kopia lustrzana https://github.com/ha7ilm/csdr
177 wiersze
7.4 KiB
C
177 wiersze
7.4 KiB
C
/*
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This software is part of libcsdr, a set of simple DSP routines for
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Software Defined Radio.
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Copyright (c) 2015, Andras Retzler <randras@sdr.hu>
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of the copyright holder nor the
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names of its contributors may be used to endorse or promote products
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derived from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL ANDRAS RETZLER BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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Copyright 1997 Tim Kientzle. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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3. All advertising materials mentioning features or use of this software
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must display the following acknowledgement:
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This product includes software developed by Tim Kientzle
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and published in ``The Programmer's Guide to Sound.''
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4. Neither the names of Tim Kientzle nor Addison-Wesley
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may be used to endorse or promote products derived from this software
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without specific prior written permission.
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THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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IN NO EVENT SHALL TIM KIENTZLE OR ADDISON-WESLEY BE LIABLE FOR
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ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/***********************************************************
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Copyright 1992 by Stichting Mathematisch Centrum, Amsterdam, The
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Netherlands.
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and its
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documentation for any purpose and without fee is hereby granted,
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provided that the above copyright notice appear in all copies and that
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both that copyright notice and this permission notice appear in
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supporting documentation, and that the names of Stichting Mathematisch
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Centrum or CWI not be used in advertising or publicity pertaining to
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distribution of the software without specific, written prior permission.
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STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
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THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
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FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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******************************************************************/
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#ifdef USE_IMA_ADPCM
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#include "ima_adpcm.h"
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const int indexAdjustTable[16] = {
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-1, -1, -1, -1, // +0 - +3, decrease the step size
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2, 4, 6, 8, // +4 - +7, increase the step size
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-1, -1, -1, -1, // -0 - -3, decrease the step size
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2, 4, 6, 8, // -4 - -7, increase the step size
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};
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const int _stepSizeTable[89] = {
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7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 19, 21, 23, 25, 28, 31, 34,
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37, 41, 45, 50, 55, 60, 66, 73, 80, 88, 97, 107, 118, 130, 143,
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157, 173, 190, 209, 230, 253, 279, 307, 337, 371, 408, 449, 494,
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544, 598, 658, 724, 796, 876, 963, 1060, 1166, 1282, 1411, 1552,
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1707, 1878, 2066, 2272, 2499, 2749, 3024, 3327, 3660, 4026,
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4428, 4871, 5358, 5894, 6484, 7132, 7845, 8630, 9493, 10442,
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11487, 12635, 13899, 15289, 16818, 18500, 20350, 22385, 24623,
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27086, 29794, 32767
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};
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static inline short ImaAdpcmDecode(unsigned char deltaCode, ima_adpcm_state_t* state) {
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// Get the current step size
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int step = _stepSizeTable[state->index];
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// Construct the difference by scaling the current step size
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// This is approximately: difference = (deltaCode+.5)*step/4
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int difference = step>>3;
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if ( deltaCode & 1 ) difference += step>>2;
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if ( deltaCode & 2 ) difference += step>>1;
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if ( deltaCode & 4 ) difference += step;
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if ( deltaCode & 8 ) difference = -difference;
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// Build the new sample
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state->previousValue += difference;
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if (state->previousValue > 32767) state->previousValue = 32767;
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else if (state->previousValue < -32768) state->previousValue = -32768;
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// Update the step for the next sample
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state->index += indexAdjustTable[deltaCode];
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if (state->index < 0) state->index = 0;
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else if (state->index > 88) state->index = 88;
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return state->previousValue;
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}
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static inline unsigned char ImaAdpcmEncode(short sample, ima_adpcm_state_t* state) {
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int diff = sample - state->previousValue;
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int step = _stepSizeTable[state->index];
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int deltaCode = 0;
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// Set sign bit
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if (diff < 0) { deltaCode = 8; diff = -diff; }
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// This is essentially deltaCode = (diff<<2)/step,
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// except the roundoff is handled differently.
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if ( diff >= step ) { deltaCode |= 4; diff -= step; }
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step >>= 1;
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if ( diff >= step ) { deltaCode |= 2; diff -= step; }
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step >>= 1;
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if ( diff >= step ) { deltaCode |= 1; diff -= step; }
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ImaAdpcmDecode(deltaCode,state); // update state
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return deltaCode;
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}
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ima_adpcm_state_t encode_ima_adpcm_i16_u8(short* input, unsigned char* output, int input_length, ima_adpcm_state_t state)
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{
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int k=0;
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for(int i=0;i<input_length/2;i++)
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{
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output[k]=ImaAdpcmEncode(input[2*i],&state);
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output[k++]|=ImaAdpcmEncode(input[2*i+1],&state)<<4;
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}
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return state;
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}
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ima_adpcm_state_t decode_ima_adpcm_u8_i16(unsigned char* input, short* output, int input_length, ima_adpcm_state_t state)
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{
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int k=0;
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for(int i=0;i<input_length;i++)
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{
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output[k++]=ImaAdpcmDecode(input[i]&0xf,&state);
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output[k++]=ImaAdpcmDecode( (input[i]>>4)&0xf,&state);
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}
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return state;
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}
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#endif
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