ZRLE no longer uses C++, but C

1 files changed, 62 insertions, 0 deletions

diff --git a/zrlepalettehelper.c b/zrlepalettehelper.c
new file mode 100644
index 0000000..70cafb4
--- /dev/null
+++ b/zrlepalettehelper.c
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2002 RealVNC Ltd.  All Rights Reserved.
+ * Copyright (C) 2003 Sun Microsystems, Inc.
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This software 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+
+#include <zrlepalettehelper.h>
+#include <assert.h>
+#include <string.h>
+
+#define ZRLE_HASH(pix) (((pix) ^ ((pix) >> 17)) & 4095)
+
+void zrlePaletteHelperInit(zrlePaletteHelper *helper)
+{
+  memset(helper->palette, 0, sizeof(helper->palette));
+  memset(helper->index, 255, sizeof(helper->index));
+  memset(helper->key, 0, sizeof(helper->key));
+  helper->size = 0;
+}
+
+void zrlePaletteHelperInsert(zrlePaletteHelper *helper, zrle_U32 pix)
+{
+  if (helper->size < ZRLE_PALETTE_MAX_SIZE) {
+    int i = ZRLE_HASH(pix);
+
+    while (helper->index[i] != 255 && helper->key[i] != pix)
+      i++;
+    if (helper->index[i] != 255) return;
+
+    helper->index[i] = helper->size;
+    helper->key[i] = pix;
+    helper->palette[helper->size] = pix;
+  }
+  helper->size++;
+}
+
+int zrlePaletteHelperLookup(zrlePaletteHelper *helper, zrle_U32 pix)
+{
+  int i = ZRLE_HASH(pix);
+
+  assert(helper->size <= ZRLE_PALETTE_MAX_SIZE);
+  
+  while (helper->index[i] != 255 && helper->key[i] != pix)
+    i++;
+  if (helper->index[i] != 255) return helper->index[i];
+
+  return -1;
+}