[pango/hyphen-log-attr: 1/4] Add hyphens to log attrs

[Matthias Clasen <matthiasc src gnome org>]

commit edf85c9a2dc5861fa8645a58a1c3f6e230ea0942
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Aug 24 22:41:15 2021 -0400

    Add hyphens to log attrs
    
    The code computing this is much better off in break.c,
    so move it there, and keep the information in the
    log attr array.

 pango/break.c       | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 pango/pango-break.h |   2 +
 2 files changed, 104 insertions(+), 3 deletions(-)
---
diff --git a/pango/break.c b/pango/break.c
index c55d5f22..11c0eb2f 100644
--- a/pango/break.c
+++ b/pango/break.c
@@ -249,6 +249,8 @@ default_break (const char    *text,
   gint last_sentence_start = -1;
   gint last_non_space = -1;
 
+  gboolean prev_space_or_hyphen;
+
   gboolean almost_done = FALSE;
   gboolean done = FALSE;
 
@@ -261,6 +263,7 @@ default_break (const char    *text,
   prev_prev_break_type = G_UNICODE_BREAK_UNKNOWN;
   prev_wc = 0;
   prev_jamo = NO_JAMO;
+  prev_space_or_hyphen = FALSE;
 
   if (length == 0 || *text == '\0')
     {
@@ -291,6 +294,8 @@ default_break (const char    *text,
       /* Emoji extended pictographics */
       gboolean is_Extended_Pictographic;
 
+      PangoScript script;
+
       wc = next_wc;
       break_type = next_break_type;
 
@@ -533,17 +538,16 @@ default_break (const char    *text,
        prev_GB_type = GB_type;
       }
 
+      script = (PangoScript)g_unichar_get_script (wc);
+
       /* ---- UAX#29 Word Boundaries ---- */
       {
        is_word_boundary = FALSE;
        if (is_grapheme_boundary ||
            G_UNLIKELY(wc >=0x1F1E6 && wc <=0x1F1FF)) /* Rules WB3 and WB4 */
          {
-           PangoScript script;
            WordBreakType WB_type;
 
-           script = (PangoScript)g_unichar_get_script (wc);
-
            /* Find the WordBreakType of wc */
            WB_type = WB_Other;
 
@@ -1552,7 +1556,68 @@ default_break (const char    *text,
            attrs[i - 1].is_white) {
            last_sentence_start++;
           }
+      }
+
+      /* --- Hyphens --- */
+      {
+        gboolean insert_hyphens;
+        gboolean space_or_hyphen = FALSE;
+
+        switch ((int)script)
+          {
+          case PANGO_SCRIPT_COMMON:
+          case PANGO_SCRIPT_HAN:
+          case PANGO_SCRIPT_HANGUL:
+          case PANGO_SCRIPT_HIRAGANA:
+          case PANGO_SCRIPT_KATAKANA:
+            insert_hyphens = FALSE;
+            break;
+          default:
+            insert_hyphens = TRUE;
+            break;
+          }
+
+        switch ((int)type)
+          {
+          case G_UNICODE_SPACE_SEPARATOR:
+          case G_UNICODE_LINE_SEPARATOR:
+          case G_UNICODE_PARAGRAPH_SEPARATOR:
+            space_or_hyphen = TRUE;
+            break;
+          case G_UNICODE_CONTROL:
+            if (wc == '\t' || wc == '\n' || wc == '\r' || wc == '\f')
+              space_or_hyphen = TRUE;
+            break;
+          default:
+            break;
+          }
+
+        if (!space_or_hyphen)
+          {
+            if (wc == '-'    || /* Hyphen-minus */
+                wc == 0x058a || /* Armenian hyphen */
+                wc == 0x1400 || /* Canadian syllabics hyphen */
+                wc == 0x1806 || /* Mongolian todo hyphen */
+                wc == 0x2010 || /* Hyphen */
+                wc == 0x2027 || /* Hyphenation point */
+                wc == 0x2e17 || /* Double oblique hyphen */
+                wc == 0x2e40 || /* Double hyphen */
+                wc == 0x30a0 || /* Katakana-Hiragana double hyphen */
+                wc == 0xfe63 || /* Small hyphen-minus */
+                wc == 0xff0d)   /* Fullwidth hyphen-minus */
+              space_or_hyphen = TRUE;
+          }
+
+        if (attrs[i].is_word_boundary)
+          attrs[i].needs_hyphen = FALSE;
+        else if (prev_space_or_hyphen)
+          attrs[i].needs_hyphen = FALSE;
+        else if (space_or_hyphen)
+          attrs[i].needs_hyphen = FALSE;
+        else
+          attrs[i].needs_hyphen = insert_hyphens;
 
+        prev_space_or_hyphen = space_or_hyphen;
       }
 
       prev_wc = wc;
@@ -1633,16 +1698,21 @@ break_attrs (const char   *text,
              int           log_attrs_len)
 {
   PangoAttrList list;
+  PangoAttrList hyphens;
   PangoAttrIterator iter;
   GSList *l;
 
   _pango_attr_list_init (&list);
+  _pango_attr_list_init (&hyphens);
+
   for (l = attributes; l; l = l->next)
     {
       PangoAttribute *attr = l->data;
 
       if (attr->klass->type == PANGO_ATTR_ALLOW_BREAKS)
         pango_attr_list_insert (&list, pango_attribute_copy (attr));
+      if (attr->klass->type == PANGO_ATTR_INSERT_HYPHENS)
+        pango_attr_list_insert (&hyphens, pango_attribute_copy (attr));
     }
 
   if (!_pango_attr_list_has_attributes (&list))
@@ -1681,7 +1751,36 @@ break_attrs (const char   *text,
   } while (pango_attr_iterator_next (&iter));
 
   _pango_attr_iterator_destroy (&iter);
+
+  _pango_attr_list_get_iterator (&hyphens, &iter);
+  do {
+    const PangoAttribute *attr = pango_attr_iterator_get (&iter, PANGO_ATTR_INSERT_HYPHENS);
+
+    if (attr && ((PangoAttrInt*)attr)->value == 0)
+      {
+        int start, end;
+        int start_pos, end_pos;
+        int pos;
+
+        pango_attr_iterator_range (&iter, &start, &end);
+        if (start < offset)
+          start_pos = 0;
+        else
+          start_pos = g_utf8_pointer_to_offset (text, text + start - offset);
+        if (end >= offset + length)
+          end_pos = log_attrs_len;
+        else
+          end_pos = g_utf8_pointer_to_offset (text, text + end - offset);
+
+        for (pos = start_pos + 1; pos < end_pos; pos++)
+          {
+            log_attrs[pos].needs_hyphen = FALSE;
+          }
+      }
+  } while (pango_attr_iterator_next (&iter));
+
   _pango_attr_list_destroy (&list);
+  _pango_attr_list_destroy (&hyphens);
 
   return TRUE;
 }
diff --git a/pango/pango-break.h b/pango/pango-break.h
index a8e6c5b9..3ac52460 100644
--- a/pango/pango-break.h
+++ b/pango/pango-break.h
@@ -72,6 +72,7 @@ G_BEGIN_DECLS
  *   This flag is particularly useful when selecting text word-by-word. This flag
  *   implements Unicode's [Word Boundaries](http://www.unicode.org/reports/tr29/)
  *   semantics. (Since: 1.22)
+ * @needs_hyphen: when breaking lines before this char, insert a hyphen. Since: 1.50
  *
  * The `PangoLogAttr` structure stores information about the attributes of a
  * single character.
@@ -91,6 +92,7 @@ struct _PangoLogAttr
   guint backspace_deletes_character : 1;
   guint is_expandable_space         : 1;
   guint is_word_boundary            : 1;
+  guint needs_hyphen                : 1;
 };
 
 PANGO_DEPRECATED_IN_1_44