1 files changed, 94 insertions, 0 deletions

diff --git a/converter/other/fiasco/codec/bintree.c b/converter/other/fiasco/codec/bintree.c
new file mode 100644
index 00000000..ddd74e15
--- /dev/null
+++ b/converter/other/fiasco/codec/bintree.c
@@ -0,0 +1,94 @@
+/*
+ *  bintree.c:		Bintree model of WFA tree	
+ *
+ *  Written by:		Ullrich Hafner
+ *		
+ *  This file is part of FIASCO («F»ractal «I»mage «A»nd «S»equence «CO»dec)
+ *  Copyright (C) 1994-2000 Ullrich Hafner <hafner@bigfoot.de>
+ */
+
+/*
+ *  $Date: 2000/06/14 20:50:51 $
+ *  $Author: hafner $
+ *  $Revision: 5.1 $
+ *  $State: Exp $
+ */
+
+#include "config.h"
+
+#include "types.h"
+#include "macros.h"
+#include "error.h"
+
+#include <math.h>
+
+#include "bintree.h"
+#include "misc.h"
+#include "cwfa.h"
+
+/*****************************************************************************
+
+				public code
+  
+*****************************************************************************/
+
+void
+tree_update (bool_t child, unsigned level, tree_t *model)
+/*
+ *  Update tree model of given 'level'.
+ *
+ *  No return value.
+ *
+ *  Side effects:
+ *	tree model is changed.
+ */
+{
+   if (!child)
+      model->total [level]++;
+   else
+   {
+      model->counts [level]++;
+      model->total [level]++;
+   }
+}
+
+real_t
+tree_bits (bool_t child, unsigned level, const tree_t *model)
+/*
+ *  Compute number of bits needed for coding element 'child' of the bintree.
+ *  For each 'level' a different context is used.
+ *
+ *  Return value:
+ *	# bits
+ */
+{
+   real_t prob = model->counts [level] / (real_t) model->total [level];
+
+   return child ? - log2 (prob) : - log2 (1 - prob);
+}
+
+void
+init_tree_model (tree_t *tree_model)
+/*
+ *  Initialize the model for the tree.
+ *  Symbol RANGE is synonymous with the '0' symbol and
+ *  symbol NO_RANGE is synonymous with the '1' symbol of the binary coder.
+ *  The 'count' array counts the number of NO_RANGE symbols.
+ *
+ *  No return value.
+ */
+{
+   unsigned level;
+   unsigned counts_0 [MAXLEVEL] = {20, 17, 15, 10, 5,  4,  3,
+				   2,  1,  1,  1,  1,  1,  1,  1,
+				   1,  1,  1,  1 , 1,  1,  1};
+   unsigned counts_1 [MAXLEVEL] = {1 , 1,  1,  1,  1,  1,  1,
+				   1,  1,  2,  3,  5,  10, 15, 20,
+				   25, 30, 35, 60, 60, 60, 60};
+   
+   for (level = 0; level < MAXLEVEL ; level++) 
+   {
+      tree_model->counts [level] = counts_1 [level];
+      tree_model->total [level]  = counts_0 [level] + counts_1 [level];
+   }
+}