core: do not display non printable chars, fix function utf8_char_size_screen

Now the function utf8_char_size_screen can return -1 when the char is not
printable.

It has a specific behavior for some chars:

- U+0009: value of option weechat.look.tab_width
- U+0001 to U+001F (except U+0009): 1
- U+00AD (soft hyphen): -1
- U+200B (zero width space): -1

2 files changed, 46 insertions, 10 deletions

diff --git a/tests/unit/core/test-core-command.cpp b/tests/unit/core/test-core-command.cpp
index 75216ebbf..7293b9f50 100644
--- a/tests/unit/core/test-core-command.cpp
+++ b/tests/unit/core/test-core-command.cpp
@@ -151,9 +151,8 @@ TEST(CoreCommand, Debug)
 {
     const char *command_debug_unicode =
         "/debug unicode "
-        "\u00AD"  /* soft hyphen */
         "\u00E9"  /* é */
-        "\u200B"  /* zero width space */
+        "\u26C4"  /* ⛄ (snowman without snow) */
         "";
 
     /* test command "/debug list" */
@@ -215,9 +214,8 @@ TEST(CoreCommand, Debug)
 
     /* test command "/debug unicode" */
     WEE_CMD_CORE(command_debug_unicode);
-    WEE_CHECK_MSG_CORE("  \"\u00AD\" (U+00AD, 173, 0xC2 0xAD): 2 / 1, 1 / 1, 1, 1, 1");
     WEE_CHECK_MSG_CORE("  \"\u00E9\" (U+00E9, 233, 0xC3 0xA9): 2 / 1, 1 / 1, 1, 1, 1");
-    WEE_CHECK_MSG_CORE("  \"\u200B\" (U+200B, 8203, 0xE2 0x80 0x8B): 3 / 1, 1 / 0, 0, 0, 0");
+    WEE_CHECK_MSG_CORE("  \"\u26C4\" (U+26C4, 9924, 0xE2 0x9B 0x84): 3 / 1, 1 / 2, 2, 2, 2");
 
     /* test command "/debug windows" */
     /* TODO: write tests */
diff --git a/tests/unit/core/test-core-utf8.cpp b/tests/unit/core/test-core-utf8.cpp
index 2bcb6f3f0..26f42bde2 100644
--- a/tests/unit/core/test-core-utf8.cpp
+++ b/tests/unit/core/test-core-utf8.cpp
@@ -45,6 +45,30 @@ extern "C"
     }
 
 /*
+ * delete:
+ *   []
+ *   U+007F (127)
+ *   UTF-8: 1 byte = 0x7F
+ */
+#define UNICODE_DELETE "\u007f"
+
+/*
+ * next line:
+ *   []
+ *   U+0085 (133)
+ *   UTF-8: 2 bytes = 0xC2 0x85
+ */
+#define UNICODE_NEXT_LINE "\u0085"
+
+/*
+ * private use two:
+ *   [’]
+ *   U+0092 (146)
+ *   UTF-8: 2 bytes = 0xC2 0X92
+ */
+#define UNICODE_PRIVATE_USE_TWO "\u0092"
+
+/*
  * soft hyphen:
  *   [­]
  *   U+00AD (173)
@@ -474,6 +498,9 @@ TEST(CoreUtf8, Size)
     LONGS_EQUAL(2, utf8_char_size ("ë"));
     LONGS_EQUAL(3, utf8_char_size ("€"));
     LONGS_EQUAL(1, utf8_char_size ("\x01"));
+    LONGS_EQUAL(1, utf8_char_size (UNICODE_DELETE));
+    LONGS_EQUAL(2, utf8_char_size (UNICODE_NEXT_LINE));
+    LONGS_EQUAL(2, utf8_char_size (UNICODE_PRIVATE_USE_TWO));
     LONGS_EQUAL(2, utf8_char_size (UNICODE_SOFT_HYPHEN));
     LONGS_EQUAL(3, utf8_char_size (UNICODE_ZERO_WIDTH_SPACE));
     LONGS_EQUAL(3, utf8_char_size (UNICODE_SNOWMAN));
@@ -495,13 +522,16 @@ TEST(CoreUtf8, Size)
     LONGS_EQUAL(1, utf8_char_size_screen ("ë"));
     LONGS_EQUAL(1, utf8_char_size_screen ("€"));
     LONGS_EQUAL(1, utf8_char_size_screen ("\x01"));
-    LONGS_EQUAL(1, utf8_char_size_screen (UNICODE_SOFT_HYPHEN));
-    LONGS_EQUAL(0, utf8_char_size_screen (UNICODE_ZERO_WIDTH_SPACE));
+    LONGS_EQUAL(-1, utf8_char_size_screen (UNICODE_DELETE));
+    LONGS_EQUAL(-1, utf8_char_size_screen (UNICODE_NEXT_LINE));
+    LONGS_EQUAL(-1, utf8_char_size_screen (UNICODE_PRIVATE_USE_TWO));
+    LONGS_EQUAL(-1, utf8_char_size_screen (UNICODE_SOFT_HYPHEN));
+    LONGS_EQUAL(-1, utf8_char_size_screen (UNICODE_ZERO_WIDTH_SPACE));
     LONGS_EQUAL(2, utf8_char_size_screen (UNICODE_SNOWMAN));
     LONGS_EQUAL(2, utf8_char_size_screen (UNICODE_CJK_YELLOW));
     LONGS_EQUAL(2, utf8_char_size_screen (UNICODE_HAN_CHAR));
     /* ë as iso-8859-15: invalid UTF-8 */
-    LONGS_EQUAL(1, utf8_char_size_screen ("\xeb"));
+    LONGS_EQUAL(-1, utf8_char_size_screen ("\xeb"));
     /* ël as iso-8859-15: invalid UTF-8 */
     LONGS_EQUAL(1, utf8_char_size_screen ("\xebl"));
     /* ëlm as iso-8859-15: invalid UTF-8 */
@@ -517,6 +547,9 @@ TEST(CoreUtf8, Size)
     LONGS_EQUAL(1, utf8_strlen ("€"));
     LONGS_EQUAL(1, utf8_strlen ("\x01"));
     LONGS_EQUAL(4, utf8_strlen (UTF8_NOEL_VALID));
+    LONGS_EQUAL(1, utf8_strlen (UNICODE_DELETE));
+    LONGS_EQUAL(1, utf8_strlen (UNICODE_NEXT_LINE));
+    LONGS_EQUAL(1, utf8_strlen (UNICODE_PRIVATE_USE_TWO));
     LONGS_EQUAL(1, utf8_strlen (UNICODE_SOFT_HYPHEN));
     LONGS_EQUAL(1, utf8_strlen (UNICODE_ZERO_WIDTH_SPACE));
     LONGS_EQUAL(1, utf8_strlen (UNICODE_SNOWMAN));
@@ -537,13 +570,18 @@ TEST(CoreUtf8, Size)
     LONGS_EQUAL(1, utf8_strlen_screen ("A"));
     LONGS_EQUAL(1, utf8_strlen_screen ("ë"));
     LONGS_EQUAL(1, utf8_strlen_screen ("€"));
-    LONGS_EQUAL(1, utf8_strlen_screen ("\x7f"));
     LONGS_EQUAL(1, utf8_strlen_screen ("\x01"));
     LONGS_EQUAL(4, utf8_strlen_screen (UTF8_NOEL_VALID));
     LONGS_EQUAL(4, utf8_strlen_screen ("abc\x01"));
     LONGS_EQUAL(8, utf8_strlen_screen ("a" "\x01" UTF8_NOEL_VALID "\x02" "b"));
-    LONGS_EQUAL(1, utf8_strlen_screen (UNICODE_SOFT_HYPHEN));
-    LONGS_EQUAL(5, utf8_strlen_screen ("a" "\x01" UNICODE_SOFT_HYPHEN "\x02" "b"));
+    LONGS_EQUAL(0, utf8_strlen_screen (UNICODE_DELETE));
+    LONGS_EQUAL(4, utf8_strlen_screen ("a" "\x01" UNICODE_DELETE "\x02" "b"));
+    LONGS_EQUAL(0, utf8_strlen_screen (UNICODE_NEXT_LINE));
+    LONGS_EQUAL(4, utf8_strlen_screen ("a" "\x01" UNICODE_NEXT_LINE "\x02" "b"));
+    LONGS_EQUAL(0, utf8_strlen_screen (UNICODE_PRIVATE_USE_TWO));
+    LONGS_EQUAL(4, utf8_strlen_screen ("a" "\x01" UNICODE_PRIVATE_USE_TWO "\x02" "b"));
+    LONGS_EQUAL(0, utf8_strlen_screen (UNICODE_SOFT_HYPHEN));
+    LONGS_EQUAL(4, utf8_strlen_screen ("a" "\x01" UNICODE_SOFT_HYPHEN "\x02" "b"));
     LONGS_EQUAL(0, utf8_strlen_screen (UNICODE_ZERO_WIDTH_SPACE));
     LONGS_EQUAL(4, utf8_strlen_screen ("a" "\x01" UNICODE_ZERO_WIDTH_SPACE "\x02" "b"));
     LONGS_EQUAL(2, utf8_strlen_screen (UNICODE_SNOWMAN));