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authorJean-Marc Valin <jmvalin@jmvalin.ca>2011-09-16 01:16:53 -0700
committerJean-Marc Valin <jmvalin@jmvalin.ca>2011-09-16 01:16:53 -0700
commit1c2f5633d101c08b5ef8095a8682d3d52cbd952d (patch)
tree66f80e67f075db5fa5233759a89f475d8bedade2 /silk/lin2log.c
parentfb3a437c9dabb4aafe4a3927158161590ed745ab (diff)
downloadopus-1c2f5633d101c08b5ef8095a8682d3d52cbd952d.tar.gz
Removed all the silk_ prefixes in source file names (not symbols)
Diffstat (limited to 'silk/lin2log.c')
-rw-r--r--silk/lin2log.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/silk/lin2log.c b/silk/lin2log.c
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+/***********************************************************************
+Copyright (c) 2006-2011, Skype Limited. All rights reserved.
+Redistribution and use in source and binary forms, with or without
+modification, (subject to the limitations in the disclaimer below)
+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 Skype Limited, nor the names of specific
+contributors, may be used to endorse or promote products derived from
+this software without specific prior written permission.
+NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
+BY THIS LICENSE. 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
+COPYRIGHT OWNER 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.
+***********************************************************************/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "SigProc_FIX.h"
+/* Approximation of 128 * log2() (very close inverse of silk_log2lin()) */
+/* Convert input to a log scale */
+opus_int32 silk_lin2log( const opus_int32 inLin ) /* I: Input in linear scale */
+{
+ opus_int32 lz, frac_Q7;
+
+ silk_CLZ_FRAC( inLin, &lz, &frac_Q7 );
+
+ /* Piece-wise parabolic approximation */
+ return silk_LSHIFT( 31 - lz, 7 ) + silk_SMLAWB( frac_Q7, silk_MUL( frac_Q7, 128 - frac_Q7 ), 179 );
+}
+