send invalid codepoints as U+FFFD

termbox2.h

@@ -1535,6 +1535,7 @@ static int send_sgr(uint32_t fg, uint32_t bg, int fg_is_default,
 static int send_cursor_if(int x, int y);
 static int send_char(int x, int y, uint32_t ch);
 static int send_cluster(int x, int y, uint32_t *ch, size_t nch);
+static int is_valid_codepoint(uint32_t ch);
 static int convert_num(uint32_t num, char *buf);
 static int cell_cmp(struct tb_cell *a, struct tb_cell *b);
 static int cell_copy(struct tb_cell *dst, struct tb_cell *src);
@@ -3225,9 +3226,13 @@ static int send_cluster(int x, int y, uint32_t *ch, size_t nch) {
     for (i = 0; i < (int)nch; i++) {
         uint32_t ch32 = *(ch + i);
         int chu8_len;
-        if (ch32 == 0) { // replace null with space (from termbox 19dbee5)
+        if (ch32 == 0) {
+            // Replace NULL with space (from termbox 19dbee5)
             chu8_len = 1;
             chu8[0] = ' ';
+        } else if (!is_valid_codepoint(ch32)) {
+            // Replace invalid codepoint with U+FFFD
+            chu8_len = tb_utf8_unicode_to_char(chu8, 0xfffd);
         } else {
             chu8_len = tb_utf8_unicode_to_char(chu8, ch32);
         }
@@ -3237,6 +3242,15 @@ static int send_cluster(int x, int y, uint32_t *ch, size_t nch) {
     return TB_OK;
 }
 
+static int is_valid_codepoint(uint32_t ch) {
+    return (
+           ch > 0x10ffff                  // out of range
+        || ((ch & 0xfffe) == 0xfffe)      // noncharacter
+        || (ch >= 0xfdd0 && ch <= 0xfdef) // noncharacter
+        || (ch >= 0xd800 && ch <= 0xdfff) // surrogate pair (UTF-16 only)
+    ) ? 0 : 1;
+}
+
 static int convert_num(uint32_t num, char *buf) {
     int i, l = 0;
     char ch;

tests/test_invalid_utf8/expected.ansi

@@ -1,5 +1,5 @@
 #5foo�
-
+#5�
 
 
 

tests/test_invalid_utf8/test.php

@@ -2,7 +2,10 @@
 declare(strict_types=1);
 
 $test->ffi->tb_init();
-$test->ffi->tb_print_ex(0, 0, 0, 0, NULL, "foo\xc2\x00password");
+
+$test->ffi->tb_print_ex(0, 0, 0, 0, NULL, "foo\xc2\x00password"); // stop at NULL
+$test->ffi->tb_set_cell(0, 1, 0xffff, 0, 0); // invalid codepoint
+
 $test->ffi->tb_present();
 
 $test->screencap();