From b2c4115f3e5b36ff04b2f7ff1af4d7bce787a16f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Fri, 1 May 2020 11:49:11 +0200
Subject: [PATCH] grid: add per-cell combining characters

The data is *not* added to the cell struct, since that one is too
performance critical.

Instead, the data is added as a separate array in the row struct.

This allows our performance critical code paths that e.g. clear cells
to perform as before.
---
 grid.c     | 6 +++++-
 terminal.h | 6 ++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/grid.c b/grid.c
index 51d76191..9da36934 100644
--- a/grid.c
+++ b/grid.c
@@ -34,10 +34,13 @@ grid_row_alloc(int cols, bool initialize)
 
     if (initialize) {
         row->cells = calloc(cols, sizeof(row->cells[0]));
+        row->comb_chars = calloc(cols, sizeof(row->comb_chars[0]));
         for (size_t c = 0; c < cols; c++)
             row->cells[c].attrs.clean = 1;
-    } else
+    } else {
         row->cells = malloc(cols * sizeof(row->cells[0]));
+        row->comb_chars = malloc(cols * sizeof(row->comb_chars[0]));
+    }
 
     return row;
 }
@@ -48,6 +51,7 @@ grid_row_free(struct row *row)
     if (row == NULL)
         return;
 
+    free(row->comb_chars);
     free(row->cells);
     free(row);
 }
diff --git a/terminal.h b/terminal.h
index 7152bc23..e653e9be 100644
--- a/terminal.h
+++ b/terminal.h
@@ -77,10 +77,16 @@ struct damage {
     int lines;
 };
 
+struct combining_chars {
+    uint8_t count;
+    wchar_t chars[5];  /* TODO: do we need this many? */
+};
+
 struct row {
     struct cell *cells;
     bool dirty;
     bool linebreak;
+    struct combining_chars *comb_chars;
 };
 
 struct sixel {