From 8f4ea2630332d7c41d9fc49182e3a83e2b7cb5cf Mon Sep 17 00:00:00 2001 From: Imbus <> Date: Wed, 10 Sep 2025 09:24:02 +0200 Subject: [PATCH] crc32 --- crc32/Makefile | 12 +++++++ crc32/crc32.h | 78 ++++++++++++++++++++++++++++++++++++++++++ crc32/crc32_nolookup.h | 33 ++++++++++++++++++ crc32/test.c | 24 +++++++++++++ 4 files changed, 147 insertions(+) create mode 100644 crc32/Makefile create mode 100644 crc32/crc32.h create mode 100644 crc32/crc32_nolookup.h create mode 100644 crc32/test.c diff --git a/crc32/Makefile b/crc32/Makefile new file mode 100644 index 0000000..7cf024d --- /dev/null +++ b/crc32/Makefile @@ -0,0 +1,12 @@ +CC ?= gcc +CFLAGS ?= -Wall -O2 + +TARGET = test.elf +SRC = test.c + +$(TARGET): $(SRC) + @echo CC $@ + @$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS) + +clean: + rm -f $(TARGET) diff --git a/crc32/crc32.h b/crc32/crc32.h new file mode 100644 index 0000000..29552eb --- /dev/null +++ b/crc32/crc32.h @@ -0,0 +1,78 @@ +#ifndef CRC32_H +#define CRC32_H + +#include +#include + +/* + * CRC-32 (IEEE 802.3, gzip, zip, etc.) + * Polynomial: 0xEDB88320 (reflected) + * Init value: 0xFFFFFFFF + * Final XOR: 0xFFFFFFFF + */ + +#define CRC32_INIT ((uint32_t)0xFFFFFFFFU) +#define CRC32_XOR ((uint32_t)0xFFFFFFFFU) + +static const uint32_t crc32_table[256] = { + 0x00000000U, 0x77073096U, 0xEE0E612CU, 0x990951BAU, 0x076DC419U, 0x706AF48FU, 0xE963A535U, 0x9E6495A3U, 0x0EDB8832U, + 0x79DCB8A4U, 0xE0D5E91EU, 0x97D2D988U, 0x09B64C2BU, 0x7EB17CBDU, 0xE7B82D07U, 0x90BF1D91U, 0x1DB71064U, 0x6AB020F2U, + 0xF3B97148U, 0x84BE41DEU, 0x1ADAD47DU, 0x6DDDE4EBU, 0xF4D4B551U, 0x83D385C7U, 0x136C9856U, 0x646BA8C0U, 0xFD62F97AU, + 0x8A65C9ECU, 0x14015C4FU, 0x63066CD9U, 0xFA0F3D63U, 0x8D080DF5U, 0x3B6E20C8U, 0x4C69105EU, 0xD56041E4U, 0xA2677172U, + 0x3C03E4D1U, 0x4B04D447U, 0xD20D85FDU, 0xA50AB56BU, 0x35B5A8FAU, 0x42B2986CU, 0xDBBBC9D6U, 0xACBCF940U, 0x32D86CE3U, + 0x45DF5C75U, 0xDCD60DCFU, 0xABD13D59U, 0x26D930ACU, 0x51DE003AU, 0xC8D75180U, 0xBFD06116U, 0x21B4F4B5U, 0x56B3C423U, + 0xCFBA9599U, 0xB8BDA50FU, 0x2802B89EU, 0x5F058808U, 0xC60CD9B2U, 0xB10BE924U, 0x2F6F7C87U, 0x58684C11U, 0xC1611DABU, + 0xB6662D3DU, 0x76DC4190U, 0x01DB7106U, 0x98D220BCU, 0xEFD5102AU, 0x71B18589U, 0x06B6B51FU, 0x9FBFE4A5U, 0xE8B8D433U, + 0x7807C9A2U, 0x0F00F934U, 0x9609A88EU, 0xE10E9818U, 0x7F6A0DBBU, 0x086D3D2DU, 0x91646C97U, 0xE6635C01U, 0x6B6B51F4U, + 0x1C6C6162U, 0x856530D8U, 0xF262004EU, 0x6C0695EDU, 0x1B01A57BU, 0x8208F4C1U, 0xF50FC457U, 0x65B0D9C6U, 0x12B7E950U, + 0x8BBEB8EAU, 0xFCB9887CU, 0x62DD1DDFU, 0x15DA2D49U, 0x8CD37CF3U, 0xFBD44C65U, 0x4DB26158U, 0x3AB551CEU, 0xA3BC0074U, + 0xD4BB30E2U, 0x4ADFA541U, 0x3DD895D7U, 0xA4D1C46DU, 0xD3D6F4FBU, 0x4369E96AU, 0x346ED9FCU, 0xAD678846U, 0xDA60B8D0U, + 0x44042D73U, 0x33031DE5U, 0xAA0A4C5FU, 0xDD0D7CC9U, 0x5005713CU, 0x270241AAU, 0xBE0B1010U, 0xC90C2086U, 0x5768B525U, + 0x206F85B3U, 0xB966D409U, 0xCE61E49FU, 0x5EDEF90EU, 0x29D9C998U, 0xB0D09822U, 0xC7D7A8B4U, 0x59B33D17U, 0x2EB40D81U, + 0xB7BD5C3BU, 0xC0BA6CADU, 0xEDB88320U, 0x9ABFB3B6U, 0x03B6E20CU, 0x74B1D29AU, 0xEAD54739U, 0x9DD277AFU, 0x04DB2615U, + 0x73DC1683U, 0xE3630B12U, 0x94643B84U, 0x0D6D6A3EU, 0x7A6A5AA8U, 0xE40ECF0BU, 0x9309FF9DU, 0x0A00AE27U, 0x7D079EB1U, + 0xF00F9344U, 0x8708A3D2U, 0x1E01F268U, 0x6906C2FEU, 0xF762575DU, 0x806567CBU, 0x196C3671U, 0x6E6B06E7U, 0xFED41B76U, + 0x89D32BE0U, 0x10DA7A5AU, 0x67DD4ACCU, 0xF9B9DF6FU, 0x8EBEEFF9U, 0x17B7BE43U, 0x60B08ED5U, 0xD6D6A3E8U, 0xA1D1937EU, + 0x38D8C2C4U, 0x4FDFF252U, 0xD1BB67F1U, 0xA6BC5767U, 0x3FB506DDU, 0x48B2364BU, 0xD80D2BDAU, 0xAF0A1B4CU, 0x36034AF6U, + 0x41047A60U, 0xDF60EFC3U, 0xA867DF55U, 0x316E8EEFU, 0x4669BE79U, 0xCB61B38CU, 0xBC66831AU, 0x256FD2A0U, 0x5268E236U, + 0xCC0C7795U, 0xBB0B4703U, 0x220216B9U, 0x5505262FU, 0xC5BA3BBEU, 0xB2BD0B28U, 0x2BB45A92U, 0x5CB36A04U, 0xC2D7FFA7U, + 0xB5D0CF31U, 0x2CD99E8BU, 0x5BDEAE1DU, 0x9B64C2B0U, 0xEC63F226U, 0x756AA39CU, 0x026D930AU, 0x9C0906A9U, 0xEB0E363FU, + 0x72076785U, 0x05005713U, 0x95BF4A82U, 0xE2B87A14U, 0x7BB12BAEU, 0x0CB61B38U, 0x92D28E9BU, 0xE5D5BE0DU, 0x7CDCEFB7U, + 0x0BDBDF21U, 0x86D3D2D4U, 0xF1D4E242U, 0x68DDB3F8U, 0x1FDA836EU, 0x81BE16CDU, 0xF6B9265BU, 0x6FB077E1U, 0x18B74777U, + 0x88085AE6U, 0xFF0F6A70U, 0x66063BCAU, 0x11010B5CU, 0x8F659EFFU, 0xF862AE69U, 0x616BFFD3U, 0x166CCF45U, 0xA00AE278U, + 0xD70DD2EEU, 0x4E048354U, 0x3903B3C2U, 0xA7672661U, 0xD06016F7U, 0x4969474DU, 0x3E6E77DBU, 0xAED16A4AU, 0xD9D65ADCU, + 0x40DF0B66U, 0x37D83BF0U, 0xA9BCAE53U, 0xDEBB9EC5U, 0x47B2CF7FU, 0x30B5FFE9U, 0xBDBDF21CU, 0xCABAC28AU, 0x53B39330U, + 0x24B4A3A6U, 0xBAD03605U, 0xCDD70693U, 0x54DE5729U, 0x23D967BFU, 0xB3667A2EU, 0xC4614AB8U, 0x5D681B02U, 0x2A6F2B94U, + 0xB40BBE37U, 0xC30C8EA1U, 0x5A05DF1BU, 0x2D02EF8DU, +}; + +static inline uint32_t crc32_update_raw(uint32_t crc, const void *data, unsigned int length) { + const uint8_t *p = (const uint8_t *)data; + while (length--) { + crc = (crc >> 8) ^ crc32_table[(crc ^ *p++) & 0xFFU]; + } + return crc; +} + +static inline uint32_t crc32(const void *data, unsigned int length) { + uint32_t crc = CRC32_INIT; + crc = crc32_update_raw(crc, data, length); + return crc ^ CRC32_XOR; +} + +static inline uint32_t crc32_init(void) { + return CRC32_INIT; +} + +static inline uint32_t crc32_update(uint32_t crc, const void *data, unsigned int length) { + return crc32_update_raw(crc, data, length); +} + +static inline uint32_t crc32_finalize(uint32_t crc) { + return crc ^ CRC32_XOR; +} + +#undef CRC32_XOR +#undef CRC32_INIT + +#endif // CRC32_H diff --git a/crc32/crc32_nolookup.h b/crc32/crc32_nolookup.h new file mode 100644 index 0000000..a594046 --- /dev/null +++ b/crc32/crc32_nolookup.h @@ -0,0 +1,33 @@ +#ifndef CRC32_H +#define CRC32_H + +#include +#include + +/* + * CRC-32 (IEEE 802.3) implementation + * Polynomial: 0xEDB88320 (reflected) + * Initial value: 0xFFFFFFFF + * Final XOR: 0xFFFFFFFF + * Input reflected: Yes + * Output reflected: Yes + */ + +static inline uint32_t crc32_ieee(const void *data, size_t len) { + const uint8_t *p = (const uint8_t *)data; + uint32_t crc = 0xFFFFFFFF; + + while (len--) { + crc ^= *p++; + for (int i = 0; i < 8; i++) { + if (crc & 1) + crc = (crc >> 1) ^ 0xEDB88320; + else + crc >>= 1; + } + } + + return crc ^ 0xFFFFFFFF; +} + +#endif // CRC32_H diff --git a/crc32/test.c b/crc32/test.c new file mode 100644 index 0000000..b3778d1 --- /dev/null +++ b/crc32/test.c @@ -0,0 +1,24 @@ +#include "crc32.h" +#include +#include + +int main(void) { + assert(crc32("123456789", 9) == 0xCBF43926); + assert(crc32("", 0) == 0x00000000); + assert(crc32("a", 1) == 0xE8B7BE43); + assert(crc32("A", 1) == 0xD3D99E8B); + assert(crc32("hello", 5) == 0x3610A686); + assert(crc32("The quick brown fox jumps over the lazy dog", 43) == 0x414FA339); + assert(crc32("The quick brown fox jumps over the lazy dog.", 44) == 0x519025E9); + + /* Keep in mind the update api requires initialization and finalization */ + uint32_t crc = crc32_init(); + crc = crc32_update_raw(crc, "a", 1); + crc = crc32_finalize(crc); + + assert(crc == crc32("a", 1)); + assert(crc == 0xE8B7BE43); + + printf("All good!\n"); + return 0; +}