1 files changed, 579 insertions, 0 deletions
diff --git a/src/include/postgres.h b/src/include/postgres.h
new file mode 100644
index 0000000..8a028ff
--- /dev/null
+++ b/src/include/postgres.h
@@ -0,0 +1,579 @@
+/*-------------------------------------------------------------------------
+ *
+ * postgres.h
+ *	  Primary include file for PostgreSQL server .c files
+ *
+ * This should be the first file included by PostgreSQL backend modules.
+ * Client-side code should include postgres_fe.h instead.
+ *
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1995, Regents of the University of California
+ *
+ * src/include/postgres.h
+ *
+ *-------------------------------------------------------------------------
+ */
+/*
+ *----------------------------------------------------------------
+ *	 TABLE OF CONTENTS
+ *
+ *		When adding stuff to this file, please try to put stuff
+ *		into the relevant section, or add new sections as appropriate.
+ *
+ *	  section	description
+ *	  -------	------------------------------------------------
+ *		1)		Datum type + support functions
+ *		2)		miscellaneous
+ *
+ *	 NOTES
+ *
+ *	In general, this file should contain declarations that are widely needed
+ *	in the backend environment, but are of no interest outside the backend.
+ *
+ *	Simple type definitions live in c.h, where they are shared with
+ *	postgres_fe.h.  We do that since those type definitions are needed by
+ *	frontend modules that want to deal with binary data transmission to or
+ *	from the backend.  Type definitions in this file should be for
+ *	representations that never escape the backend, such as Datum.
+ *
+ *----------------------------------------------------------------
+ */
+#ifndef POSTGRES_H
+#define POSTGRES_H
+
+#include "c.h"
+#include "utils/elog.h"
+#include "utils/palloc.h"
+
+/* ----------------------------------------------------------------
+ *				Section 1:	Datum type + support functions
+ * ----------------------------------------------------------------
+ */
+
+/*
+ * A Datum contains either a value of a pass-by-value type or a pointer to a
+ * value of a pass-by-reference type.  Therefore, we require:
+ *
+ * sizeof(Datum) == sizeof(void *) == 4 or 8
+ *
+ * The functions below and the analogous functions for other types should be used to
+ * convert between a Datum and the appropriate C type.
+ */
+
+typedef uintptr_t Datum;
+
+/*
+ * A NullableDatum is used in places where both a Datum and its nullness needs
+ * to be stored. This can be more efficient than storing datums and nullness
+ * in separate arrays, due to better spatial locality, even if more space may
+ * be wasted due to padding.
+ */
+typedef struct NullableDatum
+{
+#define FIELDNO_NULLABLE_DATUM_DATUM 0
+	Datum		value;
+#define FIELDNO_NULLABLE_DATUM_ISNULL 1
+	bool		isnull;
+	/* due to alignment padding this could be used for flags for free */
+} NullableDatum;
+
+#define SIZEOF_DATUM SIZEOF_VOID_P
+
+/*
+ * DatumGetBool
+ *		Returns boolean value of a datum.
+ *
+ * Note: any nonzero value will be considered true.
+ */
+static inline bool
+DatumGetBool(Datum X)
+{
+	return (X != 0);
+}
+
+/*
+ * BoolGetDatum
+ *		Returns datum representation for a boolean.
+ *
+ * Note: any nonzero value will be considered true.
+ */
+static inline Datum
+BoolGetDatum(bool X)
+{
+	return (Datum) (X ? 1 : 0);
+}
+
+/*
+ * DatumGetChar
+ *		Returns character value of a datum.
+ */
+static inline char
+DatumGetChar(Datum X)
+{
+	return (char) X;
+}
+
+/*
+ * CharGetDatum
+ *		Returns datum representation for a character.
+ */
+static inline Datum
+CharGetDatum(char X)
+{
+	return (Datum) X;
+}
+
+/*
+ * Int8GetDatum
+ *		Returns datum representation for an 8-bit integer.
+ */
+static inline Datum
+Int8GetDatum(int8 X)
+{
+	return (Datum) X;
+}
+
+/*
+ * DatumGetUInt8
+ *		Returns 8-bit unsigned integer value of a datum.
+ */
+static inline uint8
+DatumGetUInt8(Datum X)
+{
+	return (uint8) X;
+}
+
+/*
+ * UInt8GetDatum
+ *		Returns datum representation for an 8-bit unsigned integer.
+ */
+static inline Datum
+UInt8GetDatum(uint8 X)
+{
+	return (Datum) X;
+}
+
+/*
+ * DatumGetInt16
+ *		Returns 16-bit integer value of a datum.
+ */
+static inline int16
+DatumGetInt16(Datum X)
+{
+	return (int16) X;
+}
+
+/*
+ * Int16GetDatum
+ *		Returns datum representation for a 16-bit integer.
+ */
+static inline Datum
+Int16GetDatum(int16 X)
+{
+	return (Datum) X;
+}
+
+/*
+ * DatumGetUInt16
+ *		Returns 16-bit unsigned integer value of a datum.
+ */
+static inline uint16
+DatumGetUInt16(Datum X)
+{
+	return (uint16) X;
+}
+
+/*
+ * UInt16GetDatum
+ *		Returns datum representation for a 16-bit unsigned integer.
+ */
+static inline Datum
+UInt16GetDatum(uint16 X)
+{
+	return (Datum) X;
+}
+
+/*
+ * DatumGetInt32
+ *		Returns 32-bit integer value of a datum.
+ */
+static inline int32
+DatumGetInt32(Datum X)
+{
+	return (int32) X;
+}
+
+/*
+ * Int32GetDatum
+ *		Returns datum representation for a 32-bit integer.
+ */
+static inline Datum
+Int32GetDatum(int32 X)
+{
+	return (Datum) X;
+}
+
+/*
+ * DatumGetUInt32
+ *		Returns 32-bit unsigned integer value of a datum.
+ */
+static inline uint32
+DatumGetUInt32(Datum X)
+{
+	return (uint32) X;
+}
+
+/*
+ * UInt32GetDatum
+ *		Returns datum representation for a 32-bit unsigned integer.
+ */
+static inline Datum
+UInt32GetDatum(uint32 X)
+{
+	return (Datum) X;
+}
+
+/*
+ * DatumGetObjectId
+ *		Returns object identifier value of a datum.
+ */
+static inline Oid
+DatumGetObjectId(Datum X)
+{
+	return (Oid) X;
+}
+
+/*
+ * ObjectIdGetDatum
+ *		Returns datum representation for an object identifier.
+ */
+static inline Datum
+ObjectIdGetDatum(Oid X)
+{
+	return (Datum) X;
+}
+
+/*
+ * DatumGetTransactionId
+ *		Returns transaction identifier value of a datum.
+ */
+static inline TransactionId
+DatumGetTransactionId(Datum X)
+{
+	return (TransactionId) X;
+}
+
+/*
+ * TransactionIdGetDatum
+ *		Returns datum representation for a transaction identifier.
+ */
+static inline Datum
+TransactionIdGetDatum(TransactionId X)
+{
+	return (Datum) X;
+}
+
+/*
+ * MultiXactIdGetDatum
+ *		Returns datum representation for a multixact identifier.
+ */
+static inline Datum
+MultiXactIdGetDatum(MultiXactId X)
+{
+	return (Datum) X;
+}
+
+/*
+ * DatumGetCommandId
+ *		Returns command identifier value of a datum.
+ */
+static inline CommandId
+DatumGetCommandId(Datum X)
+{
+	return (CommandId) X;
+}
+
+/*
+ * CommandIdGetDatum
+ *		Returns datum representation for a command identifier.
+ */
+static inline Datum
+CommandIdGetDatum(CommandId X)
+{
+	return (Datum) X;
+}
+
+/*
+ * DatumGetPointer
+ *		Returns pointer value of a datum.
+ */
+static inline Pointer
+DatumGetPointer(Datum X)
+{
+	return (Pointer) X;
+}
+
+/*
+ * PointerGetDatum
+ *		Returns datum representation for a pointer.
+ */
+static inline Datum
+PointerGetDatum(const void *X)
+{
+	return (Datum) X;
+}
+
+/*
+ * DatumGetCString
+ *		Returns C string (null-terminated string) value of a datum.
+ *
+ * Note: C string is not a full-fledged Postgres type at present,
+ * but type input functions use this conversion for their inputs.
+ */
+static inline char *
+DatumGetCString(Datum X)
+{
+	return (char *) DatumGetPointer(X);
+}
+
+/*
+ * CStringGetDatum
+ *		Returns datum representation for a C string (null-terminated string).
+ *
+ * Note: C string is not a full-fledged Postgres type at present,
+ * but type output functions use this conversion for their outputs.
+ * Note: CString is pass-by-reference; caller must ensure the pointed-to
+ * value has adequate lifetime.
+ */
+static inline Datum
+CStringGetDatum(const char *X)
+{
+	return PointerGetDatum(X);
+}
+
+/*
+ * DatumGetName
+ *		Returns name value of a datum.
+ */
+static inline Name
+DatumGetName(Datum X)
+{
+	return (Name) DatumGetPointer(X);
+}
+
+/*
+ * NameGetDatum
+ *		Returns datum representation for a name.
+ *
+ * Note: Name is pass-by-reference; caller must ensure the pointed-to
+ * value has adequate lifetime.
+ */
+static inline Datum
+NameGetDatum(const NameData *X)
+{
+	return CStringGetDatum(NameStr(*X));
+}
+
+/*
+ * DatumGetInt64
+ *		Returns 64-bit integer value of a datum.
+ *
+ * Note: this function hides whether int64 is pass by value or by reference.
+ */
+static inline int64
+DatumGetInt64(Datum X)
+{
+#ifdef USE_FLOAT8_BYVAL
+	return (int64) X;
+#else
+	return *((int64 *) DatumGetPointer(X));
+#endif
+}
+
+/*
+ * Int64GetDatum
+ *		Returns datum representation for a 64-bit integer.
+ *
+ * Note: if int64 is pass by reference, this function returns a reference
+ * to palloc'd space.
+ */
+#ifdef USE_FLOAT8_BYVAL
+static inline Datum
+Int64GetDatum(int64 X)
+{
+	return (Datum) X;
+}
+#else
+extern Datum Int64GetDatum(int64 X);
+#endif
+
+
+/*
+ * DatumGetUInt64
+ *		Returns 64-bit unsigned integer value of a datum.
+ *
+ * Note: this function hides whether int64 is pass by value or by reference.
+ */
+static inline uint64
+DatumGetUInt64(Datum X)
+{
+#ifdef USE_FLOAT8_BYVAL
+	return (uint64) X;
+#else
+	return *((uint64 *) DatumGetPointer(X));
+#endif
+}
+
+/*
+ * UInt64GetDatum
+ *		Returns datum representation for a 64-bit unsigned integer.
+ *
+ * Note: if int64 is pass by reference, this function returns a reference
+ * to palloc'd space.
+ */
+static inline Datum
+UInt64GetDatum(uint64 X)
+{
+#ifdef USE_FLOAT8_BYVAL
+	return (Datum) X;
+#else
+	return Int64GetDatum((int64) X);
+#endif
+}
+
+/*
+ * Float <-> Datum conversions
+ *
+ * These have to be implemented as inline functions rather than macros, when
+ * passing by value, because many machines pass int and float function
+ * parameters/results differently; so we need to play weird games with unions.
+ */
+
+/*
+ * DatumGetFloat4
+ *		Returns 4-byte floating point value of a datum.
+ */
+static inline float4
+DatumGetFloat4(Datum X)
+{
+	union
+	{
+		int32		value;
+		float4		retval;
+	}			myunion;
+
+	myunion.value = DatumGetInt32(X);
+	return myunion.retval;
+}
+
+/*
+ * Float4GetDatum
+ *		Returns datum representation for a 4-byte floating point number.
+ */
+static inline Datum
+Float4GetDatum(float4 X)
+{
+	union
+	{
+		float4		value;
+		int32		retval;
+	}			myunion;
+
+	myunion.value = X;
+	return Int32GetDatum(myunion.retval);
+}
+
+/*
+ * DatumGetFloat8
+ *		Returns 8-byte floating point value of a datum.
+ *
+ * Note: this function hides whether float8 is pass by value or by reference.
+ */
+static inline float8
+DatumGetFloat8(Datum X)
+{
+#ifdef USE_FLOAT8_BYVAL
+	union
+	{
+		int64		value;
+		float8		retval;
+	}			myunion;
+
+	myunion.value = DatumGetInt64(X);
+	return myunion.retval;
+#else
+	return *((float8 *) DatumGetPointer(X));
+#endif
+}
+
+/*
+ * Float8GetDatum
+ *		Returns datum representation for an 8-byte floating point number.
+ *
+ * Note: if float8 is pass by reference, this function returns a reference
+ * to palloc'd space.
+ */
+#ifdef USE_FLOAT8_BYVAL
+static inline Datum
+Float8GetDatum(float8 X)
+{
+	union
+	{
+		float8		value;
+		int64		retval;
+	}			myunion;
+
+	myunion.value = X;
+	return Int64GetDatum(myunion.retval);
+}
+#else
+extern Datum Float8GetDatum(float8 X);
+#endif
+
+
+/*
+ * Int64GetDatumFast
+ * Float8GetDatumFast
+ *
+ * These macros are intended to allow writing code that does not depend on
+ * whether int64 and float8 are pass-by-reference types, while not
+ * sacrificing performance when they are.  The argument must be a variable
+ * that will exist and have the same value for as long as the Datum is needed.
+ * In the pass-by-ref case, the address of the variable is taken to use as
+ * the Datum.  In the pass-by-val case, these are the same as the non-Fast
+ * functions, except for asserting that the variable is of the correct type.
+ */
+
+#ifdef USE_FLOAT8_BYVAL
+#define Int64GetDatumFast(X) \
+	(AssertVariableIsOfTypeMacro(X, int64), Int64GetDatum(X))
+#define Float8GetDatumFast(X) \
+	(AssertVariableIsOfTypeMacro(X, double), Float8GetDatum(X))
+#else
+#define Int64GetDatumFast(X) \
+	(AssertVariableIsOfTypeMacro(X, int64), PointerGetDatum(&(X)))
+#define Float8GetDatumFast(X) \
+	(AssertVariableIsOfTypeMacro(X, double), PointerGetDatum(&(X)))
+#endif
+
+
+/* ----------------------------------------------------------------
+ *				Section 2:	miscellaneous
+ * ----------------------------------------------------------------
+ */
+
+/*
+ * NON_EXEC_STATIC: It's sometimes useful to define a variable or function
+ * that is normally static but extern when using EXEC_BACKEND (see
+ * pg_config_manual.h).  There would then typically be some code in
+ * postmaster.c that uses those extern symbols to transfer state between
+ * processes or do whatever other things it needs to do in EXEC_BACKEND mode.
+ */
+#ifdef EXEC_BACKEND
+#define NON_EXEC_STATIC
+#else
+#define NON_EXEC_STATIC static
+#endif
+
+#endif							/* POSTGRES_H */