180 lines
8.1 KiB
C
180 lines
8.1 KiB
C
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#ifndef HAMMING_H
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#define HAMMING_H
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// Hamming 8/4 decoding table
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// decoded_value = hamming_8_4_decode[encoded_value]
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// 0xff - double bit error that can't be corrected
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const unsigned char hamming_8_4_decode[256] = {
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0x01, 0xff, 0x01, 0x01, 0xff, 0x00, 0x01, 0xff,
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0xff, 0x02, 0x01, 0xff, 0x0a, 0xff, 0xff, 0x07,
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0xff, 0x00, 0x01, 0xff, 0x00, 0x00, 0xff, 0x00,
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0x06, 0xff, 0xff, 0x0b, 0xff, 0x00, 0x03, 0xff,
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0xff, 0x0c, 0x01, 0xff, 0x04, 0xff, 0xff, 0x07,
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0x06, 0xff, 0xff, 0x07, 0xff, 0x07, 0x07, 0x07,
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0x06, 0xff, 0xff, 0x05, 0xff, 0x00, 0x0d, 0xff,
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0x06, 0x06, 0x06, 0xff, 0x06, 0xff, 0xff, 0x07,
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0xff, 0x02, 0x01, 0xff, 0x04, 0xff, 0xff, 0x09,
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0x02, 0x02, 0xff, 0x02, 0xff, 0x02, 0x03, 0xff,
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0x08, 0xff, 0xff, 0x05, 0xff, 0x00, 0x03, 0xff,
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0xff, 0x02, 0x03, 0xff, 0x03, 0xff, 0x03, 0x03,
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0x04, 0xff, 0xff, 0x05, 0x04, 0x04, 0x04, 0xff,
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0xff, 0x02, 0x0f, 0xff, 0x04, 0xff, 0xff, 0x07,
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0xff, 0x05, 0x05, 0x05, 0x04, 0xff, 0xff, 0x05,
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0x06, 0xff, 0xff, 0x05, 0xff, 0x0e, 0x03, 0xff,
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0xff, 0x0c, 0x01, 0xff, 0x0a, 0xff, 0xff, 0x09,
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0x0a, 0xff, 0xff, 0x0b, 0x0a, 0x0a, 0x0a, 0xff,
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0x08, 0xff, 0xff, 0x0b, 0xff, 0x00, 0x0d, 0xff,
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0xff, 0x0b, 0x0b, 0x0b, 0x0a, 0xff, 0xff, 0x0b,
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0x0c, 0x0c, 0xff, 0x0c, 0xff, 0x0c, 0x0d, 0xff,
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0xff, 0x0c, 0x0f, 0xff, 0x0a, 0xff, 0xff, 0x07,
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0xff, 0x0c, 0x0d, 0xff, 0x0d, 0xff, 0x0d, 0x0d,
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0x06, 0xff, 0xff, 0x0b, 0xff, 0x0e, 0x0d, 0xff,
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0x08, 0xff, 0xff, 0x09, 0xff, 0x09, 0x09, 0x09,
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0xff, 0x02, 0x0f, 0xff, 0x0a, 0xff, 0xff, 0x09,
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0x08, 0x08, 0x08, 0xff, 0x08, 0xff, 0xff, 0x09,
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0x08, 0xff, 0xff, 0x0b, 0xff, 0x0e, 0x03, 0xff,
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0xff, 0x0c, 0x0f, 0xff, 0x04, 0xff, 0xff, 0x09,
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0x0f, 0xff, 0x0f, 0x0f, 0xff, 0x0e, 0x0f, 0xff,
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0x08, 0xff, 0xff, 0x05, 0xff, 0x0e, 0x0d, 0xff,
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0xff, 0x0e, 0x0f, 0xff, 0x0e, 0x0e, 0xff, 0x0e
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};
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const unsigned char hamming_24_18_parities[3][256] = {
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{ // Parities of first byte
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0x00, 0x21, 0x22, 0x03, 0x23, 0x02, 0x01, 0x20,
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0x24, 0x05, 0x06, 0x27, 0x07, 0x26, 0x25, 0x04,
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0x25, 0x04, 0x07, 0x26, 0x06, 0x27, 0x24, 0x05,
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0x01, 0x20, 0x23, 0x02, 0x22, 0x03, 0x00, 0x21,
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0x26, 0x07, 0x04, 0x25, 0x05, 0x24, 0x27, 0x06,
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0x02, 0x23, 0x20, 0x01, 0x21, 0x00, 0x03, 0x22,
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0x03, 0x22, 0x21, 0x00, 0x20, 0x01, 0x02, 0x23,
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0x27, 0x06, 0x05, 0x24, 0x04, 0x25, 0x26, 0x07,
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0x27, 0x06, 0x05, 0x24, 0x04, 0x25, 0x26, 0x07,
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0x03, 0x22, 0x21, 0x00, 0x20, 0x01, 0x02, 0x23,
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0x02, 0x23, 0x20, 0x01, 0x21, 0x00, 0x03, 0x22,
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0x26, 0x07, 0x04, 0x25, 0x05, 0x24, 0x27, 0x06,
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0x01, 0x20, 0x23, 0x02, 0x22, 0x03, 0x00, 0x21,
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0x25, 0x04, 0x07, 0x26, 0x06, 0x27, 0x24, 0x05,
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0x24, 0x05, 0x06, 0x27, 0x07, 0x26, 0x25, 0x04,
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0x00, 0x21, 0x22, 0x03, 0x23, 0x02, 0x01, 0x20,
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0x28, 0x09, 0x0a, 0x2b, 0x0b, 0x2a, 0x29, 0x08,
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0x0c, 0x2d, 0x2e, 0x0f, 0x2f, 0x0e, 0x0d, 0x2c,
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0x0d, 0x2c, 0x2f, 0x0e, 0x2e, 0x0f, 0x0c, 0x2d,
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0x29, 0x08, 0x0b, 0x2a, 0x0a, 0x2b, 0x28, 0x09,
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0x0e, 0x2f, 0x2c, 0x0d, 0x2d, 0x0c, 0x0f, 0x2e,
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0x2a, 0x0b, 0x08, 0x29, 0x09, 0x28, 0x2b, 0x0a,
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0x2b, 0x0a, 0x09, 0x28, 0x08, 0x29, 0x2a, 0x0b,
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0x0f, 0x2e, 0x2d, 0x0c, 0x2c, 0x0d, 0x0e, 0x2f,
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0x0f, 0x2e, 0x2d, 0x0c, 0x2c, 0x0d, 0x0e, 0x2f,
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0x2b, 0x0a, 0x09, 0x28, 0x08, 0x29, 0x2a, 0x0b,
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0x2a, 0x0b, 0x08, 0x29, 0x09, 0x28, 0x2b, 0x0a,
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0x0e, 0x2f, 0x2c, 0x0d, 0x2d, 0x0c, 0x0f, 0x2e,
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0x29, 0x08, 0x0b, 0x2a, 0x0a, 0x2b, 0x28, 0x09,
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0x0d, 0x2c, 0x2f, 0x0e, 0x2e, 0x0f, 0x0c, 0x2d,
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0x0c, 0x2d, 0x2e, 0x0f, 0x2f, 0x0e, 0x0d, 0x2c,
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0x28, 0x09, 0x0a, 0x2b, 0x0b, 0x2a, 0x29, 0x08
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},
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{ // Parities of second byte
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0x00, 0x29, 0x2a, 0x03, 0x2b, 0x02, 0x01, 0x28,
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0x2c, 0x05, 0x06, 0x2f, 0x07, 0x2e, 0x2d, 0x04,
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0x2d, 0x04, 0x07, 0x2e, 0x06, 0x2f, 0x2c, 0x05,
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0x01, 0x28, 0x2b, 0x02, 0x2a, 0x03, 0x00, 0x29,
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0x2e, 0x07, 0x04, 0x2d, 0x05, 0x2c, 0x2f, 0x06,
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0x02, 0x2b, 0x28, 0x01, 0x29, 0x00, 0x03, 0x2a,
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0x03, 0x2a, 0x29, 0x00, 0x28, 0x01, 0x02, 0x2b,
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0x2f, 0x06, 0x05, 0x2c, 0x04, 0x2d, 0x2e, 0x07,
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0x2f, 0x06, 0x05, 0x2c, 0x04, 0x2d, 0x2e, 0x07,
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0x03, 0x2a, 0x29, 0x00, 0x28, 0x01, 0x02, 0x2b,
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0x02, 0x2b, 0x28, 0x01, 0x29, 0x00, 0x03, 0x2a,
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0x2e, 0x07, 0x04, 0x2d, 0x05, 0x2c, 0x2f, 0x06,
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0x01, 0x28, 0x2b, 0x02, 0x2a, 0x03, 0x00, 0x29,
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0x2d, 0x04, 0x07, 0x2e, 0x06, 0x2f, 0x2c, 0x05,
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0x2c, 0x05, 0x06, 0x2f, 0x07, 0x2e, 0x2d, 0x04,
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0x00, 0x29, 0x2a, 0x03, 0x2b, 0x02, 0x01, 0x28,
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0x30, 0x19, 0x1a, 0x33, 0x1b, 0x32, 0x31, 0x18,
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0x1c, 0x35, 0x36, 0x1f, 0x37, 0x1e, 0x1d, 0x34,
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0x1d, 0x34, 0x37, 0x1e, 0x36, 0x1f, 0x1c, 0x35,
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0x31, 0x18, 0x1b, 0x32, 0x1a, 0x33, 0x30, 0x19,
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0x1e, 0x37, 0x34, 0x1d, 0x35, 0x1c, 0x1f, 0x36,
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0x32, 0x1b, 0x18, 0x31, 0x19, 0x30, 0x33, 0x1a,
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0x33, 0x1a, 0x19, 0x30, 0x18, 0x31, 0x32, 0x1b,
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0x1f, 0x36, 0x35, 0x1c, 0x34, 0x1d, 0x1e, 0x37,
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0x1f, 0x36, 0x35, 0x1c, 0x34, 0x1d, 0x1e, 0x37,
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0x33, 0x1a, 0x19, 0x30, 0x18, 0x31, 0x32, 0x1b,
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0x32, 0x1b, 0x18, 0x31, 0x19, 0x30, 0x33, 0x1a,
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0x1e, 0x37, 0x34, 0x1d, 0x35, 0x1c, 0x1f, 0x36,
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0x31, 0x18, 0x1b, 0x32, 0x1a, 0x33, 0x30, 0x19,
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0x1d, 0x34, 0x37, 0x1e, 0x36, 0x1f, 0x1c, 0x35,
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0x1c, 0x35, 0x36, 0x1f, 0x37, 0x1e, 0x1d, 0x34,
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0x30, 0x19, 0x1a, 0x33, 0x1b, 0x32, 0x31, 0x18
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},
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{ // Parities of third byte
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0x3f, 0x0e, 0x0d, 0x3c, 0x0c, 0x3d, 0x3e, 0x0f,
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0x0b, 0x3a, 0x39, 0x08, 0x38, 0x09, 0x0a, 0x3b,
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0x0a, 0x3b, 0x38, 0x09, 0x39, 0x08, 0x0b, 0x3a,
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0x3e, 0x0f, 0x0c, 0x3d, 0x0d, 0x3c, 0x3f, 0x0e,
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0x09, 0x38, 0x3b, 0x0a, 0x3a, 0x0b, 0x08, 0x39,
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0x3d, 0x0c, 0x0f, 0x3e, 0x0e, 0x3f, 0x3c, 0x0d,
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0x3c, 0x0d, 0x0e, 0x3f, 0x0f, 0x3e, 0x3d, 0x0c,
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0x08, 0x39, 0x3a, 0x0b, 0x3b, 0x0a, 0x09, 0x38,
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0x08, 0x39, 0x3a, 0x0b, 0x3b, 0x0a, 0x09, 0x38,
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0x3c, 0x0d, 0x0e, 0x3f, 0x0f, 0x3e, 0x3d, 0x0c,
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0x3d, 0x0c, 0x0f, 0x3e, 0x0e, 0x3f, 0x3c, 0x0d,
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0x09, 0x38, 0x3b, 0x0a, 0x3a, 0x0b, 0x08, 0x39,
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0x3e, 0x0f, 0x0c, 0x3d, 0x0d, 0x3c, 0x3f, 0x0e,
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0x0a, 0x3b, 0x38, 0x09, 0x39, 0x08, 0x0b, 0x3a,
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0x0b, 0x3a, 0x39, 0x08, 0x38, 0x09, 0x0a, 0x3b,
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0x3f, 0x0e, 0x0d, 0x3c, 0x0c, 0x3d, 0x3e, 0x0f,
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0x1f, 0x2e, 0x2d, 0x1c, 0x2c, 0x1d, 0x1e, 0x2f,
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0x2b, 0x1a, 0x19, 0x28, 0x18, 0x29, 0x2a, 0x1b,
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0x2a, 0x1b, 0x18, 0x29, 0x19, 0x28, 0x2b, 0x1a,
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0x1e, 0x2f, 0x2c, 0x1d, 0x2d, 0x1c, 0x1f, 0x2e,
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0x29, 0x18, 0x1b, 0x2a, 0x1a, 0x2b, 0x28, 0x19,
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0x1d, 0x2c, 0x2f, 0x1e, 0x2e, 0x1f, 0x1c, 0x2d,
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0x1c, 0x2d, 0x2e, 0x1f, 0x2f, 0x1e, 0x1d, 0x2c,
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0x28, 0x19, 0x1a, 0x2b, 0x1b, 0x2a, 0x29, 0x18,
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0x28, 0x19, 0x1a, 0x2b, 0x1b, 0x2a, 0x29, 0x18,
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0x1c, 0x2d, 0x2e, 0x1f, 0x2f, 0x1e, 0x1d, 0x2c,
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0x1d, 0x2c, 0x2f, 0x1e, 0x2e, 0x1f, 0x1c, 0x2d,
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0x29, 0x18, 0x1b, 0x2a, 0x1a, 0x2b, 0x28, 0x19,
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0x1e, 0x2f, 0x2c, 0x1d, 0x2d, 0x1c, 0x1f, 0x2e,
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0x2a, 0x1b, 0x18, 0x29, 0x19, 0x28, 0x2b, 0x1a,
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0x2b, 0x1a, 0x19, 0x28, 0x18, 0x29, 0x2a, 0x1b,
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0x1f, 0x2e, 0x2d, 0x1c, 0x2c, 0x1d, 0x1e, 0x2f
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}
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};
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static const unsigned char hamming_24_18_decode_d1_d4[64] = {
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0x00, 0x01, 0x00, 0x01, 0x02, 0x03, 0x02, 0x03,
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0x04, 0x05, 0x04, 0x05, 0x06, 0x07, 0x06, 0x07,
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0x08, 0x09, 0x08, 0x09, 0x0a, 0x0b, 0x0a, 0x0b,
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0x0c, 0x0d, 0x0c, 0x0d, 0x0e, 0x0f, 0x0e, 0x0f,
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0x00, 0x01, 0x00, 0x01, 0x02, 0x03, 0x02, 0x03,
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0x04, 0x05, 0x04, 0x05, 0x06, 0x07, 0x06, 0x07,
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0x08, 0x09, 0x08, 0x09, 0x0a, 0x0b, 0x0a, 0x0b,
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0x0c, 0x0d, 0x0c, 0x0d, 0x0e, 0x0f, 0x0e, 0x0f
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};
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// Mapping from parity checks in hamming_24_18_parities to incorrect bit
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// 0x80000000 - double bit error that can't be corrected
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static const unsigned int hamming_24_18_decode_correct [64] = {
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0x00000000, 0x80000000, 0x80000000, 0x80000000,
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0x80000000, 0x80000000, 0x80000000, 0x80000000,
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0x80000000, 0x80000000, 0x80000000, 0x80000000,
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0x80000000, 0x80000000, 0x80000000, 0x80000000,
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0x80000000, 0x80000000, 0x80000000, 0x80000000,
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0x80000000, 0x80000000, 0x80000000, 0x80000000,
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0x80000000, 0x80000000, 0x80000000, 0x80000000,
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0x80000000, 0x80000000, 0x80000000, 0x80000000,
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0x00000000, 0x00000000, 0x00000000, 0x00000001,
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0x00000000, 0x00000002, 0x00000004, 0x00000008,
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0x00000000, 0x00000010, 0x00000020, 0x00000040,
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0x00000080, 0x00000100, 0x00000200, 0x00000400,
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0x00000000, 0x00000800, 0x00001000, 0x00002000,
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0x00004000, 0x00008000, 0x00010000, 0x00020000,
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0x80000000, 0x80000000, 0x80000000, 0x80000000,
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0x80000000, 0x80000000, 0x80000000, 0x80000000
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};
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#endif
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