* section description
* ------- ------------------------------------------------
* 1) variable-length datatypes (TOAST support)
- * 2) datum type + support macros
+ * 2) Datum type + support macros
* 3) exception handling backend support
*
* NOTES
/* ----------------------------------------------------------------
- * Section 2: datum type + support macros
+ * Section 2: Datum type + support macros
* ----------------------------------------------------------------
*/
/*
- * Port Notes:
- * Postgres makes the following assumptions about datatype sizes:
+ * 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
- * sizeof(char) == 1
- * sizeof(short) == 2
+ * sizeof(Datum) == sizeof(void *) == 4 or 8
*
- * When a type narrower than Datum is stored in a Datum, we place it in the
- * low-order bits and are careful that the DatumGetXXX macro for it discards
- * the unused high-order bits (as opposed to, say, assuming they are zero).
- * This is needed to support old-style user-defined functions, since depending
- * on architecture and compiler, the return value of a function returning char
- * or short may contain garbage when called as if it returned Datum.
+ * The macros below and the analogous macros for other types should be used to
+ * convert between a Datum and the appropriate C type.
*/
typedef uintptr_t Datum;
#define SIZEOF_DATUM SIZEOF_VOID_P
-typedef Datum *DatumPtr;
-
-#define GET_1_BYTE(datum) (((Datum) (datum)) & 0x000000ff)
-#define GET_2_BYTES(datum) (((Datum) (datum)) & 0x0000ffff)
-#define GET_4_BYTES(datum) (((Datum) (datum)) & 0xffffffff)
-#if SIZEOF_DATUM == 8
-#define GET_8_BYTES(datum) ((Datum) (datum))
-#endif
-#define SET_1_BYTE(value) (((Datum) (value)) & 0x000000ff)
-#define SET_2_BYTES(value) (((Datum) (value)) & 0x0000ffff)
-#define SET_4_BYTES(value) (((Datum) (value)) & 0xffffffff)
-#if SIZEOF_DATUM == 8
-#define SET_8_BYTES(value) ((Datum) (value))
-#endif
-
/*
* DatumGetBool
* Returns boolean value of a datum.
*
- * Note: any nonzero value will be considered TRUE, but we ignore bits to
- * the left of the width of bool, per comment above.
+ * Note: any nonzero value will be considered true.
*/
-#define DatumGetBool(X) ((bool) (GET_1_BYTE(X) != 0))
+#define DatumGetBool(X) ((bool) ((X) != 0))
/*
* BoolGetDatum
* Returns datum representation for a boolean.
*
- * Note: any nonzero value will be considered TRUE.
+ * Note: any nonzero value will be considered true.
*/
#define BoolGetDatum(X) ((Datum) ((X) ? 1 : 0))
* Returns character value of a datum.
*/
-#define DatumGetChar(X) ((char) GET_1_BYTE(X))
+#define DatumGetChar(X) ((char) (X))
/*
* CharGetDatum
* Returns datum representation for a character.
*/
-#define CharGetDatum(X) ((Datum) SET_1_BYTE(X))
+#define CharGetDatum(X) ((Datum) (X))
/*
* Int8GetDatum
* Returns datum representation for an 8-bit integer.
*/
-#define Int8GetDatum(X) ((Datum) SET_1_BYTE(X))
+#define Int8GetDatum(X) ((Datum) (X))
/*
* DatumGetUInt8
* Returns 8-bit unsigned integer value of a datum.
*/
-#define DatumGetUInt8(X) ((uint8) GET_1_BYTE(X))
+#define DatumGetUInt8(X) ((uint8) (X))
/*
* UInt8GetDatum
* Returns datum representation for an 8-bit unsigned integer.
*/
-#define UInt8GetDatum(X) ((Datum) SET_1_BYTE(X))
+#define UInt8GetDatum(X) ((Datum) (X))
/*
* DatumGetInt16
* Returns 16-bit integer value of a datum.
*/
-#define DatumGetInt16(X) ((int16) GET_2_BYTES(X))
+#define DatumGetInt16(X) ((int16) (X))
/*
* Int16GetDatum
* Returns datum representation for a 16-bit integer.
*/
-#define Int16GetDatum(X) ((Datum) SET_2_BYTES(X))
+#define Int16GetDatum(X) ((Datum) (X))
/*
* DatumGetUInt16
* Returns 16-bit unsigned integer value of a datum.
*/
-#define DatumGetUInt16(X) ((uint16) GET_2_BYTES(X))
+#define DatumGetUInt16(X) ((uint16) (X))
/*
* UInt16GetDatum
* Returns datum representation for a 16-bit unsigned integer.
*/
-#define UInt16GetDatum(X) ((Datum) SET_2_BYTES(X))
+#define UInt16GetDatum(X) ((Datum) (X))
/*
* DatumGetInt32
* Returns 32-bit integer value of a datum.
*/
-#define DatumGetInt32(X) ((int32) GET_4_BYTES(X))
+#define DatumGetInt32(X) ((int32) (X))
/*
* Int32GetDatum
* Returns datum representation for a 32-bit integer.
*/
-#define Int32GetDatum(X) ((Datum) SET_4_BYTES(X))
+#define Int32GetDatum(X) ((Datum) (X))
/*
* DatumGetUInt32
* Returns 32-bit unsigned integer value of a datum.
*/
-#define DatumGetUInt32(X) ((uint32) GET_4_BYTES(X))
+#define DatumGetUInt32(X) ((uint32) (X))
/*
* UInt32GetDatum
* Returns datum representation for a 32-bit unsigned integer.
*/
-#define UInt32GetDatum(X) ((Datum) SET_4_BYTES(X))
+#define UInt32GetDatum(X) ((Datum) (X))
/*
* DatumGetObjectId
* Returns object identifier value of a datum.
*/
-#define DatumGetObjectId(X) ((Oid) GET_4_BYTES(X))
+#define DatumGetObjectId(X) ((Oid) (X))
/*
* ObjectIdGetDatum
* Returns datum representation for an object identifier.
*/
-#define ObjectIdGetDatum(X) ((Datum) SET_4_BYTES(X))
+#define ObjectIdGetDatum(X) ((Datum) (X))
/*
* DatumGetTransactionId
* Returns transaction identifier value of a datum.
*/
-#define DatumGetTransactionId(X) ((TransactionId) GET_4_BYTES(X))
+#define DatumGetTransactionId(X) ((TransactionId) (X))
/*
* TransactionIdGetDatum
* Returns datum representation for a transaction identifier.
*/
-#define TransactionIdGetDatum(X) ((Datum) SET_4_BYTES((X)))
+#define TransactionIdGetDatum(X) ((Datum) (X))
/*
* MultiXactIdGetDatum
* Returns datum representation for a multixact identifier.
*/
-#define MultiXactIdGetDatum(X) ((Datum) SET_4_BYTES((X)))
+#define MultiXactIdGetDatum(X) ((Datum) (X))
/*
* DatumGetCommandId
* Returns command identifier value of a datum.
*/
-#define DatumGetCommandId(X) ((CommandId) GET_4_BYTES(X))
+#define DatumGetCommandId(X) ((CommandId) (X))
/*
* CommandIdGetDatum
* Returns datum representation for a command identifier.
*/
-#define CommandIdGetDatum(X) ((Datum) SET_4_BYTES(X))
+#define CommandIdGetDatum(X) ((Datum) (X))
/*
* DatumGetPointer
*/
#ifdef USE_FLOAT8_BYVAL
-#define DatumGetInt64(X) ((int64) GET_8_BYTES(X))
+#define DatumGetInt64(X) ((int64) (X))
#else
#define DatumGetInt64(X) (* ((int64 *) DatumGetPointer(X)))
#endif
*/
#ifdef USE_FLOAT8_BYVAL
-#define Int64GetDatum(X) ((Datum) SET_8_BYTES(X))
+#define Int64GetDatum(X) ((Datum) (X))
#else
extern Datum Int64GetDatum(int64 X);
#endif
*/
#ifdef USE_FLOAT8_BYVAL
-#define DatumGetUInt64(X) ((uint64) GET_8_BYTES(X))
+#define DatumGetUInt64(X) ((uint64) (X))
#else
#define DatumGetUInt64(X) (* ((uint64 *) DatumGetPointer(X)))
#endif
*/
#ifdef USE_FLOAT8_BYVAL
-#define UInt64GetDatum(X) ((Datum) SET_8_BYTES(X))
+#define UInt64GetDatum(X) ((Datum) (X))
#else
#define UInt64GetDatum(X) Int64GetDatum((int64) (X))
#endif