From 85076d30121291a8d56fa68b29c21a47f0e59e2d Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 1 Nov 2016 19:04:38 +0530
Subject: [PATCH] Implement add combining char

---
 kitty/data-types.h       |  2 ++
 kitty/line.c             | 24 +++++++++++++++++++++---
 kitty_tests/datatypes.py | 11 ++++++++++-
 3 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/kitty/data-types.h b/kitty/data-types.h
index 8f3b1c88a..d5c0211ac 100644
--- a/kitty/data-types.h
+++ b/kitty/data-types.h
@@ -36,6 +36,8 @@ typedef unsigned int index_type;
 #define COL_MASK 0xFFFFFFFF
 #define COL_SHIFT  32
 #define HAS_BG_MASK (0xFF << COL_SHIFT)
+#define CC_MASK 0xFFFF
+#define CC_SHIFT 16
 
 typedef struct {
     PyObject_HEAD
diff --git a/kitty/line.c b/kitty/line.c
index 9b462cdfa..03fda0e73 100644
--- a/kitty/line.c
+++ b/kitty/line.c
@@ -35,7 +35,7 @@ text_at(Line* self, PyObject *x) {
         if (ans == NULL) return PyErr_NoMemory();
         PyUnicode_WriteChar(ans, 0, ch);
     } else {
-        Py_UCS4 cc1 = cc & 0xFFFF, cc2 = cc >> 16;
+        Py_UCS4 cc1 = cc & CC_MASK, cc2 = cc >> 16;
         Py_UCS4 maxc = (ch > cc1) ? MAX(ch, cc2) : MAX(cc1, cc2);
         ans = PyUnicode_New(cc2 ? 3 : 2, maxc);
         if (ans == NULL) return PyErr_NoMemory();
@@ -59,7 +59,7 @@ as_unicode(Line* self) {
         char_type ch = self->chars[i] & CHAR_MASK;
         char_type cc = self->combining_chars[i];
         buf[n++] = ch & CHAR_MASK;
-        Py_UCS4 cc1 = cc & 0xFFFF, cc2;
+        Py_UCS4 cc1 = cc & CC_MASK, cc2;
         if (cc1) {
             buf[n++] = cc1;
             cc2 = cc >> 16;
@@ -71,10 +71,28 @@ as_unicode(Line* self) {
     return ans;
 }
 
+static PyObject*
+add_combining_char(Line* self, PyObject *args) {
+    int new_char;
+    unsigned int x;
+    if (!PyArg_ParseTuple(args, "IC", &x, &new_char)) return NULL;
+    if (x >= self->xnum) {
+        PyErr_SetString(PyExc_ValueError, "Column index out of bounds");
+        return NULL;
+    }
+    combining_type c = self->combining_chars[x];
+    if (c & CC_MASK) self->combining_chars[x] = (c & CC_MASK) | ( (new_char & CC_MASK) << CC_SHIFT );
+    else self->combining_chars[x] = new_char & CC_MASK;
+    Py_RETURN_NONE;
+}
+
 // Boilerplate {{{
 static PyMethodDef methods[] = {
     {"text_at", (PyCFunction)text_at, METH_O,
-     "Return the text in the specified cell"
+     "text_at(x) -> Return the text in the specified cell"
+    },
+    {"add_combining_char", (PyCFunction)add_combining_char, METH_VARARGS,
+     "add_combining_char(x, ch) -> Add the specified character as a combining char to the specified cell."
     },
     {NULL}  /* Sentinel */
 };
diff --git a/kitty_tests/datatypes.py b/kitty_tests/datatypes.py
index 16e278e1e..babddb045 100644
--- a/kitty_tests/datatypes.py
+++ b/kitty_tests/datatypes.py
@@ -13,7 +13,7 @@ from kitty.fast_data_types import LineBuf
 
 class TestDataTypes(BaseTest):
 
-    def test_line_buf(self):
+    def test_line(self):
         lb = LineBuf(2, 3)
         for y in range(2):
             line = lb.line(y)
@@ -24,6 +24,15 @@ class TestDataTypes(BaseTest):
             lb.line(5)
         with self.assertRaises(ValueError):
             lb.line(0).text_at(5)
+        l = lb.line(0)
+        l.add_combining_char(0, '1')
+        self.ae(l.text_at(0), ' 1')
+        l.add_combining_char(0, '2')
+        self.ae(l.text_at(0), ' 12')
+        l.add_combining_char(0, '3')
+        self.ae(l.text_at(0), ' 13')
+        self.ae(l.text_at(1), ' ')
+        self.ae(str(l), ' 13  ')
 
     def test_line_ops(self):
         t = 'Testing with simple text'