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      1 /************************************************************************
      2  * Copyright (C) 2002-2009, Xiph.org Foundation
      3  * Copyright (C) 2010, Robin Watts for Pinknoise Productions Ltd
      4  * All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  *
     10  *     * Redistributions of source code must retain the above copyright
     11  * notice, this list of conditions and the following disclaimer.
     12  *     * Redistributions in binary form must reproduce the above
     13  * copyright notice, this list of conditions and the following disclaimer
     14  * in the documentation and/or other materials provided with the
     15  * distribution.
     16  *     * Neither the names of the Xiph.org Foundation nor Pinknoise
     17  * Productions Ltd nor the names of its contributors may be used to
     18  * endorse or promote products derived from this software without
     19  * specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     22  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     24  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     25  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     26  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     27  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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     31  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     32  ************************************************************************
     33 
     34  function: floor dB lookup
     35 
     36  ************************************************************************/
     37 
     38 #include "os.h"
     39 
     40 #ifdef _LOW_ACCURACY_
     41 #  define XdB(n) ((((n)>>8)+1)>>1)
     42 #else
     43 #  define XdB(n) (n)
     44 #endif
     45 
     46 const ogg_int32_t FLOOR_fromdB_LOOKUP[256]={
     47   XdB(0x000000e5), XdB(0x000000f4), XdB(0x00000103), XdB(0x00000114),
     48   XdB(0x00000126), XdB(0x00000139), XdB(0x0000014e), XdB(0x00000163),
     49   XdB(0x0000017a), XdB(0x00000193), XdB(0x000001ad), XdB(0x000001c9),
     50   XdB(0x000001e7), XdB(0x00000206), XdB(0x00000228), XdB(0x0000024c),
     51   XdB(0x00000272), XdB(0x0000029b), XdB(0x000002c6), XdB(0x000002f4),
     52   XdB(0x00000326), XdB(0x0000035a), XdB(0x00000392), XdB(0x000003cd),
     53   XdB(0x0000040c), XdB(0x00000450), XdB(0x00000497), XdB(0x000004e4),
     54   XdB(0x00000535), XdB(0x0000058c), XdB(0x000005e8), XdB(0x0000064a),
     55   XdB(0x000006b3), XdB(0x00000722), XdB(0x00000799), XdB(0x00000818),
     56   XdB(0x0000089e), XdB(0x0000092e), XdB(0x000009c6), XdB(0x00000a69),
     57   XdB(0x00000b16), XdB(0x00000bcf), XdB(0x00000c93), XdB(0x00000d64),
     58   XdB(0x00000e43), XdB(0x00000f30), XdB(0x0000102d), XdB(0x0000113a),
     59   XdB(0x00001258), XdB(0x0000138a), XdB(0x000014cf), XdB(0x00001629),
     60   XdB(0x0000179a), XdB(0x00001922), XdB(0x00001ac4), XdB(0x00001c82),
     61   XdB(0x00001e5c), XdB(0x00002055), XdB(0x0000226f), XdB(0x000024ac),
     62   XdB(0x0000270e), XdB(0x00002997), XdB(0x00002c4b), XdB(0x00002f2c),
     63   XdB(0x0000323d), XdB(0x00003581), XdB(0x000038fb), XdB(0x00003caf),
     64   XdB(0x000040a0), XdB(0x000044d3), XdB(0x0000494c), XdB(0x00004e10),
     65   XdB(0x00005323), XdB(0x0000588a), XdB(0x00005e4b), XdB(0x0000646b),
     66   XdB(0x00006af2), XdB(0x000071e5), XdB(0x0000794c), XdB(0x0000812e),
     67   XdB(0x00008993), XdB(0x00009283), XdB(0x00009c09), XdB(0x0000a62d),
     68   XdB(0x0000b0f9), XdB(0x0000bc79), XdB(0x0000c8b9), XdB(0x0000d5c4),
     69   XdB(0x0000e3a9), XdB(0x0000f274), XdB(0x00010235), XdB(0x000112fd),
     70   XdB(0x000124dc), XdB(0x000137e4), XdB(0x00014c29), XdB(0x000161bf),
     71   XdB(0x000178bc), XdB(0x00019137), XdB(0x0001ab4a), XdB(0x0001c70e),
     72   XdB(0x0001e4a1), XdB(0x0002041f), XdB(0x000225aa), XdB(0x00024962),
     73   XdB(0x00026f6d), XdB(0x000297f0), XdB(0x0002c316), XdB(0x0002f109),
     74   XdB(0x000321f9), XdB(0x00035616), XdB(0x00038d97), XdB(0x0003c8b4),
     75   XdB(0x000407a7), XdB(0x00044ab2), XdB(0x00049218), XdB(0x0004de23),
     76   XdB(0x00052f1e), XdB(0x0005855c), XdB(0x0005e135), XdB(0x00064306),
     77   XdB(0x0006ab33), XdB(0x00071a24), XdB(0x0007904b), XdB(0x00080e20),
     78   XdB(0x00089422), XdB(0x000922da), XdB(0x0009bad8), XdB(0x000a5cb6),
     79   XdB(0x000b091a), XdB(0x000bc0b1), XdB(0x000c8436), XdB(0x000d5471),
     80   XdB(0x000e3233), XdB(0x000f1e5f), XdB(0x001019e4), XdB(0x001125c1),
     81   XdB(0x00124306), XdB(0x001372d5), XdB(0x0014b663), XdB(0x00160ef7),
     82   XdB(0x00177df0), XdB(0x001904c1), XdB(0x001aa4f9), XdB(0x001c603d),
     83   XdB(0x001e384f), XdB(0x00202f0f), XdB(0x0022467a), XdB(0x002480b1),
     84   XdB(0x0026dff7), XdB(0x002966b3), XdB(0x002c1776), XdB(0x002ef4fc),
     85   XdB(0x0032022d), XdB(0x00354222), XdB(0x0038b828), XdB(0x003c67c2),
     86   XdB(0x004054ae), XdB(0x004482e8), XdB(0x0048f6af), XdB(0x004db488),
     87   XdB(0x0052c142), XdB(0x005821ff), XdB(0x005ddc33), XdB(0x0063f5b0),
     88   XdB(0x006a74a7), XdB(0x00715faf), XdB(0x0078bdce), XdB(0x0080967f),
     89   XdB(0x0088f1ba), XdB(0x0091d7f9), XdB(0x009b5247), XdB(0x00a56a41),
     90   XdB(0x00b02a27), XdB(0x00bb9ce2), XdB(0x00c7ce12), XdB(0x00d4ca17),
     91   XdB(0x00e29e20), XdB(0x00f15835), XdB(0x0101074b), XdB(0x0111bb4e),
     92   XdB(0x01238531), XdB(0x01367704), XdB(0x014aa402), XdB(0x016020a7),
     93   XdB(0x017702c3), XdB(0x018f6190), XdB(0x01a955cb), XdB(0x01c4f9cf),
     94   XdB(0x01e269a8), XdB(0x0201c33b), XdB(0x0223265a), XdB(0x0246b4ea),
     95   XdB(0x026c9302), XdB(0x0294e716), XdB(0x02bfda13), XdB(0x02ed9793),
     96   XdB(0x031e4e09), XdB(0x03522ee4), XdB(0x03896ed0), XdB(0x03c445e2),
     97   XdB(0x0402efd6), XdB(0x0445ac4b), XdB(0x048cbefc), XdB(0x04d87013),
     98   XdB(0x05290c67), XdB(0x057ee5ca), XdB(0x05da5364), XdB(0x063bb204),
     99   XdB(0x06a36485), XdB(0x0711d42b), XdB(0x0787710e), XdB(0x0804b299),
    100   XdB(0x088a17ef), XdB(0x0918287e), XdB(0x09af747c), XdB(0x0a50957e),
    101   XdB(0x0afc2f19), XdB(0x0bb2ef7f), XdB(0x0c759034), XdB(0x0d44d6ca),
    102   XdB(0x0e2195bc), XdB(0x0f0cad0d), XdB(0x10070b62), XdB(0x1111aeea),
    103   XdB(0x122da66c), XdB(0x135c120f), XdB(0x149e24d9), XdB(0x15f525b1),
    104   XdB(0x176270e3), XdB(0x18e7794b), XdB(0x1a85c9ae), XdB(0x1c3f06d1),
    105   XdB(0x1e14f07d), XdB(0x200963d7), XdB(0x221e5ccd), XdB(0x2455f870),
    106   XdB(0x26b2770b), XdB(0x29363e2b), XdB(0x2be3db5c), XdB(0x2ebe06b6),
    107   XdB(0x31c7a55b), XdB(0x3503ccd4), XdB(0x3875c5aa), XdB(0x3c210f44),
    108   XdB(0x4009632b), XdB(0x4432b8cf), XdB(0x48a149bc), XdB(0x4d59959e),
    109   XdB(0x52606733), XdB(0x57bad899), XdB(0x5d6e593a), XdB(0x6380b298),
    110   XdB(0x69f80e9a), XdB(0x70dafda8), XdB(0x78307d76), XdB(0x7fffffff),
    111 };
    112 
    113