crc.c 6.21 KB
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/* libFLAC - Free Lossless Audio Codec library
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 * Copyright (C) 2000,2001,2002,2003,2004,2005,2006,2007  Josh Coalson
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 *
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
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 * - 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.
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 */

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#if HAVE_CONFIG_H
#  include <config.h>
#endif

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#include "private/crc.h"

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/* CRC-8, poly = x^8 + x^2 + x^1 + x^0, init = 0 */

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FLAC__byte const FLAC__crc8_table[256] = {
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	0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15,
	0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D,
	0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65,
	0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D,
	0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB, 0xF2, 0xF5,
	0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,
	0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85,
	0xA8, 0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD,
	0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2,
	0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA,
	0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2,
	0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,
	0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32,
	0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A,
	0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42,
	0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A,
	0x89, 0x8E, 0x87, 0x80, 0x95, 0x92, 0x9B, 0x9C,
	0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4,
	0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC,
	0xC1, 0xC6, 0xCF, 0xC8, 0xDD, 0xDA, 0xD3, 0xD4,
	0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C,
	0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44,
	0x19, 0x1E, 0x17, 0x10, 0x05, 0x02, 0x0B, 0x0C,
	0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34,
	0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B,
	0x76, 0x71, 0x78, 0x7F, 0x6A, 0x6D, 0x64, 0x63,
	0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B,
	0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13,
	0xAE, 0xA9, 0xA0, 0xA7, 0xB2, 0xB5, 0xBC, 0xBB,
	0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83,
	0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB,
	0xE6, 0xE1, 0xE8, 0xEF, 0xFA, 0xFD, 0xF4, 0xF3
};

/* CRC-16, poly = x^16 + x^15 + x^2 + x^0, init = 0 */

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unsigned FLAC__crc16_table[256] = {
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	0x0000,  0x8005,  0x800f,  0x000a,  0x801b,  0x001e,  0x0014,  0x8011,
	0x8033,  0x0036,  0x003c,  0x8039,  0x0028,  0x802d,  0x8027,  0x0022,
	0x8063,  0x0066,  0x006c,  0x8069,  0x0078,  0x807d,  0x8077,  0x0072,
	0x0050,  0x8055,  0x805f,  0x005a,  0x804b,  0x004e,  0x0044,  0x8041,
	0x80c3,  0x00c6,  0x00cc,  0x80c9,  0x00d8,  0x80dd,  0x80d7,  0x00d2,
	0x00f0,  0x80f5,  0x80ff,  0x00fa,  0x80eb,  0x00ee,  0x00e4,  0x80e1,
	0x00a0,  0x80a5,  0x80af,  0x00aa,  0x80bb,  0x00be,  0x00b4,  0x80b1,
	0x8093,  0x0096,  0x009c,  0x8099,  0x0088,  0x808d,  0x8087,  0x0082,
	0x8183,  0x0186,  0x018c,  0x8189,  0x0198,  0x819d,  0x8197,  0x0192,
	0x01b0,  0x81b5,  0x81bf,  0x01ba,  0x81ab,  0x01ae,  0x01a4,  0x81a1,
	0x01e0,  0x81e5,  0x81ef,  0x01ea,  0x81fb,  0x01fe,  0x01f4,  0x81f1,
	0x81d3,  0x01d6,  0x01dc,  0x81d9,  0x01c8,  0x81cd,  0x81c7,  0x01c2,
	0x0140,  0x8145,  0x814f,  0x014a,  0x815b,  0x015e,  0x0154,  0x8151,
	0x8173,  0x0176,  0x017c,  0x8179,  0x0168,  0x816d,  0x8167,  0x0162,
	0x8123,  0x0126,  0x012c,  0x8129,  0x0138,  0x813d,  0x8137,  0x0132,
	0x0110,  0x8115,  0x811f,  0x011a,  0x810b,  0x010e,  0x0104,  0x8101,
	0x8303,  0x0306,  0x030c,  0x8309,  0x0318,  0x831d,  0x8317,  0x0312,
	0x0330,  0x8335,  0x833f,  0x033a,  0x832b,  0x032e,  0x0324,  0x8321,
	0x0360,  0x8365,  0x836f,  0x036a,  0x837b,  0x037e,  0x0374,  0x8371,
	0x8353,  0x0356,  0x035c,  0x8359,  0x0348,  0x834d,  0x8347,  0x0342,
	0x03c0,  0x83c5,  0x83cf,  0x03ca,  0x83db,  0x03de,  0x03d4,  0x83d1,
	0x83f3,  0x03f6,  0x03fc,  0x83f9,  0x03e8,  0x83ed,  0x83e7,  0x03e2,
	0x83a3,  0x03a6,  0x03ac,  0x83a9,  0x03b8,  0x83bd,  0x83b7,  0x03b2,
	0x0390,  0x8395,  0x839f,  0x039a,  0x838b,  0x038e,  0x0384,  0x8381,
	0x0280,  0x8285,  0x828f,  0x028a,  0x829b,  0x029e,  0x0294,  0x8291,
	0x82b3,  0x02b6,  0x02bc,  0x82b9,  0x02a8,  0x82ad,  0x82a7,  0x02a2,
	0x82e3,  0x02e6,  0x02ec,  0x82e9,  0x02f8,  0x82fd,  0x82f7,  0x02f2,
	0x02d0,  0x82d5,  0x82df,  0x02da,  0x82cb,  0x02ce,  0x02c4,  0x82c1,
	0x8243,  0x0246,  0x024c,  0x8249,  0x0258,  0x825d,  0x8257,  0x0252,
	0x0270,  0x8275,  0x827f,  0x027a,  0x826b,  0x026e,  0x0264,  0x8261,
	0x0220,  0x8225,  0x822f,  0x022a,  0x823b,  0x023e,  0x0234,  0x8231,
	0x8213,  0x0216,  0x021c,  0x8219,  0x0208,  0x820d,  0x8207,  0x0202
};


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void FLAC__crc8_update(const FLAC__byte data, FLAC__uint8 *crc)
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{
	*crc = FLAC__crc8_table[*crc ^ data];
}

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void FLAC__crc8_update_block(const FLAC__byte *data, unsigned len, FLAC__uint8 *crc)
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{
	while(len--)
		*crc = FLAC__crc8_table[*crc ^ *data++];
}

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FLAC__uint8 FLAC__crc8(const FLAC__byte *data, unsigned len)
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{
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	FLAC__uint8 crc = 0;
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	while(len--)
		crc = FLAC__crc8_table[crc ^ *data++];

	return crc;
}

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unsigned FLAC__crc16(const FLAC__byte *data, unsigned len)
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{
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	unsigned crc = 0;
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	while(len--)
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		crc = ((crc<<8) ^ FLAC__crc16_table[(crc>>8) ^ *data++]) & 0xffff;
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	return crc;
}