Implement a Line class

kitty/data-types.c

@@ -9,6 +9,7 @@
 
 extern PyTypeObject LineBuf_Type;
 extern PyTypeObject Cursor_Type;
+extern PyTypeObject Line_Type;
 
 static PyMethodDef module_methods[] = {
     {NULL, NULL, 0, NULL}        /* Sentinel */
@@ -29,6 +30,7 @@ PyInit_fast_data_types(void) {
 
     if (PyType_Ready(&LineBuf_Type) < 0) return NULL;
     if (PyType_Ready(&Cursor_Type) < 0) return NULL;
+    if (PyType_Ready(&Line_Type) < 0) return NULL;
     m = PyModule_Create(&module);
     if (m == NULL) return NULL;
 
@@ -37,6 +39,8 @@ PyInit_fast_data_types(void) {
         PyModule_AddObject(m, "LineBuf", (PyObject *)&LineBuf_Type);
         Py_INCREF(&Cursor_Type);
         PyModule_AddObject(m, "Cursor", (PyObject *)&Cursor_Type);
+        Py_INCREF(&Line_Type);
+        PyModule_AddObject(m, "Line", (PyObject *)&Line_Type);
     }
 
     return m;

kitty/data-types.h

@@ -37,6 +37,16 @@ typedef unsigned int index_type;
 #define COL_SHIFT  32
 #define HAS_BG_MASK (0xFF << COL_SHIFT)
 
+typedef struct {
+    PyObject_HEAD
+
+    char_type *chars;
+    color_type *colors;
+    decoration_type *decoration_fg;
+    combining_type *combining_chars;
+    index_type xnum, ynum;
+} Line;
+
 
 typedef struct {
     PyObject_HEAD
@@ -45,6 +55,7 @@ typedef struct {
     index_type xnum, ynum, *line_map;
     index_type block_size;
     uint8_t *continued_map;
+    Line *line;
 
     // Pointers into buf
     char_type *chars;

kitty/line-buf.c

@@ -6,6 +6,7 @@
  */
 
 #include "data-types.h"
+extern PyTypeObject Line_Type;
 
 static inline void
 clear_chars_to_space(LineBuf* linebuf, index_type y) {
@@ -38,9 +39,10 @@ LineBuf_new(PyTypeObject *type, PyObject *args, PyObject UNUSED *kwds) {
         self->buf = PyMem_Calloc(xnum * ynum, CELL_SIZE);
         self->line_map = PyMem_Calloc(ynum, sizeof(index_type));
         self->continued_map = PyMem_Calloc(ynum, sizeof(uint8_t));
-        if (self->buf == NULL || self->line_map == NULL || self->continued_map == NULL) {
+        self->line = (Line*)PyType_GenericAlloc(&Line_Type, 0);
+        if (self->buf == NULL || self->line_map == NULL || self->continued_map == NULL || self->line == NULL) {
             PyErr_NoMemory();
-            PyMem_Free(self->buf); PyMem_Free(self->line_map); PyMem_Free(self->continued_map);
+            PyMem_Free(self->buf); PyMem_Free(self->line_map); PyMem_Free(self->continued_map); Py_XDECREF(self->line);
             Py_DECREF(self);
             self = NULL;
         } else {
@@ -48,6 +50,7 @@ LineBuf_new(PyTypeObject *type, PyObject *args, PyObject UNUSED *kwds) {
             self->colors = (color_type*)(self->chars + self->block_size);
             self->decoration_fg = (decoration_type*)(self->colors + self->block_size);
             self->combining_chars = (combining_type*)(self->decoration_fg + self->block_size);
+            self->line->xnum = xnum;
             for(index_type i = 0; i < ynum; i++) {
                 self->line_map[i] = i;
                 clear_chars_to_space(self, i);
@@ -61,44 +64,31 @@ LineBuf_new(PyTypeObject *type, PyObject *args, PyObject UNUSED *kwds) {
 static void
 LineBuf_dealloc(LineBuf* self) {
     PyMem_Free(self->buf); PyMem_Free(self->line_map); PyMem_Free(self->continued_map);
+    Py_XDECREF(self->line);
     Py_TYPE(self)->tp_free((PyObject*)self);
 }
 
 static PyObject*
-text_at(LineBuf* self, PyObject *args) {
+line(LineBuf *self, PyObject *y) {
-    index_type ynum, xnum, idx;
+    unsigned long idx = PyLong_AsUnsignedLong(y);
-    char_type ch;
+    if (idx >= self->ynum) {
-    combining_type cc;
+        PyErr_SetString(PyExc_ValueError, "Line number too large");
-    PyObject * ans;
+        return NULL;
-
-    if (!PyArg_ParseTuple(args, "II", &ynum, &xnum)) return NULL;
-    if (ynum >= self->ynum) { PyErr_SetString(PyExc_ValueError, "Line number out of bounds"); return NULL; }
-    if (xnum >= self->xnum) { PyErr_SetString(PyExc_ValueError, "Column number out of bounds"); return NULL; }
-
-    idx = xnum + ynum * self->xnum;
-    ch = self->chars[idx] & CHAR_MASK;
-    cc = self->combining_chars[idx];
-    if (cc == 0) {
-        ans = PyUnicode_New(1, ch);
-        if (ans == NULL) return PyErr_NoMemory();
-        PyUnicode_WriteChar(ans, 0, ch);
-    } else {
-        Py_UCS4 cc1 = cc & 0xFFFF, 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();
-        PyUnicode_WriteChar(ans, 0, ch);
-        PyUnicode_WriteChar(ans, 1, cc1);
-        if (cc2) PyUnicode_WriteChar(ans, 2, cc2);
     }
-
+    self->line->ynum = self->line_map[idx];
-    return ans;
+    size_t off = self->line->ynum * self->xnum;
+    self->line->chars = self->chars + off;
+    self->line->colors = self->colors + off;
+    self->line->decoration_fg = self->decoration_fg + off;
+    self->line->combining_chars = self->combining_chars + off;
+    Py_INCREF(self->line);
+    return (PyObject*)self->line;
 }
 
 // Boilerplate {{{
 static PyMethodDef LineBuf_methods[] = {
-    {"text_at", (PyCFunction)text_at, METH_VARARGS,
+    {"line", (PyCFunction)line, METH_O,
-     "Return the text in the specified cell"
+     "Return the specified line as a Line object. Note the Line Object is a live view into the underlying buffer. And only a single line object can be used at a time."
     },
     {NULL}  /* Sentinel */
 };

kitty/line.c

@@ -0,0 +1,100 @@
+/*
+ * line.c
+ * Copyright (C) 2016 Kovid Goyal <kovid at kovidgoyal.net>
+ *
+ * Distributed under terms of the GPL3 license.
+ */
+
+#include "data-types.h"
+
+
+static PyObject *
+new(PyTypeObject UNUSED *type, PyObject UNUSED *args, PyObject UNUSED *kwds) {
+    PyErr_SetString(PyExc_TypeError, "Line objects cannot be instantiated directly, create them using LineBuf.line()");
+    return NULL;
+}
+
+static void
+dealloc(LineBuf* self) {
+    Py_TYPE(self)->tp_free((PyObject*)self);
+}
+
+static PyObject *
+text_at(Line* self, PyObject *x) {
+    unsigned long xval = PyLong_AsUnsignedLong(x);
+    char_type ch;
+    combining_type cc;
+    PyObject *ans;
+
+    if (xval >= self->xnum) { PyErr_SetString(PyExc_ValueError, "Column number out of bounds"); return NULL; }
+
+    ch = self->chars[xval] & CHAR_MASK;
+    cc = self->combining_chars[xval];
+    if (cc == 0) {
+        ans = PyUnicode_New(1, ch);
+        if (ans == NULL) return PyErr_NoMemory();
+        PyUnicode_WriteChar(ans, 0, ch);
+    } else {
+        Py_UCS4 cc1 = cc & 0xFFFF, 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();
+        PyUnicode_WriteChar(ans, 0, ch);
+        PyUnicode_WriteChar(ans, 1, cc1);
+        if (cc2) PyUnicode_WriteChar(ans, 2, cc2);
+    }
+
+    return ans;
+}
+
+
+// Boilerplate {{{
+static PyMethodDef methods[] = {
+    {"text_at", (PyCFunction)text_at, METH_O,
+     "Return the text in the specified cell"
+    },
+    {NULL}  /* Sentinel */
+};
+
+PyTypeObject Line_Type = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    "fast_data_types.Line",
+    sizeof(Line),
+    0,                         /* tp_itemsize */
+    (destructor)dealloc,       /* tp_dealloc */
+    0,                         /* tp_print */
+    0,                         /* tp_getattr */
+    0,                         /* tp_setattr */
+    0,                         /* tp_reserved */
+    0,                         /* tp_repr */
+    0,                         /* tp_as_number */
+    0,                         /* tp_as_sequence */
+    0,                         /* tp_as_mapping */
+    0,                         /* tp_hash  */
+    0,                         /* tp_call */
+    0,                         /* tp_str */
+    0,                         /* tp_getattro */
+    0,                         /* tp_setattro */
+    0,                         /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT,        /* tp_flags */
+    "Lines",                   /* tp_doc */
+    0,                         /* tp_traverse */
+    0,                         /* tp_clear */
+    0,                         /* tp_richcompare */
+    0,                         /* tp_weaklistoffset */
+    0,                         /* tp_iter */
+    0,                         /* tp_iternext */
+    methods,                   /* tp_methods */
+    0,                         /* tp_members */
+    0,                         /* tp_getset */
+    0,                         /* tp_base */
+    0,                         /* tp_dict */
+    0,                         /* tp_descr_get */
+    0,                         /* tp_descr_set */
+    0,                         /* tp_dictoffset */
+    0,                         /* tp_init */
+    0,                         /* tp_alloc */
+    new,                       /* tp_new */
+};
+// }}
+

kitty_tests/datatypes.py

@@ -16,12 +16,13 @@ class TestDataTypes(BaseTest):
     def test_line_buf(self):
         lb = LineBuf(2, 3)
         for y in range(2):
+            line = lb.line(y)
             for x in range(3):
-                self.ae(lb.text_at(y, x), ' ')
+                self.ae(line.text_at(x), ' ')
         with self.assertRaises(ValueError):
-            lb.text_at(1, 5)
+            lb.line(5)
         with self.assertRaises(ValueError):
-            lb.text_at(5, 1)
+            lb.line(0).text_at(5)
 
     def test_line_ops(self):
         t = 'Testing with simple text'

setup.py

@@ -68,4 +68,4 @@ if __name__ == '__main__':
     if sys.version_info < (3, 5):
         raise SystemExit('python >= 3.5 required')
     init_env()
-    compile_c_extension('kitty/fast_data_types', 'kitty/data-types.c', 'kitty/line-buf.c', 'kitty/cursor.c')
+    compile_c_extension('kitty/fast_data_types', 'kitty/line.c', 'kitty/data-types.c', 'kitty/line-buf.c', 'kitty/cursor.c')