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dep/libchdr: Add EDC computation functions

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Stenzek 2024-09-01 19:43:16 +10:00
parent e78539d7f9
commit 1b7c56ece5
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2 changed files with 48 additions and 0 deletions
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2
dep/libchdr/include/libchdr/cdrom.h
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@ -70,6 +70,8 @@ bool cdrom_parse_subtype_string(const char* typestring, uint32_t* subtype, uint3
int ecc_verify(const uint8_t *sector);
void ecc_generate(uint8_t *sector);
void ecc_clear(uint8_t *sector);
uint32_t edc_compute(const uint8_t* data, uint32_t length);
void edc_set(uint8_t* dst, uint32_t edc);
#endif

46
dep/libchdr/src/libchdr_cdrom.c
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@ -441,4 +441,50 @@ void ecc_clear(uint8_t *sector)
memset(&sector[ECC_Q_OFFSET], 0, 2 * ECC_Q_NUM_BYTES);
}
static const uint32_t edc_table[256] = {
0x00000000, 0x90910101, 0x91210201, 0x01b00300, 0x92410401, 0x02d00500, 0x03600600, 0x93f10701, 0x94810801,
0x04100900, 0x05a00a00, 0x95310b01, 0x06c00c00, 0x96510d01, 0x97e10e01, 0x07700f00, 0x99011001, 0x09901100,
0x08201200, 0x98b11301, 0x0b401400, 0x9bd11501, 0x9a611601, 0x0af01700, 0x0d801800, 0x9d111901, 0x9ca11a01,
0x0c301b00, 0x9fc11c01, 0x0f501d00, 0x0ee01e00, 0x9e711f01, 0x82012001, 0x12902100, 0x13202200, 0x83b12301,
0x10402400, 0x80d12501, 0x81612601, 0x11f02700, 0x16802800, 0x86112901, 0x87a12a01, 0x17302b00, 0x84c12c01,
0x14502d00, 0x15e02e00, 0x85712f01, 0x1b003000, 0x8b913101, 0x8a213201, 0x1ab03300, 0x89413401, 0x19d03500,
0x18603600, 0x88f13701, 0x8f813801, 0x1f103900, 0x1ea03a00, 0x8e313b01, 0x1dc03c00, 0x8d513d01, 0x8ce13e01,
0x1c703f00, 0xb4014001, 0x24904100, 0x25204200, 0xb5b14301, 0x26404400, 0xb6d14501, 0xb7614601, 0x27f04700,
0x20804800, 0xb0114901, 0xb1a14a01, 0x21304b00, 0xb2c14c01, 0x22504d00, 0x23e04e00, 0xb3714f01, 0x2d005000,
0xbd915101, 0xbc215201, 0x2cb05300, 0xbf415401, 0x2fd05500, 0x2e605600, 0xbef15701, 0xb9815801, 0x29105900,
0x28a05a00, 0xb8315b01, 0x2bc05c00, 0xbb515d01, 0xbae15e01, 0x2a705f00, 0x36006000, 0xa6916101, 0xa7216201,
0x37b06300, 0xa4416401, 0x34d06500, 0x35606600, 0xa5f16701, 0xa2816801, 0x32106900, 0x33a06a00, 0xa3316b01,
0x30c06c00, 0xa0516d01, 0xa1e16e01, 0x31706f00, 0xaf017001, 0x3f907100, 0x3e207200, 0xaeb17301, 0x3d407400,
0xadd17501, 0xac617601, 0x3cf07700, 0x3b807800, 0xab117901, 0xaaa17a01, 0x3a307b00, 0xa9c17c01, 0x39507d00,
0x38e07e00, 0xa8717f01, 0xd8018001, 0x48908100, 0x49208200, 0xd9b18301, 0x4a408400, 0xdad18501, 0xdb618601,
0x4bf08700, 0x4c808800, 0xdc118901, 0xdda18a01, 0x4d308b00, 0xdec18c01, 0x4e508d00, 0x4fe08e00, 0xdf718f01,
0x41009000, 0xd1919101, 0xd0219201, 0x40b09300, 0xd3419401, 0x43d09500, 0x42609600, 0xd2f19701, 0xd5819801,
0x45109900, 0x44a09a00, 0xd4319b01, 0x47c09c00, 0xd7519d01, 0xd6e19e01, 0x46709f00, 0x5a00a000, 0xca91a101,
0xcb21a201, 0x5bb0a300, 0xc841a401, 0x58d0a500, 0x5960a600, 0xc9f1a701, 0xce81a801, 0x5e10a900, 0x5fa0aa00,
0xcf31ab01, 0x5cc0ac00, 0xcc51ad01, 0xcde1ae01, 0x5d70af00, 0xc301b001, 0x5390b100, 0x5220b200, 0xc2b1b301,
0x5140b400, 0xc1d1b501, 0xc061b601, 0x50f0b700, 0x5780b800, 0xc711b901, 0xc6a1ba01, 0x5630bb00, 0xc5c1bc01,
0x5550bd00, 0x54e0be00, 0xc471bf01, 0x6c00c000, 0xfc91c101, 0xfd21c201, 0x6db0c300, 0xfe41c401, 0x6ed0c500,
0x6f60c600, 0xfff1c701, 0xf881c801, 0x6810c900, 0x69a0ca00, 0xf931cb01, 0x6ac0cc00, 0xfa51cd01, 0xfbe1ce01,
0x6b70cf00, 0xf501d001, 0x6590d100, 0x6420d200, 0xf4b1d301, 0x6740d400, 0xf7d1d501, 0xf661d601, 0x66f0d700,
0x6180d800, 0xf111d901, 0xf0a1da01, 0x6030db00, 0xf3c1dc01, 0x6350dd00, 0x62e0de00, 0xf271df01, 0xee01e001,
0x7e90e100, 0x7f20e200, 0xefb1e301, 0x7c40e400, 0xecd1e501, 0xed61e601, 0x7df0e700, 0x7a80e800, 0xea11e901,
0xeba1ea01, 0x7b30eb00, 0xe8c1ec01, 0x7850ed00, 0x79e0ee00, 0xe971ef01, 0x7700f000, 0xe791f101, 0xe621f201,
0x76b0f300, 0xe541f401, 0x75d0f500, 0x7460f600, 0xe4f1f701, 0xe381f801, 0x7310f900, 0x72a0fa00, 0xe231fb01,
0x71c0fc00, 0xe151fd01, 0xe0e1fe01, 0x7070ff00
};
uint32_t edc_compute(const uint8_t* data, uint32_t length)
{
uint32_t edc = 0;
for (uint32_t i = 0; i < length; i++)
edc = (edc >> 8) ^ edc_table[(edc ^ (*data++)) & 0xFF];
return edc;
}
void edc_set(uint8_t* dst, uint32_t edc)
{
// store in little-endian byte order
memcpy(dst, &edc, sizeof(edc));
}
#endif /* WANT_RAW_DATA_SECTOR */