Add GdkArray

This is a scary idea where you #define a bunch of preprocessor values
and then #include "gdkarrayimpl.c" and end up with a dynamic array for
that data type.

See https://en.wikipedia.org/wiki/X_Macro for what's going on.

What are the advantages over using GArray or GPtrArray?

 * It's typesafe
   Because it works like C++ templates, we can use the actual type of
   the object instead of having to use gpointer.

 * It's one less indirection
   instead of 2 indirections via self->array->data, this array is
   embedded, so self->array is the actual data, and just one indirection
   away. This is pretty irrelevant in general, but can be very noticable
   in tight loops.

 * It's all inline
   Because the whole API is defined as static inline functions, the
   compiler has full access to everything and can (and does) optimize
   out unnecessary calls, thereby speeding up some operations quite
   significantly, when full optimizations are enabled.

 * It has more features
   In particular preallocation allows for avoiding malloc() calls, which
   can again speed up tight loops a lot.
   But there's also splice(), which is very useful when used with
   listmodels.

gdk/gdkarrayimpl.c

@@ -0,0 +1,219 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include <glib.h>
+
+G_BEGIN_DECLS
+
+#ifndef GDK_ARRAY_TYPE_NAME
+#define GDK_ARRAY_TYPE_NAME GdkArray
+#endif
+
+#ifndef GDK_ARRAY_NAME
+#define GDK_ARRAY_NAME gdk_array
+#endif
+
+#ifndef GDK_ARRAY_ELEMENT_TYPE
+#define GDK_ARRAY_ELEMENT_TYPE gpointer
+#endif
+
+#ifdef GDK_ARRAY_PREALLOC
+#if GDK_ARRAY_PREALLOC == 0
+#undef GDK_ARRAY_PREALLOC
+#endif
+#endif
+
+/* make this readable */
+#define _T_ GDK_ARRAY_ELEMENT_TYPE
+#define GdkArray GDK_ARRAY_TYPE_NAME
+#define gdk_array_paste_more(GDK_ARRAY_NAME, func_name) GDK_ARRAY_NAME ## _ ## func_name
+#define gdk_array_paste(GDK_ARRAY_NAME, func_name) gdk_array_paste_more (GDK_ARRAY_NAME, func_name)
+#define gdk_array(func_name) gdk_array_paste (GDK_ARRAY_NAME, func_name)
+
+typedef struct GdkArray GdkArray;
+
+struct GdkArray
+{
+  _T_ *start;
+  _T_ *end;
+  _T_ *end_allocation;
+#ifdef GDK_ARRAY_PREALLOC
+  _T_ preallocated[GDK_ARRAY_PREALLOC];
+#endif
+};
+
+/* no G_GNUC_UNUSED here, if you don't use an array type, remove it. */
+static inline void
+gdk_array(init) (GdkArray *self)
+{
+#ifdef GDK_ARRAY_PREALLOC
+  self->start = self->preallocated;
+  self->end = self->start;
+  self->end_allocation = self->start + GDK_ARRAY_PREALLOC;
+#else
+  self->start = NULL;
+  self->end = NULL;
+  self->end_allocation = NULL;
+#endif
+}
+
+static inline void
+gdk_array(free_elements) (_T_ *start,
+                          _T_ *end)
+{
+#ifdef GDK_ARRAY_FREE_FUNC
+  _T_ *e;
+  for (e = start; e < end; e++)
+    GDK_ARRAY_FREE_FUNC (*e);
+#endif
+}
+
+/* no G_GNUC_UNUSED here */
+static inline void
+gdk_array(clear) (GdkArray *self)
+{
+  gdk_array(free_elements) (self->start, self->end);
+
+#ifdef GDK_ARRAY_PREALLOC
+  if (self->start != self->preallocated)
+#endif
+    g_free (self->start);
+  gdk_array(init) (self);
+}
+
+G_GNUC_UNUSED static inline _T_ *
+gdk_array(get_data) (GdkArray *self)
+{
+  return self->start;
+}
+
+G_GNUC_UNUSED static inline _T_ *
+gdk_array(index) (GdkArray *self,
+                  gsize      pos)
+{
+  return self->start + pos;
+}
+
+G_GNUC_UNUSED static inline gsize
+gdk_array(get_capacity) (GdkArray *self)
+{
+  return self->end_allocation - self->start;
+}
+
+G_GNUC_UNUSED static inline gsize
+gdk_array(get_size) (GdkArray *self)
+{
+  return self->end - self->start;
+}
+
+G_GNUC_UNUSED static inline gboolean
+gdk_array(is_empty) (GdkArray *self)
+{
+  return self->end == self->start;
+}
+
+G_GNUC_UNUSED static void
+gdk_array(reserve) (GdkArray *self,
+                    gsize      n)
+{
+  gsize new_size, size;
+
+  if (n <= gdk_array(get_capacity) (self))
+    return;
+
+  size = gdk_array(get_size) (self);
+  new_size = 1 << g_bit_storage (MAX (n, 16) - 1);
+
+#ifdef GDK_ARRAY_PREALLOC
+  if (self->start == self->preallocated)
+    {
+      self->start = g_new (_T_, new_size);
+      memcpy (self->start, self->preallocated, sizeof (_T_) * size);
+    }
+  else
+#endif
+    self->start = g_renew (_T_, self->start, new_size);
+
+  self->end = self->start + size;
+  self->end_allocation = self->start + new_size;
+}
+
+G_GNUC_UNUSED static void
+gdk_array(splice) (GdkArray *self,
+                   gsize      pos,
+                   gsize      removed,
+                   _T_       *additions,
+                   gsize      added)
+{
+  gssize size = gdk_array(get_size) (self);
+
+  g_assert (pos + removed <= size);
+
+  gdk_array(free_elements) (gdk_array(index) (self, pos),
+                            gdk_array(index) (self, pos + removed));
+
+  gdk_array(reserve) (self, size - removed + added);
+
+  if (pos + removed < size && removed != added)
+    memmove (gdk_array(index) (self, pos + added),
+             gdk_array(index) (self, pos + removed),
+             (size - pos - removed) * sizeof (_T_));
+
+  if (added)
+    memcpy (gdk_array(index) (self, pos),
+            additions,
+            added * sizeof (_T_));
+
+  /* might overflow, but does the right thing */
+  self->end += added - removed;
+}
+
+G_GNUC_UNUSED static void
+gdk_array(append) (GdkArray *self,
+                   _T_        value)
+{
+  gdk_array(splice) (self, 
+                     gdk_array(get_size) (self),
+                     0,
+                     &value,
+                     1);
+}
+
+G_GNUC_UNUSED static _T_ 
+gdk_array(get) (GdkArray *self,
+                gsize      pos)
+{
+  return *gdk_array(index) (self, pos);
+}
+
+
+#ifndef GDK_ARRAY_NO_UNDEF
+
+#undef _T_
+#undef GdkArray
+#undef gdk_array_paste_more
+#undef gdk_array_paste
+#undef gdk_array
+
+#undef GDK_ARRAY_PREALLOC
+#undef GDK_ARRAY_ELEMENT_TYPE
+#undef GDK_ARRAY_NAME
+#undef GDK_ARRAY_TYPE_NAME
+
+#endif

testsuite/gdk/array.c

@@ -0,0 +1,69 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include <locale.h>
+
+#include <gtk/gtk.h>
+
+static void
+int_free_func (int data)
+{
+}
+
+#define GDK_ARRAY_ELEMENT_TYPE int
+#define GDK_ARRAY_NAME int_array
+#define GDK_ARRAY_TYPE_NAME IntVector
+#include "arrayimpl.c"
+
+#define GDK_ARRAY_ELEMENT_TYPE int
+#define GDK_ARRAY_NAME pre_int_array
+#define GDK_ARRAY_TYPE_NAME PreIntVector
+#define GDK_ARRAY_PREALLOC 100
+#include "arrayimpl.c"
+
+#define GDK_ARRAY_ELEMENT_TYPE int
+#define GDK_ARRAY_NAME free_int_array
+#define GDK_ARRAY_TYPE_NAME FreeIntVector
+#define GDK_ARRAY_FREE_FUNC int_free_func
+#include "arrayimpl.c"
+
+#define GDK_ARRAY_ELEMENT_TYPE int
+#define GDK_ARRAY_NAME pre_free_int_array
+#define GDK_ARRAY_TYPE_NAME PreFreeIntVector
+#define GDK_ARRAY_PREALLOC 100
+#define GDK_ARRAY_FREE_FUNC int_free_func
+#include "arrayimpl.c"
+
+int
+main (int argc, char *argv[])
+{
+  g_test_init (&argc, &argv, NULL);
+  setlocale (LC_ALL, "C");
+
+  g_test_add_func ("/intarray/simple", int_array_test_simple);
+  g_test_add_func ("/intarray/prealloc/simple", pre_int_array_test_simple);
+  g_test_add_func ("/intarray/freefunc/simple", free_int_array_test_simple);
+  g_test_add_func ("/intarray/prealloc_freefunc_simple", pre_free_int_array_test_simple);
+  g_test_add_func ("/intarray/splice", int_array_test_splice);
+  g_test_add_func ("/intarray/prealloc/splice", pre_int_array_test_splice);
+  g_test_add_func ("/intarray/freefunc/splice", free_int_array_test_splice);
+  g_test_add_func ("/intarray/prealloc_freefunc_splice", pre_free_int_array_test_splice);
+
+  return g_test_run ();
+}

testsuite/gdk/arrayimpl.c

@@ -0,0 +1,108 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include <gtk/gtk.h>
+
+#define GDK_ARRAY_NO_UNDEF
+
+#include "../../gdk/gdkarrayimpl.c"
+
+static void
+gdk_array(test_simple) (void)
+{
+  GdkArray v;
+  gsize i;
+
+  gdk_array(init) (&v);
+
+  for (i = 0; i < 1000; i++)
+    {
+      g_assert_cmpint (gdk_array(get_size) (&v), ==, i);
+      g_assert_cmpint (gdk_array(get_size) (&v), <=, gdk_array(get_capacity) (&v));
+      gdk_array(append) (&v, i);
+    }
+  g_assert_cmpint (gdk_array(get_size) (&v), ==, i);
+  g_assert_cmpint (gdk_array(get_size) (&v), <=, gdk_array(get_capacity) (&v));
+
+  for (i = 0; i < 1000; i++)
+    {
+      g_assert_cmpint (gdk_array(get) (&v, i), ==, i);
+    }
+
+  gdk_array(clear) (&v);
+}
+
+static void
+gdk_array(test_splice) (void)
+{
+  GdkArray v;
+  gsize i, j, sum;
+  gsize pos, add, remove;
+  int additions[4] = { 0, 1, 2, 3 };
+
+  gdk_array(init) (&v);
+  sum = 0;
+
+  for (i = 0; i < 1000; i++)
+    {
+      gsize old_size = gdk_array(get_size) (&v);
+
+      pos = g_random_int_range (0, old_size + 1);
+      g_assert (pos <= old_size);
+      remove = g_random_int_range (0, 4);
+      remove = MIN (remove, old_size - pos);
+      add = g_random_int_range (0, 4);
+
+      for (j = 0; j < remove; j++)
+        sum -= gdk_array(get) (&v, pos + j);
+      for (j = 0; j < add; j++)
+        sum += ++additions[j];
+
+      gdk_array(splice) (&v, pos, remove, additions, add);
+      {
+        gsize total = 0;
+        for (j = 0; j < gdk_array(get_size) (&v); j++)
+          total += gdk_array(get) (&v, j);
+        g_assert_cmpint (total, ==, sum);
+      }
+
+      g_assert_cmpint (gdk_array(get_size) (&v), ==, old_size + add - remove);
+      g_assert_cmpint (gdk_array(get_size) (&v), <=, gdk_array(get_capacity) (&v));
+      for (j = 0; j < add; j++)
+        g_assert_cmpint (gdk_array(get) (&v, pos + j), ==, additions[j]);
+    }
+
+  for (i = 0; i < gdk_array(get_size) (&v); i++)
+    {
+      sum -= gdk_array(get) (&v, i);
+    }
+  g_assert_cmpint (sum, ==, 0);
+}
+
+#undef _T_
+#undef GdkArray
+#undef gdk_array_paste_more
+#undef gdk_array_paste
+#undef gdk_array
+
+#undef GDK_ARRAY_PREALLOC
+#undef GDK_ARRAY_ELEMENT_TYPE
+#undef GDK_ARRAY_NAME
+#undef GDK_ARRAY_TYPE_NAME
+

testsuite/gdk/meson.build

@@ -2,6 +2,7 @@ testexecdir = join_paths(installed_test_bindir, 'gdk')
 testdatadir = join_paths(installed_test_datadir, 'gdk')
 
 tests = [
+  'array',
   'cairo',
   'clipboard',
   'display',