vnc: tight: stop using qdict for palette stuff

Profiling with callgrind seems to show that a lot of time is spent
in the palette code (mostly due to memory allocation and qdict to int
conversion).

This patch adds a VncPalette implementation. The palette is stored
in a hash table, like qdict, but which does way less memory allocations,
and doesn't suffer from the QObject overhead.

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 136 insertions, 0 deletions

diff --git a/ui/vnc-palette.c b/ui/vnc-palette.c
new file mode 100644
index 0000000..bff6445
--- /dev/null
+++ b/ui/vnc-palette.c
@@ -0,0 +1,136 @@
+/*
+ * QEMU VNC display driver: palette hash table
+ *
+ * From libvncserver/libvncserver/tight.c
+ * Copyright (C) 2000, 2001 Const Kaplinsky.  All Rights Reserved.
+ * Copyright (C) 1999 AT&T Laboratories Cambridge.  All Rights Reserved.
+ *
+ * Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "vnc-palette.h"
+
+static VncPaletteEntry *palette_find(const VncPalette *palette,
+                                     uint32_t color, unsigned int hash)
+{
+    VncPaletteEntry *entry;
+
+    QLIST_FOREACH(entry, &palette->table[hash], next) {
+        if (entry->color == color) {
+            return entry;
+        }
+    }
+
+    return NULL;
+}
+
+static unsigned int palette_hash(uint32_t rgb, int bpp)
+{
+    if (bpp == 16) {
+        return ((unsigned int)(((rgb >> 8) + rgb) & 0xFF));
+    } else {
+        return ((unsigned int)(((rgb >> 16) + (rgb >> 8)) & 0xFF));
+    }
+}
+
+VncPalette *palette_new(size_t max, int bpp)
+{
+    VncPalette *palette;
+
+    palette = qemu_mallocz(sizeof(*palette));
+    palette->max = max;
+    palette->bpp = bpp;
+    return palette;
+}
+
+void palette_destroy(VncPalette *palette)
+{
+    int i;
+
+    if (palette == NULL) {
+        return ;
+    }
+
+    for (i = 0; i < VNC_PALETTE_HASH_SIZE; i++) {
+        VncPaletteEntry *entry = QLIST_FIRST(&palette->table[i]);
+        while (entry) {
+            VncPaletteEntry *tmp = QLIST_NEXT(entry, next);
+            QLIST_REMOVE(entry, next);
+            qemu_free(entry);
+            entry = tmp;
+        }
+    }
+
+    qemu_free(palette);
+}
+
+int palette_put(VncPalette *palette, uint32_t color)
+{
+    unsigned int hash;
+    unsigned int idx = palette->size;
+    VncPaletteEntry *entry;
+
+    hash = palette_hash(color, palette->bpp) % VNC_PALETTE_HASH_SIZE;
+    entry = palette_find(palette, color, hash);
+
+    if (!entry && palette->size >= palette->max) {
+        return 0;
+    }
+    if (!entry) {
+        VncPaletteEntry *entry;
+
+        entry = qemu_mallocz(sizeof(*entry));
+        entry->color = color;
+        entry->idx = idx;
+        QLIST_INSERT_HEAD(&palette->table[hash], entry, next);
+        palette->size++;
+    }
+    return palette->size;
+}
+
+int palette_idx(const VncPalette *palette, uint32_t color)
+{
+    VncPaletteEntry *entry;
+    unsigned int hash;
+
+    hash = palette_hash(color, palette->bpp) % VNC_PALETTE_HASH_SIZE;
+    entry = palette_find(palette, color, hash);
+    return (entry == NULL ? -1 : entry->idx);
+}
+
+size_t palette_size(const VncPalette *palette)
+{
+    return palette->size;
+}
+
+void palette_iter(const VncPalette *palette,
+                  void (*iter)(int idx, uint32_t color, void *opaque),
+                  void *opaque)
+{
+    int i;
+    VncPaletteEntry *entry;
+
+    for (i = 0; i < VNC_PALETTE_HASH_SIZE; i++) {
+        QLIST_FOREACH(entry, &palette->table[i], next) {
+            iter(entry->idx, entry->color, opaque);
+        }
+    }
+}