From f7246d83d2f43e0088e2a01ff6305ac7e25f21fe Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Sat, 5 Nov 2022 23:59:18 +0100
Subject: Fix possible crash on backspace in edit text with invalid utf8

---
 src/Text.cpp | 44 +++++++++++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 15 deletions(-)

(limited to 'src')

diff --git a/src/Text.cpp b/src/Text.cpp
index 192061f..0b6347d 100644
--- a/src/Text.cpp
+++ b/src/Text.cpp
@@ -510,21 +510,11 @@ namespace QuickMedia
                 if(emoji_codepoint_combined == "1f441-fe0f-200d-1f5e8-fe0f")
                     emoji_codepoint_combined = "1f441-200d-1f5e8";
 
-                std::string image_url;
-                bool image_local = false;
-                if(emoji_codepoint_combined != "1f3f3-fe0f-200d-26a7-fe0f") {
-                    image_url = "/usr/share/quickmedia/emoji/" + emoji_codepoint_combined + ".png";
-                    image_local = true;
-                } else {
-                    image_url = "/usr/share/quickmedia/images/troonjak.png";
-                    image_local = true;
-                }
-
                 text_element.create_text("E");
                 text_element.text_type = TextElement::TextType::EMOJI;
                 text_element.text = "E";
-                text_element.url = std::move(image_url);
-                text_element.local = image_local;
+                text_element.url = "/usr/share/quickmedia/emoji/" + emoji_codepoint_combined + ".png";
+                text_element.local = true;
                 text_element.size = { (int)vspace, (int)vspace };
                 text_element.text_num_bytes = emoji_byte_length;
                 text_elements.push_back(std::move(text_element));
@@ -602,6 +592,23 @@ namespace QuickMedia
     static mgl::vec2f vec2f_floor(mgl::vec2f value) {
         return mgl::vec2f((int)value.x, (int)value.y);
     }
+
+    static size_t utf8_get_num_codepoints(const char *str, size_t size) {
+        size_t codepoint_index = 0;
+        for(size_t i = 0; i < size;) {
+            unsigned char *cp = (unsigned char*)&str[i];
+            uint32_t codepoint;
+            size_t clen;
+            if(!mgl::utf8_decode(cp, size - i, &codepoint, &clen)) {
+                codepoint = *cp;
+                clen = 1;
+            }
+
+            i += clen;
+            ++codepoint_index;
+        }
+        return codepoint_index;
+    }
     
     void Text::updateGeometry(bool update_even_if_not_dirty) {
         if(dirtyText) {
@@ -1183,6 +1190,9 @@ namespace QuickMedia
             }
             else if(event.key.code == mgl::Keyboard::Backspace && caretIndex > 0)
             {
+                if(caretIndex < 0 || caretIndex > (int)vertices_linear.size())
+                    return;
+
                 const size_t str_index = get_string_index_from_caret_index(caretIndex);
                 if(str_index > 0 && str_index <= str.size()) {
                     const size_t codepoint_start = str_index - vertices_linear[caretIndex - 1].text_num_bytes;
@@ -1195,6 +1205,9 @@ namespace QuickMedia
             }
             else if(event.key.code == mgl::Keyboard::Delete && !caretAtEnd)
             {
+                if(caretIndex < 0 || caretIndex >= (int)vertices_linear.size())
+                    return;
+
                 const size_t str_index = get_string_index_from_caret_index(caretIndex);
                 const size_t codepoint_end = str_index + vertices_linear[caretIndex].text_num_bytes;
                 if(str_index < str.size() && codepoint_end <= str.size()) {
@@ -1266,10 +1279,11 @@ namespace QuickMedia
             std::vector<TextElement> new_text_elements;
             split_text_by_type(new_text_elements, stringToAdd);
             for(auto &text_element : new_text_elements) {
-                if(text_element.type == TextElement::Type::IMAGE || text_element.text_type == TextElement::TextType::EMOJI)
+                if(text_element.type == TextElement::Type::IMAGE || text_element.text_type == TextElement::TextType::EMOJI) {
                     caretIndex += 1;
-                else
-                    caretIndex += text_element.text_num_bytes;
+                } else {
+                    caretIndex += utf8_get_num_codepoints(text_element.text.data(), text_element.text.size());
+                }
             }
             dirty = true;
             dirtyText = true;
-- 
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