1 files changed, 101 insertions, 0 deletions
diff --git a/src/include/port/pg_crc32c.h b/src/include/port/pg_crc32c.h
new file mode 100644
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+++ b/src/include/port/pg_crc32c.h
@@ -0,0 +1,101 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_crc32c.h
+ *	  Routines for computing CRC-32C checksums.
+ *
+ * The speed of CRC-32C calculation has a big impact on performance, so we
+ * jump through some hoops to get the best implementation for each
+ * platform. Some CPU architectures have special instructions for speeding
+ * up CRC calculations (e.g. Intel SSE 4.2), on other platforms we use the
+ * Slicing-by-8 algorithm which uses lookup tables.
+ *
+ * The public interface consists of four macros:
+ *
+ * INIT_CRC32C(crc)
+ *		Initialize a CRC accumulator
+ *
+ * COMP_CRC32C(crc, data, len)
+ *		Accumulate some (more) bytes into a CRC
+ *
+ * FIN_CRC32C(crc)
+ *		Finish a CRC calculation
+ *
+ * EQ_CRC32C(c1, c2)
+ *		Check for equality of two CRCs.
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/port/pg_crc32c.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef PG_CRC32C_H
+#define PG_CRC32C_H
+
+#include "port/pg_bswap.h"
+
+typedef uint32 pg_crc32c;
+
+/* The INIT and EQ macros are the same for all implementations. */
+#define INIT_CRC32C(crc) ((crc) = 0xFFFFFFFF)
+#define EQ_CRC32C(c1, c2) ((c1) == (c2))
+
+#if defined(USE_SSE42_CRC32C)
+/* Use Intel SSE4.2 instructions. */
+#define COMP_CRC32C(crc, data, len) \
+	((crc) = pg_comp_crc32c_sse42((crc), (data), (len)))
+#define FIN_CRC32C(crc) ((crc) ^= 0xFFFFFFFF)
+
+extern pg_crc32c pg_comp_crc32c_sse42(pg_crc32c crc, const void *data, size_t len);
+
+#elif defined(USE_ARMV8_CRC32C)
+/* Use ARMv8 CRC Extension instructions. */
+
+#define COMP_CRC32C(crc, data, len)							\
+	((crc) = pg_comp_crc32c_armv8((crc), (data), (len)))
+#define FIN_CRC32C(crc) ((crc) ^= 0xFFFFFFFF)
+
+extern pg_crc32c pg_comp_crc32c_armv8(pg_crc32c crc, const void *data, size_t len);
+
+#elif defined(USE_SSE42_CRC32C_WITH_RUNTIME_CHECK) || defined(USE_ARMV8_CRC32C_WITH_RUNTIME_CHECK)
+
+/*
+ * Use Intel SSE 4.2 or ARMv8 instructions, but perform a runtime check first
+ * to check that they are available.
+ */
+#define COMP_CRC32C(crc, data, len) \
+	((crc) = pg_comp_crc32c((crc), (data), (len)))
+#define FIN_CRC32C(crc) ((crc) ^= 0xFFFFFFFF)
+
+extern pg_crc32c pg_comp_crc32c_sb8(pg_crc32c crc, const void *data, size_t len);
+extern pg_crc32c (*pg_comp_crc32c) (pg_crc32c crc, const void *data, size_t len);
+
+#ifdef USE_SSE42_CRC32C_WITH_RUNTIME_CHECK
+extern pg_crc32c pg_comp_crc32c_sse42(pg_crc32c crc, const void *data, size_t len);
+#endif
+#ifdef USE_ARMV8_CRC32C_WITH_RUNTIME_CHECK
+extern pg_crc32c pg_comp_crc32c_armv8(pg_crc32c crc, const void *data, size_t len);
+#endif
+
+#else
+/*
+ * Use slicing-by-8 algorithm.
+ *
+ * On big-endian systems, the intermediate value is kept in reverse byte
+ * order, to avoid byte-swapping during the calculation. FIN_CRC32C reverses
+ * the bytes to the final order.
+ */
+#define COMP_CRC32C(crc, data, len) \
+	((crc) = pg_comp_crc32c_sb8((crc), (data), (len)))
+#ifdef WORDS_BIGENDIAN
+#define FIN_CRC32C(crc) ((crc) = pg_bswap32(crc) ^ 0xFFFFFFFF)
+#else
+#define FIN_CRC32C(crc) ((crc) ^= 0xFFFFFFFF)
+#endif
+
+extern pg_crc32c pg_comp_crc32c_sb8(pg_crc32c crc, const void *data, size_t len);
+
+#endif
+
+#endif							/* PG_CRC32C_H */