376 lines
11 KiB
C
376 lines
11 KiB
C
/*
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* l1oip_codec.c generic codec using lookup table
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* -> conversion from a-Law to u-Law
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* -> conversion from u-Law to a-Law
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* -> compression by reducing the number of sample resolution to 4
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*
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* NOTE: It is not compatible with any standard codec like ADPCM.
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*
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* Author Andreas Eversberg (jolly@eversberg.eu)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/*
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How the codec works:
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--------------------
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The volume is increased to increase the dynamic range of the audio signal.
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Each sample is converted to a-LAW with only 16 steps of level resolution.
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A pair of two samples are stored in one byte.
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The first byte is stored in the upper bits, the second byte is stored in the
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lower bits.
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To speed up compression and decompression, two lookup tables are formed:
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- 16 bits index for two samples (law encoded) with 8 bit compressed result.
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- 8 bits index for one compressed data with 16 bits decompressed result.
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NOTE: The bytes are handled as they are law-encoded.
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*/
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#include <linux/vmalloc.h>
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#include <linux/mISDNif.h>
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#include "core.h"
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#include "l1oip.h"
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/* definitions of codec. don't use calculations, code may run slower. */
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static u8 *table_com;
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static u16 *table_dec;
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/* alaw -> ulaw */
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static u8 alaw_to_ulaw[256] =
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{
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0xab, 0x2b, 0xe3, 0x63, 0x8b, 0x0b, 0xc9, 0x49,
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0xba, 0x3a, 0xf6, 0x76, 0x9b, 0x1b, 0xd7, 0x57,
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0xa3, 0x23, 0xdd, 0x5d, 0x83, 0x03, 0xc1, 0x41,
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0xb2, 0x32, 0xeb, 0x6b, 0x93, 0x13, 0xcf, 0x4f,
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0xaf, 0x2f, 0xe7, 0x67, 0x8f, 0x0f, 0xcd, 0x4d,
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0xbe, 0x3e, 0xfe, 0x7e, 0x9f, 0x1f, 0xdb, 0x5b,
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0xa7, 0x27, 0xdf, 0x5f, 0x87, 0x07, 0xc5, 0x45,
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0xb6, 0x36, 0xef, 0x6f, 0x97, 0x17, 0xd3, 0x53,
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0xa9, 0x29, 0xe1, 0x61, 0x89, 0x09, 0xc7, 0x47,
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0xb8, 0x38, 0xf2, 0x72, 0x99, 0x19, 0xd5, 0x55,
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0xa1, 0x21, 0xdc, 0x5c, 0x81, 0x01, 0xbf, 0x3f,
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0xb0, 0x30, 0xe9, 0x69, 0x91, 0x11, 0xce, 0x4e,
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0xad, 0x2d, 0xe5, 0x65, 0x8d, 0x0d, 0xcb, 0x4b,
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0xbc, 0x3c, 0xfa, 0x7a, 0x9d, 0x1d, 0xd9, 0x59,
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0xa5, 0x25, 0xde, 0x5e, 0x85, 0x05, 0xc3, 0x43,
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0xb4, 0x34, 0xed, 0x6d, 0x95, 0x15, 0xd1, 0x51,
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0xac, 0x2c, 0xe4, 0x64, 0x8c, 0x0c, 0xca, 0x4a,
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0xbb, 0x3b, 0xf8, 0x78, 0x9c, 0x1c, 0xd8, 0x58,
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0xa4, 0x24, 0xde, 0x5e, 0x84, 0x04, 0xc2, 0x42,
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0xb3, 0x33, 0xec, 0x6c, 0x94, 0x14, 0xd0, 0x50,
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0xb0, 0x30, 0xe8, 0x68, 0x90, 0x10, 0xce, 0x4e,
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0xbf, 0x3f, 0xfe, 0x7e, 0xa0, 0x20, 0xdc, 0x5c,
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0xa8, 0x28, 0xe0, 0x60, 0x88, 0x08, 0xc6, 0x46,
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0xb7, 0x37, 0xf0, 0x70, 0x98, 0x18, 0xd4, 0x54,
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0xaa, 0x2a, 0xe2, 0x62, 0x8a, 0x0a, 0xc8, 0x48,
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0xb9, 0x39, 0xf4, 0x74, 0x9a, 0x1a, 0xd6, 0x56,
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0xa2, 0x22, 0xdd, 0x5d, 0x82, 0x02, 0xc0, 0x40,
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0xb1, 0x31, 0xea, 0x6a, 0x92, 0x12, 0xcf, 0x4f,
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0xae, 0x2e, 0xe6, 0x66, 0x8e, 0x0e, 0xcc, 0x4c,
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0xbd, 0x3d, 0xfc, 0x7c, 0x9e, 0x1e, 0xda, 0x5a,
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0xa6, 0x26, 0xdf, 0x5f, 0x86, 0x06, 0xc4, 0x44,
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0xb5, 0x35, 0xee, 0x6e, 0x96, 0x16, 0xd2, 0x52
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};
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/* ulaw -> alaw */
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static u8 ulaw_to_alaw[256] =
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{
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0xab, 0x55, 0xd5, 0x15, 0x95, 0x75, 0xf5, 0x35,
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0xb5, 0x45, 0xc5, 0x05, 0x85, 0x65, 0xe5, 0x25,
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0xa5, 0x5d, 0xdd, 0x1d, 0x9d, 0x7d, 0xfd, 0x3d,
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0xbd, 0x4d, 0xcd, 0x0d, 0x8d, 0x6d, 0xed, 0x2d,
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0xad, 0x51, 0xd1, 0x11, 0x91, 0x71, 0xf1, 0x31,
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0xb1, 0x41, 0xc1, 0x01, 0x81, 0x61, 0xe1, 0x21,
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0x59, 0xd9, 0x19, 0x99, 0x79, 0xf9, 0x39, 0xb9,
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0x49, 0xc9, 0x09, 0x89, 0x69, 0xe9, 0x29, 0xa9,
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0xd7, 0x17, 0x97, 0x77, 0xf7, 0x37, 0xb7, 0x47,
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0xc7, 0x07, 0x87, 0x67, 0xe7, 0x27, 0xa7, 0xdf,
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0x9f, 0x7f, 0xff, 0x3f, 0xbf, 0x4f, 0xcf, 0x0f,
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0x8f, 0x6f, 0xef, 0x2f, 0x53, 0x13, 0x73, 0x33,
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0xb3, 0x43, 0xc3, 0x03, 0x83, 0x63, 0xe3, 0x23,
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0xa3, 0x5b, 0xdb, 0x1b, 0x9b, 0x7b, 0xfb, 0x3b,
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0xbb, 0xbb, 0x4b, 0x4b, 0xcb, 0xcb, 0x0b, 0x0b,
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0x8b, 0x8b, 0x6b, 0x6b, 0xeb, 0xeb, 0x2b, 0x2b,
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0xab, 0x54, 0xd4, 0x14, 0x94, 0x74, 0xf4, 0x34,
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0xb4, 0x44, 0xc4, 0x04, 0x84, 0x64, 0xe4, 0x24,
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0xa4, 0x5c, 0xdc, 0x1c, 0x9c, 0x7c, 0xfc, 0x3c,
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0xbc, 0x4c, 0xcc, 0x0c, 0x8c, 0x6c, 0xec, 0x2c,
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0xac, 0x50, 0xd0, 0x10, 0x90, 0x70, 0xf0, 0x30,
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0xb0, 0x40, 0xc0, 0x00, 0x80, 0x60, 0xe0, 0x20,
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0x58, 0xd8, 0x18, 0x98, 0x78, 0xf8, 0x38, 0xb8,
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0x48, 0xc8, 0x08, 0x88, 0x68, 0xe8, 0x28, 0xa8,
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0xd6, 0x16, 0x96, 0x76, 0xf6, 0x36, 0xb6, 0x46,
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0xc6, 0x06, 0x86, 0x66, 0xe6, 0x26, 0xa6, 0xde,
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0x9e, 0x7e, 0xfe, 0x3e, 0xbe, 0x4e, 0xce, 0x0e,
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0x8e, 0x6e, 0xee, 0x2e, 0x52, 0x12, 0x72, 0x32,
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0xb2, 0x42, 0xc2, 0x02, 0x82, 0x62, 0xe2, 0x22,
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0xa2, 0x5a, 0xda, 0x1a, 0x9a, 0x7a, 0xfa, 0x3a,
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0xba, 0xba, 0x4a, 0x4a, 0xca, 0xca, 0x0a, 0x0a,
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0x8a, 0x8a, 0x6a, 0x6a, 0xea, 0xea, 0x2a, 0x2a
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};
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/* alaw -> 4bit compression */
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static u8 alaw_to_4bit[256] = {
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0d, 0x02,
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0x0e, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
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0x0d, 0x02, 0x08, 0x07, 0x0f, 0x01, 0x0a, 0x05,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x09, 0x07, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
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0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
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0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
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};
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/* 4bit -> alaw decompression */
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static u8 _4bit_to_alaw[16] = {
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0x5d, 0x51, 0xd9, 0xd7, 0x5f, 0x53, 0xa3, 0x4b,
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0x2a, 0x3a, 0x22, 0x2e, 0x26, 0x56, 0x20, 0x2c,
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};
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/* ulaw -> 4bit compression */
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static u8 ulaw_to_4bit[256] = {
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
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0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
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0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
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0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
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0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
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0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04,
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0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
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0x04, 0x04, 0x04, 0x04, 0x05, 0x05, 0x05, 0x05,
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0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
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0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
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0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
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0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x08,
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0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f,
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0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f,
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0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f,
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0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f,
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0x0f, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e,
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0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e,
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0x0e, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d,
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0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d,
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0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c,
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0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0b, 0x0b,
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0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b,
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0x0b, 0x0b, 0x0b, 0x0b, 0x0a, 0x0a, 0x0a, 0x0a,
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0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a,
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0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09,
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0x09, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
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0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
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};
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/* 4bit -> ulaw decompression */
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static u8 _4bit_to_ulaw[16] = {
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0x11, 0x21, 0x31, 0x40, 0x4e, 0x5c, 0x68, 0x71,
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0xfe, 0xef, 0xe7, 0xdb, 0xcd, 0xbf, 0xaf, 0x9f,
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};
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/*
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* Compresses data to the result buffer
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* The result size must be at least half of the input buffer.
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* The number of samples also must be even!
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*/
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int
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l1oip_law_to_4bit(u8 *data, int len, u8 *result, u32 *state)
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{
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int ii, i = 0, o = 0;
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if (!len)
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return 0;
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/* send saved byte and first input byte */
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if (*state) {
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*result++ = table_com[(((*state)<<8)&0xff00) | (*data++)];
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len--;
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o++;
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}
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ii = len >> 1;
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while (i < ii) {
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*result++ = table_com[(data[0]<<8) | (data[1])];
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data += 2;
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i++;
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o++;
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}
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/* if len has an odd number, we save byte for next call */
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if (len & 1)
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*state = 0x100 + *data;
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else
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*state = 0;
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return o;
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}
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/* Decompress data to the result buffer
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* The result size must be the number of sample in packet. (2 * input data)
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* The number of samples in the result are even!
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*/
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int
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l1oip_4bit_to_law(u8 *data, int len, u8 *result)
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{
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int i = 0;
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u16 r;
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while (i < len) {
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r = table_dec[*data++];
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*result++ = r>>8;
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*result++ = r;
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i++;
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}
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return len << 1;
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}
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/*
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* law conversion
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*/
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int
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l1oip_alaw_to_ulaw(u8 *data, int len, u8 *result)
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{
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int i = 0;
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while (i < len) {
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*result++ = alaw_to_ulaw[*data++];
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i++;
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}
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return len;
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}
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int
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l1oip_ulaw_to_alaw(u8 *data, int len, u8 *result)
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{
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int i = 0;
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while (i < len) {
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*result++ = ulaw_to_alaw[*data++];
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i++;
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}
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return len;
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}
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/*
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* generate/free compression and decompression table
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*/
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void
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l1oip_4bit_free(void)
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{
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if (table_dec)
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vfree(table_dec);
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if (table_com)
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vfree(table_com);
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table_com = NULL;
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table_dec = NULL;
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}
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int
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l1oip_4bit_alloc(int ulaw)
|
|
{
|
|
int i1, i2, c, sample;
|
|
|
|
/* in case, it is called again */
|
|
if (table_dec)
|
|
return 0;
|
|
|
|
/* alloc conversion tables */
|
|
table_com = vmalloc(65536);
|
|
table_dec = vmalloc(512);
|
|
if (!table_com | !table_dec) {
|
|
l1oip_4bit_free();
|
|
return -ENOMEM;
|
|
}
|
|
memset(table_com, 0, 65536);
|
|
memset(table_dec, 0, 512);
|
|
/* generate compression table */
|
|
i1 = 0;
|
|
while (i1 < 256) {
|
|
if (ulaw)
|
|
c = ulaw_to_4bit[i1];
|
|
else
|
|
c = alaw_to_4bit[i1];
|
|
i2 = 0;
|
|
while (i2 < 256) {
|
|
table_com[(i1<<8) | i2] |= (c<<4);
|
|
table_com[(i2<<8) | i1] |= c;
|
|
i2++;
|
|
}
|
|
i1++;
|
|
}
|
|
|
|
/* generate decompression table */
|
|
i1 = 0;
|
|
while (i1 < 16) {
|
|
if (ulaw)
|
|
sample = _4bit_to_ulaw[i1];
|
|
else
|
|
sample = _4bit_to_alaw[i1];
|
|
i2 = 0;
|
|
while (i2 < 16) {
|
|
table_dec[(i1<<4) | i2] |= (sample<<8);
|
|
table_dec[(i2<<4) | i1] |= sample;
|
|
i2++;
|
|
}
|
|
i1++;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|