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Adding iso14443b_crc_append()

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This commit is contained in:
Philippe Teuwen 2013-08-19 14:55:27 +02:00
parent bb5b712a74
commit c3a5fba028
2 changed files with 35 additions and 2 deletions
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2
include/nfc/nfc.h
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@ -135,6 +135,8 @@ NFC_EXPORT int nfc_device_set_property_bool(nfc_device *pnd, const nfc_property
/* Misc. functions */
NFC_EXPORT void iso14443a_crc(uint8_t *pbtData, size_t szLen, uint8_t *pbtCrc);
NFC_EXPORT void iso14443a_crc_append(uint8_t *pbtData, size_t szLen);
NFC_EXPORT void iso14443b_crc(uint8_t *pbtData, size_t szLen, uint8_t *pbtCrc);
NFC_EXPORT void iso14443b_crc_append(uint8_t *pbtData, size_t szLen);
NFC_EXPORT uint8_t *iso14443a_locate_historical_bytes(uint8_t *pbtAts, size_t szAts, size_t *pszTk);
NFC_EXPORT void nfc_free(void *p);

35
libnfc/iso14443-subr.c
View file

@ -41,7 +41,7 @@
/**
* @brief CRC
* @brief CRC_A
*
*/
void
@ -62,7 +62,7 @@ iso14443a_crc(uint8_t *pbtData, size_t szLen, uint8_t *pbtCrc)
}
/**
* @brief Append CRC
* @brief Append CRC_A
*
*/
void
@ -71,6 +71,37 @@ iso14443a_crc_append(uint8_t *pbtData, size_t szLen)
iso14443a_crc(pbtData, szLen, pbtData + szLen);
}
/**
* @brief CRC_B
*
*/
void
iso14443b_crc(uint8_t *pbtData, size_t szLen, uint8_t *pbtCrc)
{
uint8_t bt;
uint32_t wCrc = 0xFFFF;
do {
bt = *pbtData++;
bt = (bt ^ (uint8_t)(wCrc & 0x00FF));
bt = (bt ^ (bt << 4));
wCrc = (wCrc >> 8) ^ ((uint32_t) bt << 8) ^ ((uint32_t) bt << 3) ^ ((uint32_t) bt >> 4);
} while (--szLen);
wCrc = ~wCrc;
*pbtCrc++ = (uint8_t)(wCrc & 0xFF);
*pbtCrc = (uint8_t)((wCrc >> 8) & 0xFF);
}
/**
* @brief Append CRC_B
*
*/
void
iso14443b_crc_append(uint8_t *pbtData, size_t szLen)
{
iso14443b_crc(pbtData, szLen, pbtData + szLen);
}
/**
* @brief Locate historical bytes
* @see ISO/IEC 14443-4 (5.2.7 Historical bytes)