Initial import of libFLAC from flac-1.1.2.tar.gz

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@5983 a1c6a512-1295-4272-9138-f99709370657

apps/codecs/libFLAC/bitmath.c

@@ -0,0 +1,145 @@
+/* libFLAC - Free Lossless Audio Codec library
+ * Copyright (C) 2001,2002,2003,2004,2005  Josh Coalson
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of the Xiph.org Foundation nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "private/bitmath.h"
+#include "FLAC/assert.h"
+
+/* An example of what FLAC__bitmath_ilog2() computes:
+ *
+ * ilog2( 0) = assertion failure
+ * ilog2( 1) = 0
+ * ilog2( 2) = 1
+ * ilog2( 3) = 1
+ * ilog2( 4) = 2
+ * ilog2( 5) = 2
+ * ilog2( 6) = 2
+ * ilog2( 7) = 2
+ * ilog2( 8) = 3
+ * ilog2( 9) = 3
+ * ilog2(10) = 3
+ * ilog2(11) = 3
+ * ilog2(12) = 3
+ * ilog2(13) = 3
+ * ilog2(14) = 3
+ * ilog2(15) = 3
+ * ilog2(16) = 4
+ * ilog2(17) = 4
+ * ilog2(18) = 4
+ */
+unsigned FLAC__bitmath_ilog2(FLAC__uint32 v)
+{
+	unsigned l = 0;
+	FLAC__ASSERT(v > 0);
+	while(v >>= 1)
+		l++;
+	return l;
+}
+
+unsigned FLAC__bitmath_ilog2_wide(FLAC__uint64 v)
+{
+	unsigned l = 0;
+	FLAC__ASSERT(v > 0);
+	while(v >>= 1)
+		l++;
+	return l;
+}
+
+/* An example of what FLAC__bitmath_silog2() computes:
+ *
+ * silog2(-10) = 5
+ * silog2(- 9) = 5
+ * silog2(- 8) = 4
+ * silog2(- 7) = 4
+ * silog2(- 6) = 4
+ * silog2(- 5) = 4
+ * silog2(- 4) = 3
+ * silog2(- 3) = 3
+ * silog2(- 2) = 2
+ * silog2(- 1) = 2
+ * silog2(  0) = 0
+ * silog2(  1) = 2
+ * silog2(  2) = 3
+ * silog2(  3) = 3
+ * silog2(  4) = 4
+ * silog2(  5) = 4
+ * silog2(  6) = 4
+ * silog2(  7) = 4
+ * silog2(  8) = 5
+ * silog2(  9) = 5
+ * silog2( 10) = 5
+ */
+unsigned FLAC__bitmath_silog2(int v)
+{
+	while(1) {
+		if(v == 0) {
+			return 0;
+		}
+		else if(v > 0) {
+			unsigned l = 0;
+			while(v) {
+				l++;
+				v >>= 1;
+			}
+			return l+1;
+		}
+		else if(v == -1) {
+			return 2;
+		}
+		else {
+			v++;
+			v = -v;
+		}
+	}
+}
+
+unsigned FLAC__bitmath_silog2_wide(FLAC__int64 v)
+{
+	while(1) {
+		if(v == 0) {
+			return 0;
+		}
+		else if(v > 0) {
+			unsigned l = 0;
+			while(v) {
+				l++;
+				v >>= 1;
+			}
+			return l+1;
+		}
+		else if(v == -1) {
+			return 2;
+		}
+		else {
+			v++;
+			v = -v;
+		}
+	}
+}