (not bytes). max_chars also counts the '\0' characters. */
-	auto iter = this->buf.begin();
-	for (size_t len = 1; len < this->max_chars && iter != this->buf.end(); ++len) Utf8Consume(iter);
+	Utf8View view(text);
+	auto it = view.begin();
+	const auto end = view.end();
+	for (size_t len = 1; len < this->max_chars && it != end; ++len) ++it;
 
-	if (iter != this->buf.end()) {
-		this->buf.erase(iter, this->buf.end());
+	if (it != end) {
+		this->buf.erase(it.GetByteOffset(), std::string::npos);
 	}
 
 	this->UpdateSize();